[Cemented polyethylene insert in a well fixed Total knee replacement. Case report]. / Cementado del polietileno en una prótesis de rodilla osteointegrada. Reporte de caso.

We present the case of a 94 years- old patient, which was operated 14 years ago of a right total knee replacement for osteoarthritis, actually she suffers of pain and instability; her X ray shown polyethylene wear without loosening of the metal components. The polyethylene insert is not manufactured anymore so we decided cement a new polyethylene insert on the native tibial baseplate. The two years follow up show us a patient asymptomatic, good function and no radiolucencies on the tibial component. We only found a similar case report in Madrid and we believed that this decision, taken from total hip revisions, will succeed.

Se presenta el caso de una paciente de 94 años de edad, la cual fue intervenida hace 14 años de reemplazo articular de rodilla derecha por gonartrosis; actualmente con gonalgia y datos de inestabilidad. En las radiografías se aprecian signos de desgaste del polietileno y no se observan datos de aflojamiento en los componentes metálicos. El modelo implantado de polietileno ya no se fabrica en la actualidad y los componentes metálicos de la prótesis no presentan aflojamiento, por lo que se decide el cementado de un inserto de polietileno similar a las características previas para que se adapte al componente tibial. A dos años de evolución la paciente se reporta asintomática, con buena funcionabilidad y sin signos radiológicos de desgaste. Sólo se ha encontrado un caso clínico similar en Madrid con resultados igualmente satisfactorios, por lo que creemos que ésta puede ser una solución a un problema que se presenta cada vez más con mayor frecuencia en la práctica quirúrgica y que originalmente sólo se había descrito en revisiones de prótesis de cadera.

Propagation of flat-topped multi-Gaussian laser beams.

The multi-Gaussian beam shape is proposed as a model for aperture functions and laser beam profiles that have a nearly flat top but whose sides decrease continuously. Beams and apertures of this type represent a simple, elegant, and intuitive alternative to super-Gaussian beams, which are important in a number of applications such as laser resonator design. Analytical formulas are developed for the propagation of these beams through free space and optical systems representable by ABCD matrices.

Propagation of Laguerre-Bessel-Gaussian beams.

New exact solutions to the paraxial wave equation are obtained in the form of a product of Laguerre polynomials, Bessel functions, and Gaussian functions. In the limit of large Laguerre-Gaussian beam size, the Bessel factor dominates and the solution sets reduce to the modes of closed resonators, hollow metal waveguides, and dielectric waveguides. In the opposite limit the solutions reduce to Laguerre-Gaussian modes of open resonators and graded-index waveguides. These solutions are valid for electromagnetic waves traveling through free space, and they are valid for propagation through circularly symmetric optical systems representable by ABCD matrices as well. An interesting feature of the new solution set is the existence of three mode indices, where only two are required for an orthogonal expansion. As an example, Laguerre-Gaussian beam propagation through an optical system that contains a Bessel-like amplitude filter is discussed.

Production and propagation of Hermite-sinusoidal-Gaussian laser beams.

Hermite-sinusoidal-Gaussian solutions to the wave equation have recently been obtained. In the limit of large Hermite-Gaussian beam size, the sinusoidal factors are dominant and reduce to the conventional modes of a rectangular waveguide. In the opposite limit the beams reduce to the familiar Hermite-Gaussian form. The propagation of these beams is examined in detail, and resonators are designed that will produce them. As an example, a special resonator is designed to produce hyperbolic-sine-Gaussian beams. This ring resonator contains a hyperbolic-cosine-Gaussian apodized aperture. The beam mode has finite energy and is perturbation stable.

Phase compensation of azimuthally polarized j(1) bessel-gaussian laser beams.

As other semiconductor lasers, concentric-circle-grating, surface-emitting lasers are compact, light, and efficient. However, unlike other semiconductor lasers, they emit high-power, low-divergence azimuthally polarized J(1) Bessel-Gaussian beams. Because of their azimuthal polarization, they have a null at the center of the beam that makes them undesirable for certain applications. Binary phase compensation, a lossless technique previously used to improve the far-field profile of linearly polarized Hermite-Gaussian beams, is adapted to these azimuthally polarized beams to rid them of their axial nulls and improve their beam profile.

Efficacy of 28-day and 40-day regimens of sodium stibogluconate (Pentostam) in the treatment of mucosal leishmaniasis.

