Cation Modulation in AgSbTe2 Realizes Carrier Optimization, Defect Engineering, and a 7% Single-Leg Thermoelectric Efficiency

AgSbTe2 plays a pivotal role in mid-temperature thermoelectric generators (TEGs). Leveraging the seminal advances in cation manipulation within AgSbTe2, this study demonstrates an enhanced TE power factor (PF = S2σ) of 1.5 mWm-1 K-2 and a peak zT of 1.5 at 583 K in an off-stoichiometric Ag1.04Sb0.96Te2 crystal. The introduction of Ge in place of Ag leads to an increased nH as evidenced by the detection of trace Ge4+ through XPS analysis. Further chemical state analysis reveals the simultaneous presence of Ag+, Sb3+, and Ge4+, elucidating the effect of cation modulations. TEM characterizations validate the presence of superlattice structure, and the linear defects discerned within the AgSbTe2 matrix. Consequently, the lattice thermal conductivity κL is substantially reduced in the Ag1.02Ge0.02Sb0.96Te2 crystal, yielding a peak zT of 1.77 at 623 K. This notable advancement is attributed to the counterbalance achieved between the enhanced PF and the reduced κL, facilitated by cation modulation. Additionally, a single-leg TE device incorporating Ag1.02Ge0.02Sb0.96Te2 demonstrates a conversion efficiency of 7% across a temperature gradient (ΔT) of 350 K. This study corroborates the efficacy of cation modulation through thermodynamic approaches and establishes a relationship between transport properties and the presence of defects.

Tuning Interstitials in Fully Dense β-Zn4Sb3 Doubles Single-Leg Thermoelectric Efficiency

Zinc antimonides, particularly the β-Zn4Sb3 compound, act as prototypes in the early phases of thermoelectric generator (TEG) development. However, their potential applications are constrained by structural instability at elevated temperatures. In this study, introducing a low concentration of aluminum (Al) achieves a highly stable Al-Zn4Sb3, exhibiting an improved peak zT value compared to undoped Zn4Sb3. Notably, a single-leg device utilizing a fully dense Al0.01Zn3.99Sb3 demonstrates an impressive conversion efficiency (η) of 3% even at a temperature difference (ΔT) of 225 K. This result represents an approximately 200% increase compared with the pristine one. The combination of dilute cationic doping and phase diagram engineering solidifies the potential of Zn4Sb3 as an efficient and sustainable green energy device.

[Effects of neonatal stimulator of interferon genes innate immune signaling pathway of HBsAg-positive mothers on non/hypo-response to hepatitis B vaccine in infants]

Objective: To explore the effects of neonatal stimulator of interferon genes (STING) innate immune signaling pathway of HBsAg-positive mothers on non/hypo-response to hepatitis B vaccine (HepB) in their infants. Methods: From November 2019 to June 2022, HBsAg-positive mothers and their infants in the Third People's Hospital of Taiyuan were recruited as the study subjects. The epidemiological and clinical data were collected by questionnaire survey and medical records review. The key molecular proteins of STING innate immune signaling pathway (STING, pIRF3) and immune cells associated with vaccine response (DC, T and B and plasma cells) in neonatal cord blood were detected by flow cytometry. Follow up was conducted for infants for 1-2 months after the full vaccination of HepB. Serum hepatitis B surface antibody (anti-HBs) was detected by chemiluminescence microparticle immunoassay. Unconditional logistic regression model, nomogram and Bayesian network model were used to evaluate the effect of STING innate immune signaling pathway on non/hypo-response to HepB and related factors in infants, and the relationship between various factors. Results: A total of 195 pairs of HBsAg-positive mothers and infants were recruited, the rate of non/hypo-response to HepB in the infants was 12.31% (24/195). High maternal HBV DNA load, low expression of neonatal STING, low expression of pIRF3 and low percentage of plasma cells were risk factors for non/hypo-response to HepB in the infants (OR=4.70, 3.46, 3.18 and 2.20, all P<0.05). The nomogram constructed by these factors had good predictive efficacy (area under curve=0.81, 95%CI: 0.63-0.83). The results of Bayesian network model showed that the infants with a high maternal HBV DNA load had a higher conditional probability of low STING expression (62.50%) and a higher conditional probability of low pIRF3 expression (58.54%). The conditional probabilities of low expression of DC, T, B and plasma cells were 53.16%, 60.20%, 68.42% and 57.14%, respectively. Conclusion: Maternal HBV DNA might inhibit STING innate immune signaling pathways in infants and immune cells associated with HepB response, resulting in non/hypo-response to HepB in infants of HBsAg-positive mothers.

Substrate-Induced Anisotropic Growth of CuAlO2 Platelets in a Liquid-Solid Reaction

This study reports a simplified method to grow CuAlO₂ crystals of submillimeter sizes with a highly anisotropic shape of a platelet. The solid-state reaction of forming CuAlO₂ at ca. 1373 K in the first stage of the conventional flux method is no longer required. The CuAlO₂ platelets nucleated directly onto the (0001)_sapphire surface in a melt of Cu₂O saturated with Al₂O₃ at 1473 K. The excess flux was mostly removed by the capped alumina plate on cooling with a limited amount of residue which can be leached afterward. The CuAlO₂ platelets all have a 3R crystal structure with no line and planar defects observed by TEM. The CuAlO₂ crystals emit a luminescence at 3.49 eV associated with resonant Raman effect resulted from a band-to-band transition in room-temperature PL measurement. The facile fabrication method for growing highly anisotropic CuAlO₂ crystals paves the way for their practical application in photoelectrochemical devices.

[Preliminary study of the fourth-generation CAR-T cells targeting CS1 in the treatment of refractory and recurrent multiple myeloma]

Objective: To design the fourth-generation chimeric antigen receptor-T (CAR-T) cells that secrete interleukin-7 (IL7) and chemokine C legend 19 (CCL19) on the basis of the second-generation CAR, and to analyze and compare the differences in proliferation, chemotaxis, tumor cell clearance and persistence in the microenvironment of multiple myeloma (MM) between them. Methods: The fourth-generation CAR vector plasmid was constructed by using 2A self-cleaving peptide technology. The third-generation lentiviral packaging system was used to prepare high-titer lentivirus. Flow cytometry was used to monitor the transduction efficiency of lentivirus and the subtype changes of CAR-T cells. The enzyme-linked immunosorbent assay (ELISA) was used to quantify the IL7 and CCL19 secreted by CAR-T cells.The calculation of absolute number of CAR-T cells during culture was used to analysis cell proliferation activity. Transwell migration assay was used to verify the chemotactic ability of CAR-T cells. The specific killing activity of CAR-T cells was detected by using the luciferase bioluminescence method. The NOD-Prkdcem26Cd52Il2rgem26Cd22/Nju (NOD) mouse xenograft model was used to verify the anti-myeloma activity and safety of CAR-T cells in vivo. Results: Flow cytometry results showed that the stable CAR expression rates of the second-generation anti-CS1 CAR-T and fourth-generation anti-CS1-IL7-CCL19 CAR-T cells were (91.50±0.29)% and (46.7±0.12)%, respectively. CAR-T cells were successfully constructed. Subtype analysis demonstrated that the ratio of stem memory T cell (TSCM) in anti-CS1-IL7-CCL19 CAR-T cells was (67.58±0.59)%, which was significantly higher than (50.74 ± 1.01)% of anti-CS1 CAR-T (P=0.000 1), with more strong immune memory function and better durability. Anti-CS1-IL7-CCL19 CAR-T cells can continuously secrete IL7 and CCL19 compared to MOCK-T and anti-CS1 CAR-T (P<0.000 1). The number of anti-CS1-IL7-CCL19 CAR-T cells reached (22.77±0.79)×10(6) on the 9th day after lentivirus transduction, which was significantly higher than (9.40±0.79)×10(6) of anti-CS1 CAR-T cells (P=0.000 1), with stronger proliferation ability. The number of chemotaxis cells of anti-CS1-IL7-CCL19 CAR-T cells to reactive T cells was (109.0±4.04), which was significantly higher than (9.33±1.20) of MOCK-T (P<0.000 1) and (7.33±0.88) of anti-CS1 CAR-T (P<0.000 1), with stronger chemotactic ability. The specific killing activity showed that both anti-CS1-IL7-CCL19 CAR-T and anti-CS1 CAR-T cells had specific killing efficacies when compared with the MOCK-T cells (P<0.000 1). Animal experiment indicated that anti-CS1-IL7-CCL19 CAR-T cells significantly reduced the tumor burden (P<0.000 1) and extended the overall survival time (P=0.006 1) of tumor-bearing mice. Conclusions: The anti-CS1-IL7-CCL19 CAR-T cells designed in this study show stronger proliferative activity, chemotactic ability, and durability without affecting the anti-myeloma activity in vivo and in vivo, which provides strategies for overcoming the defects of low survival rate, poor durability and inhibition by tumor microenvironment of traditional CAR-T cells, and offers preliminary experimental basis for the clinical application of the fourth-generation CAR-T cells.

