Frequency and Risk Factors of Various Complications After Computed Tomography–Guided Radiofrequency Ablation of Lung Tumors

Objective To retrospectively determine the frequency and risk factors of various side effects and complications after percutaneous computed tomography–guided radiofrequency (RF) ablation of lung tumors. Methods We reviewed and analyzed records of 112 treatment sessions in 57 of our patients (45 men and 12 women) with unresectable lung tumors treated by ablation. Risk factors, including sex, age, tumor diameter, tumor location, history of surgery, presence of pulmonary emphysema, electrode gauge, array diameter, patient position, maximum power output, ablation time, and minimum impedance during ablation, were analyzed using univariate and multivariate analyses. Results Total rates of side effects and minor and major complications occurred in 17%, 50%, and 8% of treatment sessions, respectively. Side effects, including pain during ablation (46% of sessions) and pleural effusion (13% of sessions), occurred with RF ablation. Minor complications, including pneumothorax not requiring chest tube drainage (30% of sessions), subcutaneous emphysema (16% of sessions), and hemoptysis (9% of sessions) also occurred after the procedure. Regarding major complications, three patients developed fever >38.5°C; three patients developed abscesses; two patients developed pneumothorax requiring chest tube insertion; and one patient had air embolism and was discharged without neurologic deficit. Univariate and multivariate analyses suggested that a lesion located ≤1 cm of the chest wall was significantly related to pain (p < 0.01, hazard index 5.76). Risk factors for pneumothorax increased significantly with previous pulmonary surgery (p < 0.05, hazard index 6.1) and presence of emphysema (p <0.01, hazard index 13.6). Conclusion The total complication rate for all treatment sessions was 58%, and 25% of patients did not have any complications after RF ablation. Although major complications can occur, RF ablation of lung tumors can be considered a safe and minimally invasive procedure.     

Dual alpha(2)-adrenergic agonist and alpha(1)-adrenergic antagonist actions of dexmedetomidine on human isolated endothelium-denuded gastroepiploic arteries

The actions of dexmedetomidine (DEX) on human vascular smooth muscle are unclear. We investigated its effects on isolated, endothelium-denuded human gastroepiploic arteries in vitro and compared them with clonidine (CLO). DEX had little direct effect on resting tension, whereas CLO produced small contractile responses, an effect which is blocked by the alpha(1)-adrenergic antagonist prazosin. DEX markedly enhanced the high K(+) (40 mmol/L)-induced contraction, and this effect was reversed by the alpha(2)-adrenergic antagonists yohimbine and rauwolscine but unaffected by prazosin. However, CLO had little effect on the K(+) contractions. Interestingly, larger concentrations (>10(-7) mol/L) of both alpha(2)-adrenergic stimulants significantly inhibited the contractions elicited by the alpha(1)-adrenergic agonist phenylephrine (10(-6) mol/L) and, to a lesser extent, those elicited by the alpha(1)/alpha(2)-agonist norepinephrine (10(-6) mol/L). These results suggest the possibility that DEX and CLO each have a high affinity for alpha(1)-adrenoceptors in human isolated gastroepiploic arteries, resulting in a reduced efficacy of alpha(1)-adrenergic activation by alpha-agonists. The differing affinities of the drugs for alpha(1)- and alpha(2)-adrenoceptors may help explain their additional actions: 1) DEX enhances the high K(+)-induced contraction presumably through alpha(2)-adrenoceptor activation, and 2) CLO acts on alpha(1)-adrenoceptors as a partial agonist when present alone. IMPLICATIONS: Dexmedetomidine may not directly affect smooth muscle in human peripheral resistance vessels within the usual range of plasma concentrations (<10(-7) mol/L) achieved in clinical practice. However, in large doses, it could enhance the response to nonadrenergic vasoconstrictor agonists while antagonizing the vasoconstrictor response to alpha(1)-adrenoceptor agonists.     

Calcification and osteopontin localization in the peritoneum of patients on long-term continuous ambulatory peritoneal dialysis therapy.

