Fiber based optical trapping of aerosols.

We present the use of optical fibers to form a counter-propagating optical trap as a means of manipulating both solid and liquid aerosols. We explore the use of single and multimode fibers to achieve trapping of various particles in air, present the trapping properties of the different fiber types and compare the observed trends to those predicted by theory. Using fibers, we are able to hold suspended particles for extended periods of time and to precisely manipulate them over distances of several hundred microns. We discuss the difficulties and advantages of each fiber configuration and conclude with a demonstration that fiber based trapping offers a good candidate for studying optical binding in air.

Influence of hunting-season stage and ripening conditions on nitrogen fractions and degradation of myofibrillar proteins in venison (Cervus elaphus) chorizo sausages.

The influence of hunting-season stage (deer hunted at the start versus deer hunted at the end of the season) and ripening conditions (natural versus controlled drying rooms) on nitrogen fractions and degradation of myofibrillar proteins were studied in chorizo sausages made with venison. Variations of nitrogen fractions during 21 days of ripening were found. In all batches, myofibrillar protein content decreased and proteolysis indices were between 4.6% and 14.4% at the end of ripening. However, after 45 days of storage in vacuum packs no significant variations in nitrogen fractions contents occurred. Similar changes of electrophoretic profiles of myofibrillar proteins in batches processed under controlled conditions took place during ripening, however samples of batches processed in natural drying rooms did not show the same variation. Ripening conditions influenced the relative density of bands corresponding to 45 (actin), 37 (T-troponin), 35 (tropomyosin), 20 (C-troponin) and 19kDa, after 21 days of ripening. Hunting season stage influenced the relative density of the 49kDa band after 21 days of ripening. Changes on proteins profiles were found after storage in all four batches.

White light propagation invariant beams.

Propagation invariant light fields such as Bessel light beams are of interest in a variety of current areas such as micromanipulation of atoms and mesoscopic particles, laser plasmas, and the study of optical angular momentum. Considering the optical fields as a superposition of conical waves, we discuss how the coherence properties of light play a key role in their formation. As an example, we show that Bessel beams can be created from temporally incoherent broadband light sources including a halogen bulb. By using a supercontinuum source we elucidate how the beam behaves as a function of bandwidth of the incident light field.

Dynamic radial positioning of a hydrodynamically focused particle stream enabled by a three-dimensional microfluidic nozzle.

The ability to confine flows and focus particle streams has become an integral component of the design of microfluidic systems for the analysis of a wide range of samples. Presented here is the implementation of a 3D microfluidic nozzle capable of both focusing particles as well as dynamically positioning those particles in selected flow lamina within the downstream analysis channel. Through the independent adjustment of the three sheath inlet flows, the nozzle controlled the size of a focused stream for 6, 10, and 15 µm polystyrene microparticles. Additional flow adjustment allowed the nozzle to dynamically position the focused particle stream to a specific area within the downstream channel. This unique ability provides additional capability and sample flexibility to the system. In order to gain insight into the fluidic behavior of the system, experimental conditions and results were duplicated within 4.75 µm using a COMSOL Multiphysics(®) model to elucidate the structure, direction, proportion, and fate of fluid lamina throughout the nozzle region. The COMSOL Multiphysics model showed that the position and distribution of particles upon entering the nozzle have negligible influence over its focusing ability, extending the experimental results into a wider range of particle sizes and system flow rates. These results are promising for the application of this design to allow for a relatively simple, fast, fully fluidically controlled nozzle for selective particle focusing and positioning for further particle analysis and sorting.

Muscle cramping in phase I clinical trials of tirapazamine (SR 4233) with and without radiation.

PURPOSE: Tirapazamine (SR 4233) is a benzotriazine di-N-oxide which acts as a hypoxic cytotoxic agent and as a radiation enhancer when given shortly before or after radiation. Three Phase I clinical trials were designed to determine the maximum tolerated dose, toxicities, pharmacokinetics, and effects on irradiated tumors and normal tissues. METHODS AND MATERIALS: Tirapazamine 9 mg/m2 to 21 mg/m2 was given i.v. 1/2 to 1 h prior to irradiation on a multiple dose schedule of 10 consecutive doses. This was later revised to a three times-per-week schedule for 12 doses. In a second clinical trial, tirapazamine was given in a single dose of 18 mg/m2 to 293 mg/m2 i.v. after irradiation. In a third trial, tirapazamine was administered without irradiation in single doses of 36 mg/m2 to 250 mg/m2, with an option for retreatment. RESULTS: Subjects reported muscle cramping of varying degrees of severity on all three dose schedules. One patient experienced Grade 3 cramping and treatment was discontinued. The most frequent site of cramping were the lower extremities. Creatine phosphokinase (CPK) values were elevated in three patients with associated muscle soreness in one patient. MB (cardiac) isoenzymes were elevated in one patient with no evidence of cardiac muscle damage, and returned to baseline at drug completion. No consistent abnormalities in clinical laboratory values were found. Stretching of the muscle was most effective in relieving the cramping. CONCLUSION: Muscle cramping has been the most frequently reported toxicity in Phase I studies of tirapazamine, though it does not appear to be dose limiting. Dose escalation on the three clinical trials continues. In vitro studies to investigate the cramping are ongoing.

[Application of a preoperative evaluation model in patients undergoing elective abdominal surgery]. / Aplicación de un modelo de evaluación preoperatoria en pacientes operados de cirugia abdominal electiva.

