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Our study was done to determine the hydrodynamics of pyelorenal reflux. It is considered important in the pathophysiology of chronic pyelonephritis. An animal model of pyelorenal reflux was studied. The model seems to approximate closely the findings in man, both in the pressure required and the types of pyelorenal reflux observed.
Proteins L1, L9, L25, and L30, purified by a nondenaturing method from the 50S ribosomal subunit of Escherichia coli A19, have been characterized. The four proteins were studied under conditions which resemble those used for reconstitution experiments. These proteins have S020,W values of 2.0 S, 1.8 S, 1.8 S, and 1.0 S and D20,W values of 8.4 X 10(-7), 9.0 X 10(-7), 14.0 X 10(-7), and 15.0 X 10(-7) cm2/S. Apparent specific volumes at 20 degrees C are 0.738, 0.733, 0.700, and 0.735 mL/g for the four proteins. The respective molecular weights determined by sedimentation equilibrium are 25 000, 17 300, 12 000, and 6500. The intrinsic viscosity values for the four proteins are 4.0, 5.5, 3.6, and 3.2 mL/g. From these hydrodynamic parameters L1 and L9 appear to have globular or at most only slightly elongated shapes, whereas L25 and L30 appear to be definitely globular.
Intrinsic viscosities and sedimentation coefficients have been measured as a function of molecular weight for poly(gamma-hydroxy-L-proline) in water. The molecular weight range covered is 9,000-35,000. High molecular weight poly(gamma-hydroxy-L-proline) in water has the hydrodynamic behavior of a random coil immersed in a good solvent, as judged by d ln [eta]/d ln M, d ln so/d ln M, dbeta/dM, and the size of beta[= nu rho (-1)]/1/3etaM-2/3(1 - nurho)-1]. The characteristic ratio, ((r2)o/nplp2) infinity, is found to be 15.9 +/- 1.6, which is not significantly different from the result of 13.7 +/- 0.9 obtained for poly(L-proline) by Mattice and Mandelkern under the same conditions. This observation casts doubt on the importance of intrachain hydrogen bonded bridges from the hydroxyl group to a carbonyl oxygen via a water molecule. The characteristic ratios and the effects of calcium chloride on the hydroynamic properties suggest that poly(L-proline) and poly(gamma-hydroxy-L-proline) possess a similar source of flexibility which is often overlooked. Two possibilities for this flexibility are a second energy minimum about the Calpha-C' bond and cis-trans isomerization about the peptide bond.
The hydrodynamic changes which accompany the dissociation of metal ions, from concanavalin A at acid pH are a result of charge effects rather than of dissociation of metal ions as such. Measurements of the rotational relaxation time are discussed in terms of the hydration of the protein and its polymeric heterogeneity.
Treatment of glycogen with 2-mercaptoethanol and iodoacetamide gives rise to a modified glycogen which resembles the original glycogen in its hydrodynamic behaviour but has a pronounced tendency to aggregate. The modified glycogen can be distinguished easily, by its diffusion coefficient, from glycogen degraded by more traditional methods of extraction. The 'fundamental' glycogen particle appears to be composed of two or three glycogen beta-particles linked by a single protein chain.
Quasi-elastic light scattering and sedimentation velocity methods were used to study the hydrodynamic properties of purified dimer subunits obtained from partial digestion of chicken erythrocyte chromatin with staphylococcal nuclease. The experimental value of 1.87 +/- 0.08 X 10(-7) gram per second for the friction factor of these dimer subunits in low ionic strength buffer cannot be reasonably interpreted in terms of a contiguous sphere model. Analysis by means of an equivalent dimer method suggests that the spacer region accounts for a maximum of 19 percent of the friction properties of the dimer.
With the use of the pulse duplicator built in our laboratory, the hydrodynamic characteristics of three sizes of the four commercially available mitral bioprostheses, Hancock, Carpentier-Edwards, Angell-Shiley, and Ionescu-Shiley, were studied and compared. A wide range of performance was found: for example, during pulsatile testing, at peak flow of 15 1/min (corresonding to a normal resting cardiac output) transvalvular gradients varied from as high as 20 mm Hg (Angell-Shiley) to 5 mm Hg(Ionescu-Shiley) in the 25 mm mounting diameter size. Effective orifice areas (EOA) are significantly different in valves of the same mounting size, e.g., at peak flows of 20 1/min, the Ionescu-Shiley 25 provides an EOA of 1.7 cm2 while the Angell-Shiley provides only 1.17 cm2. The EOAs of all bioprostheses have been found to increase with increasing flow (e.g., from 10--30 1/min peak flow, the Hancock 25 changed from 1.25 cm2 to 1.50 cm2). The Gorlin formula, as constituted for calculating the area of stenotic mitral valves, is inappropriate for prosthetic valves. But the discharge coefficients of the bioprostheses have been found to be around 1 when the planimetered area of the open valve orifice is determined at a given flow. By using this discharge coefficient, the Gorlin formula will give an excellent estimate of the true orifice area of mitral bioprostheses.
