Influence of cement layer thickness on the adhesive bond strength of polyalkenoate cements.

The fracture toughness and yield stress values of model zinc polycarboxylate and glass polyalkenoate cements have been used to calculate plastic zone sizes. The size of the plastic zone at the crack tip in these materials has been used to predict whether cement layer thickness is likely to influence the adhesive bond strength. In the model zinc polycarboxylate cement studied, the plastic zone size was comparable to the cement layer thickness and had a pronounced influence on the shear bond strengths obtained. In contrast, the plastic zone sizes obtained for the glass polyalkenoate cements were much smaller and the shear bond strengths were found to be much less dependent on cement layer thickness.


Novel acrylic resins for dental applications.

A heat-cured resin based on a copolymer of bis-phenol-A glycidyl methacrylate (bis-GMA) and tetrahydrofurfuryl methacrylate (THFM) was investigated. Workable pastes were made by adding 90/10 w/w bis-GMA/THFM copolymer powder to a 70/30 w/w monomer of the same composition. The organic filler content was 60-64% w/w. Young's modulus, flexural strength, impact strength, hardness, water absorption and desorption, linear thermal expansion, polymerization shrinkage and glass transition temperature were determined. The materials studied showed high elastic modulus, hardness and glass transition temperature. A relatively low linear thermal expansion was obtained but poor impact strength and low flexural strength, indicating brittleness. Acceptable values were obtained for water absorption.


Effect of amplitude of micromotion on bone ingrowth into titanium chambers implanted in the rabbit tibia.

The micromotion chamber for implantation in the rabbit tibia consists of two titanium components that have a 1 mm contiguous pore for bone ingrowth. The fixed, outer cylinder of the chamber contains a movable inner core that can be manually rotated. The model is unique because specific, discrete, daily periods of motion of a predetermined amplitude and frequency can be delivered to the ingrowing tissue. In the present study, we compared the histological and scintigraphic results of bone ingrowth into chambers having a congruently shaped interface that was moved 20 cycles/d with an amplitude of either 0.5 or 0.75 mm. Histological sections from both amplitude groups contained extensive new woven and trabecular bone, embedded in a fibrovascular network. However, the chambers with a larger amplitude of motion yielded less bone ingrowth than those with a smaller amplitude. These studies suggest that short, discrete periods of motion can stimulate the formation of fibrous tissue rather than bone using the parameters chosen in this model.


Chitosan beads and granules for oral sustained delivery of nifedipine: in vitro studies.

Nifedipine was embedded in a chitosan matrix to develop a prolonged-release form. The in vitro release profiles of nifedipine from chitosan beads and microgranules were monitored by UV spectrophotometer. The studies were performed in a rotating shaker (100 rev min-1) in 0.1 M HCl buffer (pH 2.0) or 0.1 M phosphate buffer (pH 7.4). Comparison was made between drug-loaded microbeads and microgranules. The amount and percentage of drug release were much higher in HCl than in phosphate buffer, probably due to the salt formation of the matrix (chitosan hydrochloride) at acid pH. The release rate of nifedipine from chitosan matrix was slower for beads than granules. These findings suggest the possibility of modifying the formulations to obtain the desired controlled release of the drug in an oral sustained-delivery system.


New method for analysis of biodegradable polyesters by high-performance liquid chromatography after alkali hydrolysis.

A new method was developed for analysis of biodegradable polyesters, which involves alkali hydrolysis of polyesters to the corresponding hydroxyacids and determination of the hydroxyacids by high-performance liquid chromatography. It can be used to monitor weight change in polyesters and change in molecular ratio of the hydroxyacid constituents of polyesters during in vitro and in vivo degradation.


Soft tissue response to different types of sintered metal fibre-web materials.

Recently, it has been demonstrated that the soft tissue response to polymeric filter implants was predominantly dependent on the implant surface topography and that variation in the implant material had little effect. The purpose of this study, therefore, was to compare histologically the soft tissue response to sintered fibre-web implants made from different materials and with varying web porosity. Three different fibre-web materials with two different weights and two different porosities were used. The implants were inserted subcutaneously in the dorsum of rabbits. The implants were left in situ for 4 and 12 wk. Histological and tissue compatibility evaluations were performed. It is found that all the tested fibre-web materials show a good biocompatible behaviour. In addition, the results appear to indicate a relation between flexibility of an implant material and tissue behaviour.


[Physical mechanisms of solid-protein interactions in the interface between amorphous silicon carbide and fibrinogen].

State of the art in biomaterial research and implant design is a compromise between functionality and biocompatibility. Consequently the results often have disadvantages with respect to both aspects. In regard to biocompatibility the activation of the clotting system by alloplastic materials is of great significance, because it necessitates anticoagulant therapy. Further improvements of implant technology require an understanding of the interactions between blood and implants. Therefore a microscopic model of thrombogenesis at alloplastic surfaces will shortly be presented, which relates thrombogenicity of a material to the electronic structure of its surface. The requirements for high hemocompatibility, which result from this model--especially in regard to the density of states and the conductivity at the surface--are fulfilled by an amorphous alloy of silicon and carbon (a-SiC:H). The advantage of amorphous materials is that they do not obey stoichiometric rules. Thus they allow a continuous adjustment of the electronic parameters without fundamental changes of their mechanical and chemical properties. The theoretical results where checked by total internal reflection intrinsic fluorescence spectroscopy (TIRIF) as well as thrombelastography experiments (TEG). In comparison to conventional materials like titanium or LTI carbon the TEG-clotting time of a-SiC:H-coatings is prolonged in excess of 200%. As a consequence a-SiC:H is well suited as a hemocompatible coating material for hybrid structuring of cardiovascular implants.


[CO2 angiography: measuring blood flow with injected gas bubbles].

The use of CO2 gas as a contrast medium for visualizing blood vessels has been considerably facilitated by the development of a gas metering device for mechanical injection of CO2. The present paper describes the possibility of using CO2 not only for visualizing blood vessel morphology, but also for the diagnostic evaluation of the haemodynamics within the vessels. For this reason in vitro experiments with an artery simulation model were undertaken to examine the behaviour of injected gas bubbles. The information thus obtained was then translated to animal experiments.


[Method for in vivo measurement of intraosseous pressure of the patella].

During the development of degenerative joint disease (osteoarthritis, chondropathy), a diagnostic or even pathogenetic role is attributed to the phenomenon of intraosseous pressure (IOP). Owing to technical problems and a lack of systematic experimental or clinical studies on the control mechanisms of the IOP, the actual importance of this factor is still not known with certainty. Now, a measuring method that enables correct recording of the IOP and standardized on-line processing of the measured signal minimize artefact-related problems. The technique is evaluated for reliability in an in vitro model of the human patella and in a limited clinical study of the IOP in patients undergoing knee surgery for various reasons. Factors such as intra-articular effusion, joint position or changes in intra-articular soft tissue are examined for their influence of the primary signal.


Looking at proteins: representations, folding, packing, and design. Biophysical Society National Lecture, 1992.

Looking at proteins is an active process of interpretation and selection, emphasizing some features and deleting others. Multiple representations are needed, for such purposes as showing motions or conveying both the chain connectivity and the three-dimensional shape simultaneously. In studying and comparing protein structures, ideas are suggested about the determinants of tertiary structure and of folding (e.g., that Greek key beta barrels may fold up two strands at a time). The design and synthesis of new proteins "from scratch" provides a route toward the experimental testing of such ideas. It has also been a fruitful new perspective from which to look at structures, requiring such things as statistics on very narrowly defined structural categories and explicit attention to "negative design" criteria that actively block unwanted alternatives (e.g., reverse topology of a helix bundle, or edge-to-edge aggregation of beta sheets). Recently, the field of protein design has produced a rather unexpected general result: apparently we do indeed know enough to successfully design proteins that fold into approximately correct structures, but not enough to design unique, native-like structures. The degree of order varies considerably, but even the best designed material shows multiple conformations by NMR, more similar to a "molten globule" folding intermediate than to a well ordered native tertiary structure. In response to this conclusion, we are now working on systems that test useful questions with approximate structures (such as determining which factors most influence the choice of helix-bundle topology) and also analyzing how natural proteins achieve unique core conformations (e.g., for side chains on the interior side of a beta sheet, illustrated in the kinemages).


Conformational changes in cubic insulin crystals in the pH range 7-11.

To determine the effect of variations in the charge distribution on the conformation of a protein molecule, we have solved the structures of bovine cubic insulin over a pH range from 7 to 11 in 0.1 M and 1 M sodium salt solutions. The x-ray data were collected beyond 2-A resolution and the R factors for the refined models ranged from 0.16 to 0.20. Whereas the positions of most protein and well-ordered solvent atoms are conserved, about 30% of residues alter their predominant conformation as the pH is changed. Conformational switching of A5 Gln and B10 His correlates with the pH dependence of monovalent cation binding to insulin in cubic crystals. Shifts in the relative positions of the A chain NH2-terminal and B chain COOH-terminal groups are probably due to titration of the A1 alpha-amino group. Two alternative positions of B25 Phe and A21 Asn observed in cubic insulin at pH 11 are similar to those found in two independent molecules of the 2Zn insulin dimer at pH 6.4. The conformational changes of the insulin amino acids appear to be only loosely coupled at distant protein sites. Shifts in the equilibrium between distinct conformational substates as the charge distribution on the protein is altered are analogous to the electrostatically triggered movements that occur in many functional protein reactions.


Conformational analysis of apolipoprotein A-I and E-3 based on primary sequence and circular dichroism.

The primary and secondary structure of human plasma apolipoprotein A-I and apolipoprotein E-3 have been analyzed to further our understanding of the secondary and tertiary conformation of these proteins and the structure and function of plasma lipoprotein particles. The methods used to analyze the primary sequence of these proteins used computer programs: (a) to identify repeated patterns within these proteins on the basis of conservative substitutions and similarities within the physicochemical properties of each residue; (b) for local averaging, hydrophobic moment, and Fourier analysis of the physicochemical properties; and (c) for secondary structure prediction of each protein carried out using homology, statistical, and information theory based methods. Circular dichroism was used to study purified lipid-protein complexes of each protein and quantitate the secondary structure in a lipid environment. The data from these analyses were integrated into a single secondary structure prediction to derive a model of each protein. The sequence homology within apolipoproteins A-I, E-3, and A-IV is used to derive a consensus sequence for two 11 amino acid repeating sequences in this family of proteins.


Matrix-assisted laser desorption mass spectrometry of rhodopsin and bacteriorhodopsin.

