Effects of disease-modifying therapy on peripheral leukocytes in patients with multiple sclerosis.

Modern disease-modifying therapies (DMTs) in multiple sclerosis (MS) have variable modes of action and selectively suppress or modulate the immune system. In this review, we summarize the predicted and intended as well as unwanted adverse effects on leukocytes in peripheral blood as a result of treatment with DMTs for MS. We link changes in laboratory tests to the possible therapeutic risks that include secondary autoimmunity, infections, and impaired response to vaccinations. Profound knowledge of the intended effects on leukocyte counts, in particular lymphocytes, explained by the mode of action, and adverse effects which may require additional laboratory and clinical vigilance or even drug discontinuation, is needed when prescribing DMTs to treat patients with MS.

Early identification of renal transplant recipients with high risk of polyomavirus-associated nephropathy.

Polyomavirus BK (BKPyV) is ubiquitous among humans. Following primary infection, the virus remains latent predominantly in the hosts' uroepithelial cells. Up to 10 % of renal transplant recipients show a viral reactivation that can lead to polyomavirus-associated nephropathy (PyVAN). In the absence of early treatments, the risk of graft loss is up to 80 %. Monitoring viral load in urine and plasma by real-time PCR after transplantation is the most common diagnostic tool to detect viral reactivation. In the present retrospective study, BKPyV-DNA loads in urine and plasma by quantitative real-time PCR were associated with clinical data, including HLA haplotype, blood parameters and viral genotype, of 40 renal transplant recipients at the University Clinics of Cologne. Seventeen out of 329 patients screened for BKPyV from January 2009 to October 2013 were detected BKPyV positive in urine only, whereas in 23 patients the virus became additionally detectable in plasma. Among these, ten patients progressed to PyVAN. Overall, the present study showed that the detection from the third month onwards after transplantation of a first viruric episode with a median viral load of 1 × 10(8) copies/mL, followed after few days by a first viremic episode with a median viral load of >1 × 10(4) copies/mL, was strongly associated with the development of PyVAN. In conclusion, the viral load and the temporal profile of the first viruric and viremic episode post-transplantation, in combination with specific features of the host immune response, should be considered as relevant clinical determinants of the risk of renal transplant recipients to progress to PyVAN.

Artroplastía total de cadera primaria metal-metal con megacabezas en mayores de 75 años / Metal on metal primary total hip arthroplasty with heads greater than or equal to 38 millimeters in patients over 75 years

Objectives: Determine if patients over 75 years old that were operated by primary total hip arthroplasty, the use of heads greater than or equal to 38 mm may reduce the risk of dislocation without an increase in loosening. Knowing that press-fit was the only mean of fixing the acetabular component. Materials and Methods: A retrospective observational cohort study was conducted between 2005 and 2008. We included 25 patients over 75 years old that operated with metal on metal primary total hip arthroplasty, monoblock acetabular cup press-fit without screws and heads greater than or equal to 38 mm diameter. We conducted clinical and radiological controls at 1,3,6, 12 months and then annually, recording episodes of dislocation, signs of acetabular component loosening (migration of 2 mm, angulation more than 5 degrees and radiolucid line in the 3 Charnley-DeLee zones) and the Functional Merle Scale. Results: The mean follow up of patients was 2 years (1-4 years). The average Merle Score was 16.7 (9-18), catalogued as Very Good 17 (68 percent), Well 4 (16 percent), Fair 2 (8 percent) and Bad (4 percent) patient. Two patients had complications, nondisplaced calcar periprosthetic intraoperative fracture ans sciatic nerve injury. There were no reoperations and no cases of prosthetic dislocation or loosening. Conclusions: In thi population, the use of acetabular component fixed by only press-fit without screws associated with heads greater than or equal to 38 mm, increases stability and is a safe procedure, and so far we have not seen any loosening events.

