Computational modelling of emboli travel trajectories in cerebral arteries: influence of microembolic particle size and density.

Ischaemic stroke is responsible for up to 80% of stroke cases. Prevention of the reoccurrence of ischaemic attack or stroke for patients who survived the first symptoms is the major treatment target. Accurate diagnosis of the emboli source for a specific infarction lesion is very important for a better treatment for the patient. However, due to the complex blood flow patterns in the cerebral arterial network, little is known so far of the embolic particle flow trajectory and its behaviour in such a complex flow field. The present study aims to study the trajectories of embolic particles released from carotid arteries and basilar artery in a cerebral arterial network and the influence of particle size, mass and release location to the particle distributions, by computational modelling. The cerebral arterial network model, which includes major arteries in the circle of Willis and several generations of branches from them, was generated from MRI images. Particles with diameters of 200, 500 and 800 µm and densities of 800, 1,030 and 1,300 kg/m(3) were released in the vessel's central and near-wall regions. A fully coupled scheme of particle and blood flow in a computational fluid dynamics software ANASYS CFX 13 was used in the simulations. The results show that heavy particles (density large than blood or a diameter larger than 500 µm) normally have small travel speeds in arteries; larger or lighter embolic particles are more likely to travel to large branches in cerebral arteries. In certain cases, all large particles go to the middle cerebral arteries; large particles with higher travel speeds in large arteries are likely to travel at more complex and tortuous trajectories; emboli raised from the basilar artery will only exit the model from branches of basilar artery and posterior cerebral arteries. A modified Circle of Willis configuration can have significant influence on particle distributions. The local branch patterns of internal carotid artery to middle cerebral artery and anterior communicating artery can have large impact on such distributions.

Pancreatic ductal adenocarcinoma screening: new perspectives.

Pancreatic ductal adenocarcinoma accounts for more than 90% of all pancreatic cancers and its incidence has increased significantly worldwide. Patients with pancreatic ductal adenocarcinoma have a poor outcome and more than 95% of the people affected die from the disease within 12 mo after diagnosis. Surgery is the first-line treatment in the case of resectable neoplasm, but only 20% of patients are candidates for this approach. One of the reasons there are few candidates for surgery is that, during the early phases of the disease, the symptoms are poor or non-specific. Early diagnosis is of crucial importance to improve patient outcome; therefore, we are looking for a good screening test. The screening test must identify the disease in an early stage in order to be effective; having said this, a need exists to introduce the concept of "early" ductal adenocarcinoma. It has been reported that at least five additional years after the occurrence of the initiating mutation are required for the acquisition of metastatic ability of pancreatic adenocarcinoma and patients die an average of two years thereafter. We have reviewed the most recent literature in order to evaluate the present and future perspectives of screening programs of this deadly disease.

Cystic dystrophy of the duodenal wall is not always associated with chronic pancreatitis.

Cystic dystrophy of the duodenal wall is a rare form of the disease which was described in 1970 by French authors who reported the presence of focal pancreatic disease localized in an area comprising the C-loop of the duodenum and the head of the pancreas. German authors have defined this area as a "groove". We report our recent experience on cystic dystrophy of the paraduodenal space and systematically review the data in the literature regarding the alterations of this space. A MEDLINE search of papers published between 1966 and 2010 was carried out and 59 papers were considered for the present study; there were 19 cohort studies and 40 case reports. The majority of patients having groove pancreatitis were middle aged. Mean age was significantly higher in patients having groove carcinoma. The diagnosis of cystic dystrophy of the duodenal wall can now be assessed by multidetector computer tomography, magnetic resonance imaging and endoscopic ultrasonography. These latter two techniques may also add more information on the involvement of the remaining pancreatic gland not involved by the duodenal malformation and they may help in differentiating "groove pancreatitis" from "groove adenocarcinoma". In conclusion, chronic pancreatitis involving the entire pancreatic gland was present in half of the patients with cystic dystrophy of the duodenal wall and, in the majority of them, the pancreatitis had calcifications.

Pancreatic ductal adenocarcinoma associated with autoimmune pancreatitis.

Autoimmune pancreatitis (AIP), in contrast to other benign chronic pancreatic diseases, can be cured with immunosuppressant drugs, thus the differentiation of AIP from pancreatic cancer is of particular interest in clinical practice. There is the possibility that some patients with AIP may develop pancreatic cancer, and this possibility contributes to increasing our difficulties in differentiating AIP from pancreatic cancer. We herein report the case of a 70-year-old man in whom pancreatic adenocarcinoma and AIP were detected simultaneously. We must carefully monitor AIP patients for the simultaneous presence of pancreatic cancer, even when a diagnosis of AIP is confirmed.

