A new composite xenograft monocusp patch for reconstruction of the right ventricular outflow tract: A preliminary report

Pulmonary insufficiency secondary to outflow tract reconstruction remains an unsolved problem. Although a number of surgical techniques have been designed to avoid or palliate this condition, none so far has been satisfactory. This report describes a new composite stented porcine monocusp patch, which, because of its desirable hemodynamic characteristics, promises to yield stable and reproducible results. The clinical effectiveness of the patch is documented by its successful application in a patient with tetralogy of Fallot.     

A rapid method for determining the incompatibility group of R plasmid

A rapid method for determining plasmid incompatibility group by agarose gel electrophoresis is described. This procedure requires only 4 or 5 days and is especially useful when it is not possible to distinguish two plasmids in the same cell by their antibiotic resistance patterns.     

Architecture of the Outer Membrane of Escherichia coli III. Protein-Lipopolysaccharide Complexes in Intramembraneous Particles

In a previous paper (A. Verkleij, L. van Alphen, J. Bijvelt, and B. Lugtenberg, Biochim. Biophys. Acta 466:269-282, 1977) we have hypothesized that particles on the outer fracture face of the outer membrane ([Formula: see text]), with corresponding pits on the inner fracture face of the outer membrane ([Formula: see text]), consist of lipopolysaccharide (LPS) aggregates stabilized by divalent cations and that they might contain protein and/or phospholipid. In the present paper the roles of LPS, cations, and proteins in these [Formula: see text] particles are described more extensively, using a strain that lacks the major outer membrane proteins, b, c, and d (b(-) c(-) d(-)), and has a reduction in the number of [Formula: see text] particles of 75%. To study the role of divalent cations in the formation of [Formula: see text] particles, these b(-) c(-) d(-) cells were grown or incubated with Ca(2+), Mg(2+), or putrescine. The presence of Ca(2+) resulted in the appearance of many [Formula: see text] particles and [Formula: see text] pits. Mg(2+) and putrescine were less effective than Ca(2+). Introduction of these particles was not accompanied by alterations in the relative amounts of LPS and cell envelope proteins. Ca(2+) treatment of a heptoseless derivative of a b(-) c(-) d(-) strain did not result in morphological changes. Incubation of Ca(2+)-treated cells with ethylenediaminetetraacetate caused the disappearance of the introduced particles as well as the release of more than 60% of the cellular LPS. These results strongly support the hypothesis that LPS is involved in the formation of [Formula: see text] particles and [Formula: see text] pits. The roles of various outer membrane proteins in the formation of [Formula: see text] particles were studied by comparing the freeze-fracture morphology of b(-) c(-) d(-) cells with that of cells which contain one of the outer membrane proteins b, c, d, and e or the receptor protein for bacteriophage lambda. The results showed that the presence of any of these five proteins in a b(-) c(-) d(-) background resulted in a large increase in the number of [Formula: see text] particles and [Formula: see text] pits, indicating that these proteins are, independent of each other, involved in the formation of [Formula: see text] particles and [Formula: see text] pits. The simplest explanation for the results is that in wild-type cells each particle consists of LPS complexed with some molecules of a single protein species, stabilized by either divalent cations or polyamines. It is hypothesized that the outer membrane of the wild-type cell contains a heterogeneous population of particles, of which 75% consists of protein b-LPS, protein c-LPS, and protein d-LPS particles. A function of these particles as aqueous pores is proposed.     

CROSS-SECTIONAL ECHOCARDIOGRAPHIC FINDINGS IN VEGETATIVE AORTIC VALVE ENDOCARDITIS

M-mode echocardiograms of two patients with bacterial endocarditis of approximately 4 months' duration showed dense echoes in the area of the aortic valve. In one patient, who had no prior abnormal cardiac findings, the echoes were clearly suggestive of valvular vegetations. The second patient, however, was known to have had aortic valve disease and a systolic murmur for more than a decade; therefore, dense echoes arising from the aortic valve also could have resulted from valvular calcification. In both patients, cross-sectional echocardiography provided important information. In the first patient, retrograde cardiac catheterization was prevented by large and highly mobile masses attached to the aortic cusps that prolapsed into the left ventricular outflow tract during diastole. Aortic valve replacement without further hemodynamic evaluation was recommended. In the second patient, whose blood cultures remained negative after the acute phase of his illness had been treated, cross-sectional echocardiography showed large vegetations on the aortic valve. Intraoperative findings confirmed the echocardiographic interpretation in each case.     

The interaction of phenylglyoxal with soluble and membrane-bound chloroplast coupling factor 1

The rate of inhibition of cyclic photophosphorylation in chloroplast thylakoids by the arginine reagent phenylglyoxal was enhanced in the light, i.e., under conditions where membrane energization occurred. Uncouplers, but not energy-transfer inhibitors, prevented the effect of light. Chemical modification of chloroplast thylakoids by phenylglyoxal under dark or in light conditions affected differently the light-induced exchange of tightly bound ADP. In both cases the exchange was less inhibited than photophosphorylation. Complete inhibition of ATPase activity of soluble CF₁ was correlated with the incorporation of 8 mol [¹⁴C]phenylglyoxal per mol enzyme. About 50% of the incorporated radioactivity was lost at different rates depending on the buffer present and suggesting a change in the stoichiometry of the adduct from 2:1 to 1:1. Inhibition of ATPase and photophosphorylating activities of chloroplasts by modification with [¹⁴C]phenylglyoxal in the dark was associated with the incorporation of 1 and 2 mol reagent per mol membrane-bound CF₁, respectively. In the light the rate of incorporation was enhanced and both reactions were inactivated when 2 mol $\text{[}{}^{14}\text{C]phenylglyoxal}\text{CF}{}_1$ were bound. In all the labelling experiments the radioactivity was mainly recovered from the α- and β-subunits.     

