Side-by-side comparison of five commercial media systems in a mouse model: suboptimal in vitro culture interferes with imprint maintenance.

Assisted reproductive technologies (ARTs) are becoming increasingly prevalent and are generally considered to be safe medical procedures. However, evidence indicates that embryo culture may adversely affect the developmental potential and overall health of the embryo. One of the least studied but most important areas in this regard is the effects of embryo culture on epigenetic phenomena, and on genomic imprinting in particular, because assisted reproduction has been linked to development of the human imprinting disorders Angelman and Beckwith-Wiedemann syndromes. In this study, we performed side-by-side comparisons of five commercial embryo culture systems (KSOMaa, Global, Human Tubal Fluid, Preimplantation 1/Multiblast, and G1v5PLUS/G2v5PLUS) in relation to a best-case (in vivo-derived embryos) and a worst-case (Whitten culture) scenario. Imprinted DNA methylation and expression were examined at three well-studied loci, H19, Peg3, and Snrpn, in mouse embryos cultured from the 2-cell to the blastocyst stage. We show that embryo culture in all commercial media systems resulted in imprinted methylation loss compared to in vivo-derived embryos, although some media systems were able to maintain imprinted methylation levels more similar to those of in vivo-derived embryos in comparison to embryos cultured in Whitten medium. However, all media systems exhibited loss of imprinted H19 expression comparable to that using Whitten medium. Combined treatment of superovulation and embryo culture resulted in increased perturbation of genomic imprinting, above that from culture alone, indicating that multiple ART procedures further disrupt genomic imprinting. These results suggest that time in culture and number of ART procedures should be minimized to ensure fidelity of genomic imprinting during preimplantation development.

Investment in the public good through conditional phenotypes of large effect.

We investigate the evolution of an individual's willingness to invest in a public good (what we call, helping) in a patch-structured population with limited natal dispersal. We assume that an individual's decision to invest is informed by its dispersal status: an individual makes one decision given it is native to the patch on which it breeds, and is free to make a different decision given that it is not native to the patch on which it breeds. Unlike previous work, we assume that investment in the public good, and the public good, itself, both have a large effect on individual fecundity. Kin selection analysis reveals that only extreme investment decisions (i.e. 'always invest' or 'never invest') can be evolutionarily stable. Numerical results suggest that the evolutionary instability of the 'never invest' phenotype (what we call, complete nonhelping) implies the evolutionary stability of 'always invest' (what we call, complete helping). In addition, numerical results show that bistability of extreme phenotypes is possible, indicating that the adaptive significance of altruism, in this context, is greater than has been previously recognized. Numerical results are supported by computer simulation, and results, themselves, are briefly discussed in a concluding section.

Use of the Kalnberz external fixator on comminuted open fractures of the upper tibia caused by war injuries

Gunshot wounds of the tibia with considerable overlying skin loss frequently need flap cover; external fixation possibly bone grafting. Treatment of such injuries requires time. Rigid fixation of bone can be achieved by the use of an external fixator. If fractures are located in the upper third of the tibia only a few types of the external fixator will not compromise joint function. One such fixator is the Kalnberz apparatus. The Kalnberz fixator is a simplified version of the Ilizarov fixator. Its use involves a cruciform introduction of two pins in the plane. External fixation was first suggested by R Wittimoser (1949); but it was C A Ilizarov who began to develop the method in 1954

The use of cutaneous turnover flaps to replace skin loss in the leg

Soft tissue loss is a frequent accompaniment to open fractures of the tibia and chronic osteomyelitis associated with pseudarthrosis. In Mozambique most of these problems follow war injuries. There are many methods of closing these soft tissue defects; but the best way is the use of a flap. This paper describes the use of a one stage de-epithelialised cutaneous turnover flap in three patients. It is applicable to many circumstances and is quick and easy to perform

Revascularizacao dos membros inferiores por ponte femoro-tibial com veia safena autologa. Tecnica cirurgica e resultados a longo prazo. / Revascularization of lower extremities by femorotibial bypass with autologous saphenous vein. Surgical technic and long-term results

De 16 pacientes portadores de isquemia severa da extremidade inferior, devido a oclusao da arteria poplitea e arterias distais, com risco iminente de uma amputacao, 15 (94%) receberam pontes femoro-tibiais de veia safena autologa, na tentativa de salvar suas extremidades e o periodo de observacao se estende de 17 a 66 meses. Os autores descrevem a tecnica cirurgica e estudam os resultados a longo prazo. Das 15 pontes efetuadas, 11 (73%) permaneceram patentes por mais de 2 meses.Estudaram 14 pacientes quanto a patencia a longo prazo das pontes: tiveram 8 (57%) ocluidas (4 pacientes com oclusoes precoces que necessitaram amputacao e 4 pacientes com oclusoes tardias que tiveram suas extremidades preservadas) e 6(43%) pacientes com pontes patentes a longo prazo por periodos de 36 a 66 meses e que estao presentemente vivos e com as pontes patentes e as extremidades preservadas ou que faleceram com as pontes pervias e as extremidades preservadas. Dez pacientes (62,5% do total de 16) tiveram suas extremidades preservadas e sao os 4 pacientes com oclusoes tardias e os 6 pacientes com as pontes patentes a longo prazo