Lysine requirements of pre-lay broiler breeder pullets: Determination by indicator amino acid oxidation

The indicator amino acid oxidation (IAAO) method allows the determination of amino acid requirements under conditions of low growth rate as found in pre-laying broiler breeder pullets. Cobb 500 breeder pullets (20 wk old; 2290 +/- 280 g, n = 4) were adapted (6 d) to a pelleted, purified control diet containing all nutrients at greater than or equal to 110% of NRC recommendations. After recovery from surgery for implantation of a jugular catheter, each bird was fed, in random order, test diets containing one of nine levels of lysine (0.48, 0.96, 1.92, 2.88, 3.84, 4.80, 7.68, 9.60 and 14.40 g/kg of diet). Indicator oxidation was determined during 4-h primed (74 kBq/kg body), constant infusions (44 kBq (.) h(-1) (.) kg body(-1)) of L-[1-C-14]phenylalanine. Using the breakpoint of a one-slope broken-line model, the lysine requirement was determined to be 4.88 +/- 0.96 g/kg of diet or 366 +/- 72 mg (.) hen(-1) (.) d(-1) with an upper 95% Cl of 6.40 g/kg of diet or 480 mg (.) hen(-1) (.) d(-1). IAAO allows determination of individual bird amino acid requirements for specific ages and types of birds over short periods of time and enables more accurate broiler breeder pullet diet formulation.

Monitoring changes in nisin susceptibility of Listeria monocytogenes Scott A as an indicator of growth phase using FACS

Listeria monocytogenes has previously been shown to adapt to a wide variety of environmental niches, principally those associated with low pH, and this compromises its control in food environments. An understanding of the mechanism(s) by which L. monocytogenes survives unfavourable environmental conditions will aid in developing new food processing methods to control the organism in foodstuffs. The present Study aimed to gain a further understanding of the physiological basis for the differential effects of one control strategy, namely the use of the lantibiotic nisin. Using propidium iodide (PI) to probe membrane integrity it was shown that L. monocytogenes Scott A was sensitive to nisin (8 ng mL(-1)) but this was growth phase dependent with stationary phase cells (OD600=1.2) being much more resistant than exponential phase cells (OD600=0.38). We demonstrate that, using a combination of techniques including fluorescence activated cell sorting (FACS), the membrane adaptations underpinning nisin resistance are triggered much earlier (OD600 < 0.5) than the onset of stationary phase. The significance of these findings in terms of mechanism and application are discussed. (c) 2005 Elsevier B.V.All rights reserved.

Stage is not a reliable indicator of tumor volume in non-small cell lung cancer: a preliminary analysis of the trans-tasman radiation oncology group 99-05 database

Background: Tumor volume has been shown to be a prognostic factor for the response of some tumors to radiotherapy. TNM stage has prognostic value for patients treated surgically for non-small cell lung cancer (NSCLC), but its value is less clear for patients treated by nonsurgical means. This may be because tumor size is not a consistent determinant of T stage or stage group. As part of the preliminary analyses for the Trans-Tasman Radiation Oncology Group 99-05 study, the authors performed this analysis to determine to what extent stage reflects tumor volume. Methods: In this prospective multicenter observational study, patients had to have histologically proven NSCLC, no evidence of disease beyond the primary site or thoracic lymph nodes, and been planned for radical radiotherapy with or without chemotherapy. Tumor volume measurements were based on computed tomography-based treatment planning images. Results: Four hundred four patients were available for analysis. There was a strong correlation between (log) maximum tumor diameter and (log) tumor volume (r = 0.93, p < 0.001). Although there was a highly significant trend of increasing volume with increasing T stage and stage group, when tumors were categorized into four groups according to increasing volume, there was only 55% concordance with T stage and 67% concordance with stage group. Conclusions: There is limited correlation between tumor size and disease stage in patients with NSCLC. This justifies documentation and investigation of size as a potential prognostic factor independent of stage. Maximum tumor diameter may be an adequate substitute for volume as a measurement of size.