Clinical outcomes after self-expanding plastic stent placement for refractory benign esophageal strictures

BACKGROUND

Refractory benign esophageal strictures (RBES) are defined as those that persist structurally and symptomatically after repeated dilation sessions. Small series have reported favorable outcomes after placement and subsequent removal of Polyflex self-expanding plastic stents (SEPS).

AIMS

To characterize the outcomes after Polyflex stent placement in patients with RBES.

METHODS

Outcomes of consecutive patients who underwent Polyflex stent placement for RBES between April 15, 2005 and November 20, 2006 were analyzed retrospectively. The etiology of the stricture, number of dilations prior to initial SEPS placement, size of stent placed, stricture resolution after SEPS removal, cases of stent migration, duration of SEPS placement, time to repeat dilation and/or SEPS replacement after stent removal, and complications were assessed.

RESULTS

Twenty-three Polyflex stents were placed in 13 patients suitable for analysis. The majority of stenoses (11/13) were attributable to anastomotic strictures after curative esophagogastrectomy for esophageal neoplasms. All 11 patients in this group had satisfactory relief of dysphagia to solids determined clinically with indwelling SEPS placement. SEPS migration occurred in seven instances (30% of SEPS placed). Dysphagia remediation after subsequent SEPS removal was observed in only three patients (23%). Placement of a partially covered metal stent within a Polyflex stent was necessary in one case due to epithelial hyperplasia. The mean time for repeat dilation and/or SEPS reinsertion due to recurrent dysphagia after stent removal was 37 days (range 6-120 days).

CONCLUSIONS

Polyflex stents provided satisfactory palliation of dysphagia for RBES while in place. However, unplanned SEPS migration and dysphagia recurrence after stent removal were common.

Electrical properties and surface morphology of SiO(x)-Pt nano-composite thin films

Recently, ceramic metals (cermets) have been widely investigated for use as embedded resistor materials. In this study, SiO-Pt nano-composite cermets were developed to control the resitivity and temperature coefficients of resistance (TCR) of embedded thin film resistors. The SiO-Pt nano-composite was prepared by the co-sputtering of a SiO(x) target and Pt chips onto glass. The experiments were conducted Pt concentrations in order to find the optimum conditions to achieve a high resistivity and low TCR. The electrical properties of the sputtered SiO-Pt thin films were investigated by probe station and their crystal structures were observed by X-Ray Diffraction (XRD) and X-ray Photoelectron Spectroscopy (XPS). The surface morphology was observed by field emission scanning electron microscopy (FE-SEM) and high resolution transmission electron microscopy (HR-TEM). It was found that the Pt particles with a size of 3 approximately 5 nm were uniformly dispersed in the SiO matrix. A stable resistivity value of 26000 approximately 57000 microomega x cm and TCR value of -197 approximately -322 ppm/K were obtained at 3.5 approximately 3.7 at.% Pt.

Unusual Delayed Presentation of a Nail Gun Injury Through the Skull Base

Published reports of nail gun injuries to the face are uncommon. We describe an unusual delayed presentation with injury through the infratemporal fossa and a literature review. A 55-year-old patient presented 2 weeks after an unrecognized injury with complaints of a headache. Imaging revealed a nail traversing the infratemporal fossa with intracranial extension. The nail was removed through a preauricular approach without sequelae. Nail gun missiles to the face are uncommon, dramatic, but often nonfatal because of their relative low velocity. Patients are usually diagnosed at the time of injury, evaluated with computed tomography and angiography, and treated with surgery.

Characterization and quantification of anthocyanins in grape juices obtained from the grapes cultivated in Korea by HPLC/DAD, HPLC/MS, and HPLC/MS/MS