Compositional Fluctuations Locked by Athermal Transformation Yielding High Thermoelectric Performance in GeTe

Phase transition in thermoelectric (TE) material is a double-edged sword-it is undesired for device operation in applications, but the fluctuations near an electronic instability are favorable. Here, Sb doping is used to elicit a spontaneous composition fluctuation showing uphill diffusion in GeTe that is otherwise suspended by diffusionless athermal cubic-to-rhombohedral phase transition at around 700 K. The interplay between these two phase transitions yields exquisite composition fluctuations and a coexistence of cubic and rhombohedral phases in favor of exceptional figures-of-merit zT. Specifically, alloying GeTe by Sb₂ Te₃ significantly suppresses the thermal conductivity while retaining eligible carrier concentration over a wide composition range, resulting in high zT values of >2.6. These results not only attest to the efficacy of using phase transition in manipulating the microstructures of GeTe-based materials but also open up a new thermodynamic route to develop higher performance TE materials in general.

The Y-chromosome F haplogroup contributes to the development of Barrett's esophagus-associated esophageal adenocarcinoma in a white male population

Barrett's esophagus (BE) is a metaplastic condition of the distal esophagus, resulting from longstanding gastroesophageal reflux disease (GERD). BE predisposes for the highly malignant esophageal adenocarcinoma (EAC). Both BE and EAC have the highest frequencies in white males. Only a subset of patients with GERD develop BE, while <0.5% of BE will progress to EAC. Therefore, it is most likely that the development of BE and EAC is associated with underlying genetic factors. We hypothesized that in white males, Y-chromosomal haplogroups are associated with BE and EAC. To investigate this we conducted a multicenter study studying the frequencies of the Y-chromosomal haplogroups in GERD, BE, and EAC patients. We used genomic analysis by polymerase chain reaction and restriction fragment length polymorphism to determine the frequency of six Y-chromosomal haplogroups (DE, F(xJ,xK), K(xP), J, P(xR1a), and R1a) between GERD, BE, and EAC in a cohort of 1,365 white males, including 612 GERD, 753 BE patients, while 178 of the BE patients also had BE-associated EAC. Univariate logistic regression analysis was used to compare the outcomes. In this study, we found the R1a (6% vs. 9%, P = 0.04) and K (3% vs. 6%, P = 0.035) to be significantly underrepresented in BE patients as compared to GERD patients with an odds ratio (OR) of 0.63 (95% CI 0.42-0.95, P = 0.03) and of 0.56 (95% CI 0.33-0.96, P = 0.03), respectively, while the K haplogroup was protective against EAC (OR 0.30; 95% CI 0.07-0.86, P = 0.05). A significant overrepresentation of the F haplogroup was found in EAC compared to BE and GERD patients (34% vs. 27% and 23%, respectively). The F haplogroup was found to be a risk factor for EAC with an OR of 1.5 (95% CI 1.03-2.19, P = 0.03). We identified the R1a and K haplogroups as protective factors against development of BE. These haplogroups have low frequencies in white male populations. Of importance is that we could link the presence of the predominantly occurring F haplogroup in white males to EAC. It is possible that this F haplogroup is associated to genetic variants that predispose for the EAC development. In future, the haplogroups could be applied to improve stratification of BE and GERD patients with increased risk to develop BE and/or EAC.

Interpretation of volumetric laser endomicroscopy in Barrett's esophagus using image enhancement software

Image interpretation of Barrett's esophagus (BE) with volumetric laser endomicroscopy (VLE) can be enhanced by image processing software that highlights established features using a color-graded scale (intelligent real-time image segmentation, IRIS). This study aims to provide a description of IRIS features of various gastroesophageal tissue types using histologic correlation. A database of 80 VLE laser-marked targets with histologic correlation was reviewed for various tissue types. IRIS was applied off-line to the VLE scans, laser-marked targets were identified, and feature review was performed. Squamous epithelium targets (N = 7) showed IRIS layered architecture with lack of surface hyper-reflectivity and epithelial glands. Gastric cardia targets (N = 10) showed absent layering (100%) and surface hyper-reflectivity with epithelial glands (40%). Nondysplastic BE targets (N = 39) showed surface hyper-reflectivity (64%), epithelial glands (51%), and lack of layering (74%). Targets of BE with early neoplasia (N = 24), showed surface hyper-reflectivity (96%), epithelial glands (67%), and lack of layering (96%). IRIS features that characterize each tissue type appear to mirror the nonenhanced VLE counterparts that define them.

[Association between maternal dietary intake and the incidence of babies with small for gestational age]

Objective: To investigate the relations between dietary intake during pregnancy and the incidence of their babies with small for gestational age (SGA). Methods: Data on demographics, dietary intake of protein, fat, and carbohydrates of the pregnant mothers during the first, second and third trimester, were collected. Information related to birth weight and gestational age of the infants were also gathered. A total of 8 102 women, who delivered their babies at the First Affiliated Hospital of Shanxi Medical University from March 2012 to September 2016, were enrolled in this project. Among them, 961 mothers had infants with SGA but the other 7 141 of them having normal infants. Unconditional logistic regression model was used to analyze the effect of dietary nutrient intake on SGA the first, second and third trimester. Results: We found that low dietary intake of protein during the first trimester and following trimesters during pregnancy were positively associated with higher risk of SGA (OR=1.534, 95%CI: 1.217-1.934; OR=1.268, 95%CI: 1.005-1.599; OR=1.310, 95%CI: 1.036-1.655). When adjusting for maternal pre-pregnancy BMI, we found that when mothers were with a pre-pregnancy BMI less than 18.5 or with low maternal intake of protein during the first trimester, positive association with higher risk of SGA (OR=1.872, 95%CI: 1.033-3.395; OR=1.754, 95%CI: 1.125-2.734), was noticed. However, for mothers with a pre-pregnancy BMI between 18.5 and 24.0 or with low protein intake during the first trimester, significant association with higher risk of SGA (OR=1.465, 95%CI: 1.089-1.972) was found. Conclusions: Through our observation, maternal dietary intake during pregnancy seemed to be associated with the risk of SGA but the effects of dietary intake were different, according to the BMI of pre-pregnancy population. Early pregnancy appeares as the key period for dietary intake which may influence the SGA.

Clutch cutter is a safe device for performing endoscopic submucosal dissection of superficial esophageal neoplasms: a western experience

Although the endoscopic submucosal dissection (ESD) has been established to be more efficacious in the treatment of superficial gastrointestinal neoplasia than the piecemeal resection, its use is still limited due to the concern about serious adverse events particularly in the west. Newer ESD knives have been developed that have been said to be safer than the first-generation devices. We aimed to report a Western single center experience regarding the initial safety and performance of ESD for superficial esophageal neoplasia treated with the Clutch Cutter (DP2618DT; Fujifilm Corporation, Tokyo, Japan). Our main outcome was safety in terms of bleeding or perforation. Secondary outcomes included en bloc resection and the R0 resection. Fourteen patients with superficial esophageal neoplasia underwent 15 ESDs using the Clutch Cutter. The mean age was 65 ± 16.7 years and 10 (71.4%) males. Eight (57%) patients had esophageal adenocarcinoma, 3 (21.4%) had high-grade dysplasia, 1 (7%) had nodular low-grade dysplasia, and 2 (14.3%) had squamous cell carcinoma. Mild anticipated intraprocedural bleeding was present with most procedures. However, no significant postoperative bleeding or perforation was encountered. One patient had mild chest pain postprocedure. En bloc resection was achieved in all lesions 100%. Histological R0 was achieved in 5/12 lesions (41.6%). The mean length of the resected area was 24.8 ± 13 mm (IQR: 17-30 mm). All patients were safely discharged home after overnight observation. In conclusion, this is the largest series of esophageal ESD using the multimodal Clutch Cutter in the United States; we found that the device effectively achieved en bloc resection of superficial esophageal neoplasia without significant adverse events. The use of the Clutch Cutter should be considered as one option to minimize adverse events during ESD in the Western population.

