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Post-extractional implants and immediate loading protocols are becoming much more frequent in everyday clinical practice. Given the existing literature about tapered implants, the objective of this paper was to understand whether implant shape had a direct influence on the results of the insertion torque (IT) and implant stability quotient (ISQ). Seven tapered implant prototypes were developed and distributed into three groups and compared with a control cylindrical implant-VEGA by Klockner Implant System. The implants were inserted into bovine bone type III according to Lekholm and Zarb Classification. The sample size was n = 30 for the three groups. Final IT was measured with a torquemeter, and the ISQ was measured with Penguin Resonance Frequency Analysis (RFA). Modifications done to the Prototype I did not reveal higher values of the ISQ and IT when compared to VEGA. In the second group, when comparing the five prototypes (II-VI) with VEGA, it was seen that the values of the ISQ and IT were not always higher, but there were two values of the ISQ that were statistically significantly higher with the 4.0 mm diameter Prototypes II (76.3 ± 6.1) and IV (78 ± 3.7). Prototype VII was the one with higher and significant values of the ISQ and IT. In both diameters and in both variables, all differences were statistically significant enough to achieve the higher values of primary stability values (IT and ISQ). Given the limitations of this study, it can be concluded that when there is an increase of the diameter of the implant and body taper, there is an increase of the ISQ and IT, showing that the diameter of the implant is an important criteria to obtain higher values of primary stability.

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Several dental implants are commercially available and new prototype design are constantly being fabricated. Nevertheless, it is still unclear what parameters of the design affect most the osseointegration of dental implants. The purpose of this study is to assess the effects of the microscopic and macroscopic design of dental implants in the osseointegration by comparing three macroscopic designs (Straumann tissue level (STD), essential cone (ECD) and prototype design (PD)) and six surface treatments. A total of 96 implants were placed in 12 minipigs. The implant stability quotient (ISQ), was assessed at the time of implantation, as well as at 2, 4 and 8 weeks. Histomorphometric and statistical analyses were conducted at the different sacrifice times, being 2, 4 and 8 weeks, to analyse the bone to implant contact (BIC), the bone area density (BAT) and the density of bone outside the thread region (ROI). The macroscopic design results showed higher ISQ values for the ECD, whereas the histomorphometric analysis showed higher ossoeintegration values for the STD. Regarding the microscopic design, both Sandblasted plus acid etching (hydrochloric/sulphuric acid) in a nitrogen atmosphere (SLActive) and Shot-blasted or bombarded with alumina particles and posterior alkaline immersion and thermal treatment (ContacTi) showed superior results in terms of osseointegration and reduced the osseointegration times from 8 weeks to 4 weeks compared to the other analysed surfaces. In conclusion, each of the macroscopic and microscopic designs need to be taken into account when designing novel dental implants to enhance the osseointegration process.

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Por diversos factores el dengue ha devenido enfermedad reemergente en el hemisferio occidental y está presente prácticamente en toda la región de América Latina y el Caribe, afectando a más de un millón de personas anualmente de dengue Clásico y dengue Hemorrágico. Cuba ha sufrido varios brotes epidémicos de esta enfermedad y cada vez son más frecuentes... (AU)

Dengue has given rise to reemergent disease due to different factors in the eastern hemisphere and is practically spread in all the Latin America and Caribbean regions, affecting over a million people annually with classic dengue and hemorragic dengue. Cuba has had several epidemic outbreaks of this disease and everytime they become more frequent..(AU)