Matrix-assisted laser desorption ionization (MALDI) mass spectrometry has been used to obtain accurate molecular weight information for the integral membrane proteins bacteriorhodopsin and bovine rhodopsin desorbed from solubilized membrane preparations. Mass differences in the molecular weights measured for bleached and unbleached bacteriorhodopsin and rhodopsin indicate the removal of the retinal chromophores upon bleaching. The MALDI technique was also successful for determination of the major cleavage products obtained upon treatment of membrane bound rhodopsin with endoproteinase Asp-N and thermolysin. Our results indicate that the MALDI method is a useful means of obtaining accurate molecular weight information on hydrophobic proteins isolated in their native membranes.


Structural comparison of metarhodopsin II, metarhodopsin III, and opsin based on kinetic analysis of Fourier transform infrared difference spectra.

Fourier transform infrared difference spectra were measured at 30-s intervals after a complete bleach of rhodopsin (rho) samples at 20 degrees C and three different pH values. At each pH, all of the spectra could be fit globally to two exponential decay processes. Using a branched unimolecular kinetic model in which metarhodopsin II (meta II) is hydrolyzed to opsin and retinal both directly and through metarhodopsin III (meta III), we calculated rho-->meta II, rho-->meta III, and rho-->opsin difference spectra at each of the pH values and obtained estimates for the microscopic rate constants at each pH. Because of assumptions that had to be made about the branching ratio between the meta II decay pathways, some uncertainties remain in our calculated rho-->meta III difference spectrum at each pH. Nevertheless, our data covering long time ranges, especially those obtained at pH 8, place significant new constraints on the spectrum of meta III and thus on its structure. The rho-->meta II spectrum shows no significant pH dependence over the range examined (pH 5.5-8). However, the rho-->meta III and rho-->opsin spectra each include a limited subset of pH-dependent peaks, which are mostly attributable to titratable amino acid side chains. Our observations can be used to refine an earlier conclusion that the visual pigment refolds to a rhodopsin-like conformation during meta II decay (Rothschild, K.J., J. Gillespie, and W.J. DeGrip. 1987 Biophys. J. 51:345-350). Most of this refolding occurs in the same way at pH values ranging from 5.5 to 8 and whether meta II decays to meta III or opsin. Meta II displays unique spectral perturbations that are mostly attributable to a few residues, probably including three to four aspartic or glutamic acids and an arginine.


Single photon radioluminescence. I. Theory and spectroscopic properties.

The excitation of a fluorescent molecule by a beta-decay electron (radioluminescence) depends upon the electron energy, the distance between radioactive 'donor' and fluorescent 'acceptor', and the excitation characteristics and solvent environment of the fluorophore. The theory for calculation of single photon radioluminescence (SPR) signals is developed here; in the accompanying paper, measurement methods and biological applications are presented. To calculate the three-dimensional spatial profile for electron energy deposition in an aqueous environment, a Monte Carlo calculation was performed incorporating theories of electron energy distributions, energy loss due to interactions with matter, and deflections in electron motion due to collisions. For low energy beta emitters, 50% of energy deposition occurs within 0.63 micron (3H, 18.5 keV), 22 microns (14C, 156 keV), 25 microns (35S, 167 keV), and 260 microns (36Cl, 712 keV) of the radioisotope. In close proximity to the beta emitter (100 nm, 3H; 10 microns, 14C) the probability for fluorophore excitation is approximately proportional to the inverse square of the distance between the beta emitter and fluorophore. To investigate the other factors that determine the probability for fluorophore excitation, SPR measurements were carried out in solutions containing 3H and a series of fluorophores in different solvents. In water, the probability of fluorescence excitation was nearly proportional to the integrated absorbance over a > 1,000-fold variation in absorbances. The probability of fluorescence excitation was enhanced up to 2,600-fold when the fluorophore was in a "scintillant" aromatic or hydrocarbon solvent. SPR emission spectra were similar to fluorescence emission spectra obtained with photon excitation. The single photon signal due to Bremsstrahlung increased with wavelength in agreement with theory. The distance dependence for the SPR signal predicted by the model was in good agreement with measurements in which a 14C donor was separated by known thicknesses of water from a fluorescently-coated coverglass. Quantitative predictions for radioluminescence signal as a function of donor-acceptor distance were developed for specific radioisotope-fluorophore geometries in biological samples.


Single photon radioluminescence. II. Signal detection and biological applications.

A quantitative theory for excitation of fluorescent molecules by beta decay electrons is reported in the accompanying manuscript; experimental detection methods and biological applications are reported here. The single photon signals produced by an excited fluorophore (single photon radioluminescence, SPR) provide quantitative information about the distance between radioisotope and fluorophore. Instrumentation was constructed for SPR signal detection. Photons produced in a 0.5-ml sample volume were detected by a cooled photomultiplier and photon counting electronics. To minimize electronic noise and drift for detection of very small SPR signals, a mechanical light chopper was used for gated-signal detection, and a pulse height analyzer for noise rejection. SPR signals of approximately 1 cps were reproducibly measurable. The influence of inner filter effect, sample turbidity, and fluorophore environment (lipid, protein, and carbohydrate) on SPR signals were evaluated experimentally. SPR was then applied to measure lipid exchange kinetics, ligand binding, and membrane transport, and to determine an intermolecular distance in an intact membrane. (a. Lipid exchange kinetics.) Transfer of 12-anthroyloxystearic acid (12-AS) from sonicated lipid vesicles and micelles to vesicles containing 3H-cholesterol was measured from the time course of increasing SPR signal. At 22 degrees C, the half-times for 12-AS transfer from vesicles and micelles were 3.3 and 1.1 min, respectively. (b. Ligand binding.) Binding of 3H-oleic acid to albumin in solution, and 3H-2,2'-dihydro-4,4'-diisothiocyanodisulfonic stilbene (3H-H2DIDS) to band 3 on the erythrocyte membranes were detected by the radioluminescence of the intrinsic tryptophans. The SPR signal from 5 microCi 3H-oleic acid bound to 0.3 mM albumin decreased from 13 +/- 2 cps to 3 +/- 2 cps upon addition of nonradioactive oleic acid, giving 2.7 high affinity oleic acid binding sites per albumin. The SPR signal from 1 microCi 3H-H2DIDS bound selectively to erythrocyte band 3 in erythrocyte ghosts (1.5 mg protein/ml) was 2.2 +/- 0.8 cps. (c. Membrane transport). Dilution of J774 macrophages loaded with 3H-3-O-methylglucose and BCECF gave a decreasing SPR signal with a half-time of 81 s due to methylglucose efflux; the SPR measurement of the efflux rate was in agreement with a conventional tracer efflux rate determination by filtration. 20 microM cytochalasin B inhibited efflux by 97%. (d. Distance determination.) The SPR signal from erythrocyte membranes labeled with 27 microCi 3H-oleic acid and 10 microM of fluorescein-labeled wheat germ agglutinin was 5.7 +/- 0.5 cps, giving an average glycocalyx-to-bilayer distance of 5 nm. The results establish methods for experimental detection of SPR signals and demonstrate the applications of radioluminescence to the measurement of lipid exchange kinetics, ligand binding, membrane transport, and submicroscopic distances in intact membranes in real time.


Poisson-Boltzmann analysis of the lambda repressor-operator interaction.

A theoretical study of the ion atmosphere contribution to the binding free energy of the lambda repressor-operator complex is presented. The finite-difference form of the Poisson-Boltzmann equation was solved to calculate the electrostatic interaction energy of the amino-terminal domain of the lambda repressor with a 9 or 45 base pair oligonucleotide. Calculations were performed at various distances between repressor and operator as well as at different salt concentrations to determine ion atmosphere contributions to the total electrostatic interaction. Details in the distribution of charges on DNA and protein atoms had a strong influence on the calculated total interaction energies. In contrast, the calculated salt contributions are relatively insensitive to changes in the details of the charge distribution. The results indicate that the ion atmosphere contribution favors association at all protein-DNA distances studied. The theoretical number of ions released upon repressor-operator binding appears to be in reasonable agreement with experimental data.


Assembly-associated structural changes of bacteriophage T7 capsids. Detection by use of a protein-specific probe.

To detect changes in capsid structure that occur when a preassembled bacteriophage T7 capsid both packages and cleaves to mature-size longer (concatameric) DNA, the kinetics and thermodynamics are determined here for the binding of the protein-specific probe, 1,1'-bi(4-anilino)naphthalene-5,5'-di-sulfonic acid (bis-ANS), to bacteriophage T7, a T7 DNA deletion (8.4%) mutant, and a DNA-free T7 capsid (metrizamide low density capsid II) known to be a DNA packaging intermediate that has a permeability barrier not present in a related capsid (metrizamide high density capsid II). Initially, some binding to either bacteriophage or metrizamide low density capsid II occurs too rapidly to quantify (phase 1, duration < 10 s). Subsequent binding (phase 2) occurs with first-order kinetics. Only the phase 1 binding occurs for metrizamide high density capsid II. These observations, together with both the kinetics of the quenching by ethidium of bound bis-ANS fluorescence and the nature of bis-ANS-induced protein alterations, are explained by the hypothesis that the phase 2 binding occurs at internal sites. The number of these internal sites increases as the density of the packaged DNA decreases. The accompanying change in structure is potentially the signal for initiating cleavage of a concatemer. Evidence for the following was also obtained: (a) a previously undetected packaging-associated change in the conformation of the major protein of the outer capsid shell and (b) partitioning by a permeability barrier of the interior of the T7 capsid.


Image analysis shows that variations in actin crossover spacings are random, not compensatory.

A recent paper by Bremer et al. (1991. J. Cell Biol. 115:689-703) has argued that the random angular disorder model for actin is wrong, and that the variations in crossover spacing observed in electron micrographs of F-actin filaments can be best explained by a compensatory disorder caused by the lateral slipping of the twin (or two-start) strands which comprise the actin filament. We have analyzed the images of F-actin presented in Bremer et al. and show that their data argues against compensatory disorder and in favor of random disorder, independent of the cause of the disorder. We also revise our estimate of the angular component and show that the magnitude of this disorder is about 5-6 degrees per subunit, which is less than the 10-12 degrees that we originally proposed.


Bending stiffness of lipid bilayers. I. Bilayer couple or single-layer bending?

To describe the resistance of a bilayer to changes in curvature two mechanisms are distinguished which are termed bilayer couple bending and single-layer bending. In bilayer couple bending, the resistance arises from the 2-D isotropic elasticity of the two layers and their fixed distance. Single-layer bending covers the intrinsic bending stiffness of each monolayer. The two mechanisms are not independent. Even so, the distinction is useful since bilayer couple bending can relax by a slip between the layers from the local to the global fashion. Therefore, the bending stiffness of a bilayer depends on the time scale and on the extent of the deformation imposed on the membrane. Based on experimental data, it is shown by order of magnitude estimates that (a) the bending stiffness determined from thermally induced shape fluctuations of almost spherical vesicles is dominated by single-layer bending; (b) in the tether experiment on lipid vesicles and on red cells, a contribution of local bilayer couple bending can not be excluded; and (c) at the sharp corners at the leading and the trailing edge of tanktreading red cells, local bilayer couple bending appears to be important.


