Precipitation of calcium compounds onto rock surfaces in water with cementitious material

In this study, the precipitation of minerals onto rock surfaces was investigated to consider whether sealing of pores and cracks in rock can be accelerated. Cylindrical specimens were prepared and then kept in purified water with powders of high-strength and ultra-low-permeability concrete (HSULPC), which will be used to confine transuranic wastes in Japan. Then, the rock specimens were weighed and the surfaces of rock specimens were inspected under a microscope. It was recognized that precipitation occurred on the surface of the rock specimens. It was also shown that precipitation did not occur on rock specimens kept in water without HSULPC. The weight of all specimens stored in HSULPC increased, and the observed weight change was larger for rocks with higher porosities. It is concluded that precipitation of minerals occurs on the rock surface when the rock is kept in water with HSULPC powders. From the results obtained in this study, it is suggested that the sealing of pores and cracks in rock can be accelerated by the precipitation of calcium compounds using HSULPC. It is concluded that HSULPC is useful for underground radioactive waste disposal

Myocardial velocity gradient as a noninvasively determined index of left ventricular diastolic dysfunction in patients with hypertrophic cardiomyopathy

AbstractObjectivesWe investigated the utility of the peak negative myocardial velocity gradient (MVG) derived from tissue Doppler imaging (TDI) for evaluation of diastolic dysfunction in patients with hypertrophic cardiomyopathy (HCM).BackgroundHypertrophic cardiomyopathy is characterized by impaired diastolic function with abnormal stiffness and prolonged relaxation. However, it remains difficult to evaluate these defects noninvasively.MethodsBoth TDI and conventional echocardiography were performed in 36 patients with HCM and in 47 control subjects. Left ventricular (LV) pressure was measured simultaneously in all HCM patients and in 26 controls.ResultsThe peak negative MVG occurred soon after the isovolumic relaxation period during the initial phase of rapid filling (auxotonic relaxation). It was significantly smaller in HCM patients than in control subjects (2.32 ± 0.52/s vs. 4.82 ± 1.15/s, p < 0.0001); the cutoff value for differentiation between all HCM patients and 47 normal individuals was determined as 3.2/s. Both the left ventricular end-diastolic pressure (LVEDP) (19.6 ± 6.1 mm Hg vs. 6.5 ± 1.7 mm Hg, p < 0.0001) and the time constant of LV pressure decay during isovolumic diastole (tau) (44.0 ± 6.7 ms vs. 32.1 ± 5.5 ms, p < 0.0001) were increased in HCM patients compared with controls. The peak negative MVG was negatively correlated with both LVEDP (r= −0.75, p < 0.0001) and tau (r= −0.58, p < 0.0001).ConclusionsA reduced peak negative MVG reflects both prolonged relaxation and elevated LVEDP. The peak negative MVG might thus provide a noninvasive index of diastolic function, yielding unique information about auxotonic relaxation in patients with HCM

Selection and Outcome of Portal Vein Resection in Pancreatic Cancer

Pancreatic cancer has the worst prognosis of all gastrointestinal neoplasms. Five-year survival of pancreatic cancer after pancreatectomy is very low, and surgical resection is the only option to cure this dismal disease. The standard surgical procedure is pancreatoduodenectomy (PD) for pancreatic head cancer. The morbidity and especially the mortality of PD have been greatly reduced. Portal vein resection in pancreatic cancer surgery is one attempt to increase resectability and radicality, and the procedure has become safe to perform. Clinicohistopathological studies have shown that the most important indication for portal vein resection in patients with pancreatic cancer is the ability to obtain cancer-free surgical margins. Otherwise, portal vein resection is contraindicated

Pancreatic head resection with segmental duodenectomy: safety and long term results

To evaluate the usefulness and long-term results with pancreatic head resection with segmental duodenectomy (PHRSD; Nakao's technique) in patients with branch-duct type intraductal papillary mucinous neoplasms (IPMNs). A prospective study from Nagoya (Japan) and Barcelona (Spain). Summary Background Data: Surgery should be the first choice of treatment of IPMNs. An aggressive surgery (eg, pancreatoduodenectomy) should be questioned in patients with an indolent disease or with noninvasive tumors. Recently, organ-preserving pancreatic resections for benign and noninvasive IPMN located in the head of the pancreas have been described. We have PHRSD in which the pancreatic head can be completely resected and the major portion of the duodenum can be preserved by this procedure. There have been only 4 reports concerning PHRSD with <8 patients (each one) in the English literature. Methods: Thirty-five patients underwent PHRSD (20 men, 15 women), mean age 65.1 +/- 9.0 (range, 55-75). Mean maximal diameter of the cystic lesion was 26.4 +/- 5.3 mm (range, 20-33 mm) and mean diameter of the main pancreatic duct was 3.3 +/- 0.5 mm (range, 3.0-4.0 mm). Alimentary tract reconstruction was performed in 20 patients by pancreatogastrostomy, duodenoduodenostomy, and choledochoduodenostomy (type A) and 15 patients by pancreaticojejunostomy, duodenoduodenostomy and choledochojejunostomy (Roux-en-Y; type B). Surgical parameters, postoperative complications, endocrine function, exocrine function, and long-term outcomes were evaluated. To compare the perioperative factors, a matched-pairs analysis between PHRSD patients and patients with pylorus preserving pancreaticoduodenectomy (PPPD) was performed. In the latter group were included 32 patients with branch-duct type of IPMN operated during the same time period that patients with PHRSD. The mean follow-up period was 48.8 months. Results: Mean operative time after PHRSD was 365 +/- 50 and mean surgical blood loss was 615 +/- 251 mL. There was no mortality. Pancreatic fistula occurred in 10% and 13% with types (alimentary tract reconstruction) A and B, respectively. Noninvasive IPMN was found in 31 patients and invasive IPMN in 4 patients (11.4%). In the matched-pairs analysis between PHRSD and PPPD, the 2 procedures were comparable in regard to operation time and intraoperative blood loss. The overall incidence of pancreatic fistula was higher after PPPD than after PHRSD; the difference was not statistically significant. When fistulas occurred after PHRSD they were grade A (biochemical). In contrast, pancreatic fistulas after PPPD were grade A in 78% of cases and grade B in 22% (clinically relevant fistula). The incidence of delayed gastric emptying was significantly higher in the PPPD group compared with the PHRSD group (P < 0.01). Endocrine pancreatic function, measured by fasting blood glucose levels and HbA1, levels was unchanged in 94.28% of patients, in the PHRSD group, and in 87.87% in the PPPD group. Body weight was unchanged in 80% after PHRSD and in 59% after PPPD. Postoperative enzyme substitution was needed in 20% of patients after PHRSD and in 40% patients after PPPD. The 5-year survival rate was 100% in patients with benign IPMN and 42% in patients with invasive IPMN. Conclusion: PHRSD is a safe and reasonable technique appropriate for selected patients with branch-duct IPMN. The major advantages of PHRSD are promising long-term results in terms of pancreatic function (exocrine and endocrine) with important consequences in elderly patients. Long-term outcome was satisfactory without tumor recurrence in noninvasive carcinoma. PHRSD should therefore be considered as an adequate operation as an organ-preserving pancreatic resection for branch-duct type of IPMN located at the head of the pancreas