The characterization and quantification of anthocyanins in grape cultivars of Oll-Meoru (Vitis coignetiaexVitis labrusca), Neut-Meoru (Vitis coignetiaexVitis labrusca), Muscal Bailey A. (Vitis labruscana), and Campbell Early (Vitis labruscaxV. vinifera) cultivated in Korea were carried out by partial purification through XAD-7 column chromatography followed by C-18 HPLC/diode array detector (DAD), HPLC/MS, and HPLC/MS/MS analyses. The column oven temperature during the reverse phase C-18 HPLC greatly affected the separation of individual anthocyanins. The result showed that the optimum column oven temperature was 35 degrees C. Sixteen different anthocyanins (11 nonacylated and 5 acylated anthocyanins) were identified in the grape juices. Oll-Meoru, Neut-Meoru, and Muscat Bailey A (MBA) grape juices contained only nonacylated anthocyanins. Oll-Meoru and Neut-Meoru grape juices had same anthocyanins, but their proportions were considerably different. Peonidin 3,5-diglucoside and malvidin 3,5-diglucoside were the major anthocyanins in Oll-Meoru grape juice. Delphinidin 3-glucoside was, however, the major anthocyanin in Neut-Meoru grape juice. Peonidin 3-glucoside and malvidin 3-glucoside were the most abundant anthocyanins in Muscal Bailey A grape juice. Campbell Early grape juice contained both nonacylated and acylated anthocyanins. Cyanidin 3-(p-coumaroyl)glucoside-5-glucoside and peonidin 3-(p-coumaroyl)glucoside-5-glucoside were the most abundant anthocyanins in Campbell Early grape juice. Total anthocyanin contents were greatly different in different grape jucies, with the highest in Neut-Meoru juice (1043.5 microg/mL), followed by Oll-Meoru (997.7 microg/mL), MBA (390.2 microg/mL), and Campbell Early (183.9 microg/mL) juices. The total anthocyanin content in Neut-Meoru grape juice was 5.67 times higher than that in Campbell Early grape juice. This represents the 1st report on the systematic characterization and quantification of anthocyanins in the juices of these grapes cultivated in Korea.

A potential role for skeletal muscle caveolin-1 as an insulin sensitivity modulator in ageing-dependent non-obese type 2 diabetes: studies in a new mouse model

AIMS/HYPOTHESIS

Type 2 diabetes mellitus is a common age-dependent disease. We discovered that male offspring of non-diabetic C57BL/6 and DBA/2 mice, called JYD mice, develop type 2 diabetes when they grow old. JYD mice show characteristics of insulin resistance, hyperglycaemia and hyperinsulinaemia in old age without obesity. We postulated that the mechanism of age-dependent type 2 diabetes in this model relates to caveolin-1 status in skeletal muscle, which appears to regulate insulin sensitivity in the mice.

METHODS

We compared insulin sensitivity in aged C57BL/6 and JYD mice using glucose and insulin tolerance tests and (18)F-fluorodeoxyglucose positron emission tomography. We also determined insulin signalling molecules and caveolin proteins using western blotting, and altered caveolin-1 levels in skeletal muscle of C57BL/6 and JYD mice using viral vector systems, to examine the effect of this on insulin sensitivity.

RESULTS

In 30-week-old C57BL/6 and JYD mice, the basal levels of IRS-1, Akt and peroxisome proliferator-activated receptor-gamma decreased, as did insulin-stimulated phosphorylation of Akt and insulin receptor beta. However, caveolin-1 was only increased about twofold in 30-week-old JYD mice as compared with 3-week-old mice, whereas an eightfold increase was seen in C57BL/6 mice. Downregulation of caveolin-1 production in C57BL/6 mice caused severe impairment of glucose and insulin tolerance. Upregulation of caveolin-1 in aged diabetic JYD mice significantly improved insulin sensitivity with a concomitant increase of glucose uptake in the skeletal muscle.

CONCLUSIONS/INTERPRETATION

The level of skeletal muscle caveolin-1 is correlated with the progression of age-dependent type 2 diabetes in JYD mice.

Risk of malignancy in resected cystic tumors of the pancreas < or =3 cm in size: is it safe to observe asymptomatic patients? A multi-institutional report

