Degradation of persistent organic pollutants by Fenton's reagent facilitated by microwave or high-intensity ultrasound.

Microwave (MW) and high-intensity ultrasound (US) have emerged as powerful techniques for the elimination of persistent organic pollutants (POPs) that constitute a major health hazard, whether by direct exposure or through accumulation in biota. In order to achieve decontamination, POPs should be completely mineralized to CO2, H2O and smaller amounts of inorganic ions, or at least converted to less harmful chemical species. Under US or MW irradiation rapid degradation of aromatic halides, halogenated phenols and polychlorinated biphenyls in polluted waters was achieved at neutral pH in the presence of a moderate excess (5-30 eq) of Fenton's reagent. Acidification with acetic acid (pH 2.0-2.3) did not affect the process, but sulphuric acid (pH 1.7-2.0) facilitated complete degradation. Thus, compared to conventional methods, US and MW processes are faster and much more efficient.

The role of pelvic floor exercises on post-prostatectomy incontinence.

PURPOSE: Post-radical prostatectomy incontinence occurs in 0.5% to 87% of patients. This condition may be attributable to intrinsic sphincteric deficiency, and/or detrusor abnormalities. Previous studies of pelvic floor exercise (PFE) for improving post-prostatectomy incontinence have shown mixed results. We determined whether preoperative and early postoperative biofeedback enhanced PFE with a dedicated physical therapist would improve the early return of urinary incontinence. MATERIALS AND METHODS: A total of 38 consecutive patients undergoing radical prostatectomy from November 1998 to June 1999 were randomly assigned to a control or a treatment group. The treatment group of 19 patients was referred to physical therapy and underwent PFE sessions before and after surgery. Patients were also given instructions to continue PFE at home twice daily after surgery. The control group of 19 men underwent surgery without formal PFE instructions. All patients completed postoperative urinary incontinence questionnaires at 6, 12, 16, 20, 28 and 52 weeks. Incontinence was measured by the number of pads used with 0 or 1 daily defined as continence. RESULTS: Overall 66% of the patients were continent at 16 weeks. A greater fraction of the treatment group regained urinary continence earlier compared with the control group at 12 weeks (p <0.05). Three control and 2 treatment group patients had severe incontinence (greater than 3 pads daily) at 16 and 52 weeks. Of all patients 82% regained continence by 52 weeks. CONCLUSIONS: PFE therapy instituted prior to radical prostatectomy aids in the earlier achievement of urinary incontinence. However, PFE has limited benefit in patients with severe urinary incontinence 16 weeks after surgery. There is a minimal long-term benefit of PFE training since continence rates at 1 year were similar in the 2 groups.

Toward practical definitions of quality for food science.

A new practical approach to developing workable definitions of quality is presented to overcome the numerous semantic and conceptual difficulties that are common with the use of the word quality in food science. This approach links the concept of quality, through a general definition, by adding the missing link of specific definitions related to measurable attributes and properties determined by standard methods to provide values that can be used to evaluate foods or to set specifications. It is compatible with control, assurance, HACCP, regulatory, TQM, and other normal uses of the both the word quality, and the concept quality, in food science and technology.

Location of and post-mortem changes in some cytoskeletal proteins in pork and cod muscle.

The cytoskeletal proteins actin, nebulin, spectrin, desmin, vinculin and talin were labelled immunohistochemically in sections of muscle from commercially available pigs and cod (Gadus morhua) taken pre-rigor and from samples stored for several days. Actin, nebulin and spectrin gave similar labelling patterns in both pork and cod muscle which remained the same in stored samples. Desmin was intensely labelled at the cell boundaries and within the body of the cells in both pork and cod in the initial and the stored samples. Vinculin was readily labelled in pork muscle but showed only diffuse labelling in fish. Labelling for talin in pork muscle was intense at the sarcolemma but was not present in samples stored for 4 days. In contrast, the label for talin was concentrated at the myotendinous junction of the cod muscle throughout the storage period. These are the first reports of the detection and location of spectrin and vinculin in fish muscle and of the location of talin. The results are discussed in terms of muscle structure, function and post-mortem tenderisation. © 2000 Society of Chemical Industry.

Structure and hormone responsiveness of the gene encoding the alpha-subunit of the rat amiloride-sensitive epithelial sodium channel.

