A review of analytical parameters in 'rapid' liquid chromatographic methods for bioanalysis: Can we do better?

Rapid bioanalysis is beneficial to many applications. However, how 'rapid' a method is, or could be, is often an unanswered question. In this statistical review, the authors have assessed multiple pre-analytical (i.e. sample preparation), and analytical method parameters specifically for liquid chromatography to assist researchers in developing and validating 'rapid' bioanalytical methods. We restricted the search to urine and plasma matrices only. Data were extracted from over 2,000 recent studies and evaluated to assess how these parameters affected the 'on-instrument' analysis time. In addition to methods using ultra-violet (UV) detection, there were a large number of mass spectrometric (MS) methods, allowing additional review of the differences between high- and low-resolution MS on analysis time. We observed that most (N = 922, 70 %) methods used 5 or 10 cm columns, and that whilst uptake of ultra-high performance (U)HPLC columns was good, the use of sub-5 cm columns and/or flow rates in excess of 1 mL/min was incredibly rare (N = 25, 3 %). The detector of choice for quantitative (U)HPLC-MS remains the triple quadrupole, although a number of groups report the use of high-resolution MS for such methods.

Wastewater-based epidemiology and enantiomeric profiling for drugs of abuse in South African wastewaters.

The current study is aimed to introduce a wastewater-based epidemiology (WBE) approach for the first time on the African continent where substance abuse data is limited. The study included the quantification of several drugs of abuse (DOA) in raw wastewater samples. Quantification of urinary metabolites as drug target residues (DTR), as well as enantiomeric profiling of chiral DOA was performed to distinguish between consumption and direct disposal into sewage. Monitoring campaigns were undertaken at two South African wastewater treatment works (WWTWs) located within two provinces of the country. The presence of non-racemic 3,4-methylenedioxymethamphetamine (MDMA) and methamphetamine, as well as the metabolite of cocaine, benzoylecgonine (BEG), confirmed their consumption within the areas investigated. Enantiomeric profiling further pointed to the abuse of methamphetamine as the primary DOA with use estimates calculated between 181.9 and 1184.8mg·day-1·1000inhabitants-1. Population-normalised mass loads for MDMA and cocaine confirmed their status as secondary DOA within the study sites. Use estimates for the new psychoactive substance (NPS) mephedrone were performed for one WWTW. The minor metabolite of heroin, O-6-monoacetylmorphine (O-6-MAM), was also detected at one WWTW and served as a qualitative indicator for heroin abuse within the area. These findings provide a novel comparison of the WBE approach in a developing-country with other global studies, with the aim to strengthen this approach as a tool to inform drug prevention strategies in countries where substance abuse data is limited due to financial constraints and lack of government structures to facilitate conventional monitoring.

[Two centers with a native fistula prevalence higher than 90%: organization and activity]. / Due centri accomunati da una prevalenza di fistole con vasi nativi maggiore del 90%: attività e modelli organizzativi a confronto.

Vascular access (AV) dysfunction is a major cause of morbidity and hospitalisation in hemodialysis population. Despite of guidelines statements which consider native arteriovenous fistula (nAVF) the gold standard, epidemiological studies still show a decline in their prevalence with an increase of central venous catheters (CVC). In this study we compared the activity of two Dialysis Units both characterized by a high prevalence (> 90%) of nAVF, in order to highlight the possible reasons. No collaboration existed between the two centres until the decision to design this work. The "policy" on creation and management of vascular access and organizational models of the two centres were assessed, in particular focusing on surgeons, presence of dedicated nephrologists, preoperatory ultrasound evaluation, follow-up and diagnosis of complications, resort to interventional radiology, complications management, in particular the timing of intervention after AVF thrombosis. Of the two dialysis populations were analysed: age, time on dialysis, coexistence of diabetes and the prevalence of various types of vascular access to 31 December 2007. It was evaluated the AV incidence in the last 4 years. The statistical analysis was performed by T student and Chi square tests. There were no substantial differences in the organizational models of the two centres, which had both a routine ECD use in preoperatory mapping and in monitoring of complications; in case of thrombosis both centres performed surgery within 12-24 hours; in case of stenosis both centres performed the correction, surgical or by angioplasty, within 15 days from the diagnosis. Another common element was the presence of a multidisciplinary team with a interventionist nephrologist, a vascular surgeon and a vascular interventional radiologist, where nephrologist has the coordination role. The data analysis showed a prevalence of nAVF in the two centres of 92.5% and 96.1%, Pescara and Lecce respectively, with a prevalence of forearm nAVF of more than 80% and 90% respectively. The analysis of incident interventions showed high percentage of forearm AVF in case of revisions for complications (stenosis, thrombosis), and a little recourse to proximal AVF and graft.

Cardiovascular risk factors in severe chronic renal failure: the role of dietary treatment.

BACKGROUND: Lipoprotein abnormalities and increased oxidized LDL (OxLDL) are often observed in uremia and are reported to play a central role in the development of cardiovascular disease (CVD). Vegan diet, known for its better lipoprotein profile and antioxidant vitamins content, could protect against CVD. Aim of this study was to investigate the influence of vegan diet supplemented with essential amino acids (EAA) and ketoanalogues (VSD) on both traditional and non-traditional cardiovascular risk factors (CVRF). METHODS: Twenty-nine patients (18 M, 11 F) aged 55 years (range 29-79 years) with advanced chronic renal failure (median sCr: 5.6 mg/dl) on very low protein vegetarian diet (0.3 g/kg/day) supplemented with a mixture of EAA and ketoacids (VSD) and 31 patients (20 M, 11 F) aged 65 years (range 29 - 82 years) on conventional low-protein diet (CD: 0.6 g/kg/day) with a similar renal function (median sCr: 5.2 mg/dl), were investigated for lipids and apolipoprotein parameters (traditional CVRF) as well as for oxidative stress (oxidized LDL, antibodies against OxLDL and thiobarbituric acid-reactive substances (TBARS)), total homocysteine (tHcy), lipoprotein(a) (Lp(a)), albumin and c-reactive protein (CRP) (non-traditional CVRF) including vitamins A, E, B12 and folic acid. RESULTS: Compared to patients on CD, those on VSD showed increased HDL cholesterol levels (p < 0.005) with a reduction of LDL cholesterol (p < 0.01) and an increase of apoA1/apoB ratio (p < 0.02). Among non-traditional CVRF, a mild but significant reduction of OxLDL (p < 0.05) with lower TBARS concentrations (p < 0.01) and a significant reduction of total homocysteine (p < 0.002), Lp(a) (p < 0.002) and CRP levels (p < 0.05) were also observed in these patients. Concentrations of vitamin E and A were not different between the two groups while vitamin B12 and folic acid resulted markedly increased in patients on VSD. OxLDL significantly correlated with total and LDL cholesterol, triglycerides and Apo B in CD but not in VSD patients. Patients on CD also showed a significant correlation between urea and CRP. After a multivariate analysis, only urea (p < 0.001) and OxLDL (p < 0.006) were associated to a risk of CRP > 0.3 mg/dl. CONCLUSIONS: These results indicate a better lipoprotein profile in patients on vegan diet including non-traditional CVRF. In particular, these patients show a reduced oxidative stress with a reduced acute-phase response (CRP) as compared to patients on conventional diet. We hypothesize that urea, significantly lower in patients on VSD, may account, possibly together with the reduction of other protein breakdown products, for the decreased acute-phase response observed in these patients. Our findings suggest that low-protein diets, and vegan in particular, may exert a beneficial effect on the development of cardiovascular disease in patients with end-stage renal disease (ESRD).