Honey authenticity: the opacity of analytical reports-part 2, forensic evaluative reporting as a potential solution.

The analytical techniques applied to verify honey authenticity are multifaceted and often result in complex data rich certificates of analysis that are open to interpretation and may be opaque to stakeholders without specialist knowledge. In these cases, the drawing of an independent overarching opinion is challenging. Two questions arise: (Q1) Is it acceptable to report interpretation, particularly if it is adverse, without exhibiting the supporting data? (Q2) How may a valid overarching opinion on authenticity be derived from a large, partially conflicting, dataset? To Q1, it is demonstrated that full disclosure of the data used in interpretation is mandatory. To Q2 it is proposed, with worked examples, to adopt 'evaluative reporting'; a formalised likelihood ratio thought process used in forensic science for evaluation of findings and their strength assessment. In the absence of consensus on techniques for honey authenticity adoption of reporting conventions will allow objective assessments of reports, with equity to all and provide a better basis to identify and address fraud.

Honey authenticity: the opacity of analytical reports - part 1 defining the problem.

The composition of honey, a complex natural product, challenges analytical methods attempting to determine its authenticity particularly in the face of sophisticated adulteration. Of the advanced analytical techniques available, only isotope ratio mass spectrometry (IRMS) is generally accepted for its reproducibility and ability to detect certain added sugars, with nuclear magnetic resonance (NMR) and high-resolution mass spectrometry (HRMS) being subject to stakeholder differences of opinion. Herein, recent reviews of honey adulteration and the techniques to detect it are summarised in the light of which analytical reports are examined that underpinned a media article in late 2020 alleging foreign sugars in UK retailers' own brand honeys. The requirement for multiple analytical techniques leads to complex reports from which it is difficult to draw an overarching and unequivocal authenticity opinion. Thus arose two questions. (1) Is it acceptable to report an adverse interpretation without exhibiting all the supporting data? (2) How may a valid overarching authenticity opinion be derived from a large partially conflicting dataset?

Identification of dipeptidyl nitriles as potent and selective inhibitors of cathepsin B through structure-based drug design.

Cathepsin B is a member of the papain superfamily of cysteine proteases and has been implicated in the pathology of numerous diseases, including arthritis and cancer. As part of an effort to identify potent, reversible inhibitors of this protease, we examined a series of dipeptidyl nitriles, starting with the previously reported Cbz-Phe-NH-CH(2)CN (19, IC(50) = 62 microM). High-resolution X-ray crystallographic data and molecular modeling were used to optimize the P(1), P(2), and P(3) substituents of this template. Cathepsin B is unique in its class in that it contains a carboxylate recognition site in the S(2)' pocket of the active site. Inhibitor potency and selectivity were enhanced by tethering a carboxylate functionality from the carbon alpha to the nitrile to interact with this region of the enzyme. This resulted in the identification of compound 10, a 7 nM inhibitor of cathepsin B, with excellent selectivity over other cysteine cathepsins.

Syntheses of 5a'-homo-vinblastine and congeners designed to establish structural determinants for isolation of atropisomers.

The syntheses of 5a'-homo-vinblastine (3a) and its C-20' methyl congener 62a were achieved. In contrast to vinblastine, these compounds did not allow isolation of atropisomers because of their lower conformational inversion barrier. However, annelation of a six-membered ring to the conformationally mobile D'-piperidine ring provided an isolated atropisomer 81a, which could be converted to its lower energy conformation 65a on heating. The 5a'-homo-vinblastine congeners 3a, 62a, and 65a showed vinblastine-like inhibition of tubulin polymerization and cytotoxicity to L1210 leukemia cells, albeit at lower potency for the latter activity, than that found with the corresponding compounds in the vinblastine series.

Proximal and distal measurements of extracellular and total body water by multi-frequency bio-impedance analysis in surgical patients.

Measurements of extracellular water (ECW) and total body water (TBW) can be useful when assessing the nutritional status of surgical patients. The simple and non-invasive nature of bio-impedance techniques may allow repeat measurements to assess clinically significant changes in ECW and TBW. We have evaluated bio-impedance spectroscopy (BIS) and multi-frequency bio-impedance analysis (MFBIA) using radioisotope dilution as the independent method.

Body composition at the bedside.