Comparative assessment of atherosclerosis of rabbit femoral artery by Duplex Ultrasound Scanning, Optical Coherence Tomography and Fractional Flow Reserve

Duplex Ultrasound Scanning (DUS), Frequency-domain optical coherence tomography (FD-OCT) and fractional flow reserve (FFR) remarkably shape our understanding of the significance of coronary stenosis. The present study aimed to compare the assessment results of the atherosclerotic lesions in rabbit superficial femoral artery by DUS with that of FD-OCT and FFR. A total of 20 atherosclerotic lesions were analyzed. Morphological assessments were prospectively compared through DUS, FD-OCT and quantitative superficial femoral angiography (QFA). In addition, the correlation between DUS derived lesion parameters and FFR was determined. The results show that, compared with FD-OCT and QFA, DUS detected larger reference diameter and higher percent stenosis. However, the minimal lumen diameter (MLD) and distance from profunda femoris to MLD were equivalent measured by the three imaging modalities. There was a poor correlation between FFR and DUS-derived percent diameter stenosis (R2=0.198, P=0.049). In conclusion, hemodynamic significance of lesions assessed by FFR was only related with percent diameter stenosis measured by DUS.

[Spatial and temporal characteristics of HIV/AIDS in Hubei province, 2010-2013]

Objective: To understand the spatial and temporal distribution of HIV/AIDS in Hubei province, and provide scientific evidence for the prevention and control of AIDS. Methods: GeoDa software was used for autocorrelation analysis, SatScan 9.2 software was used for statistical analysis of spatial scanning, and finally geographic information system was used for visualization. Results: A total of 6 952 HIV/AIDS cases were reported during 2010-2013 in Hubei, and the spatial autocorrelation analysis showed that Global Moran's I index was 0.266 (P<0.05), indicating that there was a positive spatial autocorrelation of HIV/AIDS. Global Moran's I index increased year by year (P<0.05), indicating that the increased spatial aggregation of HIV/AIDS during 2010-2013. The local Moran's I index showed that " high-high" clustering areas were in Wuhan, and the number of " high-high" clustering areas increased during 2010-2013. Moreover, the " high-high" clustering areas expanded from Wuhan to surrounding areas. Spatial and temporal scan analysis revealed that 19 counties in Wuhan, Huangshi, Ezhou, Xianning with a radius of 60.01 km (LLR=625.14, RR=3.23) were the main spatial and temporal clustering area during 2012-2013. Conclusion: The spatial changes of HIV/AIDS seemed to be regular from 2010 to 2013 in Wuhan, spatial correlation at provincial level decreased and the " high-high" clustering areas gradually expanded from Wuhan to surrounding areas, indicating that it is necessary to strengthen the AIDS prevention and control in these areas in Hubei.

Prognostic utility of neuroinjury biomarkers in post out-of-hospital cardiac arrest (OHCA) patient management

Despite aggressive intervention, patients who survive an out-of-hospital cardiac arrest (OHCA) generally have very poor prognoses, with nationwide survival rates of approximately 10-20%. Approximately 90% of survivors will have moderate to severe neurological injury ranging from moderate cognitive impairment to brain death. Currently, few early prognostic indicators are considered reliable enough to support patients' families and clinicians' in their decisions regarding medical futility. Blood biomarkers of neurological injury after OHCA may be of prognostic value in these cases. When most bodily tissues are oxygen-deprived, cellular metabolism switches from aerobic to anaerobic respiration. Neurons are a notable exception, however, being dependent solely upon aerobic respiration. Thus, after several minutes without circulating oxygen, neurons sustain irreversible damage, and certain measurable biomarkers are released into the circulation. Prior studies have demonstrated value in blood biomarkers in prediction of survival and neurologic impairment after OHCA. We hypothesize that understanding peptide biomarker kinetics in the early return of spontaneous circulation (ROSC) period, especially in the setting of refractory cardiac arrest, may assist clinicians in determining prognosis earlier in acute resuscitation. Specifically, during and after immediate resuscitation and return of ROSC, clinicians and families face a series of important questions regarding patient prognosis, futility of care and allocation of scarce resources such as the early initiation of extracorporeal cardiopulmonary resuscitation (ECPR). The ability to provide early prognostic information in this setting is highly valuable. Currently available, as well as potential biomarkers that could be good candidates in prognostication of neurological outcomes after OHCA or in the setting of refractory cardiac arrest will be reviewed and discussed.

High Thermal Dissipation of Al Heat Sink When Inserting Ceramic Powders by Ultrasonic Mechanical Coating and Armoring

Aluminum alloys, which serve as heat sink in light-emitting diode (LED) lighting, are often inherent with a high thermal conductivity, but poor thermal total emissivity. Thus, high emissive coatings on the Al substrate can enhance the thermal dissipation efficiency of radiation. In this study, the ultrasonic mechanical coating and armoring (UMCA) technique was used to insert various ceramic combinations, such as Al₂O₃, SiO₂, or graphite, to enhance thermal dissipation. Analytic models have been established to couple the thermal radiation and convection on the sample surface through heat flow equations. A promising match has been reached between the theoretical predictions and experimental measurements. With the adequate insertion of ceramic powders, the temperature of the Al heat sinks can be lowered by 5–11 °C, which is highly favorable for applications requiring cooling components.

Systematic review with meta-analysis: prevalent vs. incident oesophageal adenocarcinoma and high-grade dysplasia in Barrett's oesophagus

BACKGROUND

The proportion of oesophageal adenocarcinoma that is detected concurrently with initial Barrett's oesophagus diagnosis is not well studied.

AIM

To compare the proportion of prevalent adenocarcinoma vs. incident adenocarcinoma found during surveillance of Barrett's.

METHODS

We performed a systematic search of MEDLINE, EMBASE and Web of Science (from their inception to 31 May 2015) for cohort studies in adults with Barrett's (nondysplastic Barrett's ± Barrett's with low-grade dysplasia) with minimum average follow-up of 3 years, and providing numbers of prevalent adenocarcinoma detected (concurrently with Barrett's diagnosis and up to 1 year afterwards) vs. incident adenocarcinoma detected (greater than 1 year after Barrett's diagnosis). Pooled weighted proportions of prevalent and incident adenocarcinoma were calculated, using a random effects model.

RESULTS

On meta-analysis of 13 studies reporting on 603 adenocarcinomas in 9657 Barrett's patients, 85.1% of adenocarcinomas were classified as prevalent [95% confidence interval (CI), 78.1-90.2%) and 14.9% as incident (95% CI, 9.8-21.9%), with substantial heterogeneity (I(2) = 66%). Among nine studies reporting on 787 high-grade dysplasia and oesophageal adenocarcinomas in 8098 Barrett's patients, the proportion of prevalent high-grade dysplasia-oesophageal adenocarcinoma was similar at 80.5% (95% CI, 68.1-88.8%, I(2) = 87%). These results remained stable across multiple subgroup analyses including study quality, setting, duration of follow-up and presence of baseline dysplasia.

CONCLUSIONS

In our meta-analysis, four of five patients diagnosed with adenocarcinoma or high-grade dysplasia at index endoscopy or within 1 year of Barrett's follow-up were considered to be prevalent cases. Continued efforts are needed to identify patients with Barrett's before the development of adenocarcinoma.

Medical and endoscopic management of high-grade dysplasia in Barrett's esophagus

The management of high-grade dysplasia in Barrett's esophagus has clearly changed over recent years. The risk of cancer development is still substantial, with about one in three patients developing cancer, but a number of patients do not develop cancer. The nature of high-grade dysplasia has also been genetically elucidated with more evidence of chromosomal instability being present at this stage than previously thought. Therapy of the condition has evolved more toward endoscopic therapy, given the good results of radio-frequency ablation and photodynamic therapy in eliminating dysplasia and decreasing cancer development in randomized controlled trial. The best candidates for treatment include compliant patients that have relatively short segments of Barrett's esophagus, an anatomically straight segment, lack of nodularity, and an intact p16. However, even with excellent long-term results similar to surgical resection, the risk of recurrence is present in over 14% of patients, which indicates that there will be a need to continue surveillance endoscopy in these patients.

Photodynamic therapy of intraductal papillary mucinous neoplasm

Intraductal papillary mucinous neoplasm (IPMN) of the main pancreatic duct is usually treated by surgical excision of the affected pancreas. Nonoperative ablative therapies have not been described. We treated IPMN of the pancreatic duct with photodynamic therapy (PDT) in a patient who was a poor operative candidate. Porfimer sodium was administered intravenously, and laser light was delivered by a diffusing catheter placed in the pancreatic duct during endoscopic retrograde cholangiopancreatography (ERCP). Imaging and biopsy findings of IPMN resolved after PDT, and symptoms also resolved. Metastatic cancer was diagnosed 2 years after PDT had been initiated. Pancreatic PDT was well tolerated in this case, and may be a therapeutic option for selected patients with IPMN of the main pancreatic duct.