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In Bacillus subtilis, mutant alleles of the genes sms and subA partially suppress the recombination phenotype of recU cells. When present in an otherwise Rec(+) strain, Delta sms and Delta subA alleles render cells slightly sensitive to DNA-damaging agents, and impair chromosomal transformation (3- to 10-fold reduction), but do not affect plasmid transformation (less than 1.5-fold reduction). The Delta sms and Delta subA alleles were introduced into rec-deficient strains representative of the epistatic groups alpha (recF strain), beta (addA addB), gamma (recH), epsilon (recB, Delta recU and recD strains) and zeta (Delta recS). Both the Delta sms and Delta subA mutations were found to increase sensitivity to DNA-damaging agents in recF, Delta recS and addAB cells. In contrast, the Delta sms mutations decreased the sensitivity of recB, Delta recU, recD and recH cells, and the Delta subA mutation decreased the sensitivity of recB and Delta recU cells to DNA-damaging agents. Functions classified within the epistatic groups alpha, epsilon and zeta are required for intramolecular recombination, measured as plasmid transformation. The Delta sms and Delta subA mutations, which partially suppressed the recombinational repair phenotype of mutants for functions within epistatic group epsilon, enhanced plasmid transformation of recU (recB, recD) and recS cells by 10- to 20-fold. In the absence of the proteins Sms and SubA, the recombination machinery is apparently redirected towards (an) alternative pathway(s). Furthermore, the shared ability of the Delta sms and Delta subA mutations to act as indirect suppressors of recB, recU and recD mutations supports the classification of the recBUD genes within epistatic group epsilon.

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A procedure is devised for the calculation of hydrodynamic properties of rigid macromolecules composed subunits that are modeled as ellipsoids of revolution and cylinders. Owing to the axial symmetry of these shapes, smooth shell models can be constructured for the subunit structure. The bead shell model so constructed is employed for the calculation of the properties. A computer program, HYDROSUB, has been written implementing both the model building and the hydrodynamic calculation. A detailed example of the use of this methodology is presented for the case of the solution properties of the human antibody molecule immunoglobulin G3 (IgG3). Finally, hints are given on other uses and applications of the procedure.

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The B. subtilis DeltahelD allele rendered cells proficient in transformational recombination and moderately sensitive to methyl methanesulfonate when present in an otherwise Rec(+) strain. The DeltahelD allele was introduced into rec-deficient strains representative of the alpha (recF strain), beta (addA addB), gamma (recH), epsilon (DeltarecU), and zeta (DeltarecS) epistatic groups. The DeltahelD mutation increased the sensitivity to DNA-damaging agents of addAB, DeltarecU, and DeltarecS cells, did not affect the survival of recH cells, and decreased the sensitivity of recF cells. DeltahelD also partially suppressed the DNA repair phenotype of other mutations classified within the alpha epistatic group, namely the recL, DeltarecO, and recR mutations. The DeltahelD allele marginally reduced plasmid transformation (three- to sevenfold) of mutations classified within the alpha, beta, and gamma epistatic groups. Altogether, these data indicate that the loss of helicase IV might stabilize recombination repair intermediates formed in the absence of recFLOR and render recFLOR, addAB, and recH cells impaired in plasmid transformation.

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CASE REPORT: A 68 year old woman developed a sudden decrease in her visual acuity in both eyes with several central scotomas. Funduscopy demonstrated a motted alteration of the retinal pigment epithelium in both maculae. The fluorescein angiography showed a choroidal ischemia at the macular level in both eyes. DISCUSSION: The patient was diagnosed of acute macular neuroretinopathy. This entity is included among the so-called <>. However, it is important to determine which of these diseases each patient suffers in order to determine if treatment is necessary, the visual prognosis and the possibility of recurrences.

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CASE REPORT: The case of a 63 year old woman presenting fibrous subretinal lesions in the posterior pole on a routine ocular fundus check up is reported. The angiographic study showed a choroidal origin window defect next to hypofluorescence areas. The patient did not complain of vision loss or scotomas at any time. DISCUSSION: This clinical picture could be classified as a progressive subretinal fibrosis syndrome with atypical features. However, a differential diagnosis with other choroidal inflammatory conditions should be carried out even though many authors may consider them as different developmental phases of the same entity.

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Caso clínico: Mujer de 68 años que bruscamente comenzó a notar escotomas en el campo visual central de ambos ojos con pérdida leve de la agudeza visual (AV), presentando en la biomicroscopia de polo posterior (BPP) una alteración moteada de epitelio pigmentario de la retina a nivel macular que, angiográficamente, se traducía como una isquemia coroidea macular bilateral. Discusión: Se realizó el diagnóstico de neuro-retinopatía macular aguda. Este cuadro se encuentra entre los genéricamente denominados 'síndromes de manchas blancas'. Es importante, no obstante, reconocer a cuál de ellos pertenece el cuadro clínico para saber si existe o no necesidad de tratamiento, el pronóstico visual y la posibilidad de recidivas (AU)