OBJECTIVE: To evaluate the use of an inexpensive hand-held bioelectric impedance analysis machine which measures lean body mass, by technical comparisons against standard instruments and techniques (an in-house bioelectric impedance machine and dual energy X-ray absorptiometry), and by performing body composition analyses in groups of potentially malnourished patients. DESIGN: Prospective simultaneous comparison of measurements made by the hand-held and in-house bioelectric analysis machines and dual energy x-ray absorptiometry. SETTING: Medical Physics Department and Gastrointestinal Unit in a university teaching hospital. SUBJECTS/METHODS: One hundred and sixty subjects were recruited into the study. Data from 58 adolescent and 14 adult volunteers and from 42 adult patients were used for technical comparisons (n = 114). Body composition information was evaluated (n = 102) for 60 adult volunteers and 42 patients (17 with eating disorders, 7 with chronic alcoholic pancreatitis and 18 with inflammatory bowel disease). OUTCOME MEASURES: Estimation of bias, limits of agreement and correlations on data from the three machines. Relationships between percentage body mass as lean, absolute weights and body mass index, in the adult subjects. RESULTS: Both resistance and calculated impedance measured by the hand-held machine significantly correlated with the impedance measured by the in-house machine (r = 0.996; P < 0.0001). An estimation of the level of agreement in percentage lean measurement between dual energy x-ray absorptiometry and hand-held bioelectrical impedance analysis machine by the Bland and Altman method showed a bias of -0.07% and satisfactory limits of agreement from -7.97% to 7.76%. Body mass index was similar in the groups of healthy men and women, but proportion of weight as lean was significantly higher in men than women. In underweight patients with eating disorders, the ratio of lean to fat varied widely; in inflammatory bowel disease patients, proportions of lean and fat were similar to controls; however patients with alcoholic pancreatitis had values for body mass index similar to controls, but had significantly lower proportion of their body weight as lean (P < 0.05). CONCLUSION: In non-obese and thin adults, an accurate two-compartment (lean, fat) measurement of body composition can be made in 10 min by using an inexpensive, hand-held, bioelectric impedance analysis machine.

Anomalies in the measurement of changes in total-body bone mineral by dual-energy X-ray absorptiometry during weight change.

For an eating disorder study over a period of 1 year, we measured total-body bone mineral using a Hologic QDR 1000 W in a total of 157 subjects and observed anomalies that questioned the accuracy of such measurements. Using the recommended Enhanced software, a change in total bone mineral content (delta BMC) correlated positively with a change in weight (delta W; r = 0.66), but a loss of weight was associated with an increase in bone mineral areal density (BMD; r = 0.58), arising from a reduction in bone area (AREA). Both regressions were highly significant. The dominant factor in this relationship was a strong correlation between delta AREA and delta BMC, for all parts of the skeleton, r > 0.9, with a slope close to 1. This is implausible because bone area would not be expected to change. When Standard software was used, the slope of the delta BMC/delta W correlation was steeper, but the delta BMD/delta W regression became positive. An artefact of dual-energy X-ray absorptiometry processing was suspected, and phantom measurements were made. The phantom consisted of tissue-equivalent hardboard cut and stacked to form cylinders corresponding to the head, trunk, arms, and legs of a standard man. The skeleton was constructed from layers of aluminium sheet as an approximation of the average shape, BMD, BMC, and AREA in each region. When aluminium thickness was varied, BMD thresholds were found, approximately 0.4 g/cm2 for the legs and 0.2 g/cm2 for the arms. Above these, bone area rose fairly rapidly toward a plateau. At higher skeletal densities, the relationships between measured and true BMDs were close to linear, but slopes were less than unity, so that changes would be underestimated by 10-30%. Increases of thickness of the soft tissue of the phantom lowered AREA slightly. Uniform fat proportion increases led to decreases in BMC and AREA, but lard wrapped in an annulus around the limbs led to spurious increases in BMC and AREA of a similar magnitude to those observed in vivo, while BMD fell slightly, although there had been no true change of bone variables. Similar results were obtained with lard around the limbs of a volunteer. Reanalysis of phantom scans using Standard software confirmed the software differences noted in vivo. The phantom measurements offer an explanation of the anomaly in vivo and demonstrate that, under different circumstances, change in both BMC and BMD can be wrongly recorded. We believe that no valid conclusions can be drawn from measurements by the Holgic QDR 1000 W of bone changes during weight change.

Comparison of bio-impedance spectroscopy and multi-frequency bio-impedance analysis for the assessment of extracellular and total body water in surgical patients.