Determination of transmembrane pH gradients and membrane potentials in liposomes.

Techniques for determining large transbilayer pH gradients (delta pH) and membrane potentials (delta psi) induced in response to delta pH in large unilamellar vesicle liposomal systems by measuring the transbilayer redistribution of radiolabeled compounds have been examined. For liposomes with acidic interiors, it is shown that protocols using radiolabeled methylamine in conjunction with gel filtration procedures to remove untrapped methylamine provide accurate measures of delta pH in most situations. Exceptions include gel state lipid systems, where transbilayer equilibration processes are slow, and situations where the interior buffering capacity is limited. These problems can be circumvented by incubation at elevated temperatures and by using probes with higher specific activities, respectively. Determination of delta pH in vesicles with a basic interior using weak acid probes such as radiolabeled acetate in conjunction with gel filtration was found to be less reliable, and an alternative equilibrium centrifugation protocol is described. In the case of determinations of the membrane potentials induced in response to these pH gradients, probes such as tetraphenylphosphonium and thiocyanate provide relatively accurate measures of the delta psi induced. It is shown that the maximum transmembrane pH gradient that can be stably maintained by an egg phosphatidylcholine-cholesterol 100-nm-diam large unilamellar vesicle is approximately 3.7 units, corresponding to an induced delta psi of 220 mV or transbilayer electrical field of 5 x 10(5) V/cm.


Effect of the chirality of the glycerol backbone on the bilayer and nonbilayer phase transitions in the diastereomers of di-dodecyl-beta-D-glucopyranosyl glycerol.

We have studied the physical properties of aqueous dispersions of 1,2-sn- and 2,3-sn-didodecyl-beta-D-glucopyranosyl glycerols, as well as their diastereomeric mixture, using differential scanning calorimetry and low angle x-ray diffraction. Upon heating, both the chiral lipids and the diastereomeric mixture exhibit characteristically energetic L beta/L alpha phase transitions at 31.7-32.8 degrees C and two or three weakly energetic thermal events between 49 degrees C and 89 degrees C. In the diastereomeric mixture and the 1,2-sn glycerol derivative, these higher temperature endotherms correspond to the formation of, and interconversions between, several nonlamellar structures and have been assigned to L alpha/QIIa, QIIa/QIIb, and QIIb/HII phase transitions, respectively. The cubic phases QIIa and QIIb, whose cell lattice parameters are strongly temperature dependent, can be identified as belonging to space groups Ia3d and Pn3m/Pn3, respectively. In the equivalent 2,3-sn glucolipid, the QIIa phase is not observed and only two transitions are seen at 49 degrees C and 77 degrees C, which are identified as L alpha/QIIb and QIIb/HII phase transitions, respectively. These phase transitions temperatures are some 10 degrees C lower than those of the corresponding phase transitions observed in the diastereomeric mixture and the 1,2-sn glycerol derivative. On cooling, all three lipids exhibit a minor higher temperature exothermic event, which can be assigned to a HII/QIIb phase transition. An exothermic L alpha/L beta phase transition is observed at 30-31 degrees C. A shoulder is sometimes discernible on the high temperature side of the L alpha/L beta event, which may originate from a QIIb/L alpha phase transition prior to the freezing of the hydrocarbon chains. None of the lipids show evidence of a QIIa phase on cooling. No additional exothermic transitions are observed on further cooling to -3 degrees C. However, after nucleation at 0 degrees C followed by a short period of annealing at 22 degrees C, the 1,2-sn glucolipid forms an Lc phase that converts to an L alpha phase at 39.5 degrees C on heating. Neither the diastereomeric mixture nor the 2,3-sn glycerol derivative shows such behavior even after extended periods of annealing. Our results suggest that the differences in the phase behavior of these glycolipid isomers may not be attributable to headgroup size per se, but rather to differences in the stereochemistry of the lipid polar/apolar interfacial region, which consequently effects hydrogen-bonding, hydration, and the hydrophilic/hydrophobic balance.


Streptavidin binding to biotinylated lipid layers on solid supports. A neutron reflection and surface plasmon optical study.

Neutron reflection and surface plasmon optical experiments have been performed to evaluate structural data of the interfacial binding reaction between the protein streptavidin and a solid-supported lipid monolayer partly functionalized by biotin moieties. Since both experimental techniques operate in a total internal reflection geometry at a substrate/solution interface, identical sample architectures allow for a direct comparison between the results obtained with these two recently developed methods. It is found that a monomolecular layer of dipalmitoyllecithin doped with 5 mol% of a biotinylated-phosphatidylethanolamine shows a thickness of d1 approximately (3.4 +/- 0.5) nm. Binding of streptavidin to the biotin groups results in an overall layer thickness of d = (5.9 + 0.5) nm that demonstrates the formation of a well-ordered protein monolayer with the (biotin+spacer) units of the functionalized lipids being fully embedded into the binding pocket of the proteins. It is demonstrated by model calculations that a more detailed picture of the internal structure of this supramolecular assembly can only be obtained if one uses deuterated lipid molecules, thus generating a high contrast between individual layers.


Tandem linkage of Shaker K+ channel subunits does not ensure the stoichiometry of expressed channels.

Shaker K+ channels are multimeric, probably tetrameric proteins. Substitution of a conserved leucine residue to valine (V2) at position 370 in the Drosophila Shaker 29-4 sequence results in large alterations in the voltage dependence of gating in the expressed channels. In order to determine the effects of this mutation in hybrid channels with a fixed stoichiometry of V2 and wild-type (WT) subunits we generated cDNA constructs of two linked-monomeric subunits similar to the tandem constructs previously reported by Isacoff, E. Y., Y. N. Jan, and L. Y. Jan. (1990. Nature (Lond.). 345:530-534). In addition, we constructed a tandem cDNA containing a wild-type subunit and a truncated nonfunctional subunit (Sh102) that suppresses channel expression. We report that the voltage-dependence of the channels produced with WT and V2 subunits varied significantly with the order of the subunits in the construct (WT-V2 or V2-WT), while the WT-Sh102 construct yielded currents that were much larger than expected. These results suggest that the tandem linkage of Shaker subunits does not guarantee the stoichiometry of the expressed channel proteins.


Are weakly binding bridges present in resting intact muscle fibers?

Several experimental results (Schoenberg, M. 1988. Biophys. J. 54:135-148) have shown that the force response of relaxed skinned muscle fibers to fast stretches arises from the presence of cross-bridges rapidly cycling between attached and detached states. These bridges were identified with the M.ATP<-->AM.ATP and M.ADP.Pi<-->AM.ADP.Pi states seen in solution and are commonly referred to as weakly binding bridges. In this paper we have investigated the possibility that weakly binding bridges are also present in resting intact muscle fibers. The force response to fast stretches can be accounted for by assuming the presence in the fiber of a viscous and a viscoelastic passive component arranged in parallel. None of these components has the properties previously attributed to weakly binding bridges. This shows that in intact resting fibers there is no mechanical evidence of attached cross-bridges, suggesting that, under physiological conditions, either the M.ATP or M.ADP.Pi states have a negligibly small affinity for actin or the AM.ATP and AM.ADP.Pi cross-bridge states are unable to bear tension and contribute to fiber stiffness.


The physiological role of atrial natriuretic factor.

The physiological role of atrial natriuretic factor in the regulation of cardiovascular homeostasis has not yet been defined. The principal mechanisms that control biosynthesis, secretion and clearance of the peptide, however, are well characterized. In addition, several biological functions of the peptide, originally identified by studying the results of exogenous administration, have been confirmed in humans and in experimental animals at physiological blood levels, as well as with the help of pharmacological tools such as clearance inhibitors and monoclonal antibodies. This article reviews the principal biological actions of atrial natriuretic factor in the context of their physiological significance.


Energy metabolism of the hypertrophied heart studied by 31P nuclear magnetic resonance.

We report studies on the isolated hearts of rats treated with triiodothyronine (0.2 mg/kg daily) for 14 days, on spontaneously hypertensive rats (12 and 21 weeks old, Lyon strain) and on their respective controls. A 30% increase in cardiac weight was developed with triiodothyronine and a 40% increase in heart weight in the presence of spontaneous hypertension. The hearts were perfused in the presence of 2 mM pyruvate and the intracellular content of phosphocreatine, inorganic phosphate and ATP measured by nuclear magnetic resonance spectroscopy with 31P. The left ventricular developed pressure was measured with an intraventricular balloon. Changes in contractile strength were induced by stepwise modifications of the extracellular concentration of calcium from 0.5 mM to 1.0, 1.5 and 2.0 mM. In all experimental groups, each increase in the extracellular calcium induced an increase in the developed pressure, together with a decrease in phosphocreatine and an increase in inorganic phosphate; the ATP level remained unchanged. These metabolic changes increased progressively with the increase in developed pressure. In the hearts of animals treated with triiodothyronine and of the 21 weeks old hypertensive rats, the extent of changes in phosphocreatine and inorganic phosphate was the same as in the controls; but, in the hearts of 12 weeks old hypertensive rats, the changes were significantly greater than in their controls. These observations suggest that, during the development of cardiac hypertrophy from spontaneous hypertension, there is a transitory deficiency in the capacity for aerobic ATP production relative to the rate of hydrolysis of ATP induced by an inotropic effect.


Dimensions of the left atrioventricular valve and its components in normal human hearts.

The posterior cusp of the left atrioventricular valve was studied in 100 cadavers of Brazilians. There were 58 Caucasians and 42 non-Caucasians, 65 males and 35 females. Their age ranged from 18 to 72 years. In 91% of the cases the posterior cusp had 3 leaflets (posteromedial or right, intermediate, and anterolateral or left). The intermediate leaflet was wider (mean 18.8mm) and higher (mean 12.7mm) than the other two. All leaflets of the posterior cusp were shorter than the anterior cusp, a feature that confers on the posterior cusp the role of a supporting structure in addition to its role in the completion of closure of the left atrioventricular ostium.


Regression of left ventricular hypertrophy and susceptibility to reperfusion-induced arrhythmias after DOCA-salt hypertension in the rat.

