Quenched and annealed disorder mechanisms in comb models with fractional operators.

Recent experimental findings on anomalous diffusion have demanded novel models that combine annealed (temporal) and quenched (spatial or static) disorder mechanisms. The comb model is a simplified description of diffusion on percolation clusters, where the comblike structure mimics quenched disorder mechanisms and yields a subdiffusive regime. Here we extend the comb model to simultaneously account for quenched and annealed disorder mechanisms. To do so, we replace usual derivatives in the comb diffusion equation by different fractional time-derivative operators and the conventional comblike structure by a generalized fractal structure. Our hybrid comb models thus represent a diffusion where different comblike structures describe different quenched disorder mechanisms, and the fractional operators account for various annealed disorder mechanisms. We find exact solutions for the diffusion propagator and mean square displacement in terms of different memory kernels used for defining the fractional operators. Among other findings, we show that these models describe crossovers from subdiffusion to Brownian or confined diffusions, situations emerging in empirical results. These results reveal the critical role of interactions between geometrical restrictions and memory effects on modeling anomalous diffusion.

Anomalous diffusion and transport in heterogeneous systems separated by a membrane.

Diffusion of particles in a heterogeneous system separated by a semipermeable membrane is investigated. The particle dynamics is governed by fractional diffusion equations in the bulk and by kinetic equations on the membrane, which characterizes an interface between two different media. The kinetic equations are solved by incorporating memory effects to account for anomalous diffusion and, consequently, non-Debye relaxations. A rich variety of behaviours for the particle distribution at the interface and in the bulk may be found, depending on the choice of characteristic times in the boundary conditions and on the fractional index of the modelling equations.

Diffusive process on a backbone structure with drift terms.

The effects of an external force on a diffusive process subjected to a backbone structure are investigated by considering the system governed by a Fokker-Planck equation with drift terms. Our results show an anomalous spreading which may present different diffusive regimes connected to anomalous diffusion and stationary states.

Different diffusive regimes, generalized Langevin and diffusion equations.

We investigate a generalized Langevin equation (GLE) in the presence of an additive noise characterized by the mixture of the usual white noise and an arbitrary one. This scenario lead us to a wide class of diffusive processes, in particular the ones whose noise correlation functions are governed by power laws, exponentials, and Mittag-Leffler functions. The results show the presence of different diffusive regimes related to the spreading of the system. In addition, we obtain a fractional diffusionlike equation from the GLE, confirming the results for long time.

Universal patterns in sound amplitudes of songs and music genres.

We report a statistical analysis of more than eight thousand songs. Specifically, we investigated the probability distribution of the normalized sound amplitudes. Our findings suggest a universal form of distribution that agrees well with a one-parameter stretched Gaussian. We also argue that this parameter can give information on music complexity, and consequently it helps classify songs as well as music genres. Additionally, we present statistical evidence that correlation aspects of the songs are directly related to the non-Gaussian nature of their sound amplitude distributions.

[Repair of paravalvular leak after a third mitral valve replacement].

This study reports on a 57-year-old woman who underwent a 3rd mitral valve replacement and presented with complaints of fatigue. Laboratory examination revealed severe hemolytic anemia, and trans-esophageal echocardiography revealed a paravalvular leak (PVL) around the prosthetic valve at the posterior trigone in the mitral position. PVL was regarded as the cause of hemolytic anemia. At surgery, a small tissue defect was detected around the calcified posterior trigone of the mitral annulus with no evidence of infective endocarditis. The mitral PVL was successfully repaired with suture closure of the annular defect. The postoperative course was uneventful: postoperative echocardiography revealed no evidence of PVL, and the hemolytic anemia subsided.

[Ascending aortic aneurysm following aortic valve replacement due to aortitis syndrome; report of a case].