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There is a striking disparity between the heart-shaped structure of human serum albumin (HSA) observed in single crystals and the elongated ellipsoid model used for decades to interpret the protein solution hydrodynamics at neutral pH. These two contrasting views could be reconciled if the protein were flexible enough to change its conformation in solution from that found in the crystal. To investigate this possibility we recorded the rotational motions in real time of an erythrosin-bovine serum albumin complex (Er-BSA) over an extended time range, using phosphorescence depolarization techniques. These measurements are consistent with the absence of independent motions of large protein segments in solution, in the time range from nanoseconds to fractions of milliseconds, and give a single rotational correlation time phi(BSA, 1 cP, 20 degrees C) = 40 +/- 2 ns. In addition, we report a detailed analysis of the protein hydrodynamics based on two bead-modeling methods. In the first, BSA was modeled as a triangular prismatic shell with optimized dimensions of 84 x 84 x 84 x 31.5 A, whereas in the second, the atomic-level structure of HSA obtained from crystallographic data was used to build a much more refined rough-shell model. In both cases, the predicted and experimental rotational diffusion rate and other hydrodynamic parameters were in good agreement. Therefore, the overall conformation in neutral solution of BSA, as of HSA, should be rigid, in the sense indicated above, and very similar to the heart-shaped structure observed in HSA crystals.

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Caso Clínico: Mujer de 63 años de edad, a la que en una revisión rutinaria se le apreciaron en el fondo de ojo lesiones subretinianas de aspecto fibrosocicatricial. Angiográficamente se informó de defectos de transmisión de origen coroideo junto a áreas de hipofluorescencia. La paciente no refirió haber tenido nunca ni disminución de la agudeza visual ni escotomas. Discusión: Este cuadro podría clasificarse como síndrome de fibrosis subretiniana progresiva con características atípicas. No obstante, es obligatorio realizar diagnóstico diferencial con otros cuadros inflamatorios coroideos; aunque para muchos autores podrían ser la misma entidad en diferentes estadios evolutivos (AU)

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A modified ELISA assay was used to detect IgG binding to silicone and IgG subtypes in serum of patients bearing silicone bands, silicone sponges and intraocular silicone oil. Presence of autoantibodies (rheumatoid factor, antinuclear antibody, and SCL 70) and signs and symptoms of autoimmune diseases were also checked. Antisilicone antibodies were detected in 35.7% of patients with solid silicone and in 83% in those with silicone oil. This increase in IgG is mainly due to IgG1. Nevertheless no positive results were found in detecting signs and symptoms of autoimmune diseases.

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Hydrodynamic methods provide a route for studying the low-resolution conformation--in terms of time-averaged spatial orientation of the Fab' and Fc domains relative to each other--of the human IgG subclasses, IgG1, IgG2, IgG3 and IgG4 in the environment in which many exist naturally---a solution. Representative modelling strategies are now available using 'shell-bead' or 'shell' modelling of the surface of the molecules with the size-independent programme SOLPRO [J. Garcia de la Torre, S.E. Harding, B. Carrasco, Eur. Biophys. J. 28 (1999) 119-132]. The shell model fits to the equivalent inertial surface ellipsoids of the published crystal structures for the Fab' and Fc domains of IgG are made and an apparent hydration delta(app) of 0.51g/g for Fab' and 0.70 g/g for the glycoprotein Fc are obtained, which yield an average value of (0.59+/-0.07) g/g for the intact antibody (2 Fab'+1 Fc). The relative orientations of these domains for each of the IgG subclasses is then found (using where appropriate a cylindrical hinge) from SOLPRO by modelling the Perrin function, P (i.e. 'frictional ratio due to shape') using this delta(app) and experimentally measured sedimentation coefficients. All the IgG subclasses appear as open, rather than compact structures with the degree of openness IgG3>IgG1>(IgG2, IgG4), with IgG3 and IgG1 non-coplanar. The hingeless mutant IgGMcg, with s degrees (20,w) approximately 6.8 S yields a coplanar structure rather similar to IgG2 and IgG4 and consistent with its crystallographic structure. The extension of this procedure for representing solution conformations of other antibody classes and other multi-domain proteins is indicated.