Recent international consensus guidelines propose that cystic pancreatic tumors less than 3 cm in size in asymptomatic patients with no radiographic features concerning for malignancy are safe to observe; however, there is little published data to support this recommendation. The purpose of this study was to determine the prevalence of malignancy in this group of patients using pancreatic resection databases from five high-volume pancreatic centers to assess the appropriateness of these guidelines. All pancreatic resections performed for cystic neoplasms < or =3 cm in size were evaluated over the time period of 1998-2006. One hundred sixty-six cases were identified, and the clinical, radiographic, and pathological data were reviewed. The correlation with age, gender, and symptoms (abdominal pain, nausea and vomiting, jaundice, presence of pancreatitis, unexplained weight loss, and anorexia), radiographic features suggestive of malignancy by either computed tomography, magnetic resonance imaging, or endoscopic ultrasound (presence of solid component, lymphadenopathy, or dilated main pancreatic duct or common bile duct), and the presence of malignancy was assessed using univariate and multivariate analysis. Among the 166 pancreatic resections for cystic pancreatic tumors < or =3 cm, 135 cases were benign [38 serous cystadenomas, 35 mucinous cystic neoplasms, 60 intraductal papillary mucinous neoplasms (IPMN), 1 cystic papillary tumor, and 1 cystic islet cell tumor], whereas 31 cases were malignant (14 mucinous cystic adenocarcinomas and 13 invasive carcinomas and 4 in situ carcinomas arising in the setting of IPMN). A greater incidence of cystic neoplasms was seen in female patients (99/166, 60%). Gender was a predictor of malignant pathology, with male patients having a higher incidence of malignancy (19/67, 28%) compared to female patients (12/99, 12%; p < 0.02). Older age was associated with malignancy (mean age 67 years in patients with malignant disease vs 62 years in patients with benign lesions (p < 0.05). A majority of the patients with malignancy were symptomatic (28/31, 90%). Symptoms that correlated with malignancy included jaundice (p < 0.001), weight loss (p < 0.003), and anorexia (p < 0.05). Radiographic features that correlated with malignancy were presence of a solid component (p < 0.0001), main pancreatic duct dilation (p = 0.002), common bile duct dilation (p < 0.001), and lymphadenopathy (p < 0.002). Twenty-seven of 31(87%) patients with malignant lesions had at least one radiographic feature concerning for malignancy. Forty-five patients (27%) were identified as having asymptomatic cystic neoplasms. All but three (6.6%) of the patients in this group had benign disease. Of the patients that had no symptoms and no radiographic features, 1 out of 30 (3.3%) had malignancy (carcinoma in situ arising in a side branch IPMN). Malignancy in cystic neoplasms < or =3 cm in size was associated with older age, male gender, presence of symptoms (jaundice, weight loss, and anorexia), and presence of concerning radiographic features (solid component, main pancreatic duct dilation, common bile duct dilation, and lymphadenopathy). Among asymptomatic patients that displayed no discernable radiographic features suggestive of malignancy who underwent resection, the incidence of occult malignancy was 3.3%. This study suggests that a group of patients with small cystic pancreatic neoplasms who have low risk of malignancy can be identified, and selective resection of these lesions may be appropriate.

Failure of stress-induced downregulation of Bcl-2 contributes to apoptosis resistance in senescent human diploid fibroblasts

We previously reported that senescent human diploid fibroblasts (HDFs) are resistant to apoptosis induced by H(2)O(2) and staurosporine. We report here that senescent HDFs are resistant to thapsigargin-induced apoptosis as well. These agonists caused the reductions in mitochondrial membrane potential (MMP) and in the apoptosis inhibitory protein (B-cell lymphoma) only in young HDFs but not in senescent HDFs. In addition, downregulation of Bcl-2 increased the sensitivity of senescent HDFs to apoptosis induction, suggesting the significant role of Bcl-2 in apoptosis resistance of the senescent HDFs. We further found that P-cAMP response element-binding protein (CREB), a positive regulator of Bcl-2, decreased in stress-induced apoptosis of young HDFs but not in senescent HDFs, and that Bcl-2 was markedly reduced in CREB small interfering RNA (siRNA), transfected senescent HDFs. In addition, activity of protein phosphatase 2A (PP2A), which dephosphorylates p-CREB, significantly increased in young HDFs but not in senescent HDFs treated with H(2)O(2), staurosporine or thapsigargin. Taken together, these results suggest that failure of stress-induced downregulation of Bcl-2 underlies resistance of senescent HDFs to apoptosis.

Interplay between carrier and impurity concentrations in annealed Ga1-xMnxAs: intrinsic anomalous hall effect

Investigating the scaling behavior of annealed Ga1-xMnxAs anomalous Hall coefficients, we note a universal crossover regime where the scaling behavior changes from quadratic to linear. Furthermore, measured anomalous Hall conductivities in the quadratic regime when properly scaled by carrier concentration remain constant, spanning nearly a decade in conductivity as well as over 100 K in T_[C] and comparing favorably to theoretically predicated values for the intrinsic origins of the anomalous Hall effect. Both qualitative and quantitative agreements strongly point to the validity of new equations of motion including the Berry phase contributions as well as the tunability of the anomalous Hall effect.