A 60-year-old woman had previously undergone aortic valve replacement for aortic regurgitation. As the aortic wall was elastic hard, inflammatory change was suspected; therefore, we undertook a partial biopsy of the ascending aortic wall and the intraoperative pathological specimens were compatible with aortitis syndrome. As there was no active inflammatory change, she was diagnosed as inactive aortitis syndrome and steroid therapy was not applied. Seven years later, a follow-up computed tomography (CT) showed an ascending aortic aneurysm of 65 mm in diameter. Aortic root replacement was planned based on a clinical diagnosis of an aneurysm of the ascending aorta. The patient was discharged without complication 21 days after surgery. It is possible that an inactive stage of aortitis may lead to late dilatation of the ascending aorta; therefore, careful postoperative follow-up is necessary in such cases.

Ex-vivo study of high-magnification chromoendoscopy in the gastrointestinal tract to determine the optimal staining conditions for endocytoscopy.

BACKGROUND AND STUDY AIMS: Endocytoscopy allows the observation of living cells in the gastrointestinal tract. Consistently clear views are essential for clinical application of the technique, but these are not always obtained. The aim of this study was to determine an appropriate staining regimen for endocytoscopy. MATERIALS AND METHODS: This was an ex-vivo animal study in which we stained freshly resected porcine esophagus, stomach, and colon with different concentrations of three dyes (1%, 0.5%, and 0.25% crystal violet; 5%, 2.5%, and 1% methylene blue; and 1%, 0.5%, and 0.25% toluidine blue) and assessed them after different exposure times (10 seconds, 30 seconds, 60 seconds, and 90 seconds). The images obtained were evaluated according to the staining status of the cytoplasm and the nucleus, and the contrast between the cytoplasm and the nuclei, and the optimal staining conditions for each organ were determined. Additionally, freshly resected human esophagus, stomach, and colon tissues were tested under the dye/exposure conditions that were found to be the most appropriate in the animal study. RESULTS: After intensive mucus removal, high-quality images were obtained using methylene blue and toluidine blue. The optimum conditions for endocytoscopic observation were obtained after staining with 1% methylene blue in the esophagus and with 0.25% toluidine blue in the stomach and the colon, after 60 seconds of exposure to the dye. This was confirmed in the human specimens. CONCLUSIONS: This study provides important information on appropriate staining conditions for endocytoscopy. Further ex-vivo and in-vivo studies are necessary before this technique comes into standard use, however.

A learning curve for endoscopic submucosal dissection of gastric epithelial neoplasms.

BACKGROUND AND STUDY AIMS: Endoscopic submucosal dissection (ESD) has become a widely accepted method for treating gastrointestinal neoplasms. The objective of our study was to assess the learning curve for ESD of gastric epithelial neoplasms. PATIENTS AND METHODS: Clinicopathological data were retrospectively collected from 383 ESD procedures for gastric epithelial neoplasms that were performed over a 5-year period. Thirteen endoscopists were involved as operators during this period. In study 1, the performance of the two principal operators was assessed every 25 patients. In study 2, the performance of all 13 operators was assessed according to their experience. RESULTS: In study 1, the caseloads of the two principal operators were 188 and 118 ESD procedures. There were no significant differences found between successive groups of 25 patients with regard to en-bloc resection rate and bleeding and perforation complication rates. The size of the lesions and the resected specimen diameter increased significantly as the number of treated cases increased, whereas the average procedure time decreased significantly. In study 2, the operators' caseloads ranged from 1 to 188 cases, with 11/13 operators having experience of fewer than 30 cases. There was no significant difference in treatment efficacy and complication rates between the operators throughout the study period. The lesions were mainly located in the lower part of the stomach in the procedures performed by the 11 less experienced endoscopists. The procedure times shortened as experience in the method increased. CONCLUSIONS: Constant rates of both treatment efficacy and complications were achieved over a 5-year period of experience with ESD. A decrease in procedure time was found to be a marker of proficiency in this technique.

Successful nonsurgical management of perforation complicating endoscopic submucosal dissection of gastrointestinal epithelial neoplasms.

