Rabbit antibodies specific for the 2,4,6trinitrophenyl (TNP) group can be isolated from antisera in high yield by employing various combinations of reagents for specific precipitation and elution, the choice of reagents depending on the time of bleeding after immunization and the anticipated average affinity of the antibody molecules. In particular the use of a cross-reacting hapten-protein conjugate (2,4-dinitrophenyl (DNP) protein) to precipitate antibody from serum, and a homologous hapten to elute specifically from the immune precipitates, has provided the means of obtaining very high affinity molecules in excellent yield. The binding of univalent ligands by anti-TNP antibodies has been examined by the method of fluorescence quenching and the intrinsic association constants obtained have been validated by equilibrium dialysis. Anti-TNP molecules are conspicuc V^/onsiderable information has been accumulated in the past decade on the specific binding and structural properties of antibodies to the 2,4-dinitrophenyl (DNP)1 group and on their heterogeneity. Because the 2,4,6-trinitrophenyl (TNP) group differs only by a

In a study of 1400 manufacturing butchers' premises, 2330 raw prepared meats, 2192 cooked meats and 4635 environmental samples were examined. Verocytotoxin-producing Escherichia coli O157:H7 (O157 VTEC) was isolated from five of 1400 (0.4%) premises. Three raw meat products contained O157 VTEC, and two raw meat preparation areas and two items of equipment used exclusively for cooked meats were contaminated with O157 VTEC. Salmonella spp. and Campylobacter spp. were detected in 84 of 2330 (4%) and 15 of 2330 (0.6%) raw meat products, respectively. Of the cooked meats examined, seven of 2192 (0.3%) samples were of unacceptable microbiological quality and a further 352 (16%) were of unsatisfactory quality. Of the unacceptable samples, two contained Salmonella spp. (Salm. typhimurium DT193, Salm. typhimurium PT104), three contained Staphylococcus aureus in excess of 10(4) cfu g-1, and two contained E. coli in excess of 10(4) cfu g-1. Neither Campylobacter spp. nor O157 VTEC were detected in cooked meats. In the majority of premises, raw and unwrapped cooked meat products were physically separated in displays (94%) and refrigerators (81%), and dedicated equipment/utensils (69-89%) were used for raw meat and unwrapped cooked meat products and other ready-to-eat foods. In approximately half (48%), there were separate serving counters and in 13%, separate staff for raw and cooked meats. Most managers (75%) had received some food hygiene training. However, in 29% of premises, one or more members of staff handled raw and then cooked or ready-to-eat foods without washing their hands, and in 11%, one or more staff members handled raw and cooked meats directly with bare hands. A documented hazard analysis and critical control point (HACCP) system was present in 17% of premises and in a further 31%, an undocumented HACCP system was in place. The low incidence of food-borne pathogens in cooked meat products and in the environmental areas examined, together with a high level of physical separation of raw and cooked meats, indicate that most manufacturing butchers' premises have appropriate physical control measures in place. However, HACCP and hygienic practice are areas that require improvement to reduce the risk of cross-contamination with food-borne pathogens from raw to cooked meats.

No abstract

The authors review 17 cases of aqueductal stenosis in adults and describe five modes of clinical presentation. The average duration of symptoms was 6 years. Dementia was infrequent. Skull x-ray films frequently demonstrated some degree of cranial enlargement and signs of chronic increased intracranial pressure. Characteristic alterations of the sella included elongation of the anterior wall and flattening, erosion, and anterior displacement of the dorsum. Aqueductal configurations as defined by ventriculography and pneumoencephalography in all cases, and the angiographic findings in seven cases are described. Most of the patients improved substantially after shunt insertion. The clinical findings suggested that aqueductal narrowing and associated hydrocephalus had been present in most of these patients since early life.

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