Three-dimensional (3D) reconstruction and quantitative analysis of the microvasculature in medulloblastoma and ependymoma subtypes

In the World Health Organisation (WHO) classification of tumours of the nervous system, four main histopathological subtypes of medulloblastomas (classic medulloblastoma, desmoplastic medulloblastoma, medulloblastoma with extensive nodularity and advanced neuronal differentiation and large cell/anaplastic medulloblastoma) as well as of ependymal tumours (low-grade ependymoma, anaplastic ependymoma, myxopapillary ependymoma and subependymoma) are recognised. Under the hypothesis that the microvascular architecture of tumours is a reflection of the histopathological subtype, we performed three-dimensional reconstructions of the microvasculature in these subtypes of medulloblastomas and ependymal tumours using computerised image analysis. In addition, we quantitatively assessed three microvascular parameters (number, area, perimeter) in these neoplasms. Three-dimensional reconstructions showed a dense pattern of irregular vessels in classic and large cell medulloblastoma. In desmoplastic medulloblastoma and medulloblastoma with extensive nodularity, the vessels were more unevenly distributed and organised around the nodular areas. Classic medulloblastoma and large cell medulloblastoma had on average the largest vessel area and perimeter. The highest number of vessels was seen in classic medulloblastoma and medulloblastoma with extensive nodularity. Three-dimensional analysis of ependymal tumours showed that low-grade ependymoma had larger but fewer vessels compared to anaplastic ependymoma, while myxopapillary ependymoma had a complex, heterogeneous pattern of vessels and subependymoma few but regular vessels. In ependymal tumours, the highest values for vessel number, vessel area and vessel perimeter were found in anaplastic ependymoma and the lowest values in subependymoma. We conclude that our three-dimensional reconstructions shed unprecedented light on the tumour vasculature in medulloblastomas and ependymal tumours and expect that such reconstructions are helpful tools for further studies on tumour angiogenesis.     

Macrophage reprogramming by mycolic acid promotes a tolerogenic response in experimental asthma

RATIONALE: Mycolic acid (MA) constitutes a major and distinguishing cell wall biolipid from Mycobacterium tuberculosis. MA interferes with the lipid homeostasis of alveolar macrophages, inducing differentiation into foamy macrophages exhibiting increased proinflammatory function. OBJECTIVES: We verified the interference of this altered macrophage function with inhaled antigen-triggered allergic airway inflammation and underlying Th2 lymphocyte reactivity. METHODS: Using ovalbumin (OVA) as model allergen, C57BL/6 or BALB/C mice were sensitized by OVA-alum immunization. Experimental asthma, triggered subsequently by repetitive nebulized OVA inhalation, was assessed, using as readout parameters eosinophilia, peribronchial inflammation, and Th2 cytokine function. MEASUREMENTS AND MAIN RESULTS: A single intratracheal treatment of sensitized mice with MA, inserted into liposomes as carriers, prevented the onset of OVA-triggered allergic airway inflammation and promoted unresponsiveness to a secondary set of allergen exposures. The development of this tolerant condition required an 8-d lapse after MA instillation, coinciding with the appearance of foamy alveolar macrophages. MA-conditioned CD11b(+)F4/80(+) macrophages, transferred to the airways, mimicked the tolerogenic function of instilled MA; however, without the 8-d lapse requirement. Indicative of a macrophage-mediated tolerogenic antigen-presenting function, major histocompatibility complex (MHC)-mismatched donor macrophages failed to promote tolerance. Furthermore, Treg markers were strongly increased and established tolerance was lost after in situ depletion of CD25(+) Treg cells. Contrary to the interleukin-10 dependence of tolerogenic dendritic cells, IFN-gamma deficiency but not interleukin-10 deficiency abrogated the tolerogenic capacity of MA-conditioned macrophages. CONCLUSIONS: These results document an innate-driven Mycobacterium tuberculosis MA-triggered immune regulatory mechanism in control of pulmonary allergic responses by converting macrophages into IFN-gamma-dependent tolerogenic antigen-presenting cells.     