Endoscopic ablative therapy for Barrett's esophagus: a potential cause of eosinophilic esophagitis

Markedly increased esophageal eosinophils are associated with allergy- or reflux-based eosinophilic esophagitis. Other known disorders that cause this entity are unusual. To characterize the clinical, endoscopic, and histological findings of patients who develop marked esophageal eosinophilic infiltration after ablative therapy for Barrett's dysplasia. All patients who underwent endoscopic ablation of Barrett's esophagus between 1991 and 2009 with photodynamic therapy or radio frequency were screened for a pathologic descriptor of 'eosinophils' on biopsy. Patients whose biopsies demonstrated >15 eosinophils per high power (HPF) field in squamous epithelium after ablation were reviewed and included in the study group. Thirteen of 385 (3.4%) patients underwent ablation for Barrett's esophagus and subsequently had large numbers of intraepithelial eosinophils. All patients had long segment Barrett's (mean 8.0 cm) with low- or high-grade dysplasia or adenocarcinoma. All had undergone photodynamic therapy as their form of ablation. No patients had typical symptoms or endoscopic findings of eosinophilic esophagitis. Eleven patients were on proton pump inhibitors. The time between ablation and onset of esophageal eosinophilia ranged from 83 to 692 days. Intraepithelial eosinophil counts ranged from 30 to 150/HPF (mean 90). The majority of cases showed eosinophilic degranulation, spongiosis, increased papillary height, and basal zone thickening. The natural history of esophageal eosinophilia was variable after ablation, persisting consistently or sporadically on biopsy for up to 6 years. Ablation for Barrett's dysplasia can be followed rarely by eosinophil infiltrates with a histological resemblance to allergy-based eosinophilic esophagitis, but lacking dysphagia. The pathophysiology is unknown.

Endoscopic diagnosis and resection of esophageal granular cell tumors

Granular cell tumors (GCT) are uncommon neoplasms. There is controversy regarding the endoscopic diagnosis and treatment of esophageal GCT. We studied the endoscopic diagnosis and management of esophageal GCT among 23 patients identified in a single-institution pathology database. Medical records, pathology, and endoscopic images were reviewed. All patients underwent endoscopy and endoscopic ultrasonography (EUS), and endoscopic resection was performed in 10 patients. Seven of 23 patients had more than one esophageal GCT. Only six lesions exhibited a classic yellow discoloration. Among patients with a single GCT, three, four, and nine lesions were located in the proximal, middle, and distal esophagus, respectively. EUS showed hypoechoic, smooth-edged lesions usually confined to deep mucosa and submucosa. Standard forceps biopsy was diagnostic in 19 of 23 patients (83%). Ten GCT ≤ 10 mm in diameter underwent successful endoscopic mucosal resection without complication. The endoscopic appearance, location, and number of esophageal GCT are highly variable. Histological proof is still necessary for the differential diagnosis of this rare neoplasm. Endoscopic forceps biopsy is usually diagnostic. Endoscopic resection appears safe and effective in selected cases with lesions ≤ 10 mm.

Endoscopic radiofrequency ablation for Barrett's esophagus: 5-year outcomes from a prospective multicenter trial

BACKGROUND AND STUDY AIMS

The AIM-II Trial included patients with nondysplastic Barrett's esophagus (NDBE) treated with radiofrequency ablation (RFA). Complete eradication of NDBE (complete response-intestinal metaplasia [CR-IM]) was achieved in 98.4 % of patients at 2.5 years. We report the proportion of patients demonstrating CR-IM at 5-year follow-up.

PATIENTS AND METHODS

Prospective, multicenter US trial (NCT00489268). After endoscopic RFA of NDBE up to 6 cm, patients with CR-IM at 2.5 years were eligible for longer-term follow-up. At 5 years, we obtained four-quadrant biopsies from every 1 cm of the original extent of Barrett's esophagus. All specimens were reviewed by one expert gastrointestinal pathologist, followed by focal RFA and repeat biopsy if NDBE was identified. Primary outcomes were (i) proportion of patients demonstrating CR-IM at 5-year biopsy, and (ii) proportion of patients demonstrating CR-IM at 5-year biopsy or after the single-session focal RFA.

RESULTS

Of 60 eligible patients, 50 consented to participate. Of 1473 esophageal specimens obtained at 5 years 85 % contained lamina propria or deeper tissue (per patient, mean 30 , standard deviation [SD] 13). CR-IM was demonstrated in 92 % (46 / 50) of patients, while 8 % (4 / 50) had focal NDBE; focal RFA converted all these to CR-IM. There were no buried glands, dysplasia, strictures, or serious adverse events. Kaplan-Meier CR-IM survival analysis showed probability of maintaining CR-IM for at least 4 years after first durable CR-IM was 0.91 (95 % confidence interval [CI] 0.77 - 0.97) and mean duration of CR-IM was 4.22 years (standard error [SE] 0.12).

CONCLUSIONS

In patients with NDBE treated with RFA, CR-IM was demonstrated in the majority of patients (92 %) at 5-year follow-up, biopsy depth was adequate to detect recurrence, and all failures (4 / 4, 100 %) were converted to CR-IM with single-session focal RFA.

Hydroboration kinetics: Unusual kinetics for the reaction of 9-borabicyclo[3.3.1]nonane with representative alkenes

The kinetics of hydroboration of alkenes with 9-borabicyclo[3.3.1]nonane dimer, (9-BBN)(2), exhibit interesting characteristics. With more reactive alkenes, such as 1-hexene, 2-methyl-1-pentene, 3,3-dimethyl-1-butene, and cyclopentene, the reaction exhibits first-order kinetics, first order in (9-BBN)(2) and zero order in alkene. On the other hand, with less reactive alkenes, such as cyclohexene, 1-methylcyclohexene, and 2,3-dimethyl-2-butene, the reaction exhibits three-halves-order kinetics, first order in alkene and one-half order in (9-BBN)(2). These kinetics can be accounted for in terms of the following mechanism:(9-BBN)(2) right arrow over left arrow 2 9-BBN9-BBN + alkene --> B-alkyl-9-BBNIn the case of the more reactive alkenes, the rate-determining step is the dissociation of the dimer. With less reactive alkenes, the reaction of the alkene with the monomer becomes the rate-determining step. For certain alkenes, such as 2-methyl-2-butene and cis-3-hexene, neither of the two steps is a decisive rate-determining step. Therefore, the reaction exhibits kinetic behavior between that of first- and three-halves-order kinetics.

Micromachined "Side-Viewing" Optical Sensor Probe for Detection of Esophageal Cancers

In this paper, we report the design, fabrication and testing of a new miniaturized optical sensor probe with "side viewing" capability for oblique incidence diffuse reflectance spectrometry. The sensor probe consists of a lithographically patterned polymer waveguides chip and two micromachined positioning substrates and source/collection fibers to achieve 45° light incidence and collection of spatially resolved diffuse reflectance. Diffuse reflectance of human esophageal surface has been successfully measured for differentiation of cancerous tissues from normal ones.

Noninvasive blood glucose monitoring using the optical signal of pulsatile microcirculation: a pilot study in subjects with diabetes

OBJECTIVE

The objective of this study was to determine the conditions for optimizing measurements obtained with a noninvasive blood glucose monitor using the optical signal of pulsatile microcirculation (OSPM) in both prediabetic and diabetic subjects receiving medication.

RESEARCH DESIGN AND METHODS

Eighteen subjects (3 prediabetic, 15 diabetic) aged 61.8 [15.9] years (mean [S.D.]) were studied. OSPM was the pulsatile component (P) of the signal obtained and analyzed by a blood glucose monitor. The measurement was calibrated to the fingerstick meter for each subject for personal calibration. Data were obtained from all subjects using both meters.

RESULTS

A total of 179 data pairs were measured and analyzed. The validity of the position of the tested finger was assessed using the position criterion, which resulted in the removal of 38 data pairs. The criterion for the intensity of the P signal was satisfied by 141 data pairs, with nonconforming data (with a much lower P signal) mainly occurring below 26 degrees C. A total of 113 data points passed both criteria, and 100% of them fell within Zones A and B of the Clarke error grid. Data in Zones A and B exhibited a linear relationship (r=.81; slope=0.82; intercept=28.0) between noninvasive and fingerstick measurements.