Objetivo: Determinar si en la artroplastía total de cadera (ATC) primaria en pacientes mayores de 75 años, es posible disminuir el riesgo de luxación con el uso de cabezas mayores o iguales a 38 mm, sin un aumento del aflojamiento al utilizar la fijación mecánica como único medio de fijación del componente acetrabular. Materiales y Métodos: Estudio observacional, prospectivo, del tipo cohorte, realizado entre los años 2005 y 2008. Se incluyeron 25 pacientes mayores de 75 años, sometidos a una ATC con par de fricción metal-metal, cotilo monoblock con fijación mecánica sin tornillos y megacabezas, definidas como diámetros > 38 mm. Se realizaron controles clínico radiológicos a los 1,3,6, 12 meses y luego anualmente, registrándose episodios de luxación, signos de aflojamiento del componente acetabular (migración de 2mm, angulación mayor a 5º y línea radiolúcida en las 3 zonas de Charnley-DeLee) y la Escala Funcional de Merle: Resultados: El seguimiento promedio de los pacientes fue de 2 años (1-4 años). El promedio del Score de Merle fue 16,7 (9-18), catalogándose como Muy Bueno a 17 (68 por ciento), Bueno a 4 (16 por ciento), regular a 2 (8 por ciento) y Malo a 1 (4 por ciento) paciente. Dos pacientes presentaron complicacines, y una fractura periprotésica intraoperatoria del calcar no desplazada y una lesión del nervio ciático. Ningún paciente fue reoperado. No se observaron casos de luxación protésica ni de aflojamiento. Conclusiones: En la población estudiada, el uso de componentes acetabulares fijados únicamente mediante fijación mecánica sin tornillos asociado a megacabezas, aumenta la estabilidad protésica y es un procedimiento seguro, ya que hasta la fecha no hemos presentado eventos de aflojamiento.

Factores de riesgo para fracturas periprotésicas intraoperatorias en artroplastia total de cadera / Risk factors for intraoperative periprosthetic fractures in total hip arthroplasty

Objectives: Determine periprosthetic fracture risk factors in our population, during Total Hip Arthroplasty. Material and Methods: A case-control study, comparing 52 cases of periprosthetic fracture against 100 control cases. Statistic analysis was made using Stata 11. Results: Comparing both groups, we observed a significative difference on age (p = 0.032), female gender (p = 0.05, OR 2.05), preoperative diagnosis of hip dysplasia (p = 0.043, OR 2.44), previous surgery (p = 0.005, OR 2.75), non cemented prosthesis (p = 0.001, OR 3.98), indicating that these are risk factors for periprosthetic fracture. A Poisson regression was made to evaluate surgeon experience influence on periprosthetic fractures. There was an inverse relationship between surgeon experience and fracture incidence (p < 0.01 ).We made a step-wise process to eliminate confusing factors; persisting risk factors are dysplasia, previous surgery and low surgeon experience which increase four times intraoperative risk of periprosthetic fracture. Conclusion: In our study, low surgeon experience, previous hip surgery and preoperative diagnosis of dysplasia increase four times periprosthetic fracture risk during a hip arthroplasty.

