Structure of fibrin gels studied by elastic light scattering techniques: dependence of fractal dimension, gel crossover length, fiber diameter, and fiber density on monomer concentration.

The concentration dependence of the structure of fibrin gels, formed following fibrinogen activation by thrombin at a constant molar ratio, was investigated by means of elastic light scattering techniques. The scattered intensity distributions were measured in absolute units over a wave-vector range q of about three decades ( approximately 3x10(2)-3x10(5) cm(-1)). A set of gel-characterizing parameters were recovered by accurately fitting the data with a single function recently developed by us [F.

Repair of collateral ligament instability in 2 foals by using suture anchors.

Instability of the collateral ligaments of the carpal or metacarpophalangeal joint occurred in 2 foals. The instability was repaired using commercial suture anchors. In foals, commercial suture anchors combined with external coaptation can be used successfully to repair collateral ligament instability of the carpus or the metacarpophalangeal joint.

Growth kinetics and structure of fibrin gels.

The structure and kinetics of fibrin gels grown from fibrinogen solutions under quasiphysiological conditions, but in absence of Ca++, were investigated by means of elastic light scattering. By combining classical light scattering and low-angle elastic light scattering, an overall wave-vector range of about three decades was spanned, from q approximately 3 x 10(2) to q approximately 3 x 10(5) cm(-1). The scattered intensity distribution of the gels was measured in absolute units and fitted to a single function, which was able to reproduce accurately the data over the entire wave-vector range.

Standing surgical repair of cystorrhexis in two mares.

Two surgical techniques were used to evert the bladder into the vagina for observation and repair of bladder tears that were associated with parturition. One technique involved an incision through the vaginal floor into the peritoneal cavity just caudal to the cervix, and prolapse of the bladder into the vagina. The second technique involved a 3-cm incision through the urethra, 5 cm cranial to the urethral orifice, and digital exploration of the tear and finger traction to evert the bladder through the urethral incision.

Dynamic light scattering study of fine semiflexible fibrin networks.

Fine fibrin networks have been investigated using the dynamic light scattering (DLS) technique. At the shortest delay times, t, the dynamic structure factor s(q,t) is found to depend on time according to an exponential function and, at intermediate delay times (up to 1 ms), to a stretched exponential. At longer times (t > 1 ms), a progressively increasing deviation from the stretched exponential behaviour has been observed.

Self-similarity properties of alpha-crystallin supramolecular aggregates.

The supramolecular aggregation of alpha-crystallin, the major protein of the eye lens, was investigated by means of static and dynamic light scattering. The aggregation was induced by generating heat-modified alpha-crystallin forms and by stabilizing the clusters with calcium ions. The kinetic pattern of the aggregation and the structural features of the clusters can be described according to the reaction limited cluster-cluster aggregation theory previously adopted for the study of colloidal particles aggregation systems.

Birefringence and scattering in highly oriented artificial Kerr media.

We have measured both electric birefringence and polarization-resolved static light scattering at visible wave-lengths in highly oriented aqueous suspensions of shaped microparticles. In these experiments the microparticles were oriented by a high-frequency electric field, and saturation effects were clearly observed in both the Kerr effect and light scattering. The transient dynamics of the Kerr effect was studied and a field-dependent medium response time measured.

Polarization-resolved optical phase conjugation in an artificial anisotropic Kerr medium.

Optical phase conjugation by degenerate four-wave mixing has been achieved in a liquid suspension of polymer microellipsoids as a result of light-induced rotational effects. Different polarization configurations of the pump and probe beams have been used, and the resulting conjugate polarization states have been discriminated. The results are discussed in terms of different kinds of particle orientational gratings.

Third-order nonlinearity enhancement in an artificial Kerr medium through bulk intrinsic birefringence.

Laser-induced circular birefringence measurements have been performed on a liquid suspension of polymer microellipsoids in order to study its optical nonlinearity as a function of the host liquid's refractive index n(h). The results show that the large values obtained for the chi1221((3)) term (1.6 x 10(-8) esu for n(h) = 1.

[Reliability of intrarectal echography in the staging of the T parameter in carcinoma of the medial and inferior third of the rectum].

The capabilities were evaluated of endorectal ultrasound in assessing the local extension of rectal carcinomas. The study population consisted of 50 patients with histologically proven rectal cancer. A CT scan was also performed on 45 patients, and the results were then compared to postoperative histologic findings.

Correction of bilateral ureteral defects in a foal.

Bilateral ureteral defects were diagnosed as the cause of depression and azotemia in an 8-day-old Thoroughbred filly. The azotemia resulted from accumulation of urine in the retroperitoneal area. A ventral midline laparotomy was performed, and defects found in both the left and right ureter were repaired.