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1.  Hepatic Blood Perfusion Estimated by Dynamic Contrast-Enhanced Computed Tomography in Pigs Limitations of the Slope Method 
Investigative radiology  2012;47(10):588-595.
To determine whether dynamic contrast-enhanced computed tomography (DCE-CT) and the slope method can provide absolute measures of hepatic blood perfusion from hepatic artery (HA) and portal vein (PV) at experimentally varied blood flow rates.
Materials and Methods
Ten anesthetized 40-kg pigs underwent DCE-CT during periods of normocapnia (normal flow), hypocapnia (decreased flow), and hypercapnia (increased flow), which was induced by adjusting the ventilation. Reference blood flows in HA and PV were measured continuously by surgically-placed ultrasound transit-time flowmeters. For each capnic condition, the DCE-CT estimated absolute hepatic blood perfusion from HA and PV were calculated using the slope method and compared with flowmeter based absolute measurements of hepatic perfusions and relative errors were analyzed.
The relative errors (mean±SEM) of the DCE-CT based perfusion estimates were −21±23% for HA and 81±31% for PV (normocapnia), 9±23% for HA and 92±42% for PV (hypocapnia), and 64±28% for HA and −2±20% for PV (hypercapnia). The mean relative errors for HA were not significantly different from zero during hypo- and normocapnia, and the DCE-CT slope method could detect relative changes in HA perfusion between scans. Infusion of contrast agent led to significantly increased hepatic blood perfusion, which biased the PV perfusion estimates.
Using the DCE-CT slope method, HA perfusion estimates were accurate at low and normal flow rates whereas PV perfusion estimates were inaccurate and imprecise. At high flow rate, both HA perfusion estimates were significantly biased.
PMCID: PMC3436950  PMID: 22836307
liver perfusion; dynamic CT; slope method; hepatic artery; portal vein
2.  Pancreatic cancer survival in central and northern Denmark from 1998 through 2009: a population-based cohort study 
Clinical Epidemiology  2011;3(Suppl 1):19-25.
Pancreatic cancer has a relatively low incidence but ranks fourth among cancer- related deaths in western countries. In Denmark, cancer survival generally is lower than in other countries with comparable health care systems. As a result, in 2000, a national strategy to improve cancer survival was introduced. Here we examine time trends in survival and relative mortality among pancreatic cancer patients, using Danish population and medical databases.
Using the Danish National Patient Registry (DNPR), we identified all incident pancreatic cancer patients (n = 2968) diagnosed between 1998 and 2009 in the Central and North Denmark Regions. We computed the 1-, 3-, and 5-year survival and relative mortality (MRR) and associated 95% confidence intervals (CI) adjusting for age and gender. Among surgical patients, we also computed 30-day mortality and 30-day MRR.
Median age at diagnosis was approximately 71 years. The annual number of patients increased from 189 in 1998–2000 to 302 in 2007–2009. There was a slight improvement in 1-, 3-, and 5-year survival over time from 14.8% to 17.7%; 3.5% to a predicted 5.6%; and from 2.0% to a predicted 3.8%, from 1998–2000 to 2007–2009, respectively. Correspondingly, the adjusted relative mortality decreased from 1998–2000 to 2007–2009. Thirty-day post-operative mortality decreased from 12.2% in 1998–2000 to 5.8% in 2007–2009, corresponding to a 30-day MRR of 0.38, 95% CI = 0.09, 1.6 in 2007–2009.
There was a slight, albeit modest, improvement in survival and relative mortality in pancreatic cancer patients between 1998 and 2009. As we lacked staging information, it is not clear if this improvement is attributable to earlier stage at diagnosis. However, these improvements likely reflect the national cancer strategy which aimed to centralize cancer services and involved the introduction of palliative and adjuvant chemotherapy for pancreatic cancer in Denmark. The dismal prognosis of pancreatic cancer means that efforts to improve survival need to be intensified.
PMCID: PMC3144774  PMID: 21814466
pancreatic cancer; survival; relative mortality; epidemiology
3.  Effects of ischemic pre- and postconditioning on HIF-1α, VEGF and TGF-β expression after warm ischemia and reperfusion in the rat liver 
Ischemic pre- and postconditioning protects the liver against ischemia/reperfusion injuries. The aim of the present study was to examine how ischemic pre- and postconditioning affects gene expression of hypoxia inducible factor 1α (HIF-1α), vascular endothelial growth factor A (VEGF-A) and transforming growth factor β (TGF-β) in liver tissue.
28 rats were randomized into five groups: control; ischemia/reperfusion; ischemic preconditioning (IPC); ischemic postconditioning (IPO); combined IPC and IPO. IPC consisted of 10 min of ischemia and 10 min of reperfusion. IPO consisted of three cycles of 30 sec. reperfusion and 30 sec. of ischemia.
HIF-1α mRNA expression was significantly increased after liver ischemia compared to controls (p = 0.010). HIF-1α mRNA expression was significantly lower in groups subjected to IPC or combined IPC and IPO when compared to the ischemia/reperfusion group (p = 0.002). VEGF-A mRNA expression increased in the ischemia/reperfusion or combined IPC and IPO groups when compared to the control group (p < 0.05).
Ischemic conditioning seems to prevent HIF-1α mRNA induction in the rat liver after ischemia and reperfusion. This suggests that the protective effects of ischemic conditioning do not involve the HIF-1 system. On the other hand, the magnitude of the HIF-1α response might be a marker for the degree of I/R injuries after liver ischemia. Further studies are needed to clarify this issue.
PMCID: PMC3155899  PMID: 21771288
4.  Internal gallbladder drainage prevents development of acute cholecystitis in a pig model: a randomized study 
Acute cholecystitis can be the result of retention of bile in the gallbladder with possible secondary infection and ischaemia. The aim of the present study was to investigate whether internal drainage of the gallbladder could protect against the development of acute cholecystitis in a pig model.
Materials and methods
Twenty pigs were randomized to either internal drainage (drained) or not (undrained). Day 0 acute cholecystitis was induced by ligation of the cystic artery and duct together with inoculation of bacteria. Four days later the pigs were killed and the gallbladders were removed and histologically scored for the presence of cholecystitis. Bile and blood samples were collected for bacterial culturing and biochemical analyses.
The histological examination demonstrated statistical significant differences in acute cholecystitis development between groups, the degree of inflammation being highest in undrained pigs. There were no differences in bacterial cultures between the two groups.
Internal drainage of the gallbladder protected against the development of acute cholecystitis in the present pig model. These findings support the theory that gallstone impaction of the cystic duct plays a crucial role as a pathogenetic mechanism in the development of acute cholecystitis and suggest that internal drainage may be a way to prevent and treat acute cholecystitis.
PMCID: PMC2890535  PMID: 20504296

Results 1-4 (4)