BACKGROUND AND STUDY AIMS: Endoscopic submucosal dissection (ESD) is a novel technique used for the treatment of gastrointestinal neoplasia. One of its major limitations, however, is the complication of perforation. PATIENTS AND METHODS: We included in our study all the cases of perforation that occurred during ESD procedures for gastrointestinal epithelial neoplasia between February 2000 and February 2005. Clinical outcomes after perforation were investigated. RESULTS: Perforation was experienced at 27 lesions in 27 patients (four in the esophagus, fourteen in the stomach, seven in the colon, and two in the rectum). Fibrosis under the lesions was confirmed histologically in seven patients (26 %). Immediate closure using endoclips was performed in all patients except for three asymptomatic patients in whom a stomach perforation was first noticed when free air was noticed on a radiograph the morning after the ESD procedure. Air accumulation was detected radiographically in 21 patients (78 %). The mean duration of antibiotic treatment was 6.7 days and the patients were fasted for a mean period of 5.3 days. The mean maximum body temperature was 37.3 degrees C, the mean white blood cell count was 9733/mm3, and the mean C-reactive protein level was 5.0 mg/dl. All the patients were discharged well from the ward after a mean time of 12.1 days after ESD, and no recurrence caused by tumor spread from the perforation occurred in any patient after a median follow-up period of 36 months (range 9 - 52 months). CONCLUSION: Successful nonsurgical management after ESD complicated by perforation is a highly feasible option if intensive conservative treatments are used following immediate endoscopic closure of the perforation.

Correlation of serum pepsinogens and gross appearances combined with histology in early gastric cancer.

The correlation between serum pepsinogen (PG) levels and the gross types was investigated in 128 consecutive patients with early gastric cancer. Although there was no significant difference in age, gender, cancer location, or cancer depth among gross appearances, the distribution of histological type was significantly different between polypoid and depressed cancers: all polypoid cancers except one were intestinal type, whereas nearly a third of depressed cancers were diffuse type. All the patients in whom Helicobacter pylori status was investigated had Helicobacterpylori infection. Combination of gross appearances and histology (polypoid cancer with intestinal type, depressed cancer with intestinal type and depressed cancer with diffuse type) showed a clear difference in distribution of serum PG levels and a ratio between levels of PG I and PG II (I/II ratio). In polypoid cancer with intestinal type, a PG I level and a I/II ratio were significantly lower than those of the others. In depressed cancer with diffuse type, PG I and PG II levels were significantly higher. These findings revealed that backgrounds such as intragastric acidity and extent of gastric atrophy might differ among early gastric cancers with different morphology and histology.

Endoscopic submucosal dissection for rectal epithelial neoplasia.

BACKGROUND AND STUDY AIMS: The technique of endoscopic submucosal dissection (ESD) has recently been developed for en-bloc resection of gastric tumors. For oncological reasons and in order to improve the patients' quality of life, it may be desirable to use the same technique for rectal neoplasia. PATIENTS AND METHODS: Thirty-five consecutive patients with rectal neoplasia who had a preoperative diagnosis of large intraepithelial neoplasias with submucosal fibrosis or located on the rectal folds were enrolled. ESD was carried out with the same technique previously described for the stomach, with some modifications. The efficacy, complications, and follow-up results of the treatment were assessed. RESULTS: The rates of en-bloc resection and en-bloc plus R0 resection were 88.6 % (31 of 35) and 62.9 % (22 of 35), respectively. Hemoglobin levels did not drop by more than 2 g/dl in any of the patients after ESD. None of the patients had to receive blood transfusions or undergo emergency colonoscopy due to bleeding during ESD or hematochezia after ESD. Perforation during ESD occurred in two patients (5.7 %), who were managed with conservative medical treatment after endoscopic closure of the perforation. Excluding three patients in whom additional surgery was carried out, all but one of 32 patients were free of recurrence during a mean follow-up period of 36 months (range 12 - 60 months). The exception was a patient in whom a multiple-piece resection was required; the recurrent (residual) tumor, found 2 months after ESD, was a small adenoma that was again treated endoscopically. CONCLUSIONS: ESD is applicable in the rectum with promising results, but the technique is still at a developmental stage and patients should be informed of the potential risks.

Histopathologic characteristics of gastric ulcers created by endoscopic submucosal dissection.

