Novel multi-analyte method for detection of thirty photoinitiators in breakfast cereal and packaged juice.

Multilayer print designs are commonly used in commercial food packaging to attract consumers. UV-curable ink is generally used in this type of printing due to its ease of application, space saving, and rapid drying; however, there have been a number of health alerts related to the contamination of food by photoinitiators in UV-curable ink. In this study, we established a multi-analyte method by which to detect 30 photoinitiators simultaneously. We then applied this method to the analysis of five breakfast cereals and ten types of packaged juice to detect the presence of photoinitiator contamination. Sample treatment was performed using the QuEChERS (quick, easy, cheap, effective, rugged, and safe) method for the extraction of photoinitiators. Chromatographic separation of two isomers, methylbenzophenone (MBP) and isopropylthioxanthone (ITX), was achieved using a pentafluorophenyl propyl (PFP) column (1.7 µm, 100 × 2.1 mm i.d.) and MeOH: 5 mM formic acid-ammonium formate (pH 4.0) in gradient elution. The average recovery of photoinitiators from cereal was between 62.0 and 120.3%, with a coefficient of variation between 0.4 and 14.4%. The average recovery of photoinitiators from packaged juices was between 84.4 and 122.9% with a coefficient of variation between 0.5 and 9.5%. The contamination results were as follows: 13.1 ng/g triphenyl phosphate (TPP) was detected in one breakfast cereal, and 2-hydroxy-4-methoxy benzophenone (BP-3), 1-hydroxycyclohexyl phenyl-ketone (Irgacure 184), methyl-2-benzoylbenzoate (MOBB), and 2,4-diethyl-9H-thioxanthen-9-one (DETX) were detected in one of the packaged juices at levels ranging from 2.2 to 152.9 ng/g.

Evaluation of Pain Intensity Assessment Tools Among Elderly Patients With Cancer in Taiwan.

BACKGROUND: Effective pain management requires careful assessment of pain. Auditory, visual, cognitive, and motor impairments in elderly people may affect their ability to use pain assessment tools. OBJECTIVE: The aim of this study was to evaluate the reliability, validity, and no-response rate of pain scales among elderly patients with cancer pain, as well as patient preference for the scales. METHODS: A cross-sectional correlational design was used with a convenience sample of 73 elderly cancer patients recruited at a cancer-based hospital in southern Taiwan. Participants were asked to rate their pain by using a numeric rating scale (NRS-11), a facial pain scale (FPS), a verbal descriptor scale (VDS), and a mixed scale (consisting of NRS-11, FPS, and VDS) on 2 consecutive days. RESULTS: Test-retest reliability, as indicated by Spearman rank correlation coefficients for the 24-hour interval pain ratings, ranged from 0.426 to 0.683. The criterion-related validity of the scales was supported by significant Spearman rank-order correlation. The time taken to respond to the scales ranged from 40.3 to 16.2 seconds. The no-response rates for the scales decreased in the order NRS-11 > FPS > mixed scale > VDS. Patient preference for the scales decreased in the order mixed scale > VDS > NRS-11 > FPS. CONCLUSIONS: All 4 scales were reliable and valid for assessing cancer pain among elderly patients. IMPLICATIONS FOR PRACTICE: Because the no-response rates for the scales depended on educational level and cognitive function, nurses should exercise good judgment in choosing pain intensity assessment tools for use with elderly patients.

Effect of charged amino acid side chain length on lateral cross-strand interactions between carboxylate- and guanidinium-containing residues in a ß-hairpin.

ß-Sheet is one of the major protein secondary structures. Oppositely charged residues are frequently observed across neighboring strands in antiparallel sheets, suggesting the importance of cross-strand ion pairing interactions. The charged amino acids Asp, Glu, Arg, and Lys have different numbers of hydrophobic methylenes linking the charged functionality to the backbone. To investigate the effect of side chain length of guanidinium- and carboxylate-containing residues on lateral cross-strand ion pairing interactions at non-hydrogen-bonded positions, ß-hairpin peptides containing Zbb-Agx (Zbb = Asp, Glu, Aad in increasing length; Agx = Agh, Arg, Agb, Agp in decreasing length) sequence patterns were studied by NMR methods. The fraction folded population and folding energy were derived from the chemical shift deviation data. Peptides with high fraction folded populations involved charged residue side chain lengths that supported high strand propensity. Double mutant cycle analysis was used to determine the interaction energy for the potential lateral ion pairs. Minimal interaction was observed between residues with short side chains, most likely due to the diffused positive charge on the guanidinium group, which weakened cross-strand electrostatic interactions with the carboxylate side chain. Only the Aad-Arg/Agh interactions with long side chains clearly exhibited stabilizing energetics, possibly relying on hydrophobics. A survey of a non-redundant protein structure database revealed that the statistical sheet pair propensity followed the trend Asp-Arg < Glu-Arg, implying the need for matching long side chains. This suggested the need for long side chains on both guanidinium-bearing and carboxylate-bearing residues to stabilize the ß-hairpin motif.

