CD4(+) T cells eliminate MHC class II-negative cancer cells in vivo by indirect effects of IFN-gamma

CD4(+) T cells can eliminate tumor cells in vivo in the absence of CD8(+) T cells. We have CD4(+) T cells specific for a MHC class II-restricted, tumor-specific peptide derived from a mutant ribosomal protein expressed by the UV light-induced tumor 6132A-PRO. By using neutralizing mAb specific for murine IFN-gamma and adoptive transfer of CD4(+) T cells into severe combined immunodeficient mice, we show that anti-IFN-gamma treatment abolishes the CD4(+) T cell-mediated rejection of the tumor cells in vivo. The tumor cells were MHC class II negative, and IFN-gamma did not induce MHC class II expression in vitro. Therefore, the tumor-specific antigenic peptide must be presented by host cells and not the tumor cells. Tumor cells transduced to secrete IFN-gamma had a markedly reduced growth rate in severe combined immunodeficient mice, but IFN-gamma did not inhibit the growth of the tumor cells in vitro. Furthermore, tumor cells stably expressing a dominant-negative truncated form of the murine IFN-gamma receptor alpha chain, and therefore insensitive to IFN-gamma, nevertheless were rejected by the adoptively transferred CD4(+) T cells. Thus, host cells, and not tumor cells, seem to be the target of IFN-gamma. Together, these results show that CD4(+) T cells can eliminate IFN-gamma-insensitive, MHC class II-negative cancer cells by an indirect mechanism that depends on IFN-gamma.

Internalization of the Hm1 muscarinic cholinergic receptor involves the third cytoplasmic loop

The m1 muscarinic receptor was previously shown to stimulate phosphatidyl inositol (PI) turnover and to internalize rapidly upon agonist activation. Three receptor mutants with large deletions of the third cytoplasmic loop (i3) of human Hm1, leaving only 11 and 8 amino acids at the amino and carboxy terminal junctions of i3, respectively, retained full ability to stimulate PI turnover, when expressed in U293 cells, but receptor internalization was greatly reduced in two mutants with deletions reaching close to the NH2 terminal of i3. We propose that a receptor domain located toward the amino terminal junction of i3 plays a role in Hm1 internalization.

Efficacy of herpes simplex virus thymidine kinase in combination with cytokine gene therapy in an experimental metastatic breast cancer model

Immunotherapy in combination with suicide gene therapy for breast cancer was tested using a metastatic animal model. Subcutaneous injection of the nonimmunogenic breast cancer cell line 4T1 in BALB/C mice gave rise to tumors in 100% of mice with both micrometastases and macrometastases in the lung. We used the herpes simplex virus thymidine kinase (HSV-TK) gene along with the cytokine genes granulocyte-macrophage colony-stimulating factor (GM-CSF) and interleukin-2 (IL-2) to determine their effect on tumor regression and inhibition of lung metastasis. Adenoviral (AV) vectors carrying these transgenes, in separate constructs, were used in this study. Intratumoral administration of AV-TK followed by 10 days of ganciclovir treatment resulted in a delay in tumor growth and, in some cases, in a low to moderate reduction in tumor volume. Inclusion of either GM-CSF or IL-2 gene with HSV-TK resulted in a slightly greater reduction in tumor volume, although these data were not significantly different from those obtained for TK treatment alone. However, when both cytokine genes were combined with TK, a substantial reduction in tumor growth was observed compared with HSV-TK alone (P < .02). Tumor weight data also exhibited superior efficacy of TK/GM-CSF/IL-2 treatment when compared with animals treated with TK gene only (P < .01). More importantly, TK/GM-CSF/IL-2 combination gene therapy induced a significant reduction in lung metastasis compared with any other treatment groups in the 4T1 model (P < .001 between TK GM-CSF/IL-2 versus TK only). Surgical excision of primary tumors after TK/GM-CSF/IL-2 plus ganciclovir treatment resulted in anti-metastatic activity that was similar to that observed for animals in which no surgery was performed. Survival analysis showed a significant difference between animals treated with AV-TK/GM-CSF/IL-2 and animals treated with TK only at 35 days after virus injection (P < .01). Immunophenotypic data suggest infiltration of lymphocytes within the tumor microenvironment in TK- and cytokine gene-treated animals. Thus, the overall data presented here demonstrate that TK gene therapy in combination with GM-CSF and IL-2 gene-mediated immunotherapy strategies have important implications in the treatment of breast cancer.

