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Purified C. perfringens type A enterotoxin fed orally in an amount of 5 mg caused both vomiting and diarrhea in the monkey only when the gastric juice had been neutralized. Exposure of enterotoxin to pH 4.0 or below rapidly destroyed the activity. All three monkeys receiving sodium bicarbonate and 2.4 X 10(10) viable cells grown in DS medium developed diarrhea, and only one of them vomited once. The diarrhea lasted for 13, 18 and 19 hr. The symptoms were similar to those reported in human cases of C. perfringens food poisoning. These results have verified the general notion that C. perfringens food poisoning should be categorized as a true "intravital intoxication". The reversed passive hemagglutination test detected enterotoxin directly in most fecal samples. This method may be applicable for diagnosis of human cases of C. perfringens food poisoning. Neither enterotoxin nor anti-enterotoxin was detected in serum samples taken from any monkey up to 21 days after the challenge. We are tempted to conclude, therefore, that no significant amount of C. perfringens enterotoxin is absorbed from the intestine.

Both protein and carbohydrate were necessary for sporulation and enterotoxin production of Clostridium perfringens NCTC 8239 in the ligated intestine of the rabbit. The administration of 108 vegetative cells suspended in 2ml of skim milk was confirmed to induce positive reactions consistently. However, skim milk dialysate, which contained the same amount of protein as the 10% skim milk, had no effect. An addition of 10% lactose to the skim milk dialysate restored the effect. Proteose peptone (Difco), peptone for toxin production (Mikuni), meat extract (Wako) and purified casein (Merck) could replace the skim milk dialysate.In addition to lactose, raffinose and fructose were effective as carbon sources whereas galactose, sucrose and glucose were less effective. Enterotoxin was not produced in the ligated intestine when the vegetative cells were administered together with any one of these carbohydrate or protein sources alone.

The reversed passive hemagglutination (RPHA) test yielded a positive reaction in 2 h with as little as 0.5 ng of purified Clostridium perfringens enterotoxin (CPE) per ml as well as with cultures of some C. perfringens grown in Duncan-Strong (DS) medium. This method is the most sensitive, the simplest, and the fastest among all reported. The time course of CPE production of Clostridium perfringens NCTC 8798 in DS was investigated by RPHA. CPE in culture was detectable at 4 h, increased gradually, reached a maximum at 12 to 14 h, and remained at a high level of 20 μg/ml through 48 h of incubation. CPE synthesized within cells is released easily by sonic disruption of young cultures and by aging the cultures 20 h or more. Heat shock of the cell inoculum was essential for CPE production by C. perfringens in DS.

In this study, we investigated the role of serum amyloid A protein (SAA) in the production of interleukin-6 (IL-6) using rheumatoid arthritis fibroblast-like synoviocytes (RA-FLS). Recombinant SAA stimulation induced the production of pro-inflammatory cytokine, IL-6, from RA-FLS. The signaling events induced by SAA included the activation of the mitogen-activated protein kineases, p38 and JNK1/2 and the activation of nuclear factor-kappa B (NF-kappaB). Inhibitor studies have shown SAA-induced IL-6 production to be down-regulated by NF-kappaB inhibition and partially inhibited by p38 or JNK inhibitors. Our findings demonstrate that SAA is a significant inducer of IL-6, which is critically involved in RA pathogenesis.

Purification of Clostridium perfringens type A enterotoxin from sporulated cells was simplified. The method consisted of precipitation of the enterotoxin from the extract of sonically treated cells at 40% saturation of ammonium sulfate at pH 7, differential solubilization in 0.02 M phosphate buffer, pH 6.7, and repeated gel filtration on Sephadex G-200. The purified enterotoxin was at least 98% pure in ultracentrifugation, polyacrylamide gel electrophoresis, and agar gel double diffusion. Recovery was over 74% from the sporulated cell extract. The toxin had biological activities of at least 4,700 mouse intravenous minimal lethal doses/mg of N, 3,900 capillary permeability-increasing U/mg of N in the guinea pig skin, and 210 rabbit intestinal loop distension U/mg of N. The toxin, containing no hexose, lipid, or nucleic acid, appeared to be identical in sedimentation constant, isoelectric point, and ultraviolet absorption spectrum to the toxin purified previously by different procedures.

Antibody against Clostridium perfringens type A enterotoxin was found in 82% of Brazilian and 65% of American serum samples.

Peroral administration of purified enterotoxin to human volunteers provoked diarrhoea and abdominal pain, symptoms identical with those encountered in outbreaks of Clostridium perfringens food poisoning. Eight milligrams of enterotoxin caused diarrhoea in one of two volunteers. All of five subjects given 10 and 12 mg of purified enterotoxin or crude enterotoxin developed the classical symptoms of this food poisoning. Passive haemagglutination anti-enterotoxin titres in serum increased in only 5 of 9 volunteers after exposure to enterotoxin. As such levels of anti-enterotoxin can be detected in normal serum samples, titration of anti-enterotoxin may be of little use in diagnosing Cl. perfringens food poisoning. Enterotoxin was detected in all diarrhoeal faecal specimens, and the enterotoxin level varied from 0·2–16 μg/g. Detection of enterotoxin in diarrhoeal faeces may be the most reliable procedure in diagnosing outbreaks of Cl. perfringens food poisoning.

