Intraductal papillary-mucinous tumors: an entity which is infrequent and difficult to diagnose

BACKGROUND/AIMS: Intraductal papillary-mucinous tumor of the pancreas is currently considered to be a tumor which is an entity of its own, different from classic pancreatic ductal carcinoma. It is basically characterized by slow growth and low malignancy potential, as well as by the production of mucin. The aim of this study is to contribute to world literature some clarification of its natural history, clinical presentation, the most useful diagnostic tests, methods of detection of stromal invasion and handling of treatment. METHODOLOGY: Of 297 pancreatectomies undertaken at the "12 de Octubre" hospital between May 1985 and January 1998, only 1 case of Intraductal papillary-mucinous tumor was found. We have revised 127 cases published in 10 series over the last 10 years. We also contribute a review of our own case. RESULTS: These tumors, which are very infrequent, produce non-specific symptoms, with long latency periods from the first symptom up to stromal invasion. Endoscopic retrograde cholangiopancreatography showed alterations in 100% of cases where this was undertaken. Tumor-related mortality was zero amongst patients with non-invasive tumor who underwent surgery. None of the cases published presented upper gastrointestinal hemorrhage. This indicated the correct surgery and led us to our diagnosis. CONCLUSIONS: We confirm the low frequency and difficulty of diagnosis, the sensitivity of endoscopic retrograde cholangiopancreatography, the difficulty of early detection of stromal invasion, and the high survival rate in cases where resection is done before this occurs. Early diagnosis and treatment is therefore of utmost importance.     

First egg protein with a neurotoxic effect on mice

While many invertebrates sequester toxic compounds to endow eggs with chemical defences, here we show, for the first time to our knowledge, the identification of a neurotoxin of proteinaceous nature localized inside an egg. Egg extracts from the freshwater apple snail Pomacea canaliculata displayed a neurotoxic effect in mice upon intraperitoneal injection (i.p.) (LD50, 96h 2.3mg/kg). Egg protein and total lipids were analysed separately and the only fraction displaying a highly toxic effect (LD50, 96h 0.25mg/kg, i.p.) was further purified to homogeneity as an oligomeric glyco-lipoprotein of 400kDa and two subunits biochemically and immunologically indistinguishable from the previously described perivitellin PV2. The neurotoxin was heat sensitive and there was evidence of circulating antibody response to sublethal i.p. doses on mice. Clinical signs, histopathological and immunocytochemical studies revealed damage mostly in mice spinal cord. Experiments showed chromatolysis and a decreased response to calbindin D-28K associated with a significant increase of TUNEL-positive cells in the dorsal horn neurons. These results suggest that calcium buffering and apoptosis may play a role in the neurological disorders induced by the toxin in mammalian central nervous system. This is the first report of a mollusc neurotoxin genetically encoded outside the cone-snail species.     

Diminished PGE2 content, enhanced PGE2 release and defects in 3H-PGE2 transport in embryos from overtly diabetic rats

Diminished PGE2 levels in diabetic embryos are related to the development of malformations, and thus the aim of the present study was to determine whether PGE2 levels are modified in rat embryos cultured in diabetic serum during organogenesis, and if PGE2 content and release, and 3H-PGE2 uptake and release, are altered in incubated diabetic embryos. Rats were made diabetic by steptozotocin (60 mg kg(-1)) before mating. Control rat embryos cultured for 24 h (explantation Day 9) in the presence of diabetic serum showed diminished PGE2 levels. When Day 10 diabetic embryos were incubated, embryo PGE2 levels were lower, but the PGE2 released to the incubation media was much higher than in controls. Uptake of 3H-PGE2 by diabetic embryos was initially enhanced (5-10 min), then reached similar levels to controls (20-100 min). Release of 3H-PGE2 previously incorporated during a 60-min incubation was greater in diabetic embryos than in controls. These results show diminished PGE2 content in both diabetic and normal embryos cultured in the presence of diabetic serum, but suggest that diabetic embryos have the capability to produce and release high levels of PGE2. The enhanced release of PGE2 is probably the result of transport abnormalities, and leads to the elevated PGE2 concentrations found in the incubating medium and to the diminished intraembryonic PGE2 levels that alter embryonic development.     