By animal experiments and clinically we could prove that isoglaucon instillation caused the decrease in IOP due to both increase in outflow and reduction of humor secretion; the IOP decrease and changes in hydrodynamics being manifested more markedly in the fellow-eye. As reoophthalmography demonstrated "Isoglaucon" produced lumen narrowing in the anterior portion of the uveal tract. "Isoglaucon" was prescribed to 20 patients having open-angle-glaucoma, Two hours after instillation the 23 decreased in 26 eyes (of 28) by 9.3 +/- 1.0 mm Hg. When prescribed regularly "Isoglaucon" raised the outflow facility coefficient from 0.10 +/- 0.01 to 0.20 +/-0.02. The secretion decreased from 2.0 +/- 0.2 to 0.9 +/- 0.15. Thus, IOP decrease after "Isoglaucon" is accounted for by both improved outflow and reduction of aqueous humor secretion. The "isoglucon" instillation produced a rather moderate decrease in the total arterial pressure, though no expected parallelism in arterial and intraocular pressure was marked.
DNase A studied by gel filtration on Sephadex G-100 at pH 7.4 in 40 mM Tris-HCl buffer, behaves hydrodynamically as a spherical monomeric macromolecule of around 31,000 molecular weight, with a Stokes radius = 24.7 A, f/fo = 1.19, and D20,W = 8.69. Similar results were obtained by analytical dialysis using zinc chloride-modified cellophane membranes. The elution volume of DNase A decreases as the pH increases between pH 4.7 and pH 9.5. This effect has been attributed to a change in the tridimensional structure of the protein and interpreted as a modification in the axial ratio due to unfolding of the polypeptide chain with increase in the apparent Stokes radius. The addition of Ca2+ produce reversion of the pH-induced changes at pH 9.5. The transition occurs when Ca2+ binds to at least two binding sites (n = 1.66 in a Hill plot) with a Kd = 8.9 X 10(-5) M and the effect appears to be cooperative. These findings support the hypothesis that Ca2+-binding to DNase A causes a conformational change that maintains a more active structure of the enzyme, especially when the pH-induced unfolding reduces its activity.
The effect of proteolytic activation on the tonographic indices and secretion of the aqueous humor was studied. It was found that active peptides rise the secretion of intraocular fluids increasing the permeability of capillary plexuses and decreasing the metabolic processes in the structures secreting the aqueous. They may perticipate in haemodynamic and hydrodynamic intraocular autoregulation.
The structure of ribosomal 5 S RNA has been examined using several physical biochemical techniques. Hydrodynamic measurements yield a s020,omega and [eta] of 5.5 x 10(-13) x and 6.9 ml/g, respectively. Other parameters calculated from these values indicate the shape of 5 S RNA is consistent with that of a prolate ellipsoid 160 A in length and 32 A wide. Sedimentation equilibrium results show that 5 S RNA exists as a monomer in the reconstitution buffer with an apparent molecular weight of 44,000. Ultraviolet absorption difference spectra show that approximately 75% of the bases in 5 S RNA are involved in base pairing, and of these base pairs 70% are G-C and 30% are A-U. These results on the overall shape and secondary structure of 5 S RNA have been incorporated with the results of other investigators as to the possible location of single-stranded and double-stranded helical regions, and a molecular model for 5 S RNA is proposed. The molecular model consists of three double helices in the shape of a prolate ellipsoid, with two of the double helical regions at one end of the molecule. The structure is consistent with the available data on the structure and function of 5 S RNA and bears similarity to the molecular model proposed by Osterberg et al. ((1976) Eur. J. Biochem. 68, 481-487) based on small angle x-ray scattering results and the secondary structure proposed by Madison ((1968) Annu. Rev. Biochem. 37, 131-148).