Is the pancreas affected in patients with septic shock?--a prospective study.

BACKGROUND: Hyperamylasemia can be observed anecdotally during the course of severe sepsis or septic shock. This study aimed to investigate the possibility of pancreatic involvement in patients with septic shock using serum pancreatic enzyme determinations and imaging techniques in 21 consecutive patients with septic shock and 21 healthy subjects as controls. METHODS: The serum activity of pancreatic amylase and lipase was assayed initially in all subjects and 24 and 48 hours after the initial observation in the 21 patients with septic shock. All patients also underwent radiological examination to detect pancreatic abnormalities. RESULTS: The serum activity of pancreatic amylase was significantly higher in the 21 patients with septic shock than in the 21 control subjects during the study period, while the serum activity of lipase was similar to that of the control subjects. Amylase and lipase serum activity did not significantly changed throughout the study period in the 21 patients with septic shock. None of the patients with pancreatic hyperenzymemia had clinical signs or morphological alterations compatible with acute pancreatitis. CONCLUSION: The presence of pancreatic hyperenzymemia in septic shock patients is not a biochemical manifestation of acute pancreatic damage, and the management of these patients should be dependent on the clinical situation and not merely the biochemical results.

Plasma concentrations of angiogenetic factors and angiogenetic inhibitors in patients with ductal pancreatic neoplasms. A pilot study.

BACKGROUND: The aim of the study was to evaluate the circulating concentrations of vascular endothelial growth factor (VEGF), vascular endothelial growth factor receptor-2 (VEGFR-2), vascular endothelial growth factor-D (VEGF-D) and endostatin in patients with intraductal papillary mucinous neoplasm (IPMN), and in those with ductal adenocarcinomas. METHODS: Sixty patients (32 males, 28 females, mean age 69.3±11.3 years) were enrolled: 31 (51.7%) had IPMNs and 29 (48.3%) had histologically confirmed pancreatic adenocarcinomas. Thirty blood donors were also studied as controls. In all study subjects, the concentrations of VEGF, VEGF-D, VEGFR-2, and endostatin were determined using enzyme-linked immunosorbent assays. RESULTS: Serum concentrations of VEGF, VEGF-D, and VEGFR-2 were significantly higher in patients with pancreatic ductal adenocarcinoma and those with IPMNs compared with healthy subjects, while endostatin was significantly higher only in patients with pancreatic ductal adenocarcinoma compared with healthy subjects. Within the group of patients, VEGFR-2 was significantly higher in patients with ductal adenocarcinoma compared to those with IPMNs. The sensitivity and the specificity of VEGFR-2 in differentiating patients with ductal adenocarcinomas from those with IPMN at a cut-off range of 4003-4034 pg/mL was 86.2% and 54.8%, respectively. CONCLUSIONS: IPMNs have serum VEGFR-2 concentrations different from those in patients with ductal adenocarcinomas. However, serum VEGFR-2 cannot be routinely utilized to differentiate IPMNs from pancreatic ductal adenocarcinomas.

Tyrosine kinase inhibitors, pancreatic hyperenzymemia and acute pancreatitis: a review.

The advent of new drugs can rapidly increase the number of substances causing acute pancreatitis. This is the case of tyrosine kinase inhibitors; these drugs are currently used for chronic myeloid leukemia, gastrointestinal stromal tumors, unresectable hepatocellular carcinomas and advanced renal cell carcinomas that and they have been reported to cause acute pancreatitis or asymptomatic elevations of serum pancreatic enzymes. Of the classes of drugs capable of inducing acute pancreatitis, we aimed to evaluate, in which class tyrosine kinase inhibitors can be allocated. A search was carried out using the MEDLINE database in order to select the data existing in the literature on pyrimidines and acute pancreatitis or serum lipase/amylase elevation covering the period from January 1966 to January 2010; thirteen papers were found and utilized for this review. Based on the data in the literature, we found that tyrosine kinase inhibitors may often cause an increase in pancreatic enzymes in plasma and patients treated with these drugs, especially those who are treated with sorafenib, might be at risk of developing acute pancreatitis. Whether acute pancreatitis due to tyrosine kinase inhibitors is associated only with sorafenib or may also be caused by other drugs of the same class remains an open question. Recent patents on tyrosine kinase inhibitors and acute pancreatitis are pointed out in this review.

Does ablation technique utilized in the management of unresectable locally advanced pancreatic adenocarcinoma?

Radiofrequency ablation in the management of advanced pancreatic cancer should be no longer utilized in patients with locally advanced or metastatic pancreatic adenocarcinoma.