Objetivos: Determinar los factores de riesgo de presentar una fractura periprotésica durante una artroplastía total de cadera. Materiales y Métodos: Estudio del tipo caso y control. Se compararon 52 casos de pacientes con fracturas periprotésicas con 100 pacientes de grupo control. Se realizó un análisis estadístico mediante el programa Stata 11. Resultados: Al comparar ambos grupos, se observó que existían diferencias estadísticamente significativas (DES) en la edad (p = 0,032), el género femenino (p = 0,05, Odds ratio de 2,05), el diagnóstico preoperatorio de displasia de cadera (p = 0,043, Odds Ratio de 2,44), el antecedente de una cirugía anterior (p = 0,005, Odds Ratio de 2,75), el no cementar (p = 0,001, Odds ratio de 3,98), observándose que todas estas variables constituyen factores de riesgo para la aparición de fracturas periprotésicas. Al analizar la relación entre las tasas de fracturas con la experiencia del cirujano mediante una regresión de Poisson, se observó que existía una relación inversa entre la experiencia del cirujano y la incidencia de fracturas (p <0,01). Al introducir en un proceso step-wise las variables significativas para eliminar los factores confundentes asociados, se observa que los factores de riesgo que subsisten son la displasia, la cirugía previa y la menor experiencia del cirujano, las cuales aumentan el riesgo de presentar una fractura periprotésica intraoperatoria en 4 veces. Conclusión: En nuestra población de pacientes, la menor experiencia del cirujano, el antecedente de cirugía de cadera y el diagnóstico preoperatorio de displasia de cadera aumentan más de 4 veces el riesgo de presentar una fractura periprotésica durante un procedimiento de artroplastía de cadera.

Packing pelviano retroperitoneal en fracturas inestables de pelvis: reporte de un caso y descripción de la técnica / Retroperitoneal packing in unstable pelvic fractures: case report and description of the technique

Pelvic fractures in hemodynamically unstable patients are associated with high rates of morbidity and mortality. The optimal management strategy for hemorrhage control remains controversial. We present a clinical case that was successfully treated with retroperitoneal pelvic packing. The technique is described and discussed.

Las fracturas de pelvis con inestabilidad hemodinámica se asocian a altas tasas de morbilidad y mortalidad. No existe consenso sobre la mejor manera de controlar hemorragia asociada. Se presenta un caso manejado exitosamente mediante la realización de un packing pelviano retroperitoneal. Se describe la técnica quirúrgica y se discuten sus alcances.

Towards metabolic mapping of the human retina.

Functional alterations are first signs of a starting pathological process. A device that measures parameter for the characterization of the metabolism at the human eye-ground would be a helpful tool for early diagnostics in stages when alterations are yet reversible. Measurements of blood flow and of oxygen saturation are necessary but not sufficient. The new technique of auto-fluorescence lifetime measurement (FLIM) opens in combination with selected excitation and emission ranges the possibility for metabolic mapping. FLIM not only adds an additional discrimination parameter to distinguish different fluorophores but also resolves different quenching states of the same fluorophore. Because of its high sensitivity and high temporal resolution, its capability to resolve multi-exponential decay functions, and its easy combination with laser scanner ophthalmoscopy, multi-dimensional time-correlated single photon counting was used for fundus imaging. An optimized set up for in vivo lifetime measurements at the human eye-ground will be explained. In this, the fundus fluorescence is excited at 446 or 468 nm and the time-resolved autofluorescence is detected in two spectral ranges between 510 and 560 nm as well as between 560 and 700 nm simultaneously. Exciting the fundus at 446 nm, several fluorescence maxima of lifetime t1 were detected between 100 and 220 ps in lifetime histograms of 40 degrees fundus images. In contrast, excitation at 468 nm results in a single maximum of lifetime t1 = 190 +/- 16 ps. Several fundus layers contribute to the fluorescence intensity in the short-wave emission range 510-560 nm. In contrast, the fluorescence intensity in the long-wave emission range between 560 and 700 nm is dominated by the fluorescence of lipofuscin in the retinal pigment epithelium. Comparing the lateral distribution of parameters of a tri-exponential model function in lifetime images of the fundus with the layered anatomical fundus structure, the shortest component (t1 = 190 ps) originates from the retinal pigment epithelium and the second lifetime (t2 = 1,000 ps) from the neural retina. The lifetime t3 approximately 5.5 ns might be influenced by the long decay of the fluorescence in the crystalline lens. In vitro analysis of the spectral properties of expected fluorophores under the condition of the living eye lightens the interpretation of in vivo measurements. Taking into account the transmission of the ocular media, the excitation of NADH is unlikely at the fundus.

