UV photolysis of perfluorooctanoic acid (PFOA) in dilute aqueous solution.

Perfluorooctanoic acid (PFOA) is very persistent in the environment and widely detected in the water environment. Only some advanced methods with extreme reaction conditions are shown to be capable of degrading the compound efficiently, and almost all the earlier investigations used very high PFOA concentrations. The compound is detected normally at very low concentrations in the water environment, while mild reaction conditions for its degradation are preferable. This article aimed to elucidate photodegradation of PFOA in dilute aqueous solutions by combined UV wavelengths (185 nm+254 nm) and 254 nm using a newly designed UV jacket. PFOA degradation was greatly enhanced with the combined wavelengths with almost one hundred percent PFOA removals in four-hour reaction. The removals were well described by the first-order reaction kinetic. The removal efficiencies and rate values significantly decreased with smaller initial PFOA concentrations. But defluorination was greatly enhanced with smaller PFOA concentrations possibly due to accelerated decomposition of fluorinated intermediates of PFOA. Formic acid and acetic acid were two tentatively identified intermediates of PFOA photolysis while the former was a major intermediate predominantly controlling solution pH during the oxidation. The results demonstrated that PFOA photolysis by the combined wavelengths with mild reaction conditions can be greatly enhanced by proper design of UV jacket and reactor system.

Cycle of the seminiferous epithelium in the Java fruit bat (Pteropus vampyrus) and the Japanese lesser horseshoe bat (Rhinolophus cornutus).

The cycle of the seminiferous epithelium in the Java fruit bat, Pteropus vampyrus, and the Japanese lesser horseshoe bat, Rhinolophus cornutus, was investigated by light microscopy and the characteristics of spermiogenesis were compared between these two species. In the Java fruit bat, the cycle of the seminiferous epithelium was divided into 11 stages and developing spermatids were subdivided into 13 steps. While in the Japanese lesser horseshoe bat, the cycle of the seminiferous epithelium was divided into 10 stages and developing spermatids were subdivided into 13 steps. Excepting slight morphological differences, the characteristics of acrosomal formation in both species were almost similar with each other. In the Java fruit bat after stage VII, the acrosome gradually elongated, flattened and finally became scoop-like in shape. In the Japanese lesser horseshoe bat after stage VIII, the acrosome elongated, flattened and then slightly shortened. Before spermiation, the acrosome became long spatula-like in shape. The elongation and flattening of spermatids in these two species were similar to those in insectivores. The finding may reflect the fact that the order Chiroptera is phylogenetically close to the order Insectivora.

Isolation and characterization of Escherichia coli O157 from retail beef and bovine feces in Thailand.

Antibody to Escherichia coli O157 lipopolysaccharide was detected in the sera of healthy individuals more frequently in Southern Thailand than in Japan. The result suggested possible exposure of Thai people to E. coli O157. E. coli O157:H7 or O157:H(-) was isolated from four of 95 retail beef and one of 55 bovine feces samples collected in Southern Thailand by enrichment culture followed by immunomagnetic bead separation. Four of the five strains carried the stx(2) gene alone or in combination with the stx(1) gene. The strains were shown to be genetically distinct by an arbitrarily primed PCR method.

Morphology of the intestinal tract in the white rhinoceros (Ceratotherium simum).

The intestinal tract of the white rhinoceros (Ceratotherium simun) was dissected. We observed a simple structure for the small intestine, duodenum, jejunum and ileum, and a well-developed large intestine, cecum, colon and rectus. The cecum consisted of a small chamber, whereas the colon was much enlarged; notably larger than that of the domesticated horse, which belongs to the same order, Perissodactyla. This suggests that in the white rhinoceros the cecum may be functionally replaced by the well-developed colon which may act as the main fermentation tank in this animal.

Isolation of an Escherichia coli O157:H7 strain producing Shiga toxin 1 but not Shiga toxin 2 from a patient with hemolytic uremic syndrome in Korea.

Escherichia coli strains isolated from patients with diarrhea or hemolytic uremic syndrome (HUS) at Pusan University Hospital, South Korea, between 1990 and 1996 were examined for traits of the O157:H7 serogroup. One strain isolated from a patient with HUS belonged to the O157:H7 serotype, possessed a 60-MDa plasmid, the eae gene, and ability to produce Shiga toxin 1 but not Shiga toxin 2. Arbitrarily primed PCR analysis suggested that this strain is genetically very close to a O157:H7 strain isolated in Japan.

Detection of Escherichia coli O157:H7 in the beef marketed in Malaysia.

Twelve strains of Escherichia coli O157:H7 were isolated from 9 of 25 beef samples purchased from retail stores in Malaysia. These strains produced Shiga toxin 2 with or without Shiga toxin 1 and had the eae gene and a 60-MDa plasmid. The antibiograms and the profiles of the arbitrarily primed PCR of the strains were diverse, suggesting that the strains may have originated from diverse sources.

Epstein-Barr virus-activating principle in human semen.

During the screening of natural and physiological products for their Epstein-Barr virus (EBV)-activating potency, we found that a considerable number of human semen specimens obtained from infertility clinics (30 cases) possess a marked capacity to induce EBV early antigen (EA) in non-producer Raji cell system when assayed in combination with n-butyrate. The EBV EA-inducing activity of the semen samples was comparable to that of the most efficient EBV EA inducers, the plant diterpene esters such as 12-O-tetradecanoylphorbol-13-acetate (TPA). Since many, if not all, of such active agents show overlapping with the tumor promoters in their biological reactions, these findings may provide a new insight for assessing the role of semen in the etiology of certain types of human genital malignancies.

Differential inhibitory effects of retinoic acid on Epstein-Barr virus induction in producer and nonproducer cell lines.

The effects of retinoic acid on Epstein-Barr virus (EBV) antigen induction by 12-O-tetradecanoyl-phorbol-13-acetate, 5-iodo-2'-deoxyuridine, and n-butyrate and by combinations of them were examined in two virus-producer and two nonproducer cell lines. Irrespective of the inducers used, the induction was markedly inhibited in the nonproducer lines and only weakly inhibited in the producer lines. The possible sites of action of retinoic acid are discussed.

Effect of protease inhibitors on the activation of Epstein-Barr virus repressed in cultured lymphoid cells.

The effects of five microbial and one synthetic protease inhibitors on the activation of Epstein-Barr virus expression in latency infected lymphoblastoid cells were studied. All protease inhibitors tested suppressed both viral antigen induction by 5-iododeoxyuridine treatment and cell growth in general. Among the inhibitors, however, antipain and pepstatin exerted a relatively strong and significant suppressive effect on antigen induction as compared to their inhibitory effect on cell growth.

Percutaneous transhepatic drainage: experience in 100 cases.

A two-step procedure for percutaneous transhepatic drainage (PTD) of the biliary tract was attempted on 101 patients with obstructive jaundice, 29 with benign and 71 with malignant lesions, and was successful in 100. With this procedure, marked clinical improvement, with reduction in levels of serum bilirubin, SGOT, SGPT and alkaline phosphatase, was achieved after 1-2 weeks as a preoperative step or for continuous drainage in inoperable cases. In one patient 8 dys after PTD, however, a complicating large intrahepatic hematoma proved fatal. Emergency operation was necessary in three of the four patients who developed bile peritonitis due to dislocation of the catheter and in one with intra-abdominal bleeding. Our results suggest that this procedure is very useful in the diagnosis and management of certain obstructive diseases of the biliary tract.