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The heteronuclear NMR relaxation of globular proteins depends on the anisotropic rotational diffusion tensor. Using our previous developments for prediction of hydrodynamic properties of arbitrarily shaped particles, by means of bead models, we have constructed a computational procedure to calculate the rotational diffusion tensor and other properties of proteins from their detailed, atomic-level structure. From the atomic coordinates file used to build the bead model, the orientation of the pertinent dipoles can be extracted and combined with the hydrodynamic information to predict, for each residue in the protein, the relaxation times. All of these developments have been implemented in a computer program, HYDRONMR, which will be of public domain.

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The solution properties, including hydrodynamic quantities and the radius of gyration, of globular proteins are calculated from their detailed, atomic-level structure, using bead-modeling methodologies described in our previous article (, Biophys. J. 76:3044-3057). We review how this goal has been pursued by other authors in the past. Our procedure starts from a list of atomic coordinates, from which we build a primary hydrodynamic model by replacing nonhydrogen atoms with spherical elements of some fixed radius. The resulting particle, consisting of overlapping spheres, is in turn represented by a shell model treated as described in our previous work. We have applied this procedure to a set of 13 proteins. For each protein, the atomic element radius is adjusted, to fit all of the hydrodynamic properties, taking values close to 3 A, with deviations that fall within the error of experimental data. Some differences are found in the atomic element radius found for each protein, which can be explained in terms of protein hydration. A computational shortcut makes the procedure feasible, even in personal computers. All of the model-building and calculations are carried out with a HYDROPRO public-domain computer program.

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Caso clínico: Se presenta la evolución, complicaciones y resultado funcional de un paciente varón de 21 años con retinopatía diabética, hemofilia tipo A e infección por VIH cuyo tratamiento se demoró por las alteraciones sistémicas asociadas. Discusión: El riesgo de desarrollar complicaciones no debe demorar la aplicación del tratamiento de la retinopatía diabética en pacientes hemofílicos con infección por VIH (AU)

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CASE REPORT: We report the evolution, complications and functional results of a 21-year-old patient with diabetic retinopathy, haemophilia and HIV+. DISCUSSION: The risk of developing complications should not delay the treatment in diabetic retinopathy patients with haemophilia and HIV+.

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The proliferation of hydrodynamic modeling strategies to represent the shape of quasirigid macromolecules in solution has been hampered by ambiguities caused by size. Universal shape parameters, independent of size, developed originally for ellipsoid modeling, are now available for modeling using the bead-shell approximation via the algorithm SOLPRO. This paper validates such a "size-independent" bead-shell approach by comparison with the exact hydrodynamics of 1) an ellipsoid of revolution and 2) a general triaxial ellipsoid (semiaxial ratios a/b, b/c) based on a fit using the routine ELLIPSE (. J. Mol. Graph. 1:30-38) to the chimeric (human/mouse) IgG Fab' B72.3; a similar fit is obtained for other Fabs. Size-independent application of the bead-shell approximation yields errors of only approximately 1% in frictional ratio based shape functions and approximately 3% in the radius of gyration. With the viscosity increment, errors have been reduced to approximately 3%, representing a significant improvement on earlier procedures. Combination of the Perrin frictional ratio function with the experimentally measured sedimentation coefficient for the same Fab' from B72.3 yields an estimate for the molecular hydration of the Fab' fragment of approximately (0.43 +/- 0.07) g/g. This value is compared to values obtained in a similar way for deoxyhemoglobin (0.44) and ribonuclease (0.27). The application of SOLPRO to the shape analysis of more complex macromolecules is indicated, and we encourage such size-independent strategies. The utility of modern sedimentation data analysis software such as SVEDBERG, DCDT, LAMM, and MSTAR is also clearly demonstrated.

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For the calculation of hydrodynamic properties of rigid macromolecules using bead modelling, models with overlapping beads of different sizes are used in some applications. The hydrodynamic interaction tensor between unequal overlapping beads is unknown, and an oversimplified treatment with the Oseen tensor may introduce important errors. Here we discuss some aspects of the overlapping problem, and explore an ad hoc form of the interaction tensor, proposed by Zipper and Durchschlag. We carry out a systematic numerical study of the hydrodynamic properties of a two-spheres model, showing how the Zipper-Durchschlag correction removes efficiently the numerical instabilities, and predicts the correct limits.

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