A simple and reproducible assay method using African green-monkey kidney (Vero) cells for Clostridium perfringens enterotoxin was developed. Vero cells were incubated with enterotoxin in wells on a microtiter plate for 60 min at 37 C and stained with a 0.2% nigrosin solution. A nearly linear curve was obtained between the ratio of the stained cells and the log dose of purified enterotoxin ranging from 25 to 400 ng/ml. As culture supernatant of some strains in Duncan and Strong (DS) medium caused false positive reaction, the proposed method may not be reliable for assaying enterotoxin in culture at a concentration of 250 ng/ml or lower. Dilution of the culture supernatant by 10-fold or higher with buffered saline eliminated such false positive reaction. The Vero-cell staining assay, therefore, is applicable for assaying enterotoxin in pure form and that in cultures in DS medium at 250 ng/ml or higher concentrations. It seems essential to prove that the reaction is neutrarized with anti-enterotoxin serum.

A hemolysin produced by a strain of Aeromonas hydrophila isolated from a patient with diarrhea was purified by acid precipitation and quarternary aminoethyl-Sephadex chromatography. The molecular weight of the hemolysin was estimated at 50,000 by sodium dodecyl sulfate-polyacrylamide gel electrophoresis and at 48,000 by Sephadex G-100 gel filtration. In polyacrylamide gel electrophoresis at pH 4.0 and sodium dodecyl sulfate-polyacrylamide gel electrophoresis, the hemolysin migrated as a single band, whereas electrophoresis at pH 9.4 and thin-layer isoelectric focusing demonstrated multiple bands. The results may indicate charge isomers of the hemolysin. The purified hemolysin had a hemolytic activity of 134 hemolytic units per microgram of protein on rabbit erythrocytes. It caused fluid accumulation in infant mouse intestines and rabbit ligated ileal loops. Purified hemolysin also elicited cytotoxicity to Vero cells and lethal toxicity to mice. All these biological activities were lost on heating for 5 min at 56 degrees C. These findings support the notion that A. hydrophila hemolysin is a cytotoxic enterotoxin.

The growth responses of bacteria to various B vitamins were found to be classified into four groups. In Type I the growth is affected only in shortening the lag phase of cultural development, in Type II the rate of logarithmic growth and the yield of final population are promoted, and in Type III only the final yield is enhanced leaving other phases of growth unaffected. These types of growth promotion seemed not to be a fixed character of a vitamin. Several examples showing the variability of the type for a vitamin according to the cultural conditions were presented. Physiological interpretation of these types of growth promotion was discussed. Finally, importance of the choice of test system for the turbidimetric bioassay of vitamin was suggested from the view-point of the proposed types of growth promotion.

Urethane modified polyether liquids composed of hard and soft segments exhibit either positive or negative ER effect depending on the structure. Here some model compounds of the urethane polymers were synthesized, and the influence of chemical structure, e.g. displacement of hard and soft segments and existence of branches, on the ER effect was studied. It was found that negative ER effect is enhanced by introducing a branched structure in the polyether main-chain or a hard segment at center of the linear polyether.

The thermal transitions of confined polymers are important for the application of polymers in molecular scale devices and advanced nanotechnology. However, thermal transitions of ultrathin polymer assemblies confined in subnanometre spaces are poorly understood. In this study, we show that incorporation of polyethylene glycol (PEG) into nanochannels of porous coordination polymers (PCPs) enabled observation of thermal transitions of the chain assemblies by differential scanning calorimetry. The pore size and surface functionality of PCPs can be tailored to study the transition behaviour of confined polymers. The transition temperature of PEG in PCPs was determined by manipulating the pore size and the pore–polymer interactions. It is also striking that the transition temperature of the confined PEG decreased as the molecular weight of PEG increased., Understanding the thermal transitions of confined polymers is important for the design of molecular scale devices. In this study, unusual thermal transitions are observed in polyethylene glycol chains incorporated in nanochannels of porous coordination polymers.

Previous investigations have shown that interleukin-11 (IL-11) and the IL-11 receptor (IL-11R) have been correlated with the regulation of tumor progression, cellular growth and differentiation in several malignant tumors. The objectives of this study were to clarify the role of IL-11 and IL-11Ralpha in human gastric carcinoma. IL-11 and IL-11Ralpha were studied in 73 cases of surgically resected human gastric adenocarcinomas by immunohistochemistry. The invasive activity and cell signaling pathway of gastric carcinoma cell lines were also examined. Among the 73 cases of adenocarcinoma, 53 (72.6%) and 47 cases (64.4%) showed positive staining in carcinoma cells for the IL-11 and IL-11Ralpha proteins, respectively. Histologically, IL-11 expression correlated only with Lauren's classification (p