Tratamiento de fracturas desplazadas de cuello femoral con tornillos canulados / Tratment of displaced femoral neck fractures with cannulated screws

The treatment of displaced femoral neck fractures has been matter of discussion and development in the last years. We retrospectively evaluated 23 patients with a displaced femoral neck fracture treated by fixation with cannulated screws, with at least one year of follow up. Seventeen were men and six women, with a mean age of 48 years (range 24 to 62). Twelve patients presented a high-energy accident and eleven one of low energy. Mean time between the accident and internal fixation was six hours (range 4 to 96). Nine fractures (39%) healed after one operation, osteonecrosis developed in association with nine fractures (39%) and a nonunion developed in association with five (22%). We found higher rates of osteonecrosis in those patients older than 48 years, with a mechanism of low-energy and in those treated within six hours after the injury (58,3%). The functional outcomes were excellent or good in 83% of the patients younger than fifty years, whereas 67% of the patients older than 50 years had a conversion to a total hip arthroplasty in an average of three years. Fixation of displaced femoral neck fractures with cannulated screws is a successful procedure in young patients, but it is associated with high rates of avascular necrosis of the femoral head in patients over fifty years of age.

El tratamiento de las fracturas desplazadas de cuello femoral ha sido materia de discusión y desarrollo en los últimos años. Se estudiaron en forma retrospectiva 23 pacientes con fracturas desplazadas de cuello femoral tratadas mediante osteosíntesis con tornillos canulados y con al menos un año de seguimiento. Diecisiete fueron hombres y seis mujeres, con una mediana para la edad de 48 años (rango 24 a 62). Doce pacientes habían sufrido un accidente de alta energía y once de baja energía. La mediana para el tiempo transcurrido entre el accidente y la cirugía fue de 6 horas (rango 4 a 96). Nueve fracturas (39%) lograron una adecuada consolidación tras la reducción y fijación interna, un 39% desarrolló una necrosis avascular y el 22% evolucionó con una pseudoartrosis. Se observaron tasas significativamente más altas de necrosis avascular en aquellos pacientes mayores de 48 años (67%), con mecanismo de baja energía (72,3%) y con más de 6 horas de (58,3%). Los resultados funcionales fueron buenos o excelentes en el 83% de los menores de 50 años, mientras que el 67% de los pacientes mayores de 50 años requirieron, en un promedio de tres años, una artroplastía total de cadera. La osteosíntesis con tornillos canulados es un procedimientos exitoso en pacientes jóvenes mientras que en los mayores de 50 años se asocia a una alta tasa necrosis avascular de la cabeza femoral.

Artrodesis sacroiliaca en secuelas post-traumáticas de fractura de pelvis inestable / Sacroiliac arthrodesis in post traumatic sequela of unstable pelvic fractures

Post-traumatic sacroiliac joint osteoarthritis and pseudarthrosis are rare. They generally appear as a complication of unstable pelvic fracture. The goal of this study is to describe the functional and radiographic outcome of sacroiliac joint arthrodesis (SJA) in post-traumatic sequela of unstable pelvic fractures. We perform a retrospective review of patients who underwent sacroiliac joint arthrodesis between 1984 and 2005 at the Hospital del Trabajador de Santiago with a minimum of 1 year follow up. From a total of 235 patients with the diagnosis of unstable pelvic fracture within this period, 11 presented chronic sacroiliac pain refractary to conservative treatment that required SJA. There were 9 men and 2 women with an average age of 42 years old (range 24-58). At the time of SJA, 7 patients had post-traumatic osteoarthritis and 4 posttraumatic pseudarthrosis. Time between the accident and SJA was 15.8 months in average (range 6-55). The SJA was performed using a posterior sacroiliac approach followed by curettage of the articular cartilage and bone grafting. The joint is then stabilized with the use of screws and/or plate except in 1 patient. All the patients were evaluated radiographically in the postoperative period. Functional outcome was evaluated using Majeed`s grading score. The mean follow up was 8 years (with a minimum of 1 year). Nine of the11 patients achieved solid fusion. Five of 11 had excellent and good functional results and 6 of 11 had fair or poor. The SJA is thought to be the last procedure in posttraumatic disorders of the sacroiliac joint. In this group of patient the functional outcome is less satisfactory than other sacroiliac disorders 3.