CONCLUSIONS

Environmental temperature has the greatest influence on the capability of the OSPM technique to monitoring blood glucose concentration, which is subject dependent. The position of the tested finger is the second major factor, hence a carefully designed finger adaptor is essential.

Gene expression profile comparison of Barrett's esophagus epithelial cell cultures and biopsies

Barrett's esophagus (BE) is a metaplastic process in which the normal squamous epithelium of the distal esophagus is replaced by columnar lined epithelium. The aim was to gain more insight in the process of metaplasia and to identify which genes are specifically expressed by the epithelial cells and the surrounding tissues in BE. Hereto, the gene expression profile of a BE epithelial primary cell culture was compared to that of a BE biopsy. To specifically obtain the epithelial cell layer, epithelial cells from biopsies of BE were cultured using a Barrett specific culturing medium. Serial analysis of gene expression was applied to obtain a transcription library of the primary epithelial cell culture. The transcriptome was analyzed and compared to a previously described transcriptome of a BE biopsy. Validation of results by reverse transcriptase-polymerase chain reaction was performed using tissues of 16 BE patients and 16 primary cell cultures. Over 43,000 tags were sequenced. Genes specifically expressed by the Barrett epithelial cells were for instance Lipocalin 2 and Cyclin D1, whereas annexin A10, trefoil factor (TFF)1 and TFF2 were specifically expressed in the BE biopsies. The comparison of the gene expression profiles of BE primary cultured epithelial cells with BE biopsy defines a subset of genes that are specifically expressed by the epithelial cells and another subset that most likely is expressed by the underlying stromal tissues in the BE biopsy specimens.

Phase I trial of oral MAC-321 in subjects with advanced malignant solid tumors

PURPOSE

MAC-321 is a novel taxane that has demonstrated exceptional activity in human xenograft models when administered intravenously and orally. Preclinical studies of MAC-321 have shown antitumor activity in MDR-expressing and paclitaxel-resistant tumors. This phase I dose escalation study was performed to determine the safety, tolerability, and pharmacokinetic profile of orally administered MAC-321 given once every 21 days. Preliminary antitumor activity of MAC-321 was also examined.

METHODS

Key eligibility criteria included adult subjects with refractory solid tumors or solid tumors for which conventional therapy was unsuitable or did not exist, good performance status (ECOG ( 2), and adequate hematologic, hepatic, and renal functions. Plasma pharmacokinetic (PK) sampling was performed during the first cycle of therapy.

RESULTS

Five dose levels of MAC-321 ranging from 25 to 75 mg/m(2) were evaluated in 18 subjects (four women and 14 men). MAC-321 was well tolerated at the first three dose levels (25, 37, 50 mg/m(2)). Two subjects developed dose-limiting toxicities (DLTs) at 75 mg/m(2); one subject with grade 3 and one subject with grade 4 neutropenia with fever. Three subjects treated at an intermediate dose level of 60 mg/m(2) had no DLTs. However, the study was terminated prior to completion of the maximal tolerated dose cohort after subjects treated with intravenous MAC-321 in a concurrent study experienced life-threatening toxicities. Other common toxicities included grades 1-2 fatigue and grades 1-2 diarrhea. There was substantial interpatient variability in the PK parameters. MAC-321 was rapidly absorbed with a mean C (max) value of less than 1 h. Mean C (max) and AUC values generally increased in a dose-related manner. The median terminal phase elimination half-life was 45 h (range 20-228 h). Disease stabilization was seen in four subjects with the following tumors: mesothelioma (14 cycles), chondrosarcoma (12 cycles), small cell carcinoma (10 cycles), and prostate carcinoma (6 cycles).

CONCLUSIONS

MAC-321 can be safely administered orally once every 21 days up to a dose of 60 mg/m(2). The major DLT was neutropenic fever. Four subjects had disease stabilization.

Impact of endoscopist withdrawal speed on polyp yield: implications for optimal colonoscopy withdrawal time

BACKGROUND

In 2002, a U.S. Multi-Society Task Force on Colorectal Cancer recommended that the withdrawal phase for colonoscopy should average at least 6-10 min. This was based on 10 consecutive colonoscopies by two endoscopists with different adenoma miss rates.

AIMS

To characterize the relationship between endoscopist withdrawal time and polyp detection at colonoscopy, and to determine the withdrawal time that corresponds to the median polyp detection rate.

DESIGN

Procedural data from out-patient colonoscopies performed at the Mayo Clinic, Rochester during 2003 were reviewed. Endoscopists were characterized by their mean withdrawal time for a negative procedure and individual polyp detection rate.

RESULTS

A total of 10 955 colonoscopies performed by 43 endoscopists were analysed. Median withdrawal time was 6.3 min (range: 4.2-11.9); polyp detection rate was 44.0% (all polyps), 29.8% (< or = 5 mm), 5.9% (6-9 mm), 6.7% (10-19 mm), 2.1% (> or = 20 mm). Longer withdrawal time was associated with higher polyp detection rate (r = 0.76; P < 0.0001); this relationship weakened for larger polyps (r = 0.19 for polyps 6-9 mm, r = 0.28 for polyps 10-19 mm, r = 0.02 for polyps > or = 20 mm). Overall median polyp detection rate corresponded to a withdrawal time of 6.7 min.

CONCLUSION

Our findings support a colonoscopy withdrawal time of at least 7 min, which correlates with higher colon polyp detection rates.

Serum insulin, insulin resistance, beta-cell dysfunction, and gallstone disease among type 2 diabetics in Chinese population: a community-based study in Kinmen, Taiwan

AIM

To explore the association of serum insulin, insulin resistance, and beta-cell dysfunction with gallstone disease (GSD) in type 2 diabetics.

METHODS

We used a community-based study conducted between 1991 and 1993 in Kinmen, Taiwan to identify type 2 diabetics. A screening program for GSD was performed in 2001 by a panel of specialists who employed real-time ultrasound sonography to examine the abdominal region after the patient had fasted for at least 8 h. Screening was conducted in 2001 on 848 patients diagnosed with type 2 diabetes. The HOMA method was used to compare the profile differences for insulin resistance (HOMA IR) and beta-cell dysfunction (HOMA beta-cell).

RESULTS

We studied 440 type 2 diabetics who attended sonography check-ups. After excluding eight insulin-treated diabetics, the prevalence of GSD among the remaining 432 was 13.9% (26/187) among males and 14.7% (36/245) among females. After adjustment for other GSD-associated risk factors in addition to age and obesity, GSD risk increased among females with levels of serum insulin [4(th) vs 1(st) quartile odds ratios (OR) = 4.46 (95%CI: 1.71-11.66)] and HOMA IR [4(th) vs 1(st) quartile OR = 4.46 (95%CI: 1.71-11.66)]. Better HOMA beta-cell function was significantly related to decreased risk of GSD [4(th) vs 1(st) quartile OR = 0.16 (95%CI: 0.03-1.70)]. Among males, age and central obesity were the most significant risk factors for GSD. No association of GSD with serum insulin, HOMA IR, and HOMA beta-cell was observed among males.

CONCLUSION

Serum insulin, insulin resistance, and beta-cell dysfunction are risk factors for GSD in females, but not males with type 2 diabetes.

Inhibition of p38 kinase mimics survival signal-linked protection against apoptosis in rat cerebellar granule neurons

The mitogen-activated protein kinase (MAPK) cascades are thought to be important mediators in the transduction of extracellular signals into cellular responses. The p38 kinase, a member of the MAPK superfamily, is activated by a wide variety of extracellular stimuli and has been implicated in neuronal apoptosis induced by glutamate. In this study we have examined the role of p38 kinase in the potassium deprivation model of apoptosis in rat cerebellar granule neurons (CGN). An increase in p38 kinase activity was observed with a 15-minute potassium deprivation when compared to the basal level. We also found that SB203580 and PD169316, specific p38 kinase inhibitors, significantly attenuated apoptosis in potassium-deprived cells in a dose dependent manner. A decrease in caspase-3 mediated DEVD-MCA, substrate hydrolysis and the appearance of the 120 kDa-spectrin breakdown product in cells treated with SB203580 further suggests that the p38 kinase acts upstream of caspase-3 in the apoptosis cascade. The data provides evidence for an essential role of p38 kinase in mediating apoptotic cell death in CGN and the inhibition of p38 kinase mimics the suppression of apoptosis provided by natural survival signals.

