Survey research is often deployed in the study of situational issues facing organizations and functions within organizations. One particular survey research approach can be described as follows: (1) survey questionnaires involving perceptual questions about a situational issue are administered to key informants, one key informant per unit of analysis; (2) key informants vary in a transparent manner across units of analysis such that groups of these key informants are discernible; and (3) perceptual responses, after data collection, are then pooled to create a single larger data set for subsequent statistical manipulations. In this methodological note, we draw attention to this particular survey research approach and ask the question: When is it appropriate to pool data provided by key informants with transparently different demographics across units of analysis so as to create a single larger data set for statistical manipulations? We use a simple example and data from a published study to motivate the relevance and gravity of this methodological question. Offering the concept and empirical assessment of measurement equivalence as the answer to this methodological question of data pooling, * We would like to thank the editor, the two associate editors, and the three referees whose suggestions have led to significant improvements in the structure and content of this methodological note. We also thank the Center for Supply Chain Management and Logistics, Li and Fung Institute of Supply Chain Management and Logistics, and The Chinese University of Hong Kong for its generous support. † Corresponding author. 116Pooling Data across Transparently Different Groups we prescribe and demonstrate, with the total quality management→customer satisfaction relationship, the procedural steps for evaluating the seven subdimensions of measurement equivalence. In conclusion, we highlight methods that should be adopted, before data collection, to minimize the risk of violating measurement equivalence. After data collection and for the instances when the empirical assessment for measurement equivalence advises against pooling of such data, we also offer suggestions for analyzing such data and presenting associated statistical results.

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Policosanol is a group of long chain primary alcohols and has been shown to reduce blood cholesterol levels and to inhibit the oxidation of low-density lipoprotein (LDL). The present study examined (i) the effect of policosanol supplementation in the diet on the fecal excretion of neutral and acidic sterols in hamsters and (ii) the antioxidant activity of policosanol in human LDL. Golden Syrian hamsters were divided into four groups (n = 12/each) fed one of the four diets containing 0 (control), 0.38, 0.75, and 1.50 g kg(-1) policosanol for 6 weeks. It was found that hamsters given 0.38-1.5 g kg(-1) diets had a serum total cholesterol level lowered by 15-25% and had a high-density lipoprotein cholesterol elevated by 7-16.8%. It was found that policosanol increased the excretion of acidic sterols by 25-73%. Contrary to that in previous reports, policosanol had no apparent anti-LDL oxidation activity when 1-tetracosanol, 1-hexacosanol, and 1-octacosanol were incubated in human LDL. Policosanol also possessed no scavenging activity on the free radical2,2-diphenyl-1-picrylhydrazyl. These data provide evidence that in addition to the effect of HMG-CoA reductase, the cholesterol-lowering activity of policosanol is partially mediated by its inhibition on the absorption of bile acids, but these data disprove the claim that policosanol is an antioxidant.

We performed a retrospective study to analyse the characteristics and clinical outcomes of diffuse large B-cell lymphoma (DLBCL) patients with hepatitis B virus (HBV) infection and compare with those without HBV infection. The occurrence of hepatitis after withdrawal of prophylactic antiviral treatment on completion of chemotherapy was also assessed. The HBsAg-positive patients were given prophylactic antiviral treatment until 6 months after finishing chemotherapy. A total of 81 patients were recruited with 16 in the HBsAg-positive group and 65 in the HBsAg-negative group. The clinical characteristics were similar in both groups of patients. There was no significant difference in complete remission rate between the two groups (63% in HBsAg-positive group vs. 54% in HBsAg-negative group, P = 0.59). There was also no statistically significant difference in overall survival between the two groups (P = 0.23). Four of the 16 HBsAg-positive patients (25%) had hepatitis after cessation of chemotherapy and prophylactic lamivudine. The mean time of onset of hepatitis was 3 months after stopping lamivudine. In conclusion, HBV infection did not appear to affect the prognosis of DLBCL patients given antiviral prophylaxis. It is reasonable to consider prophylactic antiviral therapy to extend to at least one year on completion of chemotherapy.

The present study was to test the relative hypercholesterolaemic and atherogenic potency of oxidised cholesterol (OxC) and non-oxidised cholesterol in hamsters. An OxC mixture, prepared by heating pure cholesterol (100 g) at 1608C in air for 72 h, contained 78 % cholesterol and 22 % OxC. Fifty Golden Syrian hamsters were randomly divided into five groups of ten animals and fed the control diet, a 0·05 % cholesterol diet (C-0·05), a 0·10 % cholesterol diet (C-0·1), a 0·05 % OxC mixture diet (OxC-0·05) or a 0·10 % OxC mixture diet (OxC-0·1), respectively. The OxC-0·05 and OxC-0·1 groups were more hypercholesterolaemic and had serum total cholesterol 22 and 12 % higher than the corresponding C-0·05 and C-0·1 hamsters (P, 0·05). The OxC-0·1 group demonstrated greater deposition of cholesterol and had a larger area of atherosclerotic plaque in the aorta than the corresponding C-0·1 hamsters (P, 0·05). Similarly, the aorta in the OxC-0·1 group showed greater inhibition on acetylcholine-induced relaxation compared with that in the C-0·1 hamsters. It was concluded that OxC was much more hypercholesterolaemic and atherogenic than cholesterol. Cholesterol: Cholesterol oxidation products: Oxidised cholesterol: OxysterolHuman diets contain both cholesterol and oxidised cholesterol (OxC). Cholesterol is susceptible to oxidation, forming a series of cholesterol oxidation products (COP) under various food processing conditions. The amount of COP can reach up to 10 % total cholesterol (TC) in foods 1 , particularly in Western countries where total fat intake is high and fried foods are popular 2 . More than thirty COP have been identified and reported 3,4 . The major COP include 7b-hydroxycholesterol, 7a-hydroxycholesterol, 5a-hydroxycholesterol, 7-ketocholesterol and a-epoxides 5 .COP have been extensively studied for their undesirable effects including cytotoxicity 6 , mutagenesis 7 and carcinogenesis 8 . In addition, COP have been shown to be absorbed in a similar way to cholesterol 9,10 , cause disturbance of lipid metabolism 11 and alter the cell membrane function 12,13 . Most importantly, COP could accelerate fatty streak lesion formation and promote atherosclerosis 14,15 . Human daily cholesterol intake is about 300-500 mg while that of COP could be up to 30 -50 mg, provided that 10 % cholesterol in the diet is oxidised. It is well known that high cholesterol consumption elevates plasma TC and LDL-cholesterol levels and increases the risk of CHD. However, the effect of COP in the diet on blood cholesterol is unfortunately ignored and there is very limited information concerning relative hypercholesterolaemic and atherosclerotic activity of COP and cholesterol itself 6 . The present study was therefore carried out to investigate the effect of OxC on blood cholesterol level, atherosclerotic plaque formation and endothelium function compared with that of non-oxidised cholesterol using hamsters as an animal model. Experimental methods Preparation of oxidised cholesterolPure cholesterol was purchased from Sigma Chemical Compa...