Tanto la artrosis como la pseudoartrosis sacroilica postraumática son entidades poco frecuentes. Se presentan generalmente como complicación del tratamiento de las fracturas de pelvis inestables y su incidencia no supera el 10 por ciento. El objetivo de este trabajo es describir los resultados funcionales y radiográficos de la artrodesis sacroiliaca (ASI) en pacientes con secuelas de fractura de pelvis inestables. Se realizó una revisión retrospectiva de pacientes con fracturas inestables de pelvis tratados por artrosis o pseudoartrosis postraumática con ASI durante el período de 1984 a 2005 en el Hospital del Trabajador de Santiago. De un total de 235 pacientes con fractura inestable de pelvis, 11 presentaron dolor crónico de origen sacroiliaco refractario a tratamiento no quirúrgico que requirió ASI. Nueve fueron hombres y 2 mujeres, el promedio de edad fue de 42 años (rango de 24 a 58). Al momento de la cirugía 7 presentaban artrosis y 4pseudoartrosis postraumática. El tiempo entre el accidente y la ASI fue de 15,8meses en promedio (rango de 6-55). La ASI fue realizada usando el abordaje sacroiliaco posterior, seguido de curetaje articular y aporte de injerto óseo. La fijación se realizó con tornillos canulados y/o placa en todos los pacientes excepto uno. Se realizó una evaluación radiográfica seriada y se utilizó la escala de Majeed para analizar el resultado funcional. El seguimiento promedio fue de 8 años (con un mínimo de un año). Nueve de 11 pacientes lograron fusión sólida. Cinco de 11obtuvieron resultados funcionales excelentes y buenos y 6 de 11 regulares y malos. La ASI se presenta como última alternativa para el manejo dolor sacroiliaco crónico. En este grupo de pacientes, los resultados funcionales logrados son menos satisfactorios que en pacientes con otros desordenes sacroiliacos.

[Limits of the confocal laser-scanning technique in measurements of time-resolved autofluorescence of the ocular fundus]. / Grenzen der konfokalen Laser Scanning Technik bei Messungen der zeitaufgelösten Autofluoreszenz am Augenhintergrund.

GOAL: The 2-dimensional measurement of the time-dependent autofluorescence has in combination of confocal laser scanner technique and time correlated single photon counting the potential for the investigation of the metabolism state at the eye ground. It was to be examined, to what extent these measurements are influenced through the auto-fluorescence of the crystalline lens. MATERIAL AND METHOD: The time-dependent auto-fluorescence was measured on eyes of 21 patients with age-related macular degeneration (AMD) and of 26 healthy subjects in 40 degrees fundus images. The experimental set-up used, was developed at the eye clinic of the University of Jena. In this scanning laser ophthalmoscope, the fundus was excited at 446 nm by pulses of 100 ps full width at half maximum and 40 MHz repetition rate. The auto-fluorescence was detected with a time resolution of 25 ps for wavelengths > 500 nm. The dynamic auto-fluorescence of each pixel was approximated by a tri-exponential model function. In order to determine the influence of the fluorescence of the crystalline lens, healthy eyes and eyes were compared with implanted artificial intra-ocular lenses. For comparison the frequency distributions were used, which the decay times t1, t2 and t3 in the fundus images had been calculated with. RESULTS: Clear differences were shown in the frequency distributions of the fluorescence lifetimes between AMD-patients and healthy subjects, It resulted, however, from a crucial analysis that the fluorescence of the crystalline lens is not suppressed by the confocal laser scanning principle sufficiently. In particular the long lifetime t3 is overlapped by the fluorescence of the crystalline lens of about 4.6 ns. To the complete suppression of the influence of the lens fluorescence in measurements of the time-resolved fundus auto-fluorescence it is suggested to combine the confocal laser scanning technique with the principle of the aperture diaphragm division. CONCLUSION: In order to be able to determine the capability of measurements of the time-dependent fundus auto-fluorescence as diagnostic tool exactly, the influence of the crystalline lens is to reduce through the combination of confocal laser scanning ophthalmoscopy with the principle of the aperture diaphragm division diversely.

