Recent Insights into Clostridium perfringens Beta-Toxin

Clostridium perfringens beta-toxin is a key mediator of necrotizing enterocolitis and enterotoxemia. It is a pore-forming toxin (PFT) that exerts cytotoxic effect. Experimental investigation using piglet and rabbit intestinal loop models and a mouse infection model apparently showed that beta-toxin is the important pathogenic factor of the organisms. The toxin caused the swelling and disruption of HL-60 cells and formed a functional pore in the lipid raft microdomains of sensitive cells. These findings represent significant progress in the characterization of the toxin with knowledge on its biological features, mechanism of action and structure-function having been accumulated. Our aims here are to review the current progresses in our comprehension of the virulence of C. perfringens type C and the character, biological feature and structure-function of beta-toxin.     

Nanoridge patterns on polymeric film by a photodegradation copying method for metallic nanowire networks

Topographical patterns are widely applied in many manufacturing areas due to the unique role in modifying performance related to physical, chemical and biological fundamentals. The patterns are usually realized by buckling or wrinkling, self-assembly or epitaxy, and lithography techniques. However, the combination of satisfactory controllability, ridge robustness, cost and dimensional precision is still difficult to achieve by any of the strategies above. A novel, simple and low-cost nanopatterning technique named “photodegradation copying method” with high technological flexibility has been initially proposed in this study. As a perfect example, a nanoridge-patterned surface has been successfully realized on a polymeric film thanks to the selective photodegradation of polymer and the shielding effect of silver nanowire (AgNW) networks. Roughness, wettability and transmittance of the polymeric film became simply and effectively controllable by adjusting the photodegradation time or the size and distribution of AgNWs. In addition, the ridge-patterned film could also be employed as a substrate in transfer printing for more flexible devices. Various topographical nanopatterns are expected to be simply realized by the photocopying method, just replacing nanowires with other masks like nanodisks, nanocubes, nanotriangles, and so on. This promising photocopying technique is believed to play an important role in the development of topographical nanopatterns, and enable more intriguing applications simply, flexibly and inexpensively.

A simple photocopying method based on selective polymer photodegradation is proposed for fabricating topographical nanopatterns. Nanoridges are structured on a polyethylene terephthalate film due to ultraviolet shielding of silver nanowire networks.     

Thermal Decomposition Behavior of Prussian Blue in Various Conditions

Prussian blue analogs (PBA) are widely studied for radioactive cesium decontamination. However, there are fewer works related to their post use storage. Considering the oxidative stabilization of the material after the selective uptake of Cs, the thermogravimetric properties in powder and bead form, with various Cs and other alkali metal ions adsorbed, and various heating rates were studied. TG-DTA taken in dry air condition shows an exothermic decomposition at ~270 °C. This temperature varied with the heating rate, mass, and the proportion of adsorbed ions. The best condition for complete oxidation of Prussian blue (PB) is found to be a gradual oxidative decomposition by heating in the temperature range of 200–220 °C until the total mass is decreased by >35%. After this, the temperature could be safely increased to >300 °C for the complete oxidative decomposition of PB that formed iron oxide and salt of the adsorbed Cs. A pilot scale test conducted using the radioactive Cs adsorbed Prussian blue microbeads (PB-b) confirmed that no Cs was released in the effluent air during the process.     

Bacterial peritonitis in a patient with malignant ascites caused by pancreatic carcinoma: Case report and review of literature

Bacterial peritonitis, an infection of the ascitic fluid, can be classified etiologically as spontaneous or secondary bacterial peritonitis. The former is mainly caused by portal hypertension and its subsequent effects, whereas the latter is caused by the direct dissemination of bacteria into the peritoneal cavity. Previous reports have described some distinguishing features of these two entities. Here, we report the first known case of bacterial peritonitis with Aeromonas hydrophilia and Escherichia coli in a patient with malignant ascites associated with pancreatic carcinoma who exhibited features of both spontaneous and secondary peritonitis. Our report suggests that clinicians should also consider bacterial peritonitis in patients with malignant ascites who present with ostensibly cancer-related symptoms.     