BACKGROUND: Peritoneal calcification is an uncommon complication of continuous ambulatory peritoneal dialysis (CAPD), which is mainly observed in patients on long-term therapy. Although some asymptomatic patients must have microscopic calcification in their peritoneum, little information on this topic has been published. Recent studies have revealed active participation of adhesive/chemotactic protein osteopontin (OPN) in dystrophic calcification. METHODS: Peritoneal tissue was obtained by biopsy or at autopsy from 18 CAPD patients (median duration, 122 months), 5 control haemodialysis (HD) patients, and 3 pre-CAPD patients. The distribution of calcium deposits and OPN protein was determined by von Kossa staining and immunohistochemistry, respectively. Smooth muscle cells and macrophages were identified with anti-alpha smooth muscle actin (alpha-SMA) and anti-CD68 antibodies. RESULTS: Calcium deposits with various configurations were observed in specimens from 12 of the 18 CAPD patients. They included massive calcification facing the peritoneal cavity, scattered granular or crystalloid deposits in the submesothelial stroma, and oval-shaped deposits formed within hyalinized vasa. Most were present in highly sclerosed areas and accompanied by extracellular OPN precipitation. Cytoplasmic OPN was detected in infiltrating leukocytes, granulation tissue cells, fibroblast-like cells and mast cells. Computerized tomography examination also detected peritoneal calcification in seven of the CAPD patients. No calcium deposits or OPN staining was detected in control specimens. CONCLUSIONS:The results of our study suggest that microscopic peritoneal calcification is frequent in patients on CAPD for more than 10 years. Myofibroblast infiltration, OPN expression, calcium deposition, and associated OPN precipitation seem to be components of the peritoneal changes in such patients.     

Hematin is one of the cytotoxic factors in pancreatitis-associated ascitic fluid that causes hepatocellular injury.

BACKGROUND: We recently demonstrated that pancreatitis-associated ascitic fluid (PAAF) contains cytotoxic factor(s), inducing apoptosis in hepatocytes, and that PAAF induces hepatic adenosine triphosphate depletion, hepatocellular acidosis, and accumulation of hepatic intracellular sodium. Because ascitic fluid and serum from patients with hemorrhagic pancreatitis contain a lot of hematin, we aimed to test the hypothesis that hematin can induce hepatocellular injury, and then we compared its cytotoxicity with that of PAAF. METHODS: In vivo effects of intraperitoneal injection of hematin into the liver of healthy rats were evaluated with in situ nick-end labeling, blood biochemical analysis, and nuclear magnetic resonance spectroscopy. In vitro cytotoxic and apoptosis-inducing activities of hematin on rat primary culture hepatocytes were investigated with a cellular proliferation assay kit and DNA fragmentation enzyme-linked immunosorbent assay, respectively. Furthermore, PAAF was fractionated with Sephacryl S-300 gel column chromatography, and cytotoxic activities of its fractions on a human hepatoma cell line (HuH-7) were compared with those of hematin. RESULTS: Intraperitoneal injection of hematin into healthy rats caused apoptosis in the hepatocytes and elevated serum glutamate oxaloacetic transaminase and lactate dehydrogenase levels. Intraperitoneal injection of hematin also caused a significant decrease in the hepatic beta-adenosine triphosphate/inorganic phosphate ratio, severe hepatic intracellular acidosis, and a significant increase of hepatic intracellular sodium (Na(+)) concentration, similar to the effects of PAAF. In vitro, hematin decreased hepatocyte viability and increased the DNA fragmentation of hepatocytes, similar to the effects of 10% PAAF. Albumin reversed the cytotoxic effects of hematin and PAAF on HuH-7 cells nearly completely and partially, respectively. Fractionation of PAAF and hematin by gel column chromatography revealed that the first peak of cytotoxic activity of PAAF corresponded to that of hematin and that the cytotoxic activity was reversed by albumin nearly completely. CONCLUSIONS: These results suggest that hematin is one of the cytotoxic factors in PAAF that causes hepatocellular injury and that cellular injuries caused by hematin may be involved in the development of multiple organ failure associated with severe acute pancreatitis.     

Mechanical analysis of the lumbar vertebrae in a three-dimensional finite element method model in which intradiscal pressure in the nucleus pulposus was used to establish the model

We established a three-dimensional finite element method (FEM) model of the 4th and 5th vertebrae, using computed tomography (CT) images (2-mm slice thickness) of a healthy 29-year-old man. Because of the lack of specific data regarding the material characteristics of the nucleus pulposus of intervertebral discs, we used intradiscal pressure in the nucleus pulposus to establish the model. We referred to data from Nachemson and from Sato et al. regarding intradiscal pressure and to the methods of Shirazi-Adl for data for other material characteristics (see text for these references). The mid-position model bears a load of 294 N in the vertical direction, while the models of the flexed and extended positions bear loads of 15 N-m. In addition, a degenerative disc model without intradiscal pressure was created for the standing model. The use of these models allowed the investigation of von Mises stress on the vertebral endplates and the annulus fibrosus. We also examined von Mises stress on the facet joint in normal and degenerative disc models. There was increased von Mises stress on the vertebral endplate in the anterior, center portions. von Mises stress on the annulus fibrosus increased in the posterior portion, the entrance to the neural foramen, and the exit of the neural foramen. von Mises stress was greater during flexion in the posterior portion; in particular, increasing to about 1.6 times the level seen with other postures. No changes were observed in von Mises stress on the vertebral endplates or annulus fibrosus in the degenerative disc model, but von Mises stress on the facet joints was about 2.5 times that seen in the normal disc model. Received: June 28, 2001 / Accepted: October 27, 2001     