Combined endoscopic mucosal resection and photodynamic therapy for esophageal neoplasia within Barrett's esophagus

BACKGROUND

Endoscopic mucosal resection (EMR) and photodynamic therapy have been proposed as treatments for early stage cancers. EMR is limited by its focal nature whereas photodynamic therapy is dependent on precise staging. The combination of EMR and photodynamic therapy were studied in the treatment of superficial cancer in patients with Barrett's esophagus.

METHODS

Seventeen consecutive nonsurgical patients with superficial cancers underwent EMR followed by photodynamic therapy with a porphyrin photosensitizer. Photoradiation was performed at 630 nm for a total dose of 200 J/cm of diffuser.

RESULTS

Seventeen patients (15 men; mean age 69 +/- 13 years) underwent EMR. The mean diameter of mucosal resection was 1 cm. The margins were involved by cancer in 3 cases. EMR improved staging in 8 patients (47%). Sixteen (94%) patients remained in remission (median follow-up 13 months). Complications included minor bleeding after EMR in 1 patient (6%), stricture in 5 (30%), cutaneous phototoxicity in 2 (12%), and supraventricular tachycardia in 1 patient (6%).

CONCLUSIONS

Combined EMR and photodynamic therapy appears to be an effective and safe therapy for superficial esophageal cancer within Barrett's esophagus. This combination improves cancer staging, removes the superficial cancer, and eliminates remaining mucosa at risk for cancer development.

Novel synthesis of 4,5-diarylphenanthrenes via C2-C6 cyclization of benzannulated enyne-allenes

A new synthetic pathway to the 4,5-diarylphenanthrenes 8 having a helical twist in their structures was developed. The synthetic sequence involves condensation of the diketone 5 with 2 equiv of the lithium acetylides derived from the diacetylenes 4 followed by protonation to produce the propargylic alcohols 6. Reduction of 6 with triethylsilane in the presence of trifluoroacetic acid furnished the tetraacetylenic hydrocarbons 7 in nearly quantitative yields. Treatment of 7 with potassium tert-butoxide under refluxing toluene at 110 degrees C for up to 10 h then furnished the 4,5-diarylphenanthrenes 8. Apparently, the transformation from 7 to 8 involves initial prototropic isomerizations to form the benzannulated enyne-allenes 9. Two subsequent formal intramolecular Diels-Alder reactions via the biradicals 10 and 12 derived from the C(2)-C(6) cyclizations then led to 13, which in turn underwent tautomerizations to give 8. The structure of 8a was established by the X-ray structure analysis, showing that the two phenyl substituents are bent away from each other and the central aromatic system is severely distorted with a helical twist. The existence of a helical twist in 8 imposed by the aryl groups at the 4- and 5-positions was also revealed with a set of AB (1)H NMR signals for the diastereotopic methylene hydrogens on the five-membered rings.

The novel calpain inhibitor SJA6017 improves functional outcome after delayed administration in a mouse model of diffuse brain injury

A principal mechanism of calcium-mediated neuronal injury is the activation of neutral proteases known as calpains. Proteolytic substrates for calpain include receptor and cytoskeletal proteins, signal transduction enzymes and transcription factors. Recently, calpain inhibitors have been shown to provide benefit in rat models of focal head injury and focal cerebral ischemia. The present study sought to investigate, in experiment 1, the time course of calpain-mediated cytoskeletal injury in a mouse model of diffuse head injury by measuring the 150- and 145-kDa alpha-spectrin breakdown products (SBDP). Secondly, in experiment 2, we examined the effect of early (20 min postinjury) administration of the novel calpain inhibitor SJA6017 on functional outcome measured 24 h following injury and its effect on posttraumatic alpha-spectrin degradation. Lastly, in experiment 3, we examined the effect of delayed (4 or 6 h postinjury) administration of SJA6017 on 24-h postinjury functional outcome. In experiment 1, isoflurane-anesthetized male CF-1 mice (18-22 g) were subjected to a 750 g-cm weight drop-induced injury and were sacrificed for SBDP analysis at postinjury times of 30 min, and 1, 2, 6, 24 and 48 h (plus sham). In experiments 2 and 3, mice were injured as described, and delivered a single tail vein injection of either SJA6017 (0.3, 1, or 3 mg/kg) or vehicle (administered immediately, 4 or 6 h postinjury [3 mg/kg]). Functional outcome was evaluated in both studies, and, in experiment 2, 24-h postinjury assessment of SBDPs was determined. Following injury, the level of SBDP 145 was significantly different from sham at 24 and 48 h in cortical and at 24 h in the hippocampal tissues and at 48 h in the striatum. Immediate postinjury administration of SJA6017 resulted in a dose-related improvement in 24-h functional outcome (p < 0.05 at 3 mg/kg). Significance was maintained after a 4-h delay of the 3 mg/kg, but was lost after a 6-h delay. Despite improvement in functional outcome at 24 h, SJA6017 did not reduce spectrin breakdown in cortical or hippocampal tissues. These results support a role for calpain-mediated neuronal injury and the potential for a practical therapeutic window for calpain inhibition following traumatic brain injury. However, measurements of regional spectrin degradation may not be the most sensitive marker for determining the effects of calpain inhibition.

Concurrent assessment of calpain and caspase-3 activation after oxygen-glucose deprivation in primary septo-hippocampal cultures

The contributions of calpain and caspase-3 to apoptosis and necrosis after central nervous system (CNS) trauma are relatively unexplored. No study has examined concurrent activation of calpain and caspase-3 in necrotic or apoptotic cell death after any CNS insult. Experiments used a model of oxygen-glucose deprivation (OGD) in primary septo-hippocampal cultures and assessed cell viability, occurrence of apoptotic and necrotic cell death phenotypes, and protease activation. Immunoblots using an antibody detecting calpain and caspase-3 proteolysis of alpha-spectrin showed greater accumulation of calpain-mediated breakdown products (BDPs) compared with caspase-3-mediated BDPs. Administration of calpain and caspase-3 inhibitors confirmed that activation of these proteases contributed to cell death, as inferred by lactate dehydrogenase release. Oxygen-glucose deprivation resulted in expression of apoptotic and necrotic cell death phenotypes, especially in neurons. Immunocytochemical studies of calpain and caspase-3 activation in apoptotic cells indicated that these proteases are almost always concurrently activated during apoptosis. These data demonstrate that calpain and caspase-3 activation is associated with expression of apoptotic cell death phenotypes after OGD, and that calpain activation, in combination with caspase-3 activation, could contribute to the expression of apoptotic cell death by assisting in the degradation of important cellular proteins.

Biradicals from benzoenyne-allenes. Application in the synthesis of 11H-benzo[b]fluoren-11-ols, 1H-cyclobut[a]indenes, and related compounds

New synthetic pathways to 11H-benzo[b]fluoren-11-ols, 1H-cyclobut[a]indenes, and related compounds via biradicals generated from benzoenyne-allenes were developed. Treatment of the diacetylenic propargylic alcohols 13, derived from condensation between benzophenones and the lithium acetylide of 1-(2-ethynylphenyl)-2-phenylethyne, with thionyl chloride produced the 11-chloro-11H-benzo[b]fluorene 14 and, after hydrolysis, the corresponding 11H-benzo[b]fluoren-11-ols 15. The transformation involved a sequence of reactions, including a biradical-forming C2-C6 cyclization (Schmittel cyclization) reaction of the chlorinated benzoenyne-allene intermediates followed by an intramolecular radical-radical coupling to form the formal Diels-Alder adducts. Interestingly, in the case of the diacetylenic propargylic alcohol 26, obtained from dibenzosuberenone (25), an intramolecular [2 + 2] cycloaddition reaction of the chlorinated benzoenyne-allene intermediate occurred, furnishing the 1H-cyclobut[a]indene 27 exclusively. The dramatic change of the reaction pathway could be attributed to the emergence of a steric strain due to the nonbonded interactions with the chloro substituent along the pathway toward the formal Diels-Alder adduct 31. On the other hand, the non-chlorinated benzoenyne-allene, derived from prototropic isomerization of the diacetylenic hydrocarbon 60, underwent a formal Diels-Alder reaction to furnish the 11H-benzo[b]fluorene-type hydrocarbon 61 exclusively.