The efficacy and toxicity of two regimens of antimony, 28 and 40 days of 20 mg of antimony/kg/day, were compared in the treatment of culture-positive mucosal leishmaniasis involving more than one anatomic site. Forty consecutive eligible Peruvians with infiltrative or ulcerative mucosal disease of the lips, nose, palate-uvula-pharynx, or larynx-epiglottis were randomized to receive either 28 days (P28) or 40 days (P40) of sodium stibogluconate (Pentostam). Treatment was prematurely terminated due to thrombocytopenia in three patients and two patients did not complete six months of follow-up. At one month post-treatment, 13% (2 of 16) of the P28 patients and 16% (3 of 19) of the P40 patients no longer had infiltrates or ulcers and were initially considered cured. During a further 11 months of follow-up, infiltrated lesions healed in eight more P28 patients and in 10 more P40 patients. The cure rate after 12 months of follow-up was therefore 63% for both groups (10 of 16 in the P28 group and 12 of 19 in the P40 group). The total of 13 patients who had infiltrates or ulcers at the 9-12-month follow-up were considered failures. All seven patients (three in the P28 group and four in the P40 group) whose lesions were culture-positive for Leishmania at some point in the 12 months after treatment, and who were thereby parasitologic failures, were also clinical failures.(ABSTRACT TRUNCATED AT 250 WORDS)

Beam propagation in parabolically tapered graded-index waveguides.

To a good approximation, the electromagnetic-propagation characteristics of graded-index waveguides can be written in terms of polynomial-Gaussian modes. For uniform quadratic-index waveguides the behavior of these modes is well known. However, there are sometimes practical reasons for using tapered waveguides, but detailed propagation solutions are known for only a few specific taper functions. The parabolic taper is perhaps the most important special case, and the solution-generating techniques that we generalize are used to obtain analytic solutions for this case.

Efficacy and toxicity of sodium stibogluconate for mucosal leishmaniasis.

OBJECTIVE: To determine the efficacy and toxicity of the World Health Organization's (WHO) recommended treatment for mucosal leishmaniasis: antimony, 20 mg/kg body weight per day for 28 days. DESIGN: Open trial with 12-month follow-up. SETTING: Inpatient unit of a regional referral hospital in a developing country. PATIENTS: Twenty-nine consecutive eligible patients with culture-confirmed infection of the mucosa with Leishmania species who were otherwise healthy. Eight patients (28%) had mild to moderate disease (confined to the nasal mucosa). Twenty-one patients (72%) had severe disease (including the oropharynx as well as the nasal mucosa). INTERVENTION: Antimony, 20 mg/kg body weight intravenously every day for 28 days. Patients received antimony in the form of sodium stibogluconate. MEASUREMENTS AND MAIN RESULTS: Initial results of therapy were as follows: 63 of 72 lesions (88%) healed or markedly improved; all lesions were culture-negative for parasites; and 18 of 29 patients (62%) showed complete clinical and parasitologic cure of all lesions. By the 12-month follow-up examinations, however, 37 lesions had recurred, 8 new lesions had appeared, and only 8 patients (30%) showed clinical cure of all lesions. Of the 8 patients with mild to moderate disease, 6 were cured compared with only 2 of the 21 patients with severe disease. Side effects of this treatment regimen included T-wave inversion on electrocardiogram (4 patients), abnormal liver function tests (10 patients), and musculoskeletal pain (24 patients). No side effects occurred during week 1 of therapy. CONCLUSIONS: The only recommended treatment for mucosal leishmaniasis is ineffective in patients with severe disease. The acceptable toxicity of the regimen suggests that longer courses of therapy with antimony, or that trials with other antileishmanial agents alone or combined with antimony be evaluated as initial therapy for this disease.

Diffuse cutaneous leishmaniasis acquired in Peru.

A case of diffuse cutaneous leishmaniasis (DCL) acquired in Peru is described. The causative agent was Leishmania mexicana amazonensis as determined by isoenzyme analysis and species-specific monoclonal antibody binding characteristics. Histological examination of biopsy material showed a large number of intracellular and extracellular amastigotes and few lymphocytes. Treatment with meglumine antimoniate (Glucantime) administered iv at a dosage of 20 mg antimony/kg body weight/day for 60 days resulted in visible improvement of the lesions, but not in clinical or parasitological cure.