Giant-block twist grain boundary smectic phases.

Study of a diverse set of chiral smectic materials, each of which has twist grain boundary (TGB) phases over a broad temperature range and exhibits grid patterns in the Grandjean textures of the TGB helix, shows that these features arise from a common structure: "giant" smectic blocks of planar layers of thickness l(b) > 200 nm terminated by GBs that are sharp, mediating large angular jumps in layer orientation between blocks (60 degrees < Delta < 90 degrees ), and lubricating the thermal contraction of the smectic layers within the blocks. This phenomenology is well described by basic theoretical models applicable in the limit that the ratio of molecular tilt penetration length-to-layer coherence length is large, and featuring GBs in which smectic ordering is weak, approaching thin, melted (nematic-like) walls. In this limit the energy cost of change of the block size is small, leading to a wide variation of block dimension, depending on preparation conditions. The models also account for the temperature dependence of the TGB helix pitch.

[Primary bladder osteosarcoma treated with hemicystectomy]. / Osteosarcoma vesical primario tratado mediante hemicistectomía.

Primary osteosarcoma of the bladder is an extremely rare type of tumour, and less than 30 adequately documented cases have been registered. From a clinical and radiological point of view, it is impossible to distinguish from other types of bladder tumours, since despite the fact that calcification of the bladder wall is common in osteosarcoma, other bladder diseases exist which may also present calcification. Prior to primary bladder osteosarcoma diagnosis, it is vital to first rule out the existence of an skeletal origin. Differential diagnosis must be carried out essentially with other bone-forming tumours, such as carcinosarcoma and transitional cell carcinoma with bone metaplasia. Prognosis for bladder osteosarcoma is extremely pessimistic, as the majority of patients do not survive beyond 6 months, regardless of the treatment carried out. We present a case of bladder osteosarcoma treated by right hemi-cystectomy, which remains disease free after a follow-up period of one year.

Osteosarcoma vesical primario tratado mediante hemicistectomía / Primary vesical osteosarcoma treated with hemicystectomy

El osteosarcoma primario de vejiga es un tumor de extraordinaria rareza, con menos de 30 casos adecuadamente documentados. Desde el punto de vista clínico y radiológico es indistinguible de otros tipos de tumor vesical, ya que aunque las calcificaciones de la pared vesical son frecuentes en el osteosarcoma, existen otras patologías vesicales que también pueden presentar calcificaciones. Para realizar el diagnóstico de osteosarcoma vesical primario es imprescindible descartar la existencia de afectación esquelética. El diagnóstico diferencial debe realizarse fundamentalmente con otros tumores formadores de hueso, como el carcinosarcoma y el carcinoma de células transicionales con metaplasia ósea. El pronóstico del osteosarcoma vesical es ominoso, ya que la mayoría de los pacientes fallecen antes de los 6 meses, independientemente del tratamiento efectuado.Presentamos un caso de osteosarcoma vesical tratado mediante hemicistectomía derecha, que permanece libre de enfermedad tras un año de seguimiento. (AU)

[Severe ischemic colitis in a patient with acute myocardial infarction]. / Colitis isquémica severa en paciente con infarto agudo de miocardio.

We discuss a case of a 68 years old man with an acute myocardial infarction and a cardiopulmonary arrest that 3 days after his admission developed a continuous abdominal pain and findings of peritoneal inflammation. The mesenteric angiographical study was normal. A laparotomy was practised and disclosed a local peritonitis and a colonic infarction without mesenteric vascular occlusion. This picture is very unusual in patients with acute myocardial infarction or cardiopulmonary arrest.

Colitis isquémica severa en paciente con infarto agudo de miocardio / Ischemic colitis following acute myocardial infarction

Se presenta el caso de un paciente de 68 años que sufrió un infarto agudo de miocardio con parada cardiaca reanimada y que al 3º día de su ingreso desarrolló un cuadro de abdomen agudo y rectorragia. Se realizó angiografía mesentérica que fue normal. Fue intervenido quirúrgicamente evidenciándose peritonitis local y una necrosis en colon ascendente secundaria a una colitis isquémica de origen no oclusivo, cuadro clínico extremadamente infrecuente en este tipo de pacientes (AU)

Pancreatic mucinous cystadenocarcinoma with pseudosarcomatous mural nodules. A report of a case with immunohistochemical study.

A case of pancreatic mucinous cystadenocarcinoma (PMC) with two pseudosarcomatous mural nodules (PMN) is described. These nodules have not been previously described in this type of tumor. In ovarian mucinous tumors (OMT), similar nodules have been reported, the nature of which has been discussed in detail. Here the similarity between the tumor described here and ovarian tumors is stressed. The immunohistochemical study carried out disclosed in the nodules strong positive staining for vimentin and moderate positivity for keratin and epithelial membrane antigen. These findings, along with histologic details, favor the epithelial nature of the nodules. It was concluded that the nodules are foci of anaplastic carcinoma with high proliferative cell rate, which could explain the coexpression of vimentin and keratin.

Case report: psychosis with Stevens-Johnson syndrome and toxic epidermal necrolysis.

A case is presented of a 36-year-old woman who developed a psychosis following an apparent systemic allergic reaction to phenytoin and/or phenobarbital. She was initially diagnosed as having Stevens-Johnson syndrome and toxic epidermal necrolysis with the subsequent development of a psychosis. The authors were able to demonstrate a previously undiagnosed neurological impairment that they feel may be related to both the drug reaction and the psychosis.

Regression of hormone-dependent mammary tumors in Sprague-Dawley rats as a result of tamoxifen or pharmacologic doses of 17 beta-estradiol: cyclic adenosine 3',5'-monophosphate-mediated events.

The estrogen and cyclic adenosine 3',5'-monophosphate (cAMP)-binding activities changed markedly when 7,12-dimethylbenz[a]anthracene-induced mammary tumors of Sprague-Dawley rats regressed following daily injections of either tamoxifen or pharmacologic doses of 17 beta-estradiol. cAMP binding increased eightfold to tenfold, whereas estrogen binding increased twofold to threefold in regressing tumor nuclei at 5 days after either treatment, which resulted in an inversion of the ratio of estrogen binding to cAMP binding found in growing tumor nuclei. Concomitantly, both binding activities were depleted from the cytosol. In the regressing tumors, the cAMP level increased twofold and nuclear cAMP-dependent protein kinase activity increased threefold to fourfold, with a 70-80% decrease in the cytoplasmic protein kinase activity. The rise in the nuclear protein kinase activity was abolished when cycloheximide was given with tamoxifen or with high doses of 17 beta-estradiol, which suggests that the increased activity is due to new protein synthesis. In the regressing tumor nuclei, the phosphorylation of the regression-associated proteins increased, whereas the phosphorylation of growth-associated proteins decreased. These data suggest that the mammary tumor regression induced by tamoxifen or high doses of estrogen proceed through a series of cAMP-mediated events.