Interplay between fermi surface topology and ordering in URu2Si2 revealed through abrupt hall coefficient changes in strong magnetic fields

Temperature- and field-dependent measurements of the Hall effect of pure and 4% Rh-doped URu2Si2 reveal low density (0.03 hole/U) high mobility carriers to be unique to the "hidden order" phase and consistent with an itinerant density-wave order parameter. The Fermi surface undergoes a series of abrupt changes as the magnetic field is increased. When combined with existing de Haas-van Alphen data, the Hall data expose a strong interplay between the stability of the "hidden order," the degree of polarization of the Fermi liquid, and the Fermi surface topology.

Role of Src-specific phosphorylation site on focal adhesion kinase for senescence-associated apoptosis resistance

A decreased apoptotic response toward noxious stress is an issuing characteristic of the aging phenotype. Hydrogen peroxide or staurosporine induced apoptosis readily in young cells but not in senescent cells. We showed that focal adhesion kinase (FAK) expression and its phosphorylation at Tyr397, autophosphorylation site for focal adhesion formation, and Tyr577, Src-dependent phosphorylation site, were both increased in senescent cells. Moreover, FAK was inactivated proteolytically by apoptotic stimuli in young cells, but not in senescent cells. In addition, senescent cells whose FAK expression was downregulated by siRNA showed the increased level of apoptosis by staurosporine treatment via caspase-3 activation but not by hydrogen peroxide treatment. Interestingly dephosphorylation at Tyr577 of FAK by PP2 treatment, Src-family kinase inhibitor, induced the apoptosis by staurosporine in senescent cells but dephosphorylation at Tyr397 by downregulation of caveolin-1 was not affected. These data suggest that FAK might differently regulate apoptosis and focal adhesion formation through site-specific tyrosine phosphorylation in senescent cells.

Phonon thermal transport of URu2Si2: broken translational symmetry and strong-coupling of the "hidden order" to the lattice

A dramatic increase in the total thermal conductivity (kappa) is observed in the hidden order (HO) state of single crystal URu2Si2. Through measurements of the thermal Hall conductivity, we explicitly show that the electronic contribution to kappa is extremely small, so that this large increase in kappa is dominated by phonon conduction. An itinerant BCS or mean-field model describes this behavior well: the increase in kappa is associated with the opening of a large energy gap at the Fermi surface, thereby decreasing electron-phonon scattering. Our analysis implies that the "hidden order" parameter is strongly coupled to the lattice, suggestive of a broken symmetry involving charge degrees of freedom.

Protease digestion indicates that endogenous presenilin 1 is present in at least two physical forms

The membrane-bound protein complex gamma-secretase is an intramembranous protease whose substrates are a number of type I transmembrane proteins including the beta-amyloid precursor protein (APP). A presenilin molecule is thought to be the catalytic unit of gamma-secretase and either of two presenilin homologues, PS1 or PS2, can play this role. Mutations in the presenilins, apparently leading to aberrant processing of APP, have been genetically linked to early-onset familial Alzheimer's disease. To look for possible molecular heterogeneity in presenilin/gamma-secretase we examined the ability of proteinase K (PK) to digest endogenously expressed presenilins in intact endoplasmic reticulum vesicles. We demonstrate the existence of two physically different forms of gamma-secretase-associated PS1, one that is relatively PK-sensitive and one that is significantly more PK-resistant. A similarly PK-resistant form of PS2 was not observed. We speculate that the structural heterogeneity we observe may underlie, at least in part, previous observations indicating the physical and functional heterogeneity of gamma-secretase. In particular, our results suggest that there are significant differences between gamma-secretase complexes incorporating PS1 and PS2. This difference may underlie the more dominant role of PS1 in the generation of beta-amyloid peptides and in familial Alzheimer's disease.