Mucinous cystic neoplasm of the pancreas presenting with hemosuccus pancreaticus: Report of a case

Hemosuccus pancreaticus (HP) is mostly induced by a ruptured pseudoaneurysm or hemorrhage from a pseudocyst in chronic pancreatitis. We herein report a rare case with HP induced by tumor hemorrhage. The present patient is a 71-year-old woman referred to us with a diagnosis of severe progressive anemia. Endoscopy revealed hemorrhage from the papilla of Vater. Computed tomography showed a multilocular cystic tumor in the tail of the pancreas. The patient underwent a distal pancreatectomy. The histopathological diagnosis was carcinoma in mucinous cystadenoma. No cancer infiltration into the pancreatic duct was detected. Pancreatography of the resected specimen demonstrated an overt communication between the main pancreatic duct and the cystic cavity of the tumor, which was not demonstrated preoperatively by endoscopic retrograde pancreatography. Although the cause of HP is mainly acute or chronic pancreatitis, we should bear in mind that a pancreatic tumor may be a possible cause of HP and that, as such, prompt and proper treatment is mandatory.     

Low-level Er:YAG laser irradiation enhances osteoblast proliferation through activation of MAPK/ERK

Although the use of high-level Er:YAG laser irradiation has been increasing in periodontal and peri-implant therapy, the effects of low-level Er:YAG laser on surrounding tissues and cells remain unclear. In the present study, the effects of low-level Er:YAG laser irradiation on osteoblast proliferation were investigated. Cells of the osteoblastic cell line MC3T3-E1 were treated with low-level Er:YAG laser irradiation with various combinations of laser settings (fluence 0.7–17.2 J/cm²) and in the absence or presence of culture medium during irradiation. On day 1 and/or day 3, cell proliferation and death were determined by cell counting and by measurement of lactate dehydrogenase (LDH) levels. Further, the role of mitogen-activated protein kinase (MAPK) pathways in laser-enhanced cell proliferation was investigated by inhibiting the MAPK pathways and then measuring MAPK phosphorylation by Western blotting. Higher proliferation rates were found with various combinations of irradiation parameters on days 1 and 3. Significantly higher proliferation was also observed in laser-irradiated MC3T3-E1 cells at a fluence of approximately 1.0–15.1 J/cm², whereas no increase in LDH activity was observed. Further, low-level Er:YAG irradiation induced the phosphorylation of extracellular signal-regulated protein kinase (MAPK/ERK) 5 to 30 min after irradiation. Although MAPK/ERK 1/2 inhibitor U0126 significantly inhibited laser-enhanced cell proliferation, activation of stress-activated protein kinases/Jun N-terminal kinase (SAPK/JNK) and p38 MAPK was not clearly detected. These results suggest that low-level Er:YAG laser irradiation increases osteoblast proliferation mainly by activation of MAPK/ERK, suggesting that the Er:YAG laser may be able to promote bone healing following periodontal and peri-implant therapy.     

Internal Hernia with Strangulation Through a Mesenteric Defect After Laparoscopy-Assisted Transverse Colectomy: Report of a Case

A 58-year-old woman underwent laparoscopy-assisted transverse colectomy for transverse colon cancer. On postoperative day 7, she experienced sudden abdominal pain accompanied by vomiting and fever. Computed tomography showed a small bowel obstruction caused by an internal hernia. Laparotomy revealed an internal hernia through the mesenteric defect at the anastomotic colonic stumps, which had not been closed in the previous operation. Almost the entire small bowel protruding through the mesenteric defect was found in the omental bursa. We resected part of the jejunal loop, which was strangulated and congested by an adherent band. Our experience suggests that if the mesenteric defect is relatively small, it should be closed completely during laparoscopy-assisted colectomy; however, more studies are required to determine the indications for closure of the mesenteric defect to prevent this complication.