Treatment with deoxycorticosterone acetate (DOCA) and salt for 12 weeks consistently induced hypertension in rats. Groups of treated rats and age-matched normotensive controls were killed 2 and 14 weeks after stopping the treatment. Two weeks after treatment with the corticoid, all the treated rats had left ventricular hypertrophy. Fourteen weeks after treatment the spontaneous regression of the hypertension was very variable, giving a wide range of ratios of left ventricular to body weight. The hearts were Langendorff-perfused and subjected to occlusion of the left coronary artery for 10 minutes at 37 degrees C. During reperfusion for 5 minutes, the severity of ventricular tachycardia and ventricular fibrillation was assessed. Two weeks after treatment, the incidence and duration of ventricular fibrillation were significantly greater in the treated hearts than in normal hearts. Fourteen weeks after treatment, the hearts with a ratio of left ventricular to body weight greater than 2.40 mg/g displayed a greater incidence of sustained ventricular fibrillation than controls and the median duration of ventricular fibrillation in this group was high. Conversely, the incidence of sustained ventricular fibrillation was lower in the treated group in which regression of the ratio of left ventricular to body weight was less than 2.40 mg/g; and the median duration of ventricular fibrillation was also reduced after regression of the left ventricular hypertrophy. This study provides evidence that regression of left ventricular hypertrophy may confer a reduced susceptibility to arrhythmias.


Diacylglycerol fatty acid composition is related to activation of protein kinase C in cultured cardiomyocytes.

Using cultures of beating neonatal rat cardiomyocytes we have studied the fatty acid composition of the diacylglycerol produced after different stimulation times with an alpha 1-agonist (phenylephrine) and we have related it to the previously reported time course of the activation of particulate protein kinase C, in control cells and in cells grown in a medium supplemented with docosahexaenoic acid. Gas chromatography of the diacylglycerol produced after stimulation revealed significant differences between control cells and cells treated with docosahexanoic acid. In the cells treated with docosahexanoic acid, the more persistent activation of the membrane-bound protein kinase C might be sustained by an enrichment of diacylglycerol with docosahexanoic acid. The modification of the fatty acid composition of diacylglycerol can cause an alteration in the response of the cells to alpha 1-adrenoceptor stimulation.


Anti-IgE autoantibodies: a possible specific feedback on the cytokine network in allergy?

We propose a theoretical model based on the cytokine network, that provides the necessary signals so that basically all human beings can produce IgE but not all have to develop allergic disease. Our hypothesis implies that anti-IgE autoantibodies are a kind of emergency brake neutralizing the IgE induced by the cytokine network. In the normal individual the system would come to halt at this point. However, the atopic individual, due to a small difference in his or her B cell repertoire, will produce the wrong type of anti-IgE antibody. Allergic disease can now develop because IgE is not perfectly neutralized. The wrong type of anti-IgE antibody that is now produced may even aggravate the disease as some of these autoantibodies may induce IgE synthesis or trigger effector cells that in turn generate a Th2 like cytokine pattern closing the vicious circle. We believe that because of the potency of the powerful and archaic cytokine network, we have to dispose of such a specific control mechanism by autoantibodies.


High-level expression and characterization of a mouse-human chimeric CD4 antibody with therapeutic potential.

The use of murine anti-CD4 monoclonal antibodies (MAbs) has shown considerable promise for the treatment of allograft rejection and rheumatoid arthritis. We have constructed mouse-human anti-CD4 antibodies with the goal of increasing their clinical potential by decreasing immunogenicity and improving effector functions. The chimeric antibodies were constructed by cloning the heavy and light chain variable regions of M-T412, a murine antibody raised against the human CD4 antigen, and joining them to the human G1, G4, or kappa constant regions in mammalian expression vectors. After transfection into mouse myeloma cells, stable cell lines were isolated that secrete up to 140 micrograms/ml chimeric antibody in static culture. The chimeric antibodies were equivalent to the murine antibody in their binding characteristics and relative affinities. However, the chimeric M-T412 MAbs have enhanced activity when compared to the murine G2a MAb in mediating antibody-dependent cell-mediated cytotoxicity using human CD4+ target and effector cells.


Immunization of SCID-Hu mice and generation of anti-hepatitis B surface antigen-specific hybridomas by electrofusion.

Human hybridomas with specificity for recombinant hepatitis B surface antigen (HBSAg) were produced by adoptive transfer of human peripheral blood mononuclear cells prepared from HBSAg-immune donors to CB.17 mice bearing the severe combined immunodeficiency (SCID) phenotype. A total of ten SCID-Hu mice were immunized with recombinant HBSAg. Eight SCID-Hu mice found to have human HBSAg antibody in their serum were sacrificed, and single-cell suspensions were made from their spleens. The SCID-Hu spleen cells were electrofused to the mouse-human fusion partner H7. HBSAg-specific hybridomas were recovered from all fusions. This method may provide the means for the production of other human hybridomas and may, in some cases, circumvent the need for in vitro immunization or Epstein-Barr virus transformation of human B lymphocytes.


The effects of interleukin-1 on pancreatic beta cell function in vitro depend on the glucose concentration.

Insulin-dependent diabetes mellitus is characterized by progressive autoimmune destruction of pancreatic Beta cells mediated by ill-defined effector mechanisms. Experimental data suggest that cytokines, e.g. interleukin 1 and tumor necrosis factor, could play a fundamental role. The aim of this study was to analyze the effect of recombinant IL-1 beta (rIL-1 beta) on both islet functional capacity and morphology, using long-term cultures and various glucose concentrations. Islet cultured with 1 g/l (5.5 mmol/l) glucose maintained normal insulin- secretion and morphology for more than two months. In contrast, islets cultured with 2 g/l (11 mmol/l) glucose showed an altered insulin secretion and a shorter survival (40 days). At 11 g/l (60 mmol/l) glucose, islets died by 2 weeks of culture. rIL-1 beta exerted a cytotoxic effect on islet cells only when added to cultures containing supraphysiological glucose concentrations. But, in the presence of 1 g/l glucose, the addition of rIL-1 beta (40 ng/ml) for prolonged periods (14 days), did not alter islet function. Our results suggest that in auto-immune type I diabetes, IL-1 beta represents an aggravating factor in lesion formation more than a primary pathogenic mechanism.


Growth of hybridoma cells and antibody production in agamma calf serum.

An agamma calf serum (ACS) was compared to fetal bovine serum (FBS) and calf serum supplemented growth media for both murine and human fusion partners and derived hybridoma cells. The variables analyzed were cloning efficiencies, growth characteristics, and MAb production levels. Cultures were established in each serum source, and supernatants were kept for analysis. For cloning efficiencies, the results indicate that although there is no clear advantage in the performance of FBS-supplemented medium, ACS-supplemented RPMI 1640 medium can be used to clone hybridomas and the fusion partners. When analyzed for MAb production in the various sera, the hybridoma cell lines used in this study appeared to produce up to twice as much immunoglobulin when grown in ACS as when grown in supplemented medium. IgG- and IgM-secreting hybridoma cultures should be checked independently for antibody production. Six out of eight murine and human hybridoma cell lines produced higher levels of MAbs when grown in ACS.


Interleukin-1 binding, internalization, and processing in a murine osteoblastic cell line, MC3T3.E1.

We have investigated the interaction of IL-1 and its receptor on a murine osteoblastic cell line, MC3T3.E1, with regard to binding, internalization, and the fate of the receptor-ligand complex following internalization. Binding experiments indicated that this cell line possesses a high affinity receptor (Kd 1.02 x 10(-10) M) that binds both IL-1 alpha and IL-1 beta, and has approximately 6500 receptors per cell. Cross-linking experiments indicated that the receptor has a molecular weight of 100,000 daltons. Binding of IL-1 to the receptor is inhibited by the Interleukin Receptor Antagonist Protein (IRAP). These characteristics suggest that the murine osteoblastic receptor resembles that found on T lymphocytes and fibroblasts. Internalization experiments showed that this process is fairly rapid and results in degradation of the ligand and subsequent loss of degraded IL-1 from the cell. In this respect, processing of the receptor-ligand complex mimics that observed with IL-1 receptors on murine bone marrow cells, pre-B cells, and macrophages. Although the reasons for these differences are unclear, it may be that, unlike fibroblasts, osteoblasts may function as an effector cell which rapidly removes IL-1 from the immediate environment via ligand degradation while at the same time initiating bone resorption via stimulation of osteopontin biosynthesis.


Organization and chromosomal localization of the human interleukin 5 receptor alpha-chain gene.

The gene for the hIL-5R alpha subunit, which is present in a single copy in the human genome, has been analysed in detail. It is located on chromosome 3 in the region 3p26. The gene organization reflects its relationship to the cytokine/haematopoietin receptor superfamily. Three introns are located in the 5' untranslated region. The subsequent exons determine the functional domains of the hIL-5R alpha protein: the signal peptide, three fibronectin type III-like (FN-like) modules, each built up by two exons, the membrane anchor and two exons forming the cytoplasmic tail, the first of which contains the proline cluster region. In addition, a specific exon generating a soluble isoform is located before the membrane anchor exon. This specific exon contains an in frame TAA stop codon, followed by a polyadenylation signal. Hence, a normal splicing event leads to a soluble IL-5R alpha variant, whereas alternative splicing is required for cell membrane anchoring. A second area of alternative splicing is found in the 5' leader sequence, and possibly relates to the presence of short open reading frames preceding the main ATG. All intron-exon junctions meet the GT-AG rule. The gene structures of all cytokine/haematopoietin receptors documented so far have also been compared with respect to intron phasing. This shows that all introns between the FN-III-like modules are of the +1 type, but in addition, splice sites within the Cys-module and WS-WS-module are invariably of the +2 and 0 type, respectively.


Assessment of memory complaint in age-associated memory impairment: the MAC-Q.

Few brief self-report memory questionnaires are available, and non has been well validated. We designed a brief questionnaire, the MAC-Q, to assess age-related memory decline. Validity and reliability of the MAC-Q were assessed in 232 subjects meeting diagnostic criteria for age-associated memory impairment (AAMI). Concurrent validity of the MAC-Q was supported by a significant correlation (r = .41, p < .001) with a lengthy, well-validated memory questionnaire. Multiple regression analysis indicated that memory test scores were significant predictors of MAC-Q scores. MAC-Q scores were not predicted by Hamilton Depression Scale scores, suggesting that memory complaint in AAMI is not related to affective status. Internal consistency and test-retest reliability of the MAC-Q were satisfactory. Our data support the validity and reliability of the MAC-Q, a new brief memory questionnaire. The MAC-Q is of particular relevance to the assessment of AAMI, but should also prove useful in any clinical or research setting requiring a brief index of memory complaint.


Personality in recovered depressed elderly.