1. Measurements of extracellular and total body water provide useful information on the nutritional status of surgical patients and may be estimated from whole-body bio-impedance measurements at different frequencies. 2. Resistance and reactance were measured at 50 frequencies from 5kHz to 1MHz in 29 surgical patients (17 males, 12 females) with a wide range of extracellular to total body water ratios. 3. A fit to the spectrum of reactance versus resistance data gave predicted resistances at frequencies zero and infinity. Values of extracellular and total body water determined by this bio-impedance spectroscopy technique were regressed against values obtained from radioisotope dilution. The standard errors of the estimate were 1.8931 and 3.2591 respectively. 4. Resistance indices (height2/resistance) at selected frequencies gave the highest correlations with extracellular and total body water at 5kHz and 200kHz respectively, and prediction equations derived from multiple stepwise regressions also showed these to be the optimum frequencies. The standard errors of the estimate for this multi-frequency bio-impedance analysis method were 1.9371 and 2.6061 for extracellular and total body water respectively. 5. To assess the ability of the two methods to measure changes in extracellular and total body water, reproducibility was assessed from repeat measurements 10 min apart in a subgroup of 15 patients. Bio-impedance spectroscopy gave mean coefficients of variation for extracellular and total body water of 0.9% and 3.0% respectively. For multi-frequency bio-impedance analysis the corresponding coefficients of variation were 0.9% and 0.6%. 6. It is concluded that a simple impedance analyser operating at only two frequencies compares favourably with the more complex spectroscopy technique for the determination of extracellular and total body water in surgical patients.

Body mass index as an estimate of body fat.

Body mass index (BMI) was compared with percentage body fat (%Fat) measured by dual energy X-ray absorptiometry (DXA) in 233 adolescent schoolgirl volunteers and 179 adult female patients. Repeat measurements were made on 67 of the adolescents and 51 of the adults. The correlations between BMI and %Fat were established from the 300 adolescent measurements and the 230 adult measurements. Although highly significant relationships were found between BMI and %Fat, only 58% of the variance in %Fat in adolescents and 66% in adults could be predicted by BMI. At the 95% confidence levels, a BMI of 20 kg m-2 can correspond to a range of 18-33% body fat in adolescents and 13-32% in adults. Without any change in BMI, an adolescent's percentage fat can change by as much as -3% to +7%. For an individual adult the same BMI can correspond to changes in fat of +/-5%. Since the strength of prediction of percentage body fat from BMI is poor, caution should be exercised in its use for eating disorders research.

Improved prediction of bone mineral content and density.

To establish improved predictive values for normal bone mineral content (BMC) and density (BMD) in adolescent girls a community based study of schoolgirl volunteers was carried out by dual energy x ray absorptimetry. Measurements were performed on 216 subjects aged 11.0 to 17.9 years; measurements were repeated one year later on 84 of the girls, providing a total of 300 studies. For total body BMC the standard error of the prediction was improved from 290.9 g to 134.1 g when weight, height, and shoulder width were added to the normal variable of age. For spine BMD the standard error of the prediction was improved from 0.105 g/cm2 to 0.066 g/cm2 when height, weight, and shoulder width were added to the normal variable of age. Significant improvements were also obtained for total BMD and spine BMC. Despite the normal practice of predicting bone density from age alone this was not selected as the first variable in a multiple stepwise regression for either total body or spine. The prediction of BMC and BMD can be significantly improved by the inclusion of simple body habitus parameters in the prediction equations. As the mean (SE) z score derived from the manufacturer's normal data was - 0.36 (0.02) these American data are probably not appropriate for use in adolescents in the UK.

Characterisation of the vasculature within a murine adenocarcinoma growing in different sites to evaluate the potential of vascular therapies.

Numerous vaso-active agents can affect vasculature in experimental solid tumours growing subcutaneously (s.c.), but these models are unlikely to reflect the vasculature of metastatic disease in man. The present study describes a murine orthotopic colon tumour which metastasises to the liver. Morphology and vascular pattern of caecal tumours is similar to s.c. tumours. Vascular occlusion caused by intravenous (i.v.) noradrenaline (NA) (160 micrograms kg-1) and hydralazine (HDZ) (10 mgkg-1) was 32% and 59% respectively for the caecal tumours compared with 35% and 78% for s.c. tumours. Significant morphological differences were seen between liver metastases and systemic deposits produced by i.v. inoculation of tumour cells. Liver metastases following orthotopic transplantation contained functional vasculature but no significant occlusion was seen with NA or HDZ. The vascular development and morphological appearance of secondary disease resulting from orthotopic implantation suggests that this would be a useful model for the study of agents that act either by vascular or anti-angiogenic mechanism.

Low bone mineral density in Crohn's disease, but not in ulcerative colitis, at diagnosis.