Electrochemically Induced RAFT Polymerization of Thermoresponsive Hydrogel Films: Impact on Film Thickness and Surface Morphology

Thin hydrogel films of the thermoresponsive polymer poly(N‐isopropylacrylamide) (pNIPAm) were prepared by electrochemically triggered reversible addition‐fragmentation chain transfer (RAFT) polymerization. Two different RAFT agents were employed, which work in either acidic or basic solution. In both cases, addition of RAFT agents had an influence on the thickness and the surface morphology of the films. At low concentration, the polymerization efficiency increased. At high concentration, the efficiency decreased at acidic pH, while it remained constant under basic conditions. Neither RAFT agent displayed electrochemical activity on its own, but they did modify the electrochemical behavior of the initiator. The addition of RAFT agent strongly enhances the homogeneity of the hydrogel surfaces, which presumably is due to a reduced amount of microgel formation.

     

A comparison of donor lymphocyte infusions or imatinib mesylate for patients with chronic myelogenous leukemia who have relapsed after allogeneic stem cell transplantation

Imatinib mesylate is highly effective in relapsed chronic myelogenous leukemia (CML) after allogeneic hematopoetic stem cell transplantation (HSCT). However, it is unknown whether imatinib produces durable molecular remissions. The outcome of CML patients transplanted at our center who had received only imatinib for relapse after HSCT was compared with that of patients treated with donor lymphocyte infusions (DLI). Imatinib therapy resulted in a higher incidence of relapse and inferior leukemia-free survival (p=0.006 and p=0.016, respectively). These data suggest that imatinib alone probably does not cure relapse after HSCT.     

Adjuvant chemotherapy with folinic acid and 5-fluorouracil in patients with locally advanced rectal cancer previously treated by preoperative radiochemotherapy and curative tumor resection

BACKGROUND AND AIMS: The role of postoperative adjuvant chemotherapy in patients with rectal cancer pretreated by preoperative radiochemotherapy (RCT) and curative surgery is still poorly investigated. PATIENTS AND METHODS: We pooled data from both arms of a phase III trial in which patients with locally advanced (T3/4) rectal cancer were randomized to preoperative RCT alone or combined with pelvic radio-frequency hyperthermia. After surgery, R0-resected patients were scheduled to adjuvant chemotherapy with four monthly courses of 50 mg folinic acid (FA) and gradually escalated 5-fluorouracil (5-FU, 350-500 mg/m2, days 1-5). Reasons preventing initiation of chemotherapy and treatment-related toxicities were evaluated. Patients' characteristics and survival parameters were compared between the treated and untreated patient groups. RESULTS: Out of 93 patients, 73 (79%) started adjuvant chemotherapy, whereas 19 (21%) did not, mostly due to perioperative complications and refusal. Chemotherapy-related toxicities were mild to moderate in most cases, but--together with protracted postoperative complications--prevented the intended dose escalation of 5-FU in 71% of patients. Distant-failure-free (p=0.03) and overall survival (p=0.03) were improved in the chemotherapy group, although there was a negative selection of patients with unfavourable characteristics into the untreated patient group. INTERPRETATION/CONCLUSION: Adjuvant chemotherapy using FA and 5-FU can be safely applied to the majority of patients with rectal cancer pretreated by RCT and surgery. Survival data are not suitable to allow far-reaching conclusions, but are in line with suggestions of a favourable effect of adjuvant chemotherapy in these patients.     

