Metastatic colon cancer involving the right atrium

Colorectal cancer rarely metastasizes to the heart. In the world medical literature, we identified only 7 cases of well-documented colorectal cancer metastasis to the right atrium. Herein, we describe the case of a 72-year-old man in whom metastatic mucinous adenocarcinoma of the colon involved the right atrium and caused superior vena cava syndrome. To our knowledge, this is the first case report of sudden cardiac death due to embolization of metastatic colon cancer from the right atrium. We also present the first comprehensive case series review of this rare entity.Given improvements in diagnostic and therapeutic methods that have increased the longevity of many cancer patients, the detection of cardiac metastases is likely to increase in frequency. Accordingly, we recommend that previously asymptomatic cancer patients with a history of colorectal cancer who develop cardiac symptoms undergo prompt investigation for possible cardiac metastasis.     

Complications of percutaneous endoscopic gastrostomy in children: results of an Italian multicenter observational study

BackgroundPercutaneous endoscopic gastrostomy is the preferred way to achieve an artificial feeding route for patients requiring long-term enteral nutrition. Although the procedure is well-standardized, it carries early and late complications.AimTo establish the mortality and morbidity of this technique in a large cohort of children.MethodsA multi-centre prospective clinical data collection from children undergoing percutaneous endoscopic gastrostomy tube implantation has been conducted from January 2004 to December 2007. Previous abdominal surgery was the only exclusion criterion. Follow-up visits were carried out at 1, 3, 6, 12, and 24 months after the procedure.Results239 children (males, 55.2%; mean age 6.05 ± 6.1 years) were enrolled from nine tertiary Italian centres. Major complications occurred in 8 patients (3.3%). The cumulative incidence of complications was 47.7% at 24 months. The presence of thoraco-abdominal deformity was an independent predictor of complications at 12 months. No risk factors were identified in association to complications during the 1st tube replacement.ConclusionIn children undergoing percutaneous endoscopic gastrostomy placement minor complications are common, while severe morbidities are rare. Accurate follow up is essential to recognize every complication, in particular when risk factors such as thoraco-abdominal deformity exist.     

Effect of extracellular volume expansion on renal cortical and medullary Na+−K+-ATPase

Summary The role of renal Na⁺–K⁺-ATPase in the acute changes in sodium reabsorption caused by isotonic volume expansion was evaluatedin vivo andin vitro in the rat and the dog. Duringin vivo volume expansion with isotonic saline in the rat, renal medullary Na⁺–K⁺-ATPase specific activity increased, while the simultaneously determined cortical Na⁺–K⁺-ATPase specific activity and kinetics remained unchanged. Furthermore, experimentsin vitro failed to demonstrate a circulating inhibitor of renal Na⁺–K⁺-ATPase both in plasma dialysates from volume-expanded rats and in plasma dialysates concentrated 20-fold by ultrafiltration from volume-expanded dogs. These results suggest that the decreased proximal tubular reabsorption of sodium during volume expansion is not mediated by inhibition of renal cortical Na⁺–K⁺-ATPase. The acute increment in medullary Na⁺–K⁺-ATPase observed could represent an adaptive response to increased sodium reabsorption by the loops of Henle, and raises the possibility that this enzyme may participate in relatively rapid adjustments in the transport of sodium by the renal tubule.     

Ependymal changes in experimental hydrocephalus

A morphologic investigation of ependyma over gray matter (caudate nucleus) and over periventricular white matter (tapetum) of the rabbit lateral ventricle was performed four months after the induction of experimental hydrocephalus. Ependymal cells over the caudate nucleus are not modified by hydrocephalus. They remain cuboidal and heavily ciliated. Numerous microvilli cover the cell surface. The extracellular space of the neuropil is not expanded. Ependymal cells over the periventricular white matter are markedly modified. The characteristic response of these ependymal cells is to enlarge and to form lacunae in their apical cytoplasm. Their apical, horizontal cytoplasmic processes elongate as adjacent ependymal cells separate. The ex-tracellular space of the neuropil is expanded. It is proposed that the changes seen in ependymal cells over periventricular white matter are a response to enlargement of the ventricular surface permitted by the orientation of neuronal and glial fibers parallel to the ventricular surface. With expansion of the ventricular surface, overlapping apical processes become elongated and modified, containing a terminal web. With further enlargement, sliding of an overlapping apical process of one cell uncovers the apical process of its neighboring cell. By this mechanism, the ventricular surface area of any ependymal cell whose surface has been partially covered by its neighbor is increased. With further progression, this compensation fails and the neuropil is exposed to the ventricular cavity. Over caudate nucleus, expansion of ventricular surface is hindered by the disposition of fascie adherentes along intercellular clefts oriented perpendicular to the ventricular surface. Lateral sliding of horizontal apical processes does not occur as such processes are not found in ependyma over the caudate nucleus. The differential response of the ventricular surface in these two areas characteristically seen in hydrocephalus is; determined by regional differences in the morphology of their ependymal cells and underlying neuropil.     

Efficient 12-mutation testing in the CFTR gene: a general model for complex mutation analysis

The identification of the cystic fibrosis transmembrane conductanceregulator (CFTR) gene has led to the identification of morethan 225 presumed disease-causing mutations at the locus. Thediagnosis of cystic fibrosis or the carrier state by directDNA analysis is hindered by this large number. A practical assaymust be able to detect enough mutations to achieve clinicallysignificant sensitivity. The use of allele-specifk oligonucleotideprobes is the most promising of the available methods. However,to date this has generally involved tedious probe-by-probe hybridizations,due to variations in the oligonucleotides' denaturation temperaturescaused by differences in their G-C base-pair content. We havedeveloped a rapid, cost-effective assay that simultaneouslydetects 12 CFTR mutations after multiplex polymerase-chain-reactionamplification of genomic DNA. The test may be readily extendedto detect additional mutations at minimal increase in the costper test or the turnaround time. We improve specificity andavoid the need for individual hybridizations by the use of tetramethylammoniumchloride to virtually eliminate the effects of G-C differences.Coupled with non-invasive sample-collection methods, this isan immediately practical assay for cystic fibrosis. More generally,it will serve as a model for the development of diagnostic testsin other genetic disorders involving complex mutation analysis.