Accumulation of non-erythroid alpha II-spectrin and calpain-cleaved alpha II-spectrin breakdown products in cerebrospinal fluid after traumatic brain injury in rats

Although a number of increased CSF proteins have been correlated with brain damage and outcome after traumatic brain injury (TBI), a major limitation of currently tested biomarkers is a lack of specificity for defining neuropathological cascades. Identification of surrogate biomarkers that are elevated in CSF in response to brain injury and that offer insight into one or more pathological neurochemical events will provide critical information for appropriate administration of therapeutic compounds for treatment of TBI patients. Non-erythroid alpha II-spectrin is a cytoskeletal protein that is a substrate of both calpain and caspase-3 cysteine proteases. As we have previously demonstrated, cleavage of alpha II-spectrin by calpain and caspase-3 results in accumulation of protease-specific spectrin breakdown products (SBDPs) that can be used to monitor the magnitude and temporal duration of protease activation. However, accumulation of alpha II-spectrin and alpha II-SBDPs in CSF after TBI has never been examined. Following a moderate level (2.0 mm) of controlled cortical impact TBI in rodents, native alpha II-spectrin protein was decreased in brain tissue and increased in CSF from 24 h to 72 h after injury. In addition, calpain-specific SBDPs were observed to increase in both brain and CSF after injury. Increases in the calpain-specific 145 kDa SBDP in CSF were 244%, 530% and 665% of sham-injured control animals at 24 h, 48 h and 72 h after TBI, respectively. The caspase-3-specific SBDP was observed to increase in CSF in some animals but to a lesser degree. Importantly, levels of these proteins were undetectable in CSF of uninjured control rats. These results indicate that detection of alpha II-spectrin and alpha II-SBDPs is a powerful discriminator of outcome and protease activation after TBI. In accord with our previous studies, results also indicate that calpain may be a more important effector of cell death after moderate TBI than caspase-3.

Caspase-mediated calcineurin activation contributes to IL-2 release during T cell activation

Calcineurin, a Ca(2+)/calmodulin-dependent Ser/Thr phosphatase (protein phosphatase 2B), plays a critical role in IL-2 production during T cell activation. It has been previously reported that IL-2 release in activated Jurkat T requires caspase-like activity (Posmantur et al. (1998) Exp. Cell. Res. 244, 302-309). We report here that the 60-kDa catalytic subunit of calcineurin A (Cn A) was partially cleaved to a 45-kDa form in phytohemagglutinin A (PHA) or phorbol ester + ionomycin (P + I)-activated Jurkat cells. In parallel, proteolytic activation of upstream caspases (caspase-8 and -9) as well as effector caspase-3 was also observed. Cn A cleavage was caspase mediated, since it was inhibitable by pan-caspase inhibitor Cbz-Asp-CH(2)OC(O)-2,6-dichlorobenzene (Z-D-DCB). Cn A cleavage was also observed when purified calcineurin was digested in vitro with caspase-3. Truncated Cn A was associated with enhanced phosphatase activity and reduced calmodulin sensitivity. Furthermore, in PHA or P + I-activated Jurkat cells, dephosphorylation of calcineurin substrate NFATc (a transcription factor known to be involved in transactivation of the IL-2 gene), was also suppressed by Z-D-DCB. Taken together, our results suggest that caspase-mediated cleavage of Cn A contributes to IL-2 production during T cell activation.

The calpain family and human disease

The number of mammalian calpain protease family members has grown to 14 on last count. Overactivation of calpain 1 and calpain 2 (and their small subunit) has long been tied to acute neurological disorders (e.g. stroke and traumatic brain injury) and recently to Alzheimer's disease. Loss-of-function mutations of the calpain 3 gene have now been identified as the cause of limb-girdle muscular dystrophy 2A. Calpain 10 was recently identified as a susceptibility gene for type 2 diabetes, whereas calpain 9 appears to be a gastric cancer suppressor. This review describes our current understanding of the calpain family members and their mechanistic linkages to the aforementioned diseases as well as other emerging pathological conditions.

Temporal and spatial profile of caspase 8 expression and proteolysis after experimental traumatic brain injury

Recent studies have demonstrated that the downstream caspases, such as caspase 3, act as executors of the apoptotic cascade after traumatic brain injury (TBI) in vivo. However, little is known about the involvement of caspases in the initiation phase of apoptosis, and the interaction between these initiator caspases (e.g. caspase 8) and executor caspases after experimental brain injuries in vitro and in vivo. This study investigated the temporal expression and cell subtype distribution of procaspase 8 and cleaved caspase 8 p20 from 1 h to 14 days after cortical impact-induced TBI in rats. Caspase 8 messenger RNA levels, estimated by semiquantitaive RT-PCR, were elevated from 1 h to 72 h in the traumatized cortex. Western blotting revealed increased immunoreactivity for procaspase 8 and the proteolytically active subunit of caspase 8, p20, in the ipsilateral cortex from 6 to 72 h after injury, with a peak at 24 h after TBI. Similar to our previous studies, immunoreactivity for the p18 fragment of activated caspase 3 also increased in the current study from 6 to 72 h after TBI, but peaked at a later timepoint (48 h) as compared with proteolyzed caspase 8 p20. Immunohistologic examinations revealed increased expression of caspase 8 in neurons, astrocytes and oligodendrocytes. Assessment of DNA damage using TUNEL identified caspase 8- and caspase 3-immunopositive cells with apoptotic-like morphology in the cortex ipsilateral to the injury site, and immunohistochemical investigations of caspase 8 and activated caspase 3 revealed expression of both proteases in cortical layers 2-5 after TBI. Quantitative analysis revealed that the number of caspase 8 positive cells exceeds the number of caspase 3 expressing cells up to 24 h after impact injury. In contrast, no evidence of caspase 8 and caspase 3 activation was seen in the ipsilateral hippocampus, contralateral cortex and hippocampus up to 14 days after the impact. Our results provide the first evidence of caspase 8 activation after experimental TBI and suggest that this may occur in neurons, astrocytes and oligodendrocytes. Our findings also suggest a contributory role of caspase 8 activation to caspase 3 mediated apoptotic cell death after experimental TBI in vivo.

Molecular cloning and characterization of a novel caspase-3 variant that attenuates apoptosis induced by proteasome inhibition

Caspase-3 plays an important role in programmed cell death as an execution-phase caspase in degradation of many substrate proteins. We identified a naturally occurring short caspase-3 variant (caspase-3s) from a human carcinoma cell line that is resulted from alternative mRNA splicing. Analysis of nucleotide sequence reveals a deletion of the exon 6 in this variant that resulted in an altered reading frame in the C-terminus, leading to an altered amino acid sequence and a truncated protein. Caspase-3s shares the same amino acid sequence as caspase-3 in the N-terminus containing the prodomain and the majority of the large subunit. The variant is 95 amino acid residues shorter at the C-terminus and is missing the conserved QACRG sequence in the catalytic site. Caspase-3 and caspase-3s are coexpressed in all human tissues examined. Several cancer cell lines also show coexpression of caspase-3 and caspase-3s, both at the mRNA and protein levels. Overexpression of caspase-3s in 293 cells is more resistant to apoptosis induced by proteasome inhibition. Furthermore, we identified that proteasome inhibition stabilized the level of caspase-3s.

Extent of high-grade dysplasia in Barrett's esophagus correlates with risk of adenocarcinoma

BACKGROUND & AIMS

The identification of any high-grade dysplasia (HGD) in Barrett's esophagus has been considered to be an indication for esophagectomy because of the increased risk of cancer. The aim of this study was to determine if a limited extent of HGD has the same potential for cancer as diffuse HGD.

METHODS

A retrospective cohort study was performed to assess the risk of developing adenocarcinoma in relationship to the extent of HGD found on endoscopic surveillance. The extent of HGD was defined as focal if cytologic and/or architectural changes of HGD were limited to a single focus of 5 or fewer crypts and diffuse if more than 5 crypts were involved in a single biopsy specimen or if HGD involved more than one biopsy fragment. The relative risk of cancer was assessed using a Cox proportional hazard model, and cancer-free survival was determined using survival curves.

RESULTS

Sixty-seven patients with diffuse HGD and 33 with focal HGD satisfied selection criteria. Cancer-free survival rates at 1 and 3 years were 93% and 86% for focal HGD compared with 62% and 44% for diffuse HGD (P < 0.001). On univariate analysis, extent of HGD (relative risk, 5.36; 95% confidence interval, 1.84-15.56), nodularity on endoscopy (relative risk, 3.98; 95% confidence interval, 1.97-8.04), and lack of acid suppression (relative risk, 2.48; 95% confidence interval, 1.16-5.28) were associated with an increased risk of esophageal adenocarcinoma. Diffuse HGD had a 3.7-fold increase in the risk of esophageal cancer compared with focal HGD (P = 0.02) on multivariate analysis.

CONCLUSIONS

Patients with focal HGD are less likely to have cancer during the first year after diagnosis or on subsequent follow-up compared with diffuse HGD.