BACKGROUND AND STUDY AIM: We have previously reported that gastric ulcers artificially created by endoscopic submucosal dissection (ESD) would heal within 8 weeks regardless of size and location. The details of the healing process remain unclear, and we aimed to clarify the mechanism by histopathological investigation. PATIENTS AND METHODS: 21 post-ESD ulcers were examined histopathologically, using surgically resected specimens from patients who had subsequently undergone gastrectomy due to submucosal invasion and/or lymphovascular infiltration by the tumor. The grade of ulcer, appearance of regenerative mucosa, scar formation, and extent of fibrosis were evaluated. RESULTS: Fibrosis and wall thickening were observed from 2 weeks after ESD, but regenerative mucosa was not observed until 5 weeks. Among 12 patients who underwent gastrectomy later than 8 weeks after ESD, a mucosal defect was still observed in two patients. In these two patients the lesion was associated with severe fibrosis due to previous peptic ulcer or submucosal invasion by the lesion. CONCLUSION: Size reduction in these ulcers occurs by contraction in the early phase, then regenerative mucosa covers the remaining mucosal defect within 8 weeks. If there is fibrosis under the lesion before ESD, there is a possibility that the artificially created ulcer will not heal within 8 weeks.

Long-term local intensive preoperative chemotherapy and joint-preserving conservative surgery for osteosarcoma around the knee.

This study evaluated conservative joint-sparing surgery for patients with osteosarcoma around the knee. Of 23 patients with stage IIB osteosarcoma around the knee, 5 were treated with long-term (30-56 weeks) local intensive preoperative chemotherapy consisting of high-dose methotrexate, intra-arterial and intravenous cisplatinum, doxorubicin, and hyperthermic isolated regional perfusion. More conservative resection, sparing the knee joint, was performed with smaller sufficient surgical margin in these 5 patients, preserving good limb function. Excellent local effects were achieved in the resected specimens. These results suggest long-term local intensive preoperative chemotherapy, including intra-arterial cisplatin and hyperthermic isolated regional perfusion, help control local tumor and allow for more conservative surgery.

HBV-related fulminant hepatic failure: successful intensive medical therapy in a candidate for liver transplantation.

Fulminant hepatic failure (FHF) usually has a fatal prognosis without liver transplantation. We describe the case of a woman who developed FHF, and was evaluated as a candidate for liver transplantation, but who was cured without transplantation through intensive medical care that included glucagon-insulin therapy, methylprednisolone pulse therapy, interferon beta and lamivudine administration, cyclosporine administration, and high-volume hemodiafiltration and plasma exchange. In a patient with FHF who is a candidate for liver transplantation but for whom the transplantation cannot be performed for some reason, intensive medical therapy, including regeneration-promoting therapy, immunosuppressive therapy, antiviral therapy, and vigorous hepatic support, should be carried out.

Molecular cloning of beta-galactosidase from Japanese pear (Pyrus pyrifolia) and its gene expression with fruit ripening.

We have cloned a cDNA fragment encoding a beta-galactosidase from Japanese pear (Pyrus pyrifolia) fruit (JP-GAL). It contained an untranslated sequence of 182 nucleotides at the 5' end, a presumptive coding sequence of 2,193 nucleotides and an untranslated sequence of 268 nucleotides including a polyadenylation signal and a poly (A) tail at the 3' end. It encoded a protein with a calculated molecular weight of 80.9 kDa which consists of 731 amino acids. Both the nucleotide and the deduced amino acid sequences showed a 98% sequence identity with that obtained from the apple beta-galactosidase cDNA. The peptide sequence obtained from the purified Japanese pear beta-galactosidase III matched the deduced amino acid sequence of SVSYDHKAIIINGQKRILISG (amino acid 25-45). Northern blot analysis showed that the probe derived from JP-GAL hybridized to a single 2.6 kb RNA. The mRNA was detected solely in the fruit; none was detected in the buds, leaves, roots or shoots of the Japanese pear. The steady-state level of the beta-galactosidase mRNA was measured during fruit ripening in three cultivars, Housui, Kousui (early ripening) and Niitaka (late ripening). The results showed that regardless of the cultivar, no JP-GAL mRNA was detected in the immature fruit. Increment of the mRNA level with fruit ripening coincided with the increase in the beta-galactosidase III activity. Our results showed that the expression of JP-GAL correlated with fruit softening and JP-GAL may be beta-galactosidase III.