Asymptomatic colorectal cancer detected by screening

PURPOSE: Colorectal cancer screening has become prevalent. To discuss the efficacy of screening, we studied the characteristics of asymptomatic Colorectal cancer detected by screening. METHODS: This is a retrospective review of patients with colorectal cancer treated at our institution. During the past 20 years, 96 of 1,046 cases of colorectal cancer were asymptomatic and detected by screening. Sixty-one of these cases were detected in the recent five years. The initial screening procedures were fecal occult blood test in 51 cases, sigmoidoscopy or colonoscopy in 18, barium enema in 9, and other tests in 18. RESULTS: Thirteen lesions (14 percent) were smaller than 1.0 cm and 32 (33 percent) were 1–2 cm in size. There were 34 Tis, 21 T1, and 8 T2 tumors. Of the 55 Tis or T1 lesions, 14 showed nonpolypoid growth (5 flat-elevated, 7 flat-elevated with depression, 1 flat, 1 depressed), and 12 of these were detected on endoscopy. Thirty-four cases were TNM Stage 0, 25 were Stage I, 16 were Stage II, 12 were Stage III, and 9 were Stage IV. Sixty-one percent of those detected by screening were in either Stage 0 or Stage I compared with 16 percent in the symptomatic group. Cumulative five-year disease-free survival rates were 100 percent for both Stage 0 and Stage I, 94 percent for Stage II, and 52 percent for Stage III. Overall cumulative five-year survival rate was 87 percent for those detected by screening, compared with 57 percent in symptomatic patients. CONCLUSIONS: Asymptomatic cancers detected by screening were at a less advanced stage. In particular, many nonpolypoid early cancers were detected by endoscopic screening.Poster presentation at the meeting of The American Society of Colon and Rectal Surgeons, Montreal, Quebec, Canada, May 7 to 12, 1995.     

Vasospasms of the radial artery after the transradial approach for coronary angiography and angioplasty

We examined vasospasms of the radial artery after a transradial approach was used for coronary angiography or angioplasty. In forty-eight patients (39 males and 9 females), arteriography of the radial artery was initially performed just after the transradial approach was used for coronary angiography and/or angioplasty. Then, five months later, a second arteriography of the radial artery was obtained after a transbrachial approach was used for coronary angiography. First and second arteriographies were compared to evaluate vaso-spasms of the radial artery. In the present study, more than 75% stenosis in the radial artery, 25-75% stenosis, and less than 25% stenosis were tentatively defined as severe spasms, moderate spasms, and mild spasms, respectively. In arteriographic studies on the radial artery, twenty-four patients (50%) had severe radial artery spasms, eleven patients (23%) had moderate spasms, and thirteen patients (27%) had mild spasms. The diameters of both the proximal and distal radial arteries in the severe spasm group were significantly smaller than those in the mild and moderate spasm groups (proximal site: severe group 2.39 +/- 0.70 mm versus mild group 2.98 +/- 0.46 mm, P < 0.05, and moderate group 2.96 +/- 0.77 mm, P < 0.05, distal site: severe group 2.26 +/- 0.60 mm versus mild group 2.73 +/- 0.47 mm, P < 0.05, and moderate group 2.86 +/- 0.71 mm, P < 0.05). We concluded that vasospasms of the radial artery occurred in most patients after the transradial approach. Furthermore, severe radial spasms were strongly correlated with the size of the diameter of the artery.     

A pediatric case of acute focal bacterial nephritis; comparison with the reports in Japanese child cases]

We report an 8-year-old boy with acute focal bacterial nephritis (AFBN). At the age of 3 months, he had a history of urinary tract infection and vesicoureteral reflux. He was admitted to our hospital because of high fever and costovertebral angle pain. Although acute pyelonephritis was suspected, neither pyuria nor cultures of blood and urine were positive. An initial ultrasonogram (US) of his kidneys was normal except for bilateral hydronephrosis. Two days later, however, a computed tomography (CT) revealed a poorly enhanced mass in the upper pole of the right kidney. Similar findings were also observed by US. Under the diagnosis of AFBN, he received antibiotics for 3 weeks. Voiding cystourethrogram showed both-sided vesicoureteral reflux and he underwent an operation. At present the mass of the kidney still remains, albeit its size tends to decrease. We suggest that an early examination of US or enhanced CT is necessary in cases with fever of unknown origin, considering the possibility of AFBN even if neither pyuria nor cultures of urine are positive.     

Analysis of malaria endemic areas on the Indochina Peninsula using remote sensing

We applied remote sensing using satellite images capable of obtaining data over a broad range, transcending national borders, as a method of rapidly, precisely, and safely increasing our understanding of the potential distribution of malaria. Our target region was the so-called Mekong malaria region on the Indochina Peninsula. As a malaria index, we used existing distribution maps of total reported malaria cases, malaria mortality, vivax malaria and falciparum malaria incidences, and so forth for 1997 and 1998. We produced monthly distribution maps of a normalized difference vegetation index (NDVI) with values of 0.2+, 0.3+, 0.35+, and 0.4+ using the geographical information system/remote sensing software based on the East Asia monthly NDVI maps of 1997. These maps were overlaid with various malaria index distribution maps, and cross-tabulations were carried out. The resulting maps with NDVI values of 0.3+ and 0.4+ matched the falciparum malaria distribution well, and we realized, in particular, that falciparum malaria is prevalent in regions in which NDVI values of 0.4+ continue for 6 months or more, while cases are fewer in regions with NDVI values of 0.4+ that continue for 5 months or less. It will be necessary in the future to examine the relationship between NDVI values and the habitats of the various vector mosquitoes using high-resolution satellite images and to implement detailed forecasts for malaria endemic areas by means of NDVI.