Personality traits in euthymic elderly subjects with and without past histories of major depressive episodes were assessed using the Structured Clinical Interview for DSM-III-R and the Social Adjustment Scale-SR. Recovered depressed subjects were characterized by significantly more personality traits from DSM-III-R Clusters B and C than controls, and they exhibited differences in social adjustment, as well. Subjects who have recovered from depressive episodes may show significant differences in personality and social adjustment that might represent residua of past depression, a trait characteristic, or a risk factor for recurrence.


The biological activities of gro beta and IL-8 on human neutrophils are overlapping but not identical.

Gro beta and IL-8 are two members of the small induced secreted (SIS) cytokine family (C-X-C subgroup) with proinflammatory activities on neutrophils. In order to assess whether or not the interaction with their receptors results in similar biological actions, we compared the two cytokines in five different bioassays. Gro beta showed similar biological activities as IL-8 in tests of chemotaxis, induction of the respiratory burst, and induction of interleukin 6 (IL-6) production. However, for two other biological activities: augmentation of the expression of CD11b on the cell surface and rapid elevation of the intracellular calcium concentration, maximal effects required 100 times more gro beta than IL-8. Taken together, these results suggest that the stimulation of the IL-8 or gro beta receptor evokes three similar responses, but that only the activation of the IL-8 receptor and not that of gro beta results in elevated CD11b expression and calcium mobilization in human neutrophils.


Soluble interleukin-2 receptor and soluble CD8 molecules in cerebrospinal fluid and serum of patients with multiple sclerosis.

The purpose of this study was to analyse soluble interleukin-2 receptor (sIL-2R) and soluble CD8 (sCD8) molecules in the cerebrospinal fluid (CSF) and serum of 18 patients with definite multiple sclerosis (MS) and of 16 with noninflammatory neurologic diseases (NIND). All MS patients suffered from an exacerbation of the relapsing-remitting form of the disease within one month before examination. The mean serum levels of sIL-2R and sCD8 in the MS patients were not significantly different from those of NIND patients. Only one patient with MS had detectable sIL-2R in the CSF. CSF sCD8 was detectable in 10 of 18 MS patients and in 1 of 16 NIND patients. Our data indicate that the CSF and serum sIL-2R concentrations do not correlate with the disease activity. Conversely, increased levels of sCD8 only in the CSF of MS patients support the hypothesis of an intrathecal activation of CD8+ cells in MS. We think that CSF sCD8 can be a useful marker for the presence of activated T cells in the central nervous system.


Safety and effectiveness of low-dose clozapine in psychogeriatric patients: a preliminary study.

The short- and long-term treatment tolerance of low-dose clozapine was retrospectively investigated in 18 psychogeriatric patients. Discontinued use of the drug because of side effects or inefficiency was required for only four patients. In the long-term treatment group leukopenia was not observed, and disturbances of liver function appeared to be very infrequent. A second group of seven severely demented psychogeriatric inpatients who were currently being treated with low-dose clozapine underwent a withdrawal study in order to evaluate the therapeutic efficacy of the drug, measured by the NOSIE and the SCAG scales. The results indicate that for patients such as these, with paranoid or socially disturbing behavior who also tend to develop severe neurological side effects with classical neuroleptics, a low-dose administration of clozapine is an acceptable alternative treatment.


Temporal patterns of agitated nursing home residents.

Twenty-four highly agitated, cognitively impaired nursing home residents were studied in depth to determine whether they manifested temporal patterns of agitation. Results demonstrated that agitated behaviors were significantly associated with temporal factors. For instance, residents made more requests for attention during lunch than other time periods, and residents screamed most often during the night. Some agitated behaviors (e.g., aggression) were manifested more frequently in the evening than in the day, consistent with the notion of sundowning in the nursing home. Implications of temporal patterns of agitation for caregivers of severely cognitively impaired and agitated nursing home residents are discussed.


The effect of a single low dose of trihexyphenidyl on memory functioning in the healthy elderly.

Medications with anticholinergic properties, when taken at therapeutic doses, are known to adversely affect memory functioning in young adults and the elderly. However, their impact at lower doses in geriatric persons has been less thoroughly studied. We investigated the impact of a single 2-mg dose of trihexyphenidyl on memory functioning in 20 healthy elderly subjects using a within-subjects, double-blind comparison with a placebo. Memory functioning was evaluated using subtests of the Wechsler Memory Scale. Subjects also rated the perceived impact of medication on their performance following memory testing. Results indicated that the single 2-mg dose of trihexyphenidyl produced impaired performance on measures of immediate and half-hour delayed recall of complex verbal and visual material when compared to the placebo condition. However, differences were not found on several other memory measures, including general orientation, attention-concentration, and learning of word associations. The significance of these selective memory deficits and suggestions regarding future research are discussed.


Facial recognition: a cognitive study of elderly dementia patients and normal older adults.

Dementia patients' and normal elderlies' recognition of familiar, ordinary emotional and facial expressions was tested. In three conditions subjects were required to name the emotions depicted in pictures and to produce them while presented with the verbal labels of the expressions. The dementia patients' best performance occurred when they had access to the verbal labels while viewing the pictures. The major deficiency in facial recognition was found to be dysnomia related. Findings of this study suggest that the connection between the gnostic units of expression and the gnostic units of verbal labeling is not impaired significantly among the dementia patients.


Clinico-tomographical aspects in the pathogenesis of vascular dementia.

This article discusses the role of some pathogenetical factors in the main morphological variants of vascular dementia and their correlation with certain clinical parameters. On the basis of computer-tomographical (CT) studies of 62 patients with dementia, it was possible to distinguish three groups of patients, according to the type of parenchymatous brain lesions: (1) 14 patients with "pure" leukoaraiosis (LA); (2) 23 patients with ischemic foci (IF), and (3) 25 patients with a combination of LA and IF. A comparative study of these groups confirmed the concept that in the development of LA and dementia related to it, a special role is being attributed to such factors as arterial hypertension and aging.


The effect of dementia on acute care in a geriatric medical unit.

Treatment of dementia costs billions of dollars in long-term care and community services every year. Dementia also burdens the acute care system and may contribute to financial problems for hospitals serving large numbers of demented elderly. In a specialized geriatric medical unit devoted to acute care of the frail elderly, Alzheimer's disease and vascular and mixed dementias afflicted 63% of inpatients and were associated with excess consumption of nursing resources, complications of treatment, nosocomial infections, lengthy hospitalizations, and financial losses to the hospital. Due in part to the effects of dementia on mobility, continence, and nutrition, demented patients suffered more frequently from life-threatening infections, sepsis, iatrogenic disease, and prolonged hospital stays. Hospital losses were 75% higher for demented patients than for nondemented patients. Dementia affected the majority of acute care patients in this study. However, it was rarely coded as an admitting diagnosis, even though it may have been the proximate cause of the medical morbidity which led to the acute hospitalization. In addition, despite the significant impact of dementia on the hospital course and costs, it was a factor in hospital reimbursement in less than one third of cases. The results indicate that dementia was not considered to be an acute diagnosis, nor was it recognized as a complex medical illness. The impact of dementia on acute hospitalization, including the mechanisms by which dementia prolongs the hospital stay, requires further investigation.


Dementia syndromes in nursing home patients.

Patients (n = 191) living in four comparable somatic nursing homes (NH) (nursing homes for physical illness) were studied in order to evaluate dementia syndromes. Dementia and symptoms of depressed mood occurred frequently (72% and 63%, respectively). Dementia was often undiagnosed at admittance. Neither the length of time spent in institutions, nor marital status, age, or sex seemed to be of more than minor importance to the prevalence of dementia syndromes. Concerning functional impairment, convergence of findings across the societies studied indicates that psychiatric symptoms and psychopathology are intrinsic parts of long-term care of the elderly.


Inappropriate placement of residents in psychiatric nursing homes in Bergen, Norway.

The mental and physical capacities of all residents in psychiatric nursing homes in Bergen were studied. It was found that 95% were moderately or severely mentally impaired and 53% received antipsychotic medication regularly. By objective criteria, 47.9% were considered improperly placed. These patients typically had had a long stay in the institution, were immobile, and were given antipsychotic drugs infrequently.


The natural immune barrier to xenotransplantation.

As the shortage of available organs for transplantation becomes critical, many investigators have turned to the possibility of using animals as a source of donor organs. Although there have been several attempts to use organs from closely related species for transplantation into human, there is relatively little experience in the use of nonprimate animals as clinical donor animals. The major problem in transplants between widely disparate species is hyperacute rejection, a rapid and violent rejection reaction that leads to the destruction of the graft within minutes or hours. Hyperacute rejection appears to be triggered by components of natural immunity, most notably natural antibodies and complement. Recent data suggest that hyperacute rejection may not represent an insurmountable barrier to discordant xenotransplantation. There have recently been several examples of survival of grafts in recipients in the face of antigraft antibodies and an intact complement system referred to as accommodation. Once hyperacute rejection can be averted, it becomes necessary to consider elicited cellular responses. There are a number of issues to be considered in the clinically relevant model of porcine to primate xenografts. These include the size of the responding T-cell repertoire and the extent to which the cell adhesion molecules and cytokines of the donor will be able to stimulate recipient immune responses. Finally, the interactions between T cells and the cells forming the inner layer of blood vessels may have profound effects on the outcome of the graft.


Chronic lactic acidosis in a patient with acquired immunodeficiency syndrome and mitochondrial myopathy: biochemical studies.

A 30-yr-old man with acquired immunodeficiency syndrome treated with zidovudine developed biopsy-proven mitochondrial myopathy. Chronic lactic acidosis (lactate, 10 +/- 1 mmol/L) persisted for more than 5 wk. Liver function tests were normal, but the concentration of lactose rose to 16.1 mmol/L when 500 mmol of ethanol was infused. The concentration of lactose rose by only 1.5 mmol/L with maximally tolerated exercise. If this mitochondrial lesion compromised flux through the electron transport system, increased turnover of ATP with exercise should have exacerbated the degree of lactic acidosis because of increased need to regenerate ATP via glycolysis. Two possible explanations will be discussed: first, there was both a rapid rate of production of lactic acid in affected muscles in conjunction and an equally rapid rate of removal by uninvolved organs. Second, there was a low net rate of production of lactic acid in involved muscles despite the exercise.


Flow cytometric evaluation of cytotoxic peripheral blood lymphocytes in acute renal graft rejection.