Extensive mesenteric vein and portal vein thrombosis successfully treated by thrombolysis and anticoagulation.

Mesenteric vein thrombosis is generally difficult to diagnose and can be fatal. A case of extensive thrombosis of the mesenteric and portal veins was diagnosed early and successfully treated in a 26-year-old man with Down syndrome who was admitted to hospital because of abdominal pain, severe nausea and high fever. Ultrasonography revealed moderate ascites, and there was minimal flow in the portal vein (PV) on the Doppler examination. Computed tomography (CT) showed remarkable thickening of the walls of the small intestine and extensive thrombosis of the mesenteric, portal and splenic veins. Because neither intestinal infarction nor peritonitis was seen, combined thrombolysis and anticoagulation therapy without surgical treatment was chosen. Urokinase was administered intravenously and later through a catheter in the superior mesenteric artery. Heparin and antibiotics were given concomitantly. The patient's symptoms and clinical data improved gradually. After 10 days, CT revealed that collateral veins had developed and the thrombi in the distal portions of the mesenteric veins had dissolved, although the main trunk of the PV had not recanalized. The only risk factor of thrombosis that was detected was decreased protein S activity.

Mechanical failure of unsupported Huckstep intramedullary nail in malignant bone tumor reconstruction.

Seventeen segmental resections of diaphyseal tumors and five knee resection arthrodeses were reconstructed using the Huckstep nail with intercalary bone grafts (fibula), cementation, and ceramic and titanium spacers. Although the bone defects were 0 to 25.5 cm in length (mean, 13.1 cm), all patients had relief of pain and were able to move alone with a wheelchair or a cane. Nail breakage occurred in four patients who had reconstruction surgery using a ceramic spacer (four patients without intercalary fibula graft and one patient with intercalary fibula graft). The nail survival rate was significantly better in the patients with reinforcement by vascularized fibular graft (100% at 5 years and 75% at 10 years; n = 8) than in the patients without reinforcement by vascularized fibular graft (87.5% at 3 years and 0% at 5 years; n = 14). Huckstep nailing is a useful option for reconstruction of large bone defects in diaphyseal tumors and knee resection arthrodesis. It should be used in combination with a vascularized fibula graft to prevent mechanical failure and to achieve durability of limbs with defects from primary bone tumors. Huckstep nailing with nonbiologic augmentation is good for palliative surgery for bone metastases in patients with a shorter expected survival rate.

Fas antigen expression and outcome of oral squamous cell carcinoma.

Paraffin sections of biopsy specimens obtained from 46 patients with oral squamous cell carcinomas were stained with both anti-peptide antibody against human Fas antigen and monoclonal mouse antibody against human proliferating cell nuclear antigen (PCNA). The patients received chemotherapy with a combination of carboplatin and peplomycin sulfate or mitomycin C and peplomycin sulfate before surgery. The relation between the expression of Fas antigen and the clinical features of each case was examined. The correlation between PCNA and Fas antigen expression was also studied. The mean PCNA labeling index of the 22 Fas-negative cases was 46.9%, which was significantly higher than that of the 24 Fas-positive cases (39.5%). Strong correlations were found between the expression of Fas antigen and the response to chemotherapy, tumor recurrence, and survival. The Fas-negative group had only a minor response to chemotherapy and a poor outcome, whereas the Fas-positive group had a better response to chemotherapy and a good outcome. Although lymph node metastasis was significantly related to survival, there was no correlation between Fas antigen expression and lymph node metastasis. The Kaplan-Meier survival curve of patients positive for Fas antigen was significantly better than that of patients negative for Fas antigen. Our results suggest that Fas antigen expression is an independent predictor of outcome whose usefulness should be evaluated in prospective studies.