Splenectomy for splenomegaly and secondary hypersplenism

Splenomegaly and secondary hypersplenism may be associated with acute and chronic infections, autoimmune states, portal hypertension or splenic vein thrombosis, and a number of infiltrative and neoplastic conditions involving the spleen. Our experience and that of others with these various conditions demonstrates that the decision to perform splenectomy should be based on well-defined and often strictly limited indications. Except for idiopathic splenomegaly, the presence and severity of secondary hypersplenism or severely symptomatic splenomegaly should be well documented. In each case, the potential for palliation and known mean duration of expected response must be weighed against the increased morbidity and mortality of splenectomy (as compared to operation for “primary” hypersplenism) . La splénomégalie avec hypersplénisme secondaire relève de multiples causes: infection aigue ou chronique, états autoimmunologiques, hypertension portale, thrombose de la veine splénique, lésions tumorales spléniques. L'expérience de l'auteur qui rejoint celle de nombreux collègues lui permet d'affirmer que les indications de la splénectomie doivent être bien définies et sont strictement limitées. A l'exception de la splénomégalie idiopathique, l'existence et l'intensité de l'hypersplénisme, l'importance des symptomes provoqués par la splénomégalie doivent être aprréciées avec précision. Dans chaque cas le potentiel de la rémission de l'affection et la durée de la rémission doivent être pris en considération en fonction de l'éventuelle morbidité et de l'éventuelle mortalité de la splénectomie (par comparaison avec la splénectomie pour hypersplénisme primaire). Eplenomegalia e hiperesplenismo secundario pueden estar asociados con infecciones agudas y crónicas, estados autoinmunes (síndrome de Felty, lupus eritematoso sistémico), “esplenomegalia congestiva” por hipertensión portal o trombosis de la vena esplénica y con una variedad de entidades de tipo infiltrativo y neoplásico que afectan al bazo (sarcoidosis, enfermedad de Gaucher, varios desórdenes mieloproliferativos y linfomas). Nuestra experiencia, y aquella de otros autores, con tales condiciones demuestra que la decisión de realizar esplenectomía debe estar fundamentada en indicaciones bien definidas y estrictamente limitadas. Excepto en casos de esplenomegalia idiopática, la presencia y severidad del hiperesplenismo secundario o de esplenomegalia severamente sintomática debe ser bien documentada. En cada caso debe determinarse el potencial de paliación y la duración de la respuesta que se espera obtener frente a la incrementada morbilidad y mortalidad de la esplenectomía (en comparación con la operación que se realiza por hiperesplenismo “primario”).Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/41318/1/268_2005_Article_BF01655279.pd

Quantum chaos in ultracold collisions between Yb(1S0^1S_0) and Yb(3P2^3P_2)

We calculate and analyze Feshbach resonance spectra for ultracold Yb(1S0)+Yb(3P2) collisions as a function of an interatomic potential scaling factor λ and external magnetic field. We show that, at zero field, the resonances are distributed randomly in λ, but that signatures of quantum chaos emerge as a field is applied. The random zero-field distribution arises from superposition of structured spectra associated with individual total angular momenta. In addition, we show that the resonances with respect to magnetic field in the experimentally accessible range of 400 to 2000 G are chaotically distributed, with strong level repulsion that is characteristic of quantum chaos

Approach to chaos in ultracold atomic and molecular physics: Statistics of near-threshold bound states for Li+CaH and Li+CaF

We calculate near-threshold bound states and Feshbach resonance positions for atom–rigid-rotor models of the highly anisotropic systems Li+CaH and Li+CaF. We perform statistical analysis on the resonance positions to compare with the predictions of random matrix theory. For Li+CaH with total angular momentum J=0 we find fully chaotic behavior in both the nearest-neighbor spacing distribution and the level number variance. However, for J>0 we find different behavior due to the presence of a nearly conserved quantum number. Li+CaF (J=0) also shows apparently reduced levels of chaotic behavior despite its stronger effective coupling. This may indicate the development of another good quantum number relating to a bending motion of the complex. However, continuously varying the rotational constant over a wide range shows unexpected structure in the degree of chaotic behavior, including a dramatic reduction around the rotational constant of CaF. This demonstrates the complexity of the relationship between coupling and chaotic behavior