The presence of the S6F1+ epitope on the surface of CD8+ lymphocytes is believed to be uniquely representative of cytotoxic subpopulations. A preliminary study was conducted to evaluate the CD8+ S6F1+ peripheral lymphocytes by flow cytometry in patients undergoing renal allograft biopsy for allograft dysfunction. Lymphocytes, obtained at the time of biopsy, were analyzed by flow cytometry with CD8-FITC/S6F1-RD1 as the test monoclonal antibody and MsIgG-RD1/MsIgG-FITC as internal control. A 100% increase in S6F1+ cells over internal control was considered to be positive result. The results were correlated with the histopathologic findings in 14 instances of allograft dysfunction occurring 26.5 +/- 11.6 days posttransplantation. The histopathologic diagnosis was acute cellular rejection in eight cases, acute tubular necrosis in four, and cyclosporine nephrotoxicity in two. Flow cytometric detection of an increase in S6F1+ cells yielded a sensitivity of 87.5% and a specificity of 83.3% for the diagnosis of acute rejection. It would appear that the use of a monoclonal antibody to detect increases in the number of CD8+ S6F1+ peripheral lymphocytes is a valuable test for the detection of acute allograft rejection in the initial period after transplantation.


A multivariate analysis of mortality and hospital admissions with high-flux dialysis.

The use of high-flux dialysis in clinical practice increased rapidly despite an absence of reports on the clinical effectiveness of the technique. Mortality and hospital admission rates of patients treated with high-flux dialysis were evaluated and compared with those of patients treated with conventional dialysis in a hospital-based renal dialysis unit in northern California. By use of a retrospective, cross-over design, 253 patients enrolled in the dialysis unit from January 1987 to January 1991 were studied. During this period, 107 patients were treated with high-flux dialysis for at least 1 month, and all but 17 of them had received conventional dialysis before switching to high-flux dialysis. The remaining 146 patients were treated with only conventional dialysis. Of the 80 patients who died during the study period, 69 were receiving conventional dialysis and 11 were receiving high-flux dialysis. The multivariate analyses, adjusted for age, gender, ethnic background, type of renal failure, comorbid conditions, and duration of ESRD, showed that annual mortality was substantially less for patients treated with high-flux dialysis compared with that for patients treated with conventional dialysis (7 versus 20%; P < 0.001). The difference in the rate of hospital admissions was not statistically significant. In this nonexperimental study, methods were applied to control for selectivity bias and other factors that might confound the apparent treatment effect. The findings suggest that the potential benefits of high-flux dialysis are sufficient to justify further confirmation in a randomized, controlled trial.


Outcomes of cardiopulmonary resuscitation in dialysis patients.

Patients with renal failure are believed to have a poor survival rate after cardiopulmonary resuscitation, but there is little specific information about the outcomes of cardiopulmonary resuscitation in dialysis patients. To be better able to inform dialysis patients and assist them in decision making about cardiopulmonary resuscitation, the eight-year experience with cardiopulmonary resuscitation in dialysis patients at a university dialysis program was analyzed and outcomes were compared with those of a control group of nondialysis patients undergoing cardiopulmonary resuscitation during the same time period in the same hospital. Of 221 dialysis patients experiencing cardiopulmonary arrest, 74 (34%) had CPR compared with 247 (21%) of 1,201 control patients (P = 0.0002). Six of 74 (8%; 95% confidence interval, 2 to 14%) dialysis patients survived to hospital discharge compared with 30 of 247 (12%; 95% confidence interval, 8 to 16%) control patients (P = not significant). At 6 months after CPR, 2 (3%) of 74 dialysis patients were still alive compared with 23 (9%) of 247 controls (P = 0.044); this difference was not explained by age or comorbid conditions. Twenty-one (78%) of the 27 successfully resuscitated dialysis patients died a mean of 4.4 days later; 95% were on mechanical ventilation in an intensive care unit at the time of death. It was concluded that cardiopulmonary resuscitation is a procedure that rarely results in extended survival for dialysis patients. In discussions about cardiopulmonary resuscitation with dialysis patients, nephrologists should provide this information.


Eosinophilia and cellular cytokine responsiveness in hemodialysis patients.

Eosinophilia in hemodialysis (HD) patients has been associated with allergy to dialyzers and exaggerated activation of complement during HD. Its etiology, however, remains unknown. Complement activation can lead to cytokine production, and interleukin-2 (IL-2) administration has been shown to cause eosinophilia. Because abnormalities in cellular cytokine production in renal patients were previously demonstrated, the relationship between dialysis-associated eosinophilia and IL production in this HD population was studied. Twelve patients on chronic HD therapy with normal eosinophil counts (mean, 0.23 +/- 0.03 cells/nL) were compared with nine patients with eosinophilia (mean, 0.85 +/- 0.17 cells/nL). Measurements of cellular IL-1 and IL-2 production were performed before (pre) and after (post) HD with cuprammonium dialyzers. In patients with eosinophilia, stimulated cellular IL-1 production increased by 117 +/- 40% (P < 0.01) when post-HD measurements were compared with pre-HD values and IL-2 production increased by 127 +/- 65% (P < 0.05). In contrast, there was no difference in stimulated cellular cytokine production when values before and after HD were compared in patients without eosinophilia. Individual responses were reproducible during subsequent dialysis. It was concluded that cellular cytokine production in response to HD is not uniform. Eosinophilia is a clinically useful marker of exaggerated HD-associated cytokine production. Cytokine production depends on individual responsiveness and is probably related to atopy.(ABSTRACT TRUNCATED AT 250 WORDS)


Phosphate transport in brush border membranes from uremic rats. Response to phosphonoformic acid.

Phosphate retention in chronic renal failure may result in the development of secondary hyperparathyroidism and renal osteodystrophy. Thus, the addition of a specific phosphaturic agent may be beneficial in the treatment of chronic renal failure. Phosphonoformic acid (PFA), a specific and competitive inhibitor of Na(+)-Pi cotransport in renal and intestinal brush border membrane vesicles (BBMV), can induce phosphaturia in thyroparathyroidectomized (TPTX) rats. The aim of this study was to determine if PFA retains its inhibitory activity in uremic intestine and kidney. The effect of PFA, and its derivative phosphonoacetic acid (PAA), added in vitro, on Pi transport in BBMV prepared from the intestine and the remnant kidney of 5/6 nephrectomized (NX) rats was studied. In intestinal BBMV, the time course of Pi transport was not significantly different between NX and sham-operated (SH) control rats. Compared with SH, Na(+)-dependent Pi transport was reduced in BBMV from remnant kidney of NX, with no difference in Na(+)-independent or equilibrium uptakes. The reduced transport was specific for Pi with no change in Na+ gradient-dependent L-proline uptake, suggesting a normal Na+ conductance in uremic BBM. PFA and PAA produced a marked inhibition of Na(+)-Pi cotransport in intestinal and renal BBMV from NX and SH with similar relative inhibitory potency in uremic and control BBMV. It was concluded that the relative inhibitory potency of PFA or PAA on intestinal and renal Na(+)-Pi cotransport is preserved in uremia.


Measurement of albumin reflection coefficient with isolated rat glomeruli.

Macromolecular permeability of the glomerular capillary has been inferred from the clearance of endogenous protein or infused macromolecules. Permeability is increased after treatment with polycations as well as after renal injury. It has previously been shown that the capillaries of glomeruli isolated from normal mammals expand or collapse in response to transcapillary albumin gradients and that the magnitude of the changes in capillary volume and in total glomerular volume are directly proportional to the applied oncotic gradients. In the experiments presented here, the volume responses of control glomeruli and of glomeruli treated with protamine (100 to 600 micrograms/mL for up to 60 min) were used to calculate the albumin reflection coefficient, sigma albumin, and the convectional permeability, P convectional albumin = (1 - sigma albumin), of the capillary wall. Sigma albumin for normal glomeruli was about 1 (P convectional albumin = 0); sigma albumin fell to a minimum of 0.2 +/- 0.1 (P convectional albumin = 0.8 +/- 0.1) after incubation with protamine sulfate (600 micrograms/mL) for 30 min. Retraction and fusion of podocyte foot processes and denudation of the underlying matrix was seen on scanning electron micrographs of protamine-treated glomeruli. These results confirm that it is possible to study macromolecular permeability of the glomerular capillary in vitro and to calculate sigma albumin independent of hemodynamic and systemic humoral influences. This method will permit the assessment of the effects of individual mediators of glomerular injury and the study of glomeruli from kidneys affected by experimentally induced or naturally occurring renal diseases.


Rat glomerular epithelial cells in culture express characteristics of parietal, not visceral, epithelium.

Glomerular epithelial cells (GEC) in culture are derived from intact isolated glomeruli. Although there is general agreement about distinguishing GEC from mesangial and endothelial cells, there is still uncertainty regarding the visceral versus parietal origin of cultured GEC. If these cells are to provide a useful model system, it is necessary to establish well-defined cell populations. The purpose of this study was to evaluate this important issue by comparing the characteristics of cultured GEC with glomerular epithelium from rat kidney sections. By electron microscopy, GEC were polygonal, with cilia and desmosomes between cells, similar to parietal cells in situ. Because intermediate filaments are specifically expressed in differentiated cells in the kidney, the expression of intermediate filaments in cultured GEC were compared with those of intact glomeruli. Cultured GEC are positive for cytokeratin and negative for vimentin and desmin, identical to parietal cells in situ. In contrast, podocytes are positive for vimentin and desmin and negative for cytokeratin. In vivo, podocytes express gp330 and puromycin-aminonucleoside (PAN) susceptibility, which are used as markers for cultured GEC. Immunoperoxidase staining of rat kidney sections with monoclonal anti-gp330 demonstrated gp330 localization to the cell surface and coated pits of the parietal cells, similar to its localization in podocytes. The presence of gp330 in cultured GEC was confirmed by immunoblot. PAN administration to rats induced vacuolization and detachment from the basement membrane in the parietal cells of Bowman's capsule, similar to the cytotoxicity observed in podocytes.(ABSTRACT TRUNCATED AT 250 WORDS)


Plasma renin activity and the renal response to nitric oxide synthesis inhibition.

Inhibition of systemic endothelium-derived relaxing factor (EDRF) synthesis with L-Nw-nitroarginine (L-NAME) results in decreased RBF, which can be reversed by acute blockade of angiotensin II (AII). Because AII is particularly elevated in the renal circulation, it was hypothesized that the degree of renal vasoconstriction produced by L-NAME in Inactin-anesthetized rats is related to PRA. To test this, PRA was chronically increased or suppressed by the manipulation of dietary sodium (eating 0.03% sodium chow or deoxycorticosterone acetate plus drinking 1% NaCl, respectively). After 10 days, rats were anesthetized for determination of blood pressure (BP) and RBF before and after L-NAME (10 mg/kg body wt). In rats with high PRA (61.6 +/- 10.4 ng of angiotensin I [Al]/mL/h; N = 8), L-NAME increased BP by 29 +/- 2 mm Hg (from 110 +/- 4 to 139 +/- 5 mm Hg; P < 0.001), decreased RBF by 27% (from 7.9 +/- 0.3 to 5.8 +/- 0.3 mL/min/g kidney wt; P < 0.001), and increased renal vascular resistance (RVR) by 67% (from 14.5 +/- 0.9 to 24.2 +/- 1.1 resistance units [RU]; P < 0.001). When rats with high PRA (N = 8) were treated with 10 mg/kg body wt of DuP 753, on AII receptor antagonist, L-NAME similarly increased BP by 30 +/- 5 mm Hg (from 81 +/- 3 to 111 +/- 5; P < 0.001) but RBF did not change and RVR increased by only 31% (from 10.9 +/- 0.8 to 13.3 +/- 0.7 RU; P < 0.005).(ABSTRACT TRUNCATED AT 250 WORDS)


A new noninvasive quantification of renal blood flow with N-13 ammonia, dynamic positron emission tomography, and a two-compartment model.

