Evaluation of dual-phase multi-detector-row CT for detection of intestinal bleeding using an experimental bowel model

To evaluate dual-phase multi-detector-row computed tomography (MDCT) in the detection of intestinal bleeding using an experimental bowel model and varying bleeding velocities. The model consisted of a high pressure injector tube with a single perforation (1 mm) placed in 10-m-long small bowel of a pig. The bowel was filled with water/contrast solution of 30–40 HU and was incorporated in a phantom model containing vegetable oil to simulate mesenteric fat. Intestinal bleeding in different locations and bleeding velocities varying from zero to 1 ml/min (0.05 ml/min increments, constant bleeding duration of 20 s) was simulated. Nineteen complete datasets in arterial and portal-venous phase using increasing bleeding velocities, and seven negative controls were measured using a 64 MDCT (3-mm slice thickness, 1.5-mm reconstruction increment). Three radiologists blinded to the experimental settings evaluated the datasets in a random order. The likelihood for intestinal bleeding was assessed using a 5-point scale with subsequent ROC analysis. The sensitivity to detect bleeding was 0.44 for a bleeding velocity of 0.10–0.50 ml/min and 0.97 for 0.55–1.00 ml/min. The specificity was 1.00. The area under the curve was calculated to be 0.73, 0.88 and 0.89 for reader 1, 2 and 3, respectively. Dual-phase MDCT provides high sensitivity and specificity in the detection of intestinal bleeding with bleeding velocities of 0.5–1.0 ml/min. Therefore, MDCT should be considered as a primary diagnostic technique in the management of patients with suspected intestinal bleeding.     

Comparison of changes in tumor metabolic activity and tumor size during chemotherapy of adenocarcinomas of the esophagogastric junction.

We evaluated the temporal relationship between chemotherapy-induced changes in tumor glucose use and tumor size. METHODS: Twenty patients with adenocarcinoma of the esophagogastric junction (AEG) were studied by 18F-FDG PET and CT scans before neoadjuvant chemotherapy, 14 d after the initiation of therapy, and 4 wk after the completion of therapy. RESULTS: The relative change in 18F-FDG uptake was more than 2 times larger than the decrease in tumor size at all time points (P<0.01). At 14 d after the initiation of chemotherapy, there was no correlation between the reduction in 18F-FDG uptake and tumor wall thickness. The change in 18F-FDG uptake after 14 d of therapy was significantly correlated with the reduction in tumor size after the completion of therapy. CONCLUSION: In AEG, changes in tumor metabolism are a more sensitive parameter for assessing the effects of chemotherapy than are changes in tumor size. Early changes in metabolic activity predict the subsequent reduction in tumor size.     

Probucol inhibits not only the progression of atherosclerotic disease,but causes a different composition of atherosclerotic lesions in WHHL-rabbits

Watanabe heritable hyperlipidaemic (WHHL)-rabbits develop premature atherosclerosis due to an inborn defect of the low-density lipoprotein (LDL) receptor causing severe hypercholesterolaemia. Probucol, which possesses a lipid lowering and an antioxidative potency, has been shown to reduce the extent of atherosclerotic disease in this animal. The object of the present study was the detailed analysis of the cellular and non-cellular composition of atherosclerosic lesions in WHHL-rabbits treated with probucol when compared with untreated controls. In two independent sets of experiments, each consisting of one litter, a total number of 5 animals was fed a diet containing 1% (w/w) probucol. Four animals served as controls and 2 animals were sacrificed before treatment (at 2 and 4 months of age, respectively) to define the baseline level of the atherosclerotic disease. Morphometric analysis was employed in order to determine plaque area macroscopically by planimetry and plaque thickness and composition histologically, in 30 cross-sections of the aorta of each animal. In the group treated with probucol, a diminution of plaque area and thickness, as well as a decrease of foam cell and — especially in one experiment — necrotic content of atherosclerotic lesions, was observed. Plaques from aortas of animals treated with probucol consisted predominantly of smooth muscle cells and compact intercellular fibrous structures. Furthermore, as an additional characteristic feature of the typical probucol plaque, they usually lacked confluent necrotic cores. In comparison with untreated animals, there was also a decrease in intracellular apolipoprotein B (apo B) as determined by immunohistochemistry. These data confirm the antiatherosclerotic potency of probucol in the WHHL-rabbit. Moreover, it was demonstrated that there is a different type of atherosclerosis present in the group treated with probucol. The mechanism behind these shifts may be based on the antioxidative property as well as on direct effects of probucol on cellular plaque components.     

Extracellular superoxide dismutase accelerates endothelial recovery and inhibits in-stent restenosis in stented atherosclerotic Watanabe heritable hyperlipidemic rabbit aorta.