[Fundus spectrometry in age-related maculopathy]. / Fundusspektrometrie bei altersbezogener Makulopathie.

BACKGROUND: Spectroscopic methods permit the non-invasive detection of fundus pigments by the wavelength-dependent absorption of fluorescence as well as by the fluorescence lifetime. From the relative concentrations of haemoglobin and oxyhaemoglobin, the oxygen saturation can be calculated. The onset of age-related maculopathy might be delayed by a high optical density of xanthophyll. The detection of alterations in fundus autofluorescence points to age-related pathomechanisms (accumulation of lipofuscin, formation of connective tissue). The detection of autofluorescence of redox-pairs of coenzymes results in information about metabolic states at the cellular level, and might make possible an early detection of age-related changes when they are still reversible. METHOD: The evaluation of reflectance spectra, detected by imaging ophthalmo-spectrometry, results in the calculation of oxygen saturation or in the optical density of xanthophyll or of melanin. Fluorescence spectra can be measured also by this technique. For the 2-dimensional determination of the distribution of xanthophyll, a very simple method was developed, requiring fundus illumination by one wavelength only. In the detection of time-resolved autofluorescence, the fluorescence lifetime is used for the determination of endogenous fluorophores. RESULTS: As result of comparing studies between ARM patients and healthy subjects, the consumption of retinal oxygen was increased already in the children of ARM patients. An increasing optical density of xanthophyll was determined after lutein supplementation. Differences in fluorescence lifetime were determined between ARM patients and healthy subjects, but their interpretation requires investigations of cell or of organ model cultures. CONCLUSIONS: The described methods permit in vivo basic investigations of ARM and can be considered as impulses for the development of diagnostic devices.

[Spectral separation in ocular fundus autofluorescence images in patients suffering from age-related macular degeneration]. / Spektrale Differenzierung in Eigenfluoreszenzbildern des Augenhintergrunds von Patienten mit altersabhängiger Makuladegeneration.

INTRODUCTION: Alterations in the intrinsic ocular fundus fluorescence are under discussion particularly in connection with age-related macular degeneration. However, further knowledge of the chemical substrate of fluorescence is necessary. METHOD: Ocular fundus autofluorescence was observed using a fundus camera. The fluorescence emission was recorded using a 3-chip CCD camera. For comparison, the fluorescence spectra of lipofuscin, A2-E, FAD, NADH(2) and AGE's were recorded by the Jena ophthalmo-spectrometer. RESULTS: In contrast to the homogeneous intrinsic fluorescence of a normal fundus, the fluorescence images of patients suffering from AMD showed remarkable local differences. The detected fluorescence spectra showed remarkable overlaps. DISCUSSION: We introduced a new technique enabling the detection of spectral differences in images of ocular fundus autofluorescence. Besides the fluorescence of lipofuscin, we found a green one in patients suffering from nonexudative AMD.