In order to determine if dynamic positron emission tomography (PET) and N-13 ammonia can be used to quantitate regional RBF (rRBF) noninvasively, six anesthetized dogs were examined with PET imaging after an iv bolus administration of 5 mCi of N-13 ammonia. Renal time activity curves and the arterial input function were derived from regions of interest drawn over the renal cortex and abdominal aorta, respectively. For calculation of rRBF, less than 120 s of the initial data were used to minimize contamination by plasma metabolites of N-13 radioactivity. rRBF was quantitated with a two-compartment model, and the results were compared with simultaneously acquired microsphere blood flow measurement. Fourteen experiments were performed in six dogs, and four regions of interest on renal cortex were selected on each PET image. RBF derived from dynamic PET imaging with N-13 ammonia was linearly related to microsphere (MS) values (rRBF = 1.06 x MS - 0.17; r = 0.91). Mean rRBF in the canine experiments was 4.0 mL/min/g. The results indicate that dynamic N-13 ammonia renal PET can provide noninvasively quantitative rRBF.


Additive antiproteinuric effect of converting enzyme inhibition and a low protein intake.

The hypothesis that converting enzyme inhibition and a protein-restricted diet could have additive antiproteinuric effects has been tested. A group of 17 patients with proteinuria in excess of 3 g/24 h per 1.73 m2 of body surface area were submitted to a 3-wk period of study, after a 4-wk wash-out period during which protein intake was 1.0 g/kg per day and in the absence of any medication. During the first and second weeks of the study, protein intake was lowered to 0.3 g/kg per day, and in the third week, it returned to 1.0 g/kg per day. Enalapril (20 mg daily) was administered during the second and third weeks of the study. Initially and at the end of each week thereafter, we determined blood pressure, GFR (inulin clearance), RPF (para-aminohippurate clearance), plasma sodium and potassium, PRA and aldosterone, and the 24-h urine excretion of sodium potassium, protein, and urea. The low protein intake during the first week induced a significant fall of proteinuria (P < 0.01), GFR (P < 0.01), and RPF (P < 0.01) in the absence of changes in filtration fraction. The addition of enalapril induced a further decrease of proteinuria (P < 0.01) and a fall in filtration fraction (P < 0.05), whereas plasma potassium, PRA, GFR, and RPF values increased (P < 0.01). The rise in protein intake during the last week of the study induced a significant rise in proteinuria, GFR, and RPF (P < 0.01), although the first of these parameters attained values significantly lower (P < 0.05) than those observed initially.(ABSTRACT TRUNCATED AT 250 WORDS)


Amelioration of ischemic acute renal failure by dietary fish oil administration in conscious dogs.

The hypothesis that dietary fish oil would protect dogs from ischemic acute renal failure was tested. Fish oil (eicosapentaenoic acid, 55 mg/kg per day, and docosahexaenoic acid, 40 mg/kg per day was given to eight instrumented, female, beagle dogs for 6 wk, while seven control dogs received vehicle. After 3 wk, unilateral nephrectomy was performed and a pneumatic cuff with flow probe was placed around the remaining renal artery of each dog. Three weeks thereafter, the cuff was inflated for 120 min. Renal function, RBF, and prostanoid excretion were measured 24 and 72 h after ischemia. In dogs receiving fish oil, blood pressure, GFR, RBF, renal vascular resistance (RVR), cholesterol, triglycerides, and prostanoid excretion were measured weekly for 6 wk. Further, cytosolic calcium was measured before and five times after fish oil. Blood pressure decreased, serum cholesterol and triglycerides decreased, and the cytosolic calcium within platelets decreased. The urinary excretion (expressed as picograms per milligram of creatinine) of the thromboxane (TX) metabolite TXB2 and the excretion of prostaglandin (PG)E2, as well as the excretion of the PGI2 metabolite 6-keto PGF1 alpha were decreased. GFR, RBF (Cl inulin and Cl para-aminohippuric acid), and RVR were not influenced by fish oil. Unilateral nephrectomy decreased GFR and RBF and increased RVR as expected, whereas it further decreased prostanoid excretion. Acute renal ischemia caused a significant, reversible decrease in GFR and urine volume in vehicle-treated animals, whereas no significant effect on renal function or urine volume was observed in animals pretreated with fish oil.(ABSTRACT TRUNCATED AT 250 WORDS)


Omega-3 fatty acid supplementation in primary nephrotic syndrome: effects on plasma lipids and coagulopathy.

The effect of fish oil dietary supplementation on the dyslipidemia and coagulopathy of seven patients with nephrotic syndrome and hypoalbuminemia due to primary kidney disease was studied. Plasma lipids, platelet aggregation studies, simplate bleeding time, and fibrinogen levels were determined before and after 6 wk of treatment with fish oil (15 g/day of MaxEPA; 2.7 g of eicosapentenoic acid (EPA) and 1.8 g of docosahexenoic acid. Urea kinetics were determined from urine-urea concentration, urinary proteina, and urine volume. A 3-day dietary intake record was obtained from each patient before and after 6 wk of fish oil supplementation. There was no significant dietary change in protein, fat, or carbohydrate intake over the time period of the study. At study end, total triglycerides decreased from 2.98 +/- 1.31 to 2.18 +/- 1.14 mmol/L (P = 0.002), and very low-density lipoprotein-triglycerides decreased from 2.35 +/- 1.34 to 1.28 +/- 1.07 mmol/L (P = 0.01). Low-density lipoprotein (LDL) cholesterol increased from 5.18 +/- 1.74 to 7.35 +/- 2.83 mmol/L (P = 0.005). No significant changes occurred in bleeding time, platelet count, hematocrit, red blood cell flexibility, or whole blood viscosity. Platelet aggregation responses to collagen and arachidonic acid were consistently reduced after treatment, but there was no change in platelet response to ADP. The platelet membrane phospolipids showed a significantly increased incorporation of EPA after the fish oil diet (P = 0.03).(ABSTRACT TRUNCATED AT 250 WORDS)


Hypo-triploid acute myeloid leukemia with isochromosome 11q.

A 78-year-old male developed acute myeloid leukemia (AML, M2) with an isochromosome 11q (i(11q)) in hypo-triploid populations. He died 2 months later from the leukemia without having responded to chemotherapy. We reviewed 12 cases in the literature with i(11q) in hematopoietic neoplasms and found that the i(11q) is associated with complex chromosome abnormalities and with elderly patients. Ten out of the 13 patients had an AML phenotype, and they had poor response to chemotherapy and a short survival. The i(11q) may be a non-random chromosome aberration in hematopoietic neoplasms.


Analysis of growth failure in children treated for acute lymphoblastic leukemia.

Growth patterns were surveyed in 303 children with acute lymphoblastic leukemia who had remained in continuous first complete remission for a minimum of 1 year (median 3 years). Chemotherapy was given for 3 years, and central nervous system prophylaxis consisted of cranial irradiation at a total dose of 18 Gy or intravenous high-dose methotrexate (1.5-6 g/m2 for three to six doses). Intensive chemotherapy, including cyclophosphamide, doxorubicin, and cytosine arabinoside was given to children with high-risk features. Two of 205 children with low- or intermediate-risk features and 13 of 98 children with high-risk features showed a decrease in the growth rate of less than -2 SD. In 14 of these 15 patients, the age at onset was over 9 years and growth failure became most predominant in the prepubertal period: ten of these children showed a tendency toward delayed pubertal development, but eight showed later catch-up growth with pubertal maturation after completion of chemotherapy. Thus, chemotherapy appeared to contribute temporarily to the growth failure and gonadal impairment that occurred in the prepubertal period. No obvious correlation between the administered cranial irradiation and growth failure was found, but further study with a longer follow-up will be necessary to determine the long-term effects of irradiation on subsequent growth patterns in children.


Intracellular and serum levels of aldolase activity in B chronic lymphocytic leukemia.

Intracellular and serum activities of aldolase (ALS) were biochemically determined in lymphocyte subpopulations from normal subjects and patients with B-chronic lymphocytic leukemia (B-CLL). Aldolase activity was significantly lower in T cells of CLL than in normal T cells (2.9 +/- 1.5 vs. 4.7 +/- 2.1 Sigma Units (SU)/6 x 10(6) cells, p < 0.05). The aldolase activity also was significantly (p < 0.001) lower (3.1 +/- 1.9 SU/6 x 10(6) cells) in CLL B lymphocytes than in normal B lymphocytes (18.1 +/- 6.5 SU/6 x 10(6) cells). Moreover, the serum levels of ALS in all patients with B-CLL were higher than that in normal subjects (8.1 +/- 5.8 vs. 2.2 +/- 0.8 SU/ml, p < 0.02). Our findings demonstrate that T lymphocytes from patients with B-CLL display enzyme activity different from that of normal T cells. This may reflect the abnormal maturity of the residual T cell population in B-CLL.


Electrostatic interaction influences cell adhesion?

The effect of electrostatic forces on the adhesion of LEP-19 diploid embryonal fibroblasts, Hep-2 laryngeal carcinoma cells, Raji lymphoblastoma cells and Sp 2/0 myeloma cells was examined in vitro. Adhesivity of all tested cell lines was higher on the cationized glass than on untreated or anionized glass. The negatively charged sialic acids on the cell surface play a role in cell adhesion. The participation of electrostatic interaction is independent of the energy metabolism in serum-free conditions.


Target antigens of anti-platelet antibodies in patients with steroid-resistant ITP of recent onset. Canadian Apheresis Study Group.