Assessment of the “Skin Reservoir” of Urea by Confocal Raman Microspectroscopy and Reverse Iontophoresis <Emphasis Type="BoldItalic">in vivo</Emphasis>

Purpose To demonstrate the “skin reservoir” of urea by confocal Raman microspectroscopy in vivo and to evaluate its impact on the non-invasive monitoring of the analyte by reverse iontophoresis. Methods Urea was extracted iontophoretically over a 2-h period across the skin of adult volunteers and patients with chronic kidney disease. Confocal Raman microspectroscopic profiles of skin were recorded before and after 30 min of current application. Results Urea extraction was higher at the beginning of current passage, but then decreased to achieve stable values after 2 h of iontophoresis. After 30 min of iontophoresis, the Raman spectra highlighted a clear depletion of urea at the surface of the skin. Lactate distribution was also modified both at the surface and deeper into the skin. Conclusions A source of urea in the skin, unrelated to the concentration circulating in the blood, was strongly suggested by extracted urea flux observed over time and by the Raman spectroscopy. This “urea reservoir” must be removed before systemic urea levels can be non-invasively monitored by reverse iontophoresis.     

Oxidative stress in response to xenobiotics in the blue mussel Mytilus edulis L.: evidence for variation along a natural salinity gradient of the Baltic Sea

Blue mussels (Mytilus edulis L.) collected at three sampling sites in each of three geographical regions (South, Middle, North) along the permanent longitudinal South-North salinity gradient of the Baltic Sea, were exposed for 10 days to copper (35ppb) or 95 octane petrol (0.3 per thousand). During the experiment, they were maintained at the respective sampling site salinity. Scope for growth (SFG) was determined, and biochemical stress markers (protein carbonyl groups, disulfide bond formation, and glutathione transferase (GST), and catalase (CAT) activities) were investigated in gill tissue upon termination of the experiment. Treatment and regional effects for SFG and protein carbonyl groups were all significant for petrol. The largest increase in protein carbonyl groups was observed in the North. Mussels from the southern, more saline ( approximately 7 per thousand) region had the highest SFG, and displayed the largest SFG decrease in response to treatment, indicating that they had the most energy available for allocation to stress response. They also displayed the least increase in the level of protein carbonyl groups. Mussels from the Northern, less saline ( approximately 5%) region had the highest degree of protein carbonyl groups in response to both treatments, and lowest average SFG. Silver stained diagonal gels for samples from one sampling site in South and North, respectively, demonstrated differences in disulfide bond profiles for both stress treatments. There was also a regional difference in the number of protein disulfides observed on diagonal gels. The most diverse protein disulfide response was found in South. No treatment related effects on GST and CAT activities were observed. We suggest that both SFG and protein carbonyl groups show that geographical difference in stress susceptibility, previously established between the North and the Baltic Seas, also apply on a regional scale within the Baltic Sea, along the salinity gradient.     

Effects of glucose infusion on neuroendocrine and cognitive parameters in Addison disease

Sucrose intake has been shown to suppress increased adrenocorticotropic hormone (ACTH) levels in adrenalectomized rats, suggesting that increased cerebral energy supply can compensate for the loss of glucocorticoid feedback inhibition of the hypothalamo-pituitary-adrenal axis. We hypothesized that glucose infusion might acutely down-regulate increased ACTH secretion in patients with Addison disease. We studied 8 patients with primary adrenal insufficiency (Addison group) with short-term discontinuation of hydrocortisone substitution and 8 matched healthy controls in 2 randomized conditions. Subjects received either intravenous glucose infusion (0.75 g glucose per kilogram body weight for 2.5 hours) or placebo. Concentrations of ACTH, cortisol, catecholamines, growth hormone, glucagon, and insulin were measured; and cognitive functions as well as neuroglycopenic and autonomic symptoms were assessed. The ACTH concentrations were not affected by glucose infusion either in the Addison or in the control group. Likewise, concentrations of cortisol, epinephrine, norepinephrine, growth hormone, and glucagon remained unchanged in both groups. Neurocognitive performance and symptom scores were likewise not affected. Independent of glucose infusion, attention of the Addison patients was impaired in comparison with the control group. Our study in patients with Addison disease was not able to support the assumption of a compensatory effect of intravenous glucose infusion on hormonal parameters and neurocognitive symptoms in states of chronic cortisol deficiency. Further studies should examine whether different regimens of glucose administration are more effective.