The results of experimental studies of hydrodynamics in acute drainage are described. Four series of experiments were carried on a transparent model filled with a liquid. The authors have revealed the phenomenon of dyraulic "strokes" which promote mechanical purification of the cavity from the purulent content. It has been established that a running-water fractional regimen of washing should be used for the cavities of more than 15--20 cm3 volume.
The biophysical and technical base as well as clinical applications of a new functional diagnostic system of sinus frontalis disorders are described. The system consists of a ventilation test and the so called "resistometry". The principle of the resistometry is the generation of a fluid flow in the frontal sinus duct system by a pressure regulated injector, the measurement and registration of flow and pressure and the calculation of the hydrodynamic resistance of the duct system. The resistance is determined in "Resistance Units" (RU). The possibilities of the proposed diagnostic system in differential diagnosis are shown in 156 cases. Apart from the quantitative assessment of the classical inflammations of the frontal sinus the functional diseases of the duct system may be discriminated with certainity.
There is no general agreement on the size and shape of the fibrinogen molecule. We have studied the diffusion of the fibrinogen in solution by means of dynamic light scattering, nanosecond fluorescence depolarization and analytical ultracentrifugation. The results obtained under physiological concentration, pH an ionic strength are DT = 2.0 X 10(7) cm2sec-1, DR perpendicular = 40'000 sec 1. Nanosecond fluorescence depolarization yielded DR parallel = 1.6 x 10(6) sec-1. Tentatively this value is interpreted as DR parallel, namely rotational diffusion about the major axis of the molecule. The sedimentation coefficient is 8.1 S. The hydrodynamic parameters derived from our measurements were compared with those calculated on the basis of the models proposed by Hall and Slayter, Hudry-Clergeon and Marguerie et al., Bachmann and Lederer, and Köppel. The agreement is poor even if the degree of hydration is varied within wide limits. However, satisfactory agreement can be achieved by assuming a flexible molecule of about 900 A length corresponding to two end-to-end bound trinodular structures of the Hall and Slayter type, with a nodule diameter of about 45 A. Experimental evidence indicates that the discrepancies between the different models might be due to different techniques of sample preparation leading to different conformations of the molecule.
We have investigated the association of non-tubulin microtubule proteins with tubulin to form the ring-shaped oligomeric structures found in microtubule preparations. We have found that the two oligomeric species present in our preparations of microtubule protein (s020,w = 18 and 30 S) each require non-tubulin factors for their formation. Two types of non-tubulin protein, the high molecular weight proteins (HMW) and the tau proteins were found to be active in ring formation. The HMW proteins promoted the formation of the 30 S oligomer, while the tau proteins promoted the formation of an oligomer of s020,w = 20 S. Analysis of the 30 S oligomer by gel filtration chromatography showed that the ratio of HMW proteins to tubulin was about twice that in the microtubule. The HMW proteins could be destroyed by exposure to trypsin, resulting in a marked increase in the sedimentation coefficient of the 30 S oligomer to 39 S. The 20, 30, and 39 S species were identified as rings by electron microscopy. The identity of the 18 S structure as a ring was called into question. Our data indicate that the 20 S species is a single ring and that the 30 S oligomer is a two-layered ring bearing HMW projections which contribute substantial hydrodynamic drag to the particle. We compare the organization of tubulin subunits and HMW molecules in the 30 S ring with the organization of these components in the microtubule and suggest that the organization in the ring is conserved in the microtubule.
Problems arising in devising the assisted circulation apparatus and artificial heart can be solved only with investigations conducted on hydrodynamic models of the circulation system--the stands. An analysis of literature sources dealing with test stands justifies their classification according to the purpose, the types of tests, the specific structure and basic characteristics. It is necessary to proceed with further improvement of the stand equipment in the direction of creating a sufficiently accurate imitation of the anatomic structure and resilient properties of major arteries and veins, of constructing a geometrical and elastic model of the aorta, of pressure and flow control instruments at different points of the vessels, of the ones regulating the energy parameters, as well as of working out criteria for effectiveness of the devices to be used.
A comparative hydrodynamic study of artificial heart valves with spherical, hemispherical and lentil-shaped obturative elements has been carried out under the non-stationary conditions. The valves resistance coefficient is higher in the lentil-shaped valves. With the increase of pulse rate the stroke volume of the valves of all the types drops, and the regurgitation increases.
In this text, we describe a new protein spinning process called hydrodynamic process. Parameters which are related to production of fibers and which can influence diameter and texture are explained extensively. In this process, a spinning dope is extruded through a spinnerette in a moving coagulation bath in which the fibers are coagulated, stretched and carried.