OBJECTIVES: This study examined whether local gene therapy with extracellular superoxide dismutase (EC-SOD) could inhibit in-stent restenosis in atherosclerotic Watanabe heritable hyperlipidemic rabbits. BACKGROUND: Stenting causes an acute increase in superoxide anion production and oxidative stress; EC-SOD is a major component of antioxidative defense in blood vessels and has powerful cardioprotective effects in ischemic myocardium. METHODS: Endothelial denudation and stenting were done in 36 adult (15 to 18 months old) rabbits. Catheter-mediated intramural delivery of clinical good manufacturing practice-grade adenoviruses encoding rabbit EC-SOD were done simultaneously with stenting. Control animals received adenovirus-encoding nuclear-targeted beta-galactosidase (AdLacZ). Circulating markers for oxidative stress (nonesterified 8-iso-prostaglandin F2 alpha) were measured. Analysis of 6-day, 28-day, and 90-day vessel histology, radical production, oxidation-specific epitopes, and expression studies were performed. RESULTS: The EC-SOD treatment reduced oxidant production in stented vessels compared with control vessels. Early systemic recovery of total SOD activity was observed in the treated rabbits. The EC-SOD significantly accelerated endothelial recovery (67.4% +/- 10.8% vs. 24.2.1% +/- 4.6% at 6 days, p < 0.05; 89.3% +/- 3.7% vs. 45.1% +/- 9.6% at 28 days, p < 0.05), and the beneficial effect involved increased proliferation of regenerating endothelium. The EC-SOD group showed a 61.3% lower (p < 0.05) neointimal formation at 28 days, with a similar, albeit nonsignificant trend at 90 days (1.20 +/- 0.32 mm2 vs. 1.88 +/- 0.24 mm2, p = 0.06). CONCLUSIONS: The results suggest a central pathogenetic role of oxidation sensitive signaling processes in endothelial recovery and developing in-stent restenosis in atherosclerotic vessels. Local therapy against oxidative stress represents a promising therapeutic strategy in stent-induced vascular injury.     

Falsely Low Serum Prolactin in Two Cases of Invasive Macroprolactinoma

The differential diagnosis of tumors at the base of the skull comprises meningiomas, neurinomas, gliomas, metastatic carcinomas, chordomas, epidermoids, and pituitary adenomas. About half of the pituitary adenomas are prolactinomas which are unique in a sense that medical therapy causes rapid tumor shrinkage and symptomatic improvement. We report on two patients in which the diagnosis of an invasive macroprolactinoma was masked by apparently low prolactin levels caused by a high-dose hook effect in the chemiluminometric assay. The first case a 49 year old male with impairment of hearing on the left side was presented in the Department of Otorhinolaryngology. A massive invasively growing tumor was demonstrated on a cranial MRI. Endocrine tests revealed normal pituitary function and normoprolactinemia. The patient underwent debulking surgery, occipitocervical fusion because of destruction of the first cervical vertebra and subsequent irradiation. The histopathological diagnosis was invasive prolactinoma. A repeat prolactin (PRL) sample, which was assayed using serial dilutions, revealed a real PRL level of 89,700 ng/ml. Dopamine agonist therapy was initiated under which PRL levels declined in parallel with tumor size. The second case a 40 year old male was presented with acute visual loss. Cranial MRI showed a large tumor at the base of the skull. Based on a transnasal biopsy, the preliminary diagnosis was a poorly differentiated carcinoma for which emergency irradiation was performed. Endocrine tests demonstrated partial hypopituitarism and moderate hyperprolactinemia. Hydrocortisone was substituted and dopamine agonist therapy was started because of moderate hyperprolactinemia. The final histopathological diagnosis was invasive prolactinoma. A repeat PRL sample assayed in serial dilution demonstrated an apparent rise in PRL with a maximum value of 6,460 ng/ml. Under dopamine agonist therapy, PRL declined to normal values, tumor size decreased and cranial nerve palsies disappeared. The apparently falsely low prolactin levels in the initial work-up of both patients were caused by a high-dose hook effect in the PRL assay. Serial dilutions of serum PRL samples is, therefore, mandatory in the diagnostic work-up of patients with large invasive tumors at the base of the skull. This avoids unnecessary aggressive and dangerous treatment like surgery or radiotherapy in cases where pharmacological treatment may be the choice.     

CD28-ζ CAR T Cells Resist TGF-β Repression through IL-2 Signaling,Which Can Be Mimicked by an Engineered IL-7 Autocrine Loop

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The beating heart of melanomas: a minor subset of cancer cells sustains tumor growth

The recent observation that targeted elimination of a minor subpopulation of melanoma cells can lastingly eradicate the tumor lesion provides strong evidence that an established melanoma lesion is hierarchically organized and maintained by definite subset of cells but not by every random cancer cell. This review discusses the concepts of discrete cancer stem cells and of a cellular hierarchy in melanomas, the rationale for shifting therapies from broad tumor cell cytotoxicity into selective cancer cell elimination strategies and the challenges for future therapeutic concepts.     

Exercise Capacity Affects Quality of Life in Patients with Pulmonary Hypertension

Background

The objective of this prospective study was to evaluate the impact of exercise capacity, mental disorders, and hemodynamics on quality-of-life (QoL) parameters in patients with pulmonary arterial hypertension (PAH) and chronic thromboembolic pulmonary hypertension (CTEPH).

Methods

Sixty-three patients with invasively diagnosed PAH (n = 48) or CTEPH (n = 15) underwent a broad panel of assessments, including cardiopulmonary exercise testing (CPET), 6-minute walking distance (6-MWD), World Health Organization functional class (WHO-FC), and assessment of hemodynamics. QoL was evaluated by the 36-item Medical Outcome Study Short Form Health Survey Questionnaire (SF-36). Exercise capacity, hemodynamics, age, gender, and mental disorders (anxiety and depression) were assessed for association with QoL subscores by uni- and multivariate regression analyses.

Results

Exercise capacity, WHO-FC, oxygen therapy, symptoms of right heart failure, right atrial pressure, and mental disorders were significantly associated with QoL (p < 0.05). In the stepwise backward selection multivariate analysis, depression remained an independent parameter in seven of eight subscales of the SF-36. Furthermore, peak oxygen uptake (peakVO₂) during CPET, 6-MWD, anxiety, long-term oxygen therapy, right heart failure, and age remained independent factors for QoL. Hemodynamic parameters at rest did not independently correlate with any domain of the SF-36 QoL subscores.

Conclusions

Mental disorders, exercise capacity, long-term oxygen therapy, right heart failure, and age play important role in the quality of life in patients with PAH and CTEPH.