BACKGROUND/AIMS: The pathogenesis of low bone mineral density in patients with inflammatory bowel disease is unclear, and the relevance of secondary osteopenic influences is controversial. Our aim was to study bone mineral density in newly diagnosed patients. METHODS: Bone mineral density and biochemical parameters of bone metabolism were measured in 15 patients with Crohn's disease and 15 patients with ulcerative colitis, all of whom were newly diagnosed. Lumbar and forearm bone mineral densities were measured by dual energy x-ray absorptiometry, and Z scores were obtained by comparison with age- and sex-matched normal values. Twenty-three patients had repeat measurements 1 year later, and 20 had received systemic steroids. RESULTS: At diagnosis, the mean Z score for patients with Crohn's disease (spine, -1.06 +/- 0.86; forearm, -1.04 +/- 0.86) was significantly lower than that for patients with ulcerative colitis (spine, -0.03 +/- 1.16; forearm, 0.11 +/- 1.24). Inflammatory activity, disease localization, body mass index, smoking habits, sex, physical activity, or biochemical parameters did not account for this difference. Spine and forearm Z scores were significantly correlated. Mean Z scores after 1 year were not significantly different from initial Z scores. CONCLUSIONS: At diagnosis, low bone mineralization is a feature of Crohn's disease but not ulcerative colitis. Treatment with corticosteroids did not result in further bone loss in 1 year.

Evaluation of multi-frequency bio-impedance analysis for the assessment of extracellular and total body water in surgical patients.

1. Multi-frequency bio-impedance analysis has been used to estimate extracellular and total body water in a heterogeneous group of 43 surgical patients (23 males, 20 females). 2. Radioisotope-dilution methods were used for the measurement of extracellular and total body water. 3. Resistance and reactance were measured between wrist and ankle at frequencies from 5 kHz to 1 MHz. 4. Extracellular and total body water were estimated by multiple stepwise regression using the radioisotope values as the dependent variables. The parameters included in the regression were: resistance and reactance at each frequency, body habitus parameters, plasma albumin and plasma sodium. 5. The standard errors of the estimates between the measured and estimated values were 1.73 litres (coefficient of variation 9.6%) and 2.17 litres (coefficient of variation 6.0%) for extracellular and total body water, respectively. 6. These errors represent a useful improvement relative to those obtained from anthropometric estimates. However, the improvements relative to the use of a single frequency (50 kHz) are not clinically significant.

Can bioelectrical impedance improve the prediction of body fat in patients with eating disorders?

Prediction equations for percentage body fat have been derived for a group of 93 female patients being treated for eating disorders, using fat measured by dual-energy X-ray absorptiometry (DXA) as the reference method. Separate bioelectrical impedance analysis (BIA) prediction equations were derived for patients with a body mass index above and below 16 kg/m2. This provided an improvement compared with the equations supplied by the manufacturer. The standard error of the estimate (SEE) for the entire group was 3.2% (r = 0.922). However, an alternative prediction equation based on anthropometry alone gave an SEE of 4.2% (r = 0.861). The ability of BIA and anthropometry alone to measure changes in percentage fat was assessed in a separate group of 24 females during treatment for eating disorders. The SEEs using the BIA and anthropometry prediction equations were 2.6% (r = 0.931) and 2.7% (r = 0.901) respectively. We conclude that in patients with eating disorders BIA does not provide any significant improvement over simple anthropometry prediction equations for the assessment of percentage fat or its changes. The apparently reasonable agreement between fat predicted by BIA and that measured by DXA is largely due to the inclusion of body habitus parameters in the BIA prediction equations.

Osteoporosis and normal weight bulimia nervosa--which patients are at risk?

This study assesses the degree of bone mineral loss in women with active DSM IIIR bulimia nervosa. The subjects in this study were 20 GP-referred female patients of normal weight who met criteria for bulimia nervosa and 16 healthy age, sex and weight matched controls. Dual energy X-ray densitometry of lumbar L1-L4 vertebrae was performed on all subjects. The patients with bulimia nervosa had a significantly lower mean lumbar bone mineral density (0.964 g/cm2) than the control group (1.043 g/cm2, p < 0.01). Within the patient group only subjects with a past history of anorexia nervosa had a significantly lower mean bone mineral density (BMD) than the controls. Small sample sizes limit the power of the study, however significant correlations were found between duration of amenorrhoea, low BMI and lumbar BMD. Bulimic patients do suffer from osteoporosis. Risk factors for this may be; a past history of anorexia nervosa, prolonged secondary amenorrhoea, and a persistently low body mass index.