Investigation of human erythrocyte ghost membranes with intramolecular excimer probes

Human erythrocyte ghost membranes have been investigated using two intramolecular excimer probes, di(1-pyrenyl)propane and di(1-pyrenylmethyl) ether. Values for the viscosity of the direct probe environment in the ghost membranes range from 76 cP at 37°C to 570 cP at 5°C, as reported for di(1-pyrenyl)propane, with liquid paraffin as the reference solvent. For the activation energy of the excimer formation process, determined here mainly by the viscosity of the medium, a value of 37 kJ/mol is obtained. The other probe molecule reports a higher local viscosity, 133 cP at 37°C, as well as a higher activation energy of excimer formation, 54 kJ/mol. Neither thermotropic phase transitions nor temperature hysteresis effects are observed within the temperature range (0 to 40°C) studied. From the vibrational structure of the fluorescence spectrum of di(1-pyrenylmethyl) ether, a polarity of the probe environment close to that of hexanol ($\text{? = 13.3}$) results for the erythrocyte ghost membranes. The polarity measured in egg phosphatidylcholine membranes and in multibilayers of dimyristoylphosphatidylcholine is slightly larger, comparable to that of butanol ($\text{? = 17.5}$), whereas a polarity comparable to that of methanol ($\text{? = 32.7}$) is observed for aqueous micellar solutions of sodium dodecyl sulphate. Further, from the wavelength shifts in the absorption spectrum of di(1-pyrenyl)propane and di(1-pyrenylmethyl) ether, the polarizability of the probe surroundings can be determined, leading to a surprisingly high value for the apparent refractive index. This is attributed to a high local density of the direct environment of the probe, for which a location between the membrane/water interface and the unpolar bilayer mid-plane is deduced.     

Studies on the adenosine 3′,5′-monophosphate-dependent protein kinase of Blastocladiella emersonii

Using a combination of Chromatographic and sucrose density gradient techniques under carefully controlled conditions of pH and protease inhibitors, we demonstrate that there is only one form of adenosine 3′,5′-monophosphate-dependent protein kinase in the cytosol fraction of the Blastocladiella emersonii zoospore. If any of these conditions are omitted during extract preparation, one obtains what are apparently multiple forms of the enzyme, which are in reality artifacts due to extensive endogenous proteolytic activity. This endogenous protease is stimulated by alkaline pH and inhibited by antipain. The zoospore protein kinase is similar to type II protein kinase from mammalian cells in several aspects including Chromatographic behavior on DEAE-cellulose column, conditions for subunit dissociation and reassociation, as well as the molecular weight value of the regulatory subunit.     

Separation and identification of O-acetyl-O-methyl-galactononitriles by gas-liquid chromatography and mass spectrometry

The gas-liquid-chromatographic retention-times and the mass-spectral features of partially methylated d-galactononitrile acetates are reported. Distinctive fragmentation of each of the mono-O-methyl derivatives allows their identification, and the results are applicable to the same substituted derivatives of the other aldohexoses. A new fragmentation-pathway, typical of the acetylated and the O-acetyl-O-methylaldononitriles, is proposed in order to justify previously unexplained fragments. This fragmentation competes with the known ones in derivatives that do not carry vicinal methoxyl groups.     

Burrowing beetles of the genus Bledius (Staphylinidae) as agents of bioturbation in the emergent areas and shores of an athalassic inland lake (Fuente de Piedra,southern of Spain)

Bledius (Elbidus) bicornis (Germ.) and B. (Eucerotobledius) furcatus (Oliv.) (Coleoptera: Staphylinidae) are the most important burrowing species in the emergent areas and shores in the athalassic lake of Fuente de Piedra (Málaga, S. of Spain). A first estimate of the importance of these organisms in this system is presented. These insects kick out sediment during their burrowing activity, which accumulates on the surface near the burrows as tumuli which can be easily eroded. The lake perimeter (17 km) is densely colonized (usual densities from 1700 to 2500 ind m⁻²). The amount of granulated material that can be potentially kicked out was 46.22 g dry wt m⁻² day⁻¹. At the same time, the material that constitutes the tumuli shows different characteristics from the compact ground below the surface. Thus, it is relatively enriched with organic matter (6.15 g per square meter), soluble phosphate (406.5 μg m⁻²) and ammonium (4856 μg m⁻²), whereas it lacks nitrate. Results of a transect from uninhabited areas to zones of maximum population density also show a similarity between the higher ground level of ammonium and phosphate concentrations and population density.     

Influence of temperature and salinity on carbon and nitrogen content in Dunaliella viridis teodoresco under nitrogen sufficiency

Cell carbon and nitrogen in D. viridis are strongly dependent on the culturing conditions. Both elements increase with increasing salinity. At 31°C cell carbon is maximum and cell nitrogen minimum. This temperature was described previously (Jiménez, C., Niell, F. X. & Fernandez, J. A. (1990). Hydrobiologia, 197, 165-72) as the optimal one for achieving the maximum oxygen evolution. These results point out a possible competence for the reducing power during carbon and nitrogen assimilation processes, and under conditions of high photosynthesis (carbon assimilation) there is a partial inhibition of nitrate reduction, making C:N ratio maximum under conditions of maximum net photosynthesis.The study of cell glycerol, nitrate, structural proteins and free amino acids indicates that all of these solutes accumulate in the cells as a result of the high salinity adaptation.