Effect of each guanidinium group on the RNA recognition and cellular uptake of Tat-derived peptides.

The six arginine (Arg) residues in the human immunodeficiency virus transactivator of transcription protein (HIV Tat protein) basic region (residues 47-57) are crucial for two bioactivities: RNA recognition and cellular uptake. Herein, we report a systematic study to investigate the role of the guanidinium group on Arg at each position in Tat-derived peptides for the two bioactivities. Tat-derived peptides, in which each guanidinium-bearing arginine was replaced with a urea-bearing citrulline (Cit) or an ammonium-bearing Lys, were synthesized by solid phase peptide synthesis. RNA recognition of the peptides was studied by electrophoretic mobility shift assays, and cellular uptake into Jurkat cells was determined by flow cytometry. Our results showed that removing the positive charge and altering the hydrogen bonding capacity of Arg affect the two biological functions differently. Furthermore, the effects are position dependent. These findings should be useful for the development of functional molecules containing guanidinium, urea, and ammonium groups for RNA recognition to affect biological processes and for cellular uptake for drug delivery.

Effect of charged amino acid side chain length on lateral cross-strand interactions between carboxylate-containing residues and lysine analogues in a ß-hairpin.

ß-Sheets are one of the fundamental three-dimensional building blocks for protein structures. Oppositely charged amino acids are frequently observed directly across one another in antiparallel sheet structures, suggesting the importance of cross-strand ion pairing interactions. Despite the apparent electrostatic nature of ion pairing interactions, the charged amino acids Asp, Glu, Arg, Lys have different numbers of hydrophobic methylenes linking the charged functionality to the backbone. Accordingly, the effect of charged amino acid side chain length on cross-strand ion pairing interactions at lateral non-hydrogen bonded positions was investigated in a ß-hairpin motif. The negatively charged residues with a carboxylate (Asp, Glu, Aad in increasing length) were incorporated at position 4, and the positively charged residues with an ammonium (Dap, Dab, Orn, Lys in increasing length) were incorporated at position 9. The fraction folded population and folding free energy were derived from the chemical shift deviation data. Double mutant cycle analysis was used to determine the interaction energy for the potential lateral ion pairs. Only the Asp/Glu-Dap interactions with shorter side chains and the Aad-Orn/Lys interactions with longer side chains exhibited stabilizing energetics, mostly relying on electrostatics and hydrophobics, respectively. This suggested the need for length matching of the interacting residues to stabilize the ß-hairpin motif. A survey of a nonredundant protein structure database revealed that the statistical sheet pair propensity followed the trend Asp-Lys < Glu-Lys, also implying the need for length matching of the oppositely charged residues.

A prospective study of pain treatment for patients with advanced cancer who receive hospice home care.

BACKGROUND: Pain is often inadequately treated in patients with cancer. Previous studies have demonstrated the effectiveness of the World Health Organization (WHO) analgesic ladder in cancer pain management. METHODS: A total of 131 consecutive patients with advanced cancer referred to a hospice home care program were enrolled over one year period from Jan. 1 to Dec. 31, 2000. We assessed the adequacy of prescribed analgesic drugs using guidelines developed by the WHO. Age, gender, Eastern Cooperative Oncology Group performance status, pain mechanism at referral, pain and symptom intensity, and doses and days of drug administration during the course of treatment were recorded at regular intervals. RESULTS: Eighty-two percent of the patients (107 of 131) had pain symtoms at referral. Forty-seven patients were excluded from this study due to inadequate follow-up times or inability to express the pain intensity. Sixty patients who had measurable pain intensity requiring analgesic therapy were followed up until death for a mean duration of 65 days. At referral, 46% of the patients (28 of 60) received inadequate treatment. In the last week of life, 2%, 26% and 70% of patients were taking non-opioid drugs, moderate opioids and strong opioids, respectively. A significant improvement in pain and symptom intensity was achieved after referral. A minority of the patients (10%) had inadequate pain control in the last week of life. CONCLUSIONS: This study demonstrates that a managed hospice home care system enables patients to receive adequate pain treatment, according to WHO guidelines.