Visual impairment in severe and profound sensorineural deafness

The frequency of reversible and irreversible visual impairment was determined in children with severe and profound sensorineural deafness, as subnormal vision can adversely affect their educational and social development. Eighty three of 87 such children attending an audiology service were examined to assess the incidence and severity of visual impairment. Each child underwent a detailed ophthalmic assessment. The criteria for visual impairment were visual acuity < 6/9 Snellen or equivalent and/or abnormal binocular vision. Forty five had a normal ophthalmic examination (54.2%). Twenty nine had visual impairment (34.9%) and nine had ophthalmological abnormalities that did not interfere with vision (10.9%). A higher proportion of children with risk factors for visual pathology demonstrated visual impairment than those in whom there were no risk factors. None the less, 44% of visual impairment was among patients without risk factors. The results underline the need to examine all children with severe and profound sensorineural deafness soon after diagnosis and indicate that children with multiple handicaps have a greater likelihood of visual impairment (11 of 14 cases).     

Analysis of Fgf15 expression pattern in the mouse neural tube

The dynamic process of neural tube regionalization in vertebrates is regulated by the expression of developmental genes which appear in characteristic patterns at neuroepithelial transversal domains, which are called secondary organizers. The molecular code present in these neuroepithelial organizers controls the generation of morphogenetic signals that induce and maintain regional characteristics in the surrounding neuroepithelium. The product of the Fgf8 gene is a secreted protein that has been demonstrated to be the key molecule for the isthmic organizer and is also expressed in two other organizer regions: the zona limitans and the anterior neural ridge. Here we analyze the expression of Fgf15 at different stages of mouse development in relation to Fgf8 and Otx2 expression patterns.     

Rescue of a pathogenic Marek's disease virus with overlapping cosmid DNAs: use of a pp38 mutant to validate the technology for the study of gene function

Marek's disease virus (MDV) genetics has lagged behind that of other herpesviruses because of the lack of tools for the introduction of site-specific mutations into the genome of highly cell-associated oncogenic strains. Overlapping cosmid clones have been successfully used for the introduction of mutations in other highly cell-associated herpesviruses. Here we describe the development of overlapping cosmid DNA clones from a very virulent oncogenic strain of MDV. Transfection of these cosmid clones into MDV-susceptible cells resulted in the generation of a recombinant MDV (rMd5) with biological properties similar to the parental strain. To demonstrate the applicability of this technology for elucidation of gene function of MDV, we have generated a mutant virus lacking an MDV unique phosphoprotein, pp38, which has previously been associated with the maintenance of transformation in MDV-induced tumor cell lines. Inoculation of Marek's disease-susceptible birds with the pp38 deletion mutant virus (rMd5 Delta pp38) revealed that pp38 is involved in early cytolytic infection in lymphocytes but not in the induction of tumors. This powerful technology will speed the characterization of MDV gene function, leading to a better understanding of the molecular mechanisms of MDV pathogenesis. In addition, because Marek's disease is a major oncogenic system, the knowledge obtained from these studies may shed light on the oncogenic mechanisms of other herpesviruses.     

Role of Clostridium difficile infection in the relapse of ulcerative colitis

A case of nosocomial diarrhea by Clostridium difficile in an older woman with an old history of increasing stool frequency, is reported. Colonoscopy and biopsy was performed due to an incomplete response to vancomicyn, and the diagnosis of underlying ulcerative colitis was made. The incidence of Clostridium difficile infection associated with the relapse of ulcerative colitis is nearly 10%. In patients with ulcerative colitis, macroscopic pseudomembranes and the usual predisposing factors for Clostridium difficile infection, usually, are not present. It seems to exist a significant correlation between the severity of the relapse and Clostridium difficile. The specific treatment of the pseudomembranous colitis, in the majority of the cases, is sufficient for a correct control of relapse of ulcerative colitis.