The rat amiloride-sensitive epithelial sodium channel (rENaC) is the rate-limiting step for vectorial transport of Na+ across tight epithelia. The complex is composed of three subunits, alpha, beta, and gamma. Expression of the subunits has been shown to be tissue-specific and developmentally and hormonally regulated. To study mechanisms involved in transcriptional regulation of alpharENaC, we determined the genomic organization of the alpharENaC gene. By 5' rapid amplification of cDNA ends and primer extension, two transcriptional start sites were detected 453 base pairs (bp) apart, resulting in alternative 5' untranslated region (UTR) lengths of 515 or 62 bp. The longer 5' UTR is more prevalent in fetal lung than in adult lung or kidney. The 5' untranslated and coding regions are contained within 12 exons, with the translation start site located within the first exon. Sequence analysis of approximately 1,500 bp of 5' flanking DNA identified putative binding sites for transcription factors PEA3, SP1, AP-1, nuclear factor-kappaB, and thyroid and glucocorticoid receptors. alpharENaC promoter-reporter gene constructs produced low levels of reporter gene activity in transiently transfected cells, which could be increased by dexamethasone (DEX) treatment. Tri-iodothyronine treatment alone had no effect but potentiated stimulation by DEX.

Volatile components associated with bacterial spoilage of tropical prawns.

Analysis of headspace volatiles by gas chromatography/mass spectrometry from king (Penaeus plebejus), banana (P. merguiensis), tiger (P. esculentus/semisulcatus) and greasy (Metapenaeus bennettae) prawns stored in ice or ice slurry, which is effectively an environment of low oxygen tension, indicated the presence of amines at the early stages of storage (less than 8 days) irrespective of the nature of the storage media. Esters were more prevalent in prawns stored on ice (normal oxygen conditions) at the latter stages of storage (more than 8 days) and were only produced by Pseudomonas fragi, whereas sulphides and amines occurred whether the predominant spoilage organism was Ps. fragi or Shewanella putrefaciens. The free amino acid profiles of banana and king prawns were high in arginine (12-14%) and low in cysteine (0.1-0.17%) and methionine (0.1-0.2%). Filter sterilised raw banana prawn broth inoculated with a total of 15 cultures of Ps. fragi and S. putrefaciens and incubated for two weeks at 5 degrees C, showed the presence of 17 major compounds in the headspace volatiles analysed using gas chromatography/mass spectrometry (GC/MS). These were mainly amines, sulphides, ketones and esters. Principal Component Analysis of the results for the comparative levels of the volatiles produced by pure cultures, inoculated into sterile prawn broth, indicated three subgroupings of the organisms; I, Ps. fragi from a particular geographic location; II, S. putrefaciens from another geographic location; and III, a mixture of Ps. fragi and S. putrefaciens from different geographic locations. The sensory impression created by the cultures was strongly related to the chemical profile as determined by GC/MS. Organisms, even within the same subgrouping classified as identical by the usual tests, produced a different range of volatiles in the same uniform substrate.

Characterization of type I collagen from the skin of blue grenadier (Macruronus novaezelandiae).

The skin collagen of a fish, blue grenadier (Macruronus novaezelandiae), has been purified and characterized. The fish skin was readily soluble in dilute acetic acid, with no pepsin treatment needed. The collagen was purified by salt precipitation. Skin samples from fish of various ages showed that even in the oldest sample, more than 8 years of age, the collagen was still readily acid soluble. The purified collagen had a melting temperature of 22 degrees C; the shrinkage temperature for the skin was 48 degrees C. Its tissue distribution, examined by immunohistology, and its chemical properties indicated a close homology to mammalian type I collagen. However, sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) showed that three distinct alpha-chains were present. These were purified by ion-exchange chromatography on CM-cellulose and by gel permeation chromatography on Superose 6. The three purified alpha-chain fractions were examined by amino acid analysis and by SDS-PAGE of their cyanogen bromide fragments. These data indicated that the additional chain was genetically distinct, and most closely related to the alpha 1-chain, from which it was poorly resolved on SDS-PAGE.

Effect of Potassium Sorbate on Spoilage of Blue Grenadier ( Macruronus novaezelandiae ) as Assessed by Microbiology and Sensory Profiles.

Blue grenadier filets ( Macruronus novaezelandiae ), pH 6.7, which had been stored frozen for 3 wk were thawed and repacked under vacuum and in air with and without the addition of 0.1% potassium sorbate. The effects of these treatments on microbial flora were noted after subsequent storage of the fillets at 4°C, Pseudomonads comprised >90% of the total flora of sorbate-treated fish, whereas Vibrio spp. (85%) and Moraxella spp. (70%) predominated in vacuum-packed and aerobically stored fillets, respectively. Sensory profiles of odor and flavor of the stored material were constructed. The acceptability of the aerobically stored fillets had significantly decreased after 7 d of storage. Vacuum packaging in conjunction with 0.1% potassium sorbate results in a minimal extension of shelf-life.