The effect of thrombin on astrocyte stellation with regional specificity

In this study, we have examined the possible existence of astrocyte regional heterogeneity in thrombin effect on astrocyte stellation. Neonatal astrocytes were cultured for 2 weeks from six different regions of the neonatal rat brain, including the cerebral cortex, hippocampus, brainstem, midbrain, hypothalamus and cerebellum. Culture medium was changed to DMEM containing 8-CPT-cyclic AMP (cAMP) or isoproterenol plus various concentrations of thrombin for 2 hr. Thrombin effectively blocked both cAMP- and isoproterenol-induced cell stellation in a dose-dependent manner in all regional astrocytes except cerebellar astrocytes. RT-PCR analysis showed that thrombin receptor mRNA was expressed in all regional astrocytes, suggesting that cerebellar astrocytes may maintain a unique signaling pathway downstream of the thrombin receptor.

Wire-guided pancreatic pseudocyst drainage by using a modified needle knife and therapeutic echoendoscope

BACKGROUND

Various methods to drain pancreatic pseudocysts by using EUS guidance have been reported in the literature.

OBJECTIVE

A new drainage technique is described that uses a modified needle knife advanced over a guidewire positioned in the pseudocyst by EUS guidance.

DESIGN

Retrospective chart review.

SETTING

Academic medical center.

PATIENTS

Consecutive subjects from December 1, 2002, to January 10, 2005, with symptomatic pseudocysts in whom EUS-guided drainage was attempted.

INTERVENTIONS

By using a therapeutic linear echoendoscope, a 19-gauge aspiration needle was inserted into the pseudocyst. A guidewire was placed through the needle, and a needle knife with the cutting wire protruding and bent was advanced over the guidewire to contact the stomach mucosa. The needle knife was then advanced by using electrocautery into the pseudocyst. The cystenterostomy was dilated by using a balloon over the guidewire. One to 4 stents were placed through the tract.

MAIN OUTCOME MEASUREMENTS

Successful pseudocyst drainage.

RESULTS

A total of 21 of 23 patients underwent technically successful pseudocyst drainage. One patient had self-limited hypotension during the procedure. Another patient had free intraperitoneal air after the procedure but correct stent placement.

LIMITATIONS

Retrospective analysis, small sample size.

CONCLUSIONS

In this preliminary experience, wire-guided pseudocyst drainage with a modified needle knife appears effective and safe while allowing for a more controlled pseudocyst puncture.

Disseminated histoplasmosis in a liver transplant recipient

A 61-yr-old liver transplant recipient presented with abdominal cramping and nonbloody diarrhea resulting in orthostasis. Multiple ulcerations throughout the colon were seen during endoscopy, and biopsies from the ulcer edges revealed histoplasmosis. Treatment with a course of itraconazole improved the diarrhea. The patient later presented with pericarditis and symptomatic pleural effusions, the latter of which was confirmed to be a result of disseminated histoplasmosis. Treatment with amphotericin B led to resolution. Histoplasmosis should be considered in liver transplant patients with diarrhea and large ulcers in the colon. The presence of disseminated histoplasmosis should be ruled out once colonic histoplasmosis has been diagnosed.

Effect of gamma-secretase inhibitors on muscarinic receptor-mediated calcium signaling in human salivary epithelial cells

Altered intracellular Ca(2+) signaling has been observed in cells derived from Alzheimer's disease patients, and a possible link between gamma-secretase activity and the content of intracellular Ca(2+) stores has been suggested. To test this hypothesis we studied the effects of several gamma-secretase inhibitors on muscarinic receptor-mediated intracellular calcium release in the human salivary gland cell line HSG. Although several inhibitors in the peptide aldehyde class partially blocked carbachol-induced Ca(2+) transients, these effects did not appear to be due to gamma-secretase inhibition, and overall we found no evidence that inhibition of gamma-secretase activity had any significant effect on agonist-induced intracellular calcium release in HSG cells. In complementary experiments with presenilin-null cells we found that the reconstitution of gamma-secretase activity by transfection with wild-type presenilin 1 likewise had no significant effect on thapsigargin-induced Ca(2+) release. In a test of the specific hypothesis that the level of APP intracellular domain (AICD), the intracellular fragment of the beta-amyloid precursor protein (APP) resulting from gamma-secretase cleavage, can modulate the Ca(2+) content of the endoplasmic reticulum, we were unable to demonstrate any effect of APP small interfering RNA on the magnitude of carbachol-induced intracellular calcium release in HSG cells. Together our data cast considerable doubt on the hypothesis that there is a direct link between gamma-secretase activity and the content of intracellular Ca(2+) stores.