We used a preoperative evaluation model based on the clinical history in order to determine the clinical characteristics of the patients. We also estimated the prevalence of asymptomatic disease in ASA1 patients and described the frequency of diagnosis that motivated suspension of the surgery during the preoperative time. Another purpose was to establish the perioperative complications according to the risk index and to detect the medical reasons for suspension of surgery during hospitalization. A total of 777 patients having an indication of surgery were evaluated in this program. Only 507 completed the preoperative evaluation. Of these, 57.79%, had at least one known disease or were diagnosed by their clinical history. Preoperative tests were indicated according to age in ASA1 patients. Complementary studies were indicated in relationship to the history and physical examination in ASA2 and ASA3 patients. After the evaluation, 27 surgeries were suspended: 21 were considered high risk, 2 suffered unknown active infections, and 4 ASA1 patients had severe asymptomatic anemia. A total of 328 patients were admitted for surgery. In 5 of these patients the anesthesiologist stopped the procedure in the operating room. The causes were acute decompensations of known pathologies. There were no complications or deaths related to unknown diseases and no patients died from cardiopulmonary or metabolic complications. In ASA1 patients, there were no complications related to this evaluation. This study allowed us to determine the clinical status of the patients and in consequence high-risk surgeries were canceled. In admitted patients a few surgeries were canceled for clinical reasons. This program probably decreased patient morbimortality, unnecessary hospitalization and costs.

[The therapeutic advances in adult acute nonlymphoblastic leukemia. The experience at the Hospital de Especialidades of the Centro Médico Nacional Siglo XXI]. / Avances terapéuticos en la leucemia aguda no linfoblástica del adulto. Experiencia en el Hospital de Especialidades del Centro Médico Nacional Siglo XXI.

Acute adult nonlymphoblastic leukemia (ANLL) involves a large group of diseases which originate in an abnormal process of differentiation of the hematopoietic stem cell. This paper analyses the historical background of such a group of malignant hemopathies, current criteria to perform the diagnosis and also the most important therapies used in both the stage of remission induction and the period following this stage (post-remission status). In this context, the therapeutic achievements that have had place during the last two decades at the Hospital de Especialidades del Centro Medico Nacional Siglo XXI are analyzed.

[Advances in the treatment of aplastic anemia]. / Avances en el tratamiento de la anemia aplástica.

The purpose of this paper is to describe the current advances in the pathogenesis, classification and treatment of acquired aplastic anemia (AA). The therapeutical experience obtained at the Servicio de Hematología, Centro Medico Nacional, Siglo XXI is described. Bone marrow transplantation is the first choice therapy for severe AA. This procedure succeeds in obtaining complete remission in nearly 80% of the cases. Nevertheless, few patients are eligible for such therapy, consequently other treatments should be considered. In this context some immunosuppressive therapies such as antilymphocyte globulin had shown to produce favorable responses in 60% of the patients. In addition, androgens and immunosuppressive drugs like methylprednisolone bolus and cyclosporin A do not have a definitive place in severe AA. Finally, it is important to describe the experience with lymphocytapheresis, a new procedure, that decreases the immunological response against the normal hematopoiesis by removing the population of T-lymphocytes inducing complete remission in a few patients.

[Effectiveness of sodium hyaluronate in patients with gonarthrosis: randomized comparative study]. / Efectividad del hialuronato de sodio en pacientes con gonartrosis, estudio comparativo y aleatorizado.

INTRODUCTION: Hyaluronic acid is a major component of synovial fluid and cartilage; it plays an essential role in joint function. This concept is based on the hypothesis that intraarticular sodium hyaluronate injections improve articular function upon restoring synovial fluid viscosupplementation and promoting endogenous synthesis. MATERIAL AND METHODS: Forty randomly selected patients older than 50 years of age, with a diagnosis of gonarthrosis, standard treatment-naïve, were divided into two 20-patient groups. The first group was treated with five 2.5 ml doses of hyaluronic acid, at one dose per week. The second group was treated with a single 2 ml dose of intraarticular methylprednisolone. A survey containing the Womac functional scale and the pain visual analogue scale was applied to both groups before and 3 months after treatment. RESULTS: A statistically significant reduction in pain (visual analogue scale) was observed 3 months after treatment in group H (1.6 +/- 0.88) and group M (2.95 +/- 1.84), as well as a functional post-treatment improvement in the Womac scale. Results for post-treatment pain were 5.43 +/- 1.05 for group H and 7.86 +/- 0.77 for group M; results for post-treatment stiffness were 3.05 +/- 0.82 for group H and 3.7 +/- 0.85 for group M; and finally for post-treatment functional capacity the results were 12.25 +/- 0.82 for group H and 18.95 +/- 0.85 for group M. CONCLUSION: Intraarticular sodium hyaluronate is more effective for pain and function than methylprednisolone. However, it involves higher costs than conservative treatment and fewer costs than surgical treatment, as well as the discomfort resulting from repeated intraarticular injections and the possibility of anaphylactic reaction.

La escarificacion en el tratamiento de las infecciones de los huesos. / Scarification in the treatment of bone infection

Se describe un metodo que permite eliminar la infeccion osea de manera confiable al favorecer la revascularizacion de los tejidos blandos y del hueso. La escarificacion sigue siempre a un primer tiempo de desbudacion quirurgica, en el cual se hace reseccion generosa de tejidos blandos y economica del huesto, sin llegar nunca a la diafisectomia, para facilitar la consolidacion en casos de fracturas. La escarificacion es un estimulo simple que, repetido sistematicamente, logra la granulacion, lo que a su vez estimula las defensas inmunitarias locales y facilita la eliminacion de la infeccion en mas de 98 por ciento de los casos tratados