Impact of EUS-guided fine-needle aspiration on lymph node staging in patients with esophageal carcinoma

BACKGROUND

Preoperative identification of lymph node metastases associated with esophageal carcinoma may influence treatment. EUS is the most accurate method for locoregional staging of these tumors. The impact of EUS-guided fine-needle aspiration (EUS-FNA) on lymph node staging in esophageal carcinoma is unclear.

METHODS

From May 1996 to May 1999, 74 patients with esophageal carcinoma underwent preoperative EUS. After October 1998 EUS-guided FNA was performed on nonperitumoral lymph nodes greater than 5 mm in width. The results of EUS with and without FNA were retrospectively reviewed and compared. Final diagnosis was based on surgical results or EUS-guided FNA malignant cytology. Ten of the 74 patients had to be excluded for lack of lymph node stage confirmation. Final diagnosis was obtained in the remaining 64 patients (33 from the EUS only group and 31 from the EUS-FNA group).

RESULTS

The results of EUS versus EUS-FNA for lymph node staging were sensitivity 63% versus 93% (p = 0.01), specificity 81% versus 100% (not significant), and accuracy 70% versus 93% (p = 0.02), respectively. Complications comprised 1 patient who developed self-limited bleeding after dilation that did not preclude completion of the EUS (1%, 95% CI [0%, 7%]).

CONCLUSIONS

EUS-FNA is more sensitive and accurate than EUS alone for preoperative staging of locoregional and celiac lymph nodes associated with esophageal carcinoma. EUS-FNA of nonperitumoral lymph nodes in patients with esophageal carcinoma is safe and should be routinely performed when treatment decisions will be affected by nodal stage.

TNF-alpha stimulates caspase-3 activation and apoptotic cell death in primary septo-hippocampal cultures

Primary septo-hippocampal cell cultures were incubated in varying concentrations of tumor necrosis factor (TNF-alpha; 0.3-500 ng/ml) to examine proteolysis of the cytoskeletal protein alpha-spectrin (240 kDa) to a signature 145 kDa fragment by calpain and to the apoptotic-linked 120-kDa fragment by caspase-3. The effects of TNF-alpha incubation on morphology and cell viability were assayed by fluorescein diacetate-propidium iodide (FDA-PI) staining, assays of lactate dehydrogenase (LDH) release, nuclear chromatin alterations (Hoechst 33258), and internucleosomal DNA fragmentation. Incubation with varying concentrations of TNF-alpha produced rapid increases in LDH release and nuclear PI uptake that were sustained over 48 hr. Incubation with 30 ng/ml TNF-alpha yielded maximal, 3-fold, increase in LDH release and was associated with caspase-specific 120-kDa fragment but not calpain-specific 145-kDa fragment as early as 3.5 hr after injury. Incubation with the pan-caspase inhibitor, carbobenzosy- Asp-CH(2)-OC (O)-2-6-dichlorobenzene (Z-D-DCB, 50-140 microM) significantly reduced LDH release produced by TNF-alpha. Apoptotic-associated oligonucleosomal-sized DNA fragmentation on agarose gels was detected from 6 to 72 hr after exposure to TNF-alpha. Histochemical changes included chromatin condensation, nuclear fragmentation, and formation of apoptotic bodies. Results of this study suggest TNF-alpha may induce caspase-3 activation but not calpain activation in septo-hippocampal cultures and that this activation of caspase-3 at least partially contributes to TNF-alpha-induced apoptosis.

EUS-guided fine-needle aspiration combined with flow cytometry and immunocytochemistry in the diagnosis of lymphoma

BACKGROUND

Limited information is available regarding the use of EUS-guided fine-needle aspiration (EUS-FNA) in the diagnosis of lymphoproliferative disorders. The aim of this study was to evaluate the yield of this technique in the primary diagnosis of lymphoma.

METHODS

The records were reviewed of 38 consecutive patients with GI lesions and/or enlarged lymph nodes identified on imaging studies that raised a suspicion of lymphoma who underwent EUS-FNA of lymph nodes or the gut wall. Final diagnosis was based on clinical follow-up, imaging studies, or surgical findings.

RESULTS

Twenty-three patients with lymphoma and 15 patients with benign disease or reactive lymphadenopathy were identified. The overall sensitivity, specificity, and accuracy of EUS-FNA cytology with flow cytometry/immunocytochemistry (FC/IC) for the diagnosis of lymphoma were, respectively, 74%, 93%, and 81%. When comparing patients who had EUS-FNA with FC/IC versus those who had EUS-FNA without FC/IC, sensitivity was 86% versus 44% (p = 0.04), specificity was 100% versus 90% (not significant), and accuracy was 89% versus 68% (not significant).

CONCLUSION

EUS-FNA can provide cytology specimens diagnostic for lymphoma. Selective use of FC/IC in patients with suspected lymphoma improves the yield of EUS-FNA and may guide diagnostic evaluation and treatment decisions.

Endoscopic application of photodynamic therapy for cholangiocarcinoma

BACKGROUND

Previous studies indicate that photodynamic therapy provides effective relief from biliary obstruction in advanced cholangiocarcinoma. This report describes a method of applying photodynamic therapy in the biliary tract by using accessories available in the United States.

METHODS

Endoscopic retrograde cholangiography was performed to define the proximal and distal extent of intraductal tumor. Patients were injected with 2 mg/kg of sodium porfimer. Forty-eight hours later a commercially available cylindrical diffusing laser fiber was inserted into an 8F biliary catheter equipped with a 0.038 inch side-hole at its distal tip. After positioning of a 0.035 inch guidewire proximal to the biliary stricture, the preloaded catheter was advanced over the guidewire by using the monorail technique. Laser light was applied at a power of 400 mW/cm fiber for a total energy of 180 J/cm.(2)

RESULTS

Fourteen treatments were performed on 6 patients with tumors of Bismuth types IV (n = 2), III (n = 3), or II (n = 1). By using the preloaded biliary catheter, adequate positioning of the laser fiber was achieved in all patients. A fracture of the diffuser tip occurred during 1 of the treatments. Two patients developed acute cholangitis and 2 patients experienced skin phototoxicity.

CONCLUSIONS

Photodynamic therapy for cholangiocarcinoma is safe and technically feasible with a preloaded biliary catheter and a monorail technique for catheter positioning.

Biomarkers in Barrett esophagus

Barrett esophagus is a premalignant condition that may progress to adenocarcinoma. The risk of developing cancer has been estimated to be approximately 1 in 250 patient-years of observation; however, there appear to be subsets of patients at much higher risk. Risk stratification has previously been determined by histological identification of dysplasia. Several new biomarkers are being tested to help clinicians better determine the risk of cancer development. Although none of these biomarkers has been proven in a prospective study to predict the onset of cancer, they have been correlated with cancer development. Most of these are factors that have been associated with cancer development in other organs. These include assessment of cell proliferation, expression of cyclooxygenase 2, growth factors and oncogenes, secretory factors, cell cycle proteins, adhesion molecules, and aneuploidy and other genetic abnormalities. In addition to their role as potential cancer biomarkers, these factors have increasingly been reported as surrogate markers to monitor the effectiveness of conservative treatments for Barrett esophagus. In this article, biological markers are reviewed for their relevance in Barrett esophagus. Although most biological markers need to be evaluated further and, for most, prospective follow-up studies are lacking, at present abnormal ploidy status, P16 and P53 gene abnormalities, or allelic losses are the most extensively documented.

Mucosal ablation therapy of barrett esophagus

Barrett esophagus is defined by the metaplasia of existing squamous mucosa into a specialized intestinal-type mucosa. The importance of this metaplasia is the association of this condition with the development of adenocarcinoma of the esophagus. Elimination of the metaplastic mucosa may decrease the cancer risk. Currently, several forms of therapy have evolved with the goal of replacing the specialized mucosa with normal squamous mucosa. These proposed treatments include photodynamic therapy and thermal techniques. The effectiveness of photodynamic therapy varies depending on the pharmaceutical photosensitizer used and the wavelength of light applied to activate the drug. Thermal techniques include multipolar coagulation, argon plasma coagulation, KTP:YAG laser therapy, Nd:YAG laser therapy, and argon laser therapy. Finally, mucosal resection has been attempted through the endoscope to remove large areas of the Barrett mucosa. All of these ablative strategies attempt to destroy the metaplastic mucosa and promote the regrowth of squamous epithelium. These therapies have demonstrated the ability to "reverse" the metaplasia to varying degrees, but a decrease in cancer risk has not been demonstrated conclusively with any of these treatment methods.