Analysis of visual scanning patterns of pistol shooters

Visual behaviour of pistol shooters of various levels of experience was studied using a video-oculometric technique to record the direction of gaze. A spatio-temporal analysis of the fixation patterns of subjects (five international pistol shooters and five international pentathletes) found that patterns were related to the level of skill. The pentathletes, whose level was lower, positioned their gaze on the weapon sight and visually followed the movement of the weapon towards the target. The pistol shooters appeared to use negative feedback in bringing up their weapons, so reducing the angle formed by the weapon, target and gaze. They fixed their gaze directly on the target or between the target and the weapon. Observations showed a prolonged time of attack (means = 1.107 s vs 0.558 s; P less than 0.001) and a shorter stabilization time (means = 0.714 s vs 1.216 s; P less than 0.001) for the most expert shooters. The psycho-physiological mechanisms which were the basis of these patterns and the reasons why shooters chose them are discussed.

Maintenance rituximab after autologous stem cell transplantation in patients with mantle cell lymphoma

BACKGROUND

High-dose therapy and autologous stem cell transplantation (ASCT) improves outcomes for patients with mantle cell lymphoma (MCL), but relapse ultimately occurs in most patients. Recently presented interim results from a phase III prospective trial suggest maintenance rituximab (MR) after ASCT for MCL improves progression-free survival (PFS). The maturation of these data and any benefit of MR on overall survival (OS) remain to be defined.

PATIENTS AND METHODS

In this retrospective study, we examined a cohort of consecutive patients with MCL that underwent ASCT for MCL at our center and evaluated their outcomes according to whether they received MR after ASCT (n = 50) or did not (n = 107). MR was treated as a time-dependent covariate to account for variation in timing of its initiation.

RESULTS

MR was associated with an improved PFS [hazard ratio (HR) 0.44; confidence interval (CI) (0.24-0.80), P = 0.007] and overall survival (OS; HR 0.46; CI 0.23-0.93, P = 0.03) following a multivariate adjustment for confounding factors with a median follow-up of ∼5 years. Grade 4 neutropenia was increased (34% versus 18%, P = 0.04) in the MR group, but no effect on the rate of mortality unrelated to relapse was observed.

CONCLUSIONS

These data support that MR after ASCT for MCL confers a benefit in PFS and additionally suggest it may improve OS. General application of this strategy will require confirmation of benefit in prospective randomized trials.

Mutational analysis of third cytoplasmic loop domains in G-protein coupling of the HM1 muscarinic receptor

We measured dose-response curves for carbachol stimulation of phosphatidyl inositol (PI) turnover with mutants of the Hm1 muscarinic cholinergic receptor having various deletions from amino acids 219 to 358 of the large third intracellular (i3) loop (208 to 366). These deletions had only small or no effects on the ability of Hm1 transfected into HEK 293 cells to stimulate PI turnover. This result indicates that only small regions of 9 to 11 amino acids adjacent to trans-membrane domains (TMDs) 5 and 6 can be directly involved in G protein coupling. Point mutations were constructed to test the role of charged amino acids in these junctions. A triple point mutation of Hm1 (E214 A/ E216K/ E221 K), which mimics the charge distribution in Hm2 (negatively coupled to cAMP) over the first 14 amino acids of i3, and a double point mutation in the N terminal junction, K359A/K361A, both failed to affect carbachol stimulated PI turnover. Therefore, charge distribution in the loop junctions appears to play a minor role in G protein coupling of Hm1 in HEK 293 cells.

Structure and function of G protein coupled receptors

The G protein coupled receptors (GPC-Rs) comprise a large superfamily of genes encoding numerous receptors which all show common structural features, e.g., seven putative membrane spanning domains. Their biological functions are extremely diverse, ranging from vision and olfaction to neuronal and endocrine signaling. The GPC-Rs couple via multiple G proteins to a growing number of recognized second messenger pathway, e.g., cAMP and phosphatidyl inositol turnover. This review summarizes our current knowledge of the molecular mechanisms by which the GPC-Rs activate second messenger systems, and it addresses their regulation and structure.

Dendritic cells loaded with MART-1 peptide or infected with adenoviral construct are functionally equivalent in the induction of tumor-specific cytotoxic T lymphocyte responses in patients with melanoma

Immunization with tumor-specific-associated antigen--pulsed dendritic cells has proved to be efficacious in various animal models and is being evaluated for the treatment of cancer in humans. Use of dendritic cells pulsed with specific peptides or transfected with tumor-associated antigen genes has been a focused area of investigation for inducing potent tumor and viral immune responses. In this study, the authors demonstrate transgene expression, including the lacZ and MART-1 genes, in dendritic cells infected with adenoviral constructs. These transiently transduced dendritic cells, derived from melanoma patients' monocytes cultured with granulocyte-macrophage colony-stimulating factor and interleukin-4, express the transgene and can stimulate patients' CD8+ T cells to elicit an antitumor immune response comparable to dendritic cells loaded with a defined peptide. These cytotoxic T lymphocytes were able to recognize both known and unknown tumor-associated antigen epitopes and exhibited cytolytic activity against HLA-matched tumor cells expressing the antigen. The ability to induce tumor-specific cytotoxic T lymphocytes in vitro using gene-modified dendritic cells that transiently express tumor-associated antigens demonstrates the potential use of these antigen-presenting cells for developing in vivo cancer vaccines.

Reusable needles--a major risk factor for acute virus B hepatitis

We conducted a case control study to find the extent to which acute virus B hepatitis was hospital acquired. One hundred and sixty consecutive cases of acute virus B hepatitis were compared with age (+/- 3 years) and sex matched healthy hospital visitors. Exposure to reusable needles, blood or blood products, therapeutic and diagnostic procedures, common razors and sexual practices were elicited by means of a questionnaire. Only exposures in the incubation period (6 weeks to 6 months before the onset of symptoms) were included in the analysis. The odds ratio (OR) for injections for reusable needles was 6.3 [95% confidence interval (CI) = 3.8-10.6]. The OR for single injection (OR = 3.9; 95% CI = 2.0-7.3) was less than that for multiple injections (OR = 9.8; 95% CI = 3.8-26.3), showing a dose response relationship. The proportion of cases of acute virus B hepatitis attributable to hospital related exposures was 67%. Proper aseptic techniques and sterilization practices can substantially reduce the incidence of acute hepatitis B in the population.

Nucleosome core histone complex isolated gently and rapidly in 2 M NaCl is octameric

A relatively stable specific complex of the chromatin core histones H2A, H2B, H3, and H4 has been obtained in 2 M NaCl/25 mM sodium phosphate buffer, pH 7.0. The histone core complex has an apparent specific volume of 0.73 ml/g. Its sedimentation coefficient was dependent on rotor speed (angular velocity, omega) and attained different stable values at low and high rotor speeds. The drop in sedimentation coefficient occurred sharply between omega 2 values of about 9 x 10(6) and 1.1 x 10(7) (radians/sec)2. The s020,w corresponding to zero angular velocity (1 atmosphere pressure) was 6.6 S +/- (SEM) 0.1 S. At high rotor speeds the value decreased to 3.8 S +/- 0.1 S. The core complex has a diffusion coefficient, D20,w, of 5.4 x 10(-7) cm2/sec and a molecular weight of 108,000 +/- (SD) 2500.

Enhanced expression of granulosa cell low density lipoprotein receptor activity in response to in vitro culture conditions

Previous studies have shown that the B/E (low density lipoprotein [LDL]) receptor pathway plays a minor role in cholesterol uptake in the intact rat ovary, but when granulosa cells are isolated and maintained in culture, the cells develop a fully functional B/E receptor system. In the current study we examined the development of the B/E receptor over time (96 h) in culture and compared its physiological function, expression of mRNA and protein levels, and morphological events to the upregulation induced in 24 h by hormone (human chorionic gonadotropin [hCG] or Bt2cAMP). With both protocols, increased progestin production occurs and is associated with elevated binding, uptake, and degradation of LDL in the medium although the impact of Bt2cAMP stimulation on all these measurements is several times that observed with time alone. Only the hormone-stimulated LDL receptor response was associated with an increase in receptor protein (Western blot) or mRNA levels (RNase protection assay). We conclude that unstimulated granulosa cells show posttranslational increases in B/E receptor activity with time in culture, but transcriptional changes in B/E receptor follow stimulation with trophic hormone or its second messenger, cAMP.

Thyroid dysfunction in Down's syndrome and screening for hypothyroidism in children and adolescents using capillary TSH measurement

Thyroid dysfunction is more common in individuals with Down's syndrome (DS) than in the general population, whose clinical features can mask the presenting signs and symptoms of hypothyroidism. Biochemical screening is necessary; however, venepuncture may be difficult.

AIMS

To assess the prevalence of thyroid dysfunction in children and adolescents with DS and the feasibility of screening for hypothyroidism using capillary dried blood spot thyroid stimulating hormone (TSH) from infancy.

METHODS

394 children (217 boys, 177 girls) were clinically assessed for thyroid dysfunction and 305 children (aged 4 months to 18.9