Recent application of Western blotting procedures in the detection of anti-platelet antibodies has permitted more refined definition of reactivity. We report on the results of anti-platelet antibody assays in a series of 19 patients with recently diagnosed (less than 6 months duration) steroid-resistant, idiopathic thrombocytopenia purpura (ITP). At presentation, six of the 19 patients had a positive test for platelet-associated IgG (PAIgG) as measured by the direct radial-immunodiffusion (RID) assay, whereas three of the 19 were positive with the direct-platelet-suspension-immunofluorescence test (DPSIFT). The indirect-platelet-suspension-immunofluorescence test (IPSIFT) demonstrated antibodies in seven of the sera. Following Western blot (WB) analysis, the serum of 7/19 patients (only three of which were positive in the IPSIFT) could be shown to react with platelet antigens. Two patterns were seen: in four cases there were bands of apparent molecular weights of 60,000, 55,000 and 50,000; in the other three samples, a single band near 90,000 was demonstrated. Unlike the situation reported for chronic ITP, no reactivity was seen against higher molecular weight antigens other than the 'non-specific' binding at apparent molecular weight 200,000 which is also seen with normal sera. The data suggest that antibodies reacting against specific platelet antigens are present in the serum of some patients with recent onset ITP.


Cavitating Pneumocystis pneumonia in an autopsied case of adult T-cell leukemia.

Cavitating necrosis is rare in Pneumocystis carinii pneumonia. In this report, we describe an autopsy patient with adult T-cell leukemia associated with cavitating Pneumocystis carinii pneumonia. The patient, a 61-year-old woman, died of an acute crisis of adult T-cell leukemia associated with diffuse pulmonary infection of Pneumocystis carinii. Postmortem examination revealed necrotic foci in both lungs, one of which, in the left lower lobe, had a central cavitation. Microscopically, leukemic cell infiltration was abundant in the lung parenchyma but not in the necrotic lesions. Pneumocystis carinii organisms were distributed diffusely in the alveoli and also in the cavity wall. Intranuclear and intracytoplasmic inclusion bodies were scattered in the lung indicating cytomegalovirus infection. However, no bacterial or fungal infection was detected in the lungs, even in the necrotic lesions. Cavitating Pneumocystis carinii pneumonia occurs in other immunodeficiency diseases apart from AIDS. To our knowledge, this report is the first case of cavitating Pneumocystis carinii pneumonia in adult T-cell leukemia.


[Effects of verapamil on the development of pain syndrome in rats after section of the sciatic nerve].

The effect of daily verapamil administration (5 mg/kg) on pain sensitivity, bioelectric activity of cerebral cortex and microcirculation was studied in rats with cut sciatic nerve. Verapamil untreated rats showed hyperalgesia, autotomies and hypersynchronic discharges in contralateral hemisphere, increased range of evoked potentials and disorders in microcirculatory system which evidence developing pain syndrome. Early introduction of verapamil after the nerve cut prevented the emergence of pain syndrome.


[Effects of haloperidol on extracellular contents of dopamine and its metabolites in the septum of rats during interspecies aggression].

The extracellular levels of dopamine (DA) and its metabolites in the septum of freely moving rats were studied using "push-pull" method during muricidal aggression before and after haloperidol (2 mg/kg, i. p.) treatment. Mouse-killing activity of the rats was accompanied by significant reduction of the output of DA and metabolites in this brain area. Haloperidol suppressed muricidal activity of the rats and increased the extracellular levels of DA metabolites. In contrast, the decrease of DA release monitoring during killing activity was not affected by haloperidol administration. Possible role of the septal dopaminergic mechanisms underlying muricidal behaviour and the drug effects is discussed.


[Protection of cultured hippocampal neurons in hypoxia and subsequent reoxygenation by antioxidant from the spatially hindered phenols class].

The influence of antioxidant from hindered phenols (U-18) on a hypoxic neurodestructive effect in mouse hippocampal cell cultures was studied. Morphological and biochemical quantitative analysis of neuronal damage showed that U-18 attenuates nerve cell death resultant from 6-7-hour hypoxia and subsequent 12-hour posthypoxic reoxygenation. This antidestructive action of U-18 was observed upon its introduction in nutrient medium both before and immediately after hypoxic period. Thus, our results suggest that peroxidant reactions play a pivotal role in hypoxic neuronal injury and probably participate in this neurodestructive process mainly during posthypoxic reoxygenation period.


[Comparative electrophoretic characteristics of alkaline phosphatase isoforms in maternal blood and shaggy chorion extracts at various periods of pregnancy].

A comparative study of enzyme alkaline phosphatase (AP) of plasma and chorion placental extracts was made in various terms of pregnancy by PAAG electrophoresis. It is shown that the first three month chorion extract contained 1 thermolabile (TL) and 1 or 3 thermostable (TS) fractions of AP. In the second trimester of intrauterine development the activity of TL fraction disappeared, the number of TS forms increased. The early plasma period (6-12 weeks) was characterized by 2 TL non-placental forms, from the second half they added to 1 or 3 TS placental fractions, and before delivery TS enzyme appeared in the liver AP which had no analogue in the placenta. It is concluded that only the fastest placental TS AP forms (1 or 3) appear in maternal blood from the second trimester of gestation.


[Functional heterogeneity of the atrial myocardium in patients with congenital and acquired heart defects].

In experiments on atrium trabeculae the heterogeneity of myocardium contractile activity in patients operated on for inborn or acquired heart defects was studied. Contractile activity was assessed in isometric regime of muscle drugs work. The degree of functional heterogeneity was reported to differ in myocardium biopsies from patients with inborn or acquired heart defects. The difference was expressed in susceptibility to stimulating action or electrical impulses and in the degree of the change of myocardium contractile activity. The study of human myocardium functional heterogeneity is likely to present a new approach to increase efficacy of the work of pathologically changed heart muscle.


[Effects of ultraviolet irradiation on the Na/H exchange rate in erythrocytes of healthy subjects and patients with atherosclerosis of lower limb arteries].

Na+/H+ exchange rate in erythrocytes of patients with atherosclerosis of lower limb arteries is less than in erythrocytes of healthy subjects. Ultraviolet exposure of the patients blood in vitro activates Na/H exchange in erythrocytes.


[Phenotypes of dendritic cells in central lymph of healthy rabbits and during correction of experimental atherosclerosis].

Dendritic cells of central lymph of rabbits have been identified according to the form of the cell body, characteristics of formation and branchiness of its processes in health, in atherosclerosis, its correction with radon, polyphenol preparations made of Sanguisorba officinalis and in combination of the latter. Two main types of dendritic cells have been distinguished. Type I is characterized by a rounded body with clear outlines, protrusions and one compact process. Such cells are often found in lymph of intact animals. Type II has a cell body of various forms with two and more compact or branching processes. This type is mainly detected in atherosclerosis and its correction. The prevalence of the above phenotypes of dendritic cells is attributed to the response of the immune system to atherosclerosis and its correction.


[Dynamics of glycosylated hemoglobin and malondialdehyde contents in experimental diabetes mellitus].

The levels of HbAIc, malonic dialdehyde (MDA), sugar and insulin were measured in the blood of dogs with experimental diabetes mellitus. HbAIc increased from postoperative week 4 to week 8 of the observation period. MDA levels stood high for postoperative week 1, returned to the baseline, rerose on week 4 and remained high till week 8. Hyperglycemia was observed through the whole experiment.


[Study of tissue proteoglycans by means of infrared spectroscopy].

The infrared spectra of the hyalin cartilage vitreous body, cornea, sclera and spectra of standard normal Na(+)-salts of hyaluronic acid, chondroitin-4-sulfate, chondroitin-6-sulfate, protein-chondroitin-keratan-sulfate, aggregates of proteoglycans of the hyalin cartilage, heparin fractions containing 3 and 4 residues of sulfuric acid per dimer of polymer were obtained. The comparative analysis of the spectra for tissues and of the spectra for proteoglycans made it possible to identify different proteoglycans in the same tissues.


[Organic calcium antagonists verapamil and ryodipine prevent an increase of free calcium in synaptosomes of the rat brain during corazol kindling].

In experiments on Wistar male rats it was shown that i.p. administration of verapamil or ryodipine (1,4-dihydropyridine) 15 min before each daily injection of pentylenetetrazol (PTZ) in a subconvulsive dose 30 mg/kg during 28 days significantly delayed the development of PTZ-induced kindling and attenuated kindled seizure reactions during 21-23 days as compared with control. One week after kindling an increase in free Ca2+ concentration in control rat brain synaptosomes by 60% was revealed; the treatment by verapamil and ryodipine prevented this increase. Nevertheless, Ca2+ antagonists studied at least under our experimental conditions inspite of a significant decrease in free Ca2+ concentration in synaptosomes would not completely prevent the development of kindling. Thus, an alteration in calcium homeostasis will not be the only mechanism of plasticity and long-term changes of neurons during kindling.


[Oxygen tension and water-soluble products of lipid peroxidation in blood of volunteers in hypobaric hyperoxia].

Oxygen tension in the arterial blood with transcutaneous method (tcPO2) and TBA-active products of venous blood plasma were measured during simulation of extravehicular activity. There was a parallel increase of tcPO2 and the level of TBA-active products upon introduction of hypobaric hyperoxia factor. Detrimental action of lipid peroxidation products on erythrocyte membranes can be one of the factors of anemia during space flight.


[Experimental atherosclerosis and its correction with Co-35].

Initial and Co-35-induced parameters of lipid metabolism and hemostasis were studied in rabbits with experimental atherosclerosis. Control atherosclerotic animals were administered cobalt chloride and placebo. The findings demonstrated initially increased levels of cholesterol, lecithin, beta-lipoproteins, lysolecithin, sphingomyelin, cephalin, saturated acids in low levels of phosphatidylserine, polyglycerophosphatide and unsaturated acids. Hemostasis was characterized by hypercoagulation. A course of Co-35 brought about positive shifts in both lipid metabolism and hemostasis. Co-35 is recommended as an effective means against atherosclerosis.


[Thymosin alpha(1)--an endogenous modulator of alpha-thrombin recognition site].

Thymosin alpha 1-inhibited fibrinogen clotting activity of alpha-thrombin, but not amidolysis of H-D-Phe-Pip-Arg-pNA. Modulation of thrombin interaction with rat peritoneal mast cells (RPMC) by suppressors of additional recognition binding site (thymosin and heparin) was studied. Thrombin-induced pHi changes of RPMC were controlled with pH-sensitive fluorescent dye, BCECF. Thrombin caused a biphasic changes in pHi: rapid cell acidification (0.02) followed by slow alkalinization (0.06 above baseline for 18 min). Thymosin suppressed thrombin-induced pHi increase above resting level. Similar changes in pHi were observed after modification of additional recognition binding site by heparin. Beta/gamma-thrombin with disrupted additional binding site was shown to induce only a decrease of pHi. It is concluded that thymosin alpha 1 is endogenous modulator of alpha-thrombin activity.