Artroplastía total de cadera híbrida primaria / Primary hybrid total hip arthroplasty

Se analizan cincuenta y nueve artroplastías totales de cadera híbrida primaria realizadas en 55 pacientes (59 caderas) entre julio de 1992 y diciembre de 1999, que corresponden a 31 (56 por ciento) de mujeres y 24 (44 por ciento) hombres, con edad promedio de 62 (41-74) años y con seguimiento promedio de 5,2 años (3-10). El diagnóstico preoperatorio principal fue artrosis 85 por ciento de los casos. El componente acetabular usado fue Osteonics en 88 por ciento y Ringloc en 12 por ciento. El vástago femoral fue Ostenoics en 85 por ciento, Bimetric en 12 por ciento y autobloqueante en 3 por ciento. El cemento usado fue Polacos con Gentamicina en el 100 por ciento de los casos. Los resultados clínicos según la Escala de Merle D' Aubigne fueron excelentes en 76 por ciento, buenos 15 por ciento, aflojamiento aséptico en 2 casos, fractura del vástago en 1 caso. Los resultados obtenidos son comparables con la literatura referida a prótesis total híbrida primaria en pacientes en edad promedio de 60 años.

Fracturas ocultas de cadera: diagnóstico y tratamiento / Hidden hip fractures: diagnosis and management

Las fracturas ocultas de cadera se definen como las fracturas con clínicas sugerente, pero con radiología negativa, y que necesitan pruebas de imágenes especiales para ser diagnosticadas. La presentación clínica de este cuadro es diversa, siendo el único factor en común la persistencia de dolor por lo que se requiere un alto índice de sospecha para su diagnóstico. Existen múltiples alternativas de imágenes para el diagnóstico de estas facturas, siendo la RMI el examen de elección actualmente. En cuanto al tratamiento, se debe ser agresivo, realizando una cirugía profiláctica a la brevedad, para así evitar desplazamientos y tratamientos de mayor complejidad

Fracturas subtrocantéreas en pacientes jóvenes: experiencia de 23 años / Subtrochanteric fractures in young patients: experience of 23 years

Se analizaron 34 pacientes con fracturas subtrocantéreas tratadas entre 1977 y 2000. Todos fueron hombres, edad promedio 34 años (16-57). En un 97 por ciento fueron secundarias a trauma de alta energía. Utilizamos la clasificación de Seinsheimer encontrando que en un 58 por ciento correspondieron a tipos IV y V. Todas fueron tratadas quirúrgicamente. Los resultados funcionales fueron satisfactorios en un 77 por ciento. Las complicaciones observadas fueron retardo de consolidación en 11 casos, consolidación en varo en 6 casos y fractura post retiro de OTS en 4 casos. Sólo en un 53 por ciento de los casos, la patología fue resuelta en una sola cirugía

Statistical mechanics of canonical-dissipative systems and applications to swarm dynamics.

We develop the theory of canonical-dissipative systems, based on the assumption that both the conservative and the dissipative elements of the dynamics are determined by invariants of motion. In this case, known solutions for conservative systems can be used for an extension of the dynamics, which also includes elements such as the takeup/dissipation of energy. This way, a rather complex dynamics can be mapped to an analytically tractable model, while still covering important features of nonequilibrium systems. In our paper, this approach is used to derive a rather general swarm model that considers (a) the energetic conditions of swarming, i.e., for active motion, and (b) interactions between the particles based on global couplings. We derive analytical expressions for the nonequilibrium velocity distribution and the mean squared displacement of the swarm. Further, we investigate the influence of different global couplings on the overall behavior of the swarm by means of particle-based computer simulations and compare them with the analytical estimations.

Racial and ethnic disparities in infant mortality: risk in social context.

This article presents the multifaceted efforts of Syracuse Healthy Start, a federally funded initiative of the Onondaga County Health Department and over 20 partnering agencies to reduce racial and ethnic disparities in infant mortality. The analyses presented in this article demonstrate that many women--Caucasian, African American, and Hispanic--have serious risks for low birth weight and infant death. In many cases, multiple, simultaneous risks complicate a pregnant woman's situation and in other cases the longitudinal cumulative risks impact health across generations. Infant mortality decreased overall, and for both Caucasian and African American infants during the first 3 years of the project.