Pancreaticopleural fistula: report of two cases and review of the literature

Pancreaticopleural fistulas are a rare complication of pancreatitis. We report two cases from our institution and review 37 cases of pancreaticopleural fistulas identified in the literature. Endoscopic retrograde cholangiopancreatography was more sensitive compared to computed tomography in demonstrating pancreaticopleural fistulas (79% versus 43%, respectively). Medical therapy with total parenteral nutrition, octreotide, and/or chest tube placement was successful in resolving the pancreaticopleural fistula in up to 33% of cases. None of the patients who underwent pancreatic duct stent and/or nasopancreatic drain placement required surgical intervention. Endoscopic retrograde cholangiopancreatography is the initial test of choice when the diagnosis of pancreaticopleural fistula is suspected. Early endoscopic intervention with pancreatic duct stent placement is recommended given its high success rate in fistula closure. Medical therapies are useful adjuncts to endoscopic therapy, but rarely result in pancreaticopleural fistula closure alone. Surgical interventions should only be considered after failure of endoscopic and medical therapies.

Topology of the C-terminal fragment of human presenilin 1

Mutations of human presenilin 1 (PS1) have been genetically linked to early-onset familial Alzheimer's disease. PS1 contains 10 hydrophobic regions (HRs) sufficiently long to be alpha-helical membrane spanning segments. Most previous topology studies agree that the N-terminus of PS1 is cytosolic and HRs 1-6 span the membrane but HR 7 does not. However, whether HRs 8 and 9 are membrane spanning segments remains controversial. Here we study the topology and biogenesis of this region of PS1 using a reporter gene fusion approach, where portions of the PS1 sequence containing possible membrane spanning segments were fused up- or downstream of a reporter sequence whose translocation into the endoplasmic reticulum could be monitored via its glycosylation. We provide strong evidence, supported by cysteine accessibility studies in full-length PS1, that HRs 8 and 9 are indeed membrane spanning and that the integration of HR 8 into the membrane is dependent on the presence of HR 9. We also explain how our results reconcile previous apparently divergent conclusions regarding the topology of HRs 8 and 9.

Histochemical and Electron Microscopic Study on Motor Neurone Degeneration Following Transient Spinal Cord Ischaemia at Normothermic Conditions in Rabbits

This study was carried out to investigate the motor neurone degeneration in the ventral horn following transient spinal cord ischaemia at normothermic conditions in rabbits. Transient spinal cord ischaemia was induced by occlusion of the abdominal aorta underneath the left renal artery for 15 min at normothermia (38.7 degrees C). Sections at the level of L7 were examined using histochemical and electron microscopic methods. Cresyl violet-positive motor neurones began to reduce in number at 3 h after ischaemia reperfusion, and were not detectable at 48 h after ischaemia reperfusion. Acid fuchsin-positive motor neurones were detected at 1 h after ischaemia reperfusion, significantly increased up to 6 h after the ischaemia reperfusion, and eventually disappeared by 48 h after ischaemia reperfusion. In electron microscopic findings, the disintegration of cytoplasmic membranes, and the disruption of mitochondria and endoplasmic reticulum were observed in motor neurones at 30 min after ischaemia reperfusion. Motor neurones showed necrotic findings with pyknotic degeneration at 1 h after ischaemia reperfusion. The necrotic degeneration became severer time dependently after ischaemia reperfusion. At 48 h after ischaemia reperfusion, cellular components were not detectable in motor neurones. In conclusion, we suggest that the degeneration pattern of motor neurones of the ischaemic spinal cord was necrotic after ischaemia reperfusion under normothermic conditions.

Clinical applications of endoscopic ultrasound to oncology

Endoscopic ultrasound (EUS) is a useful imaging modality in patients with certain gastrointestinal malignancies as well as lung cancer. In many cases, EUS has been shown to have superior staging accuracy compared with other imaging techniques such as computed tomography, magnetic resonance imaging and positron emission tomography. This article will review the role of EUS in diagnosing and staging esophageal, rectal, pancreatic and lung cancers as well as subepithelial lesions. Newer therapeutic applications of EUS, namely endoscopic mucosal resection for removal of localized lesions as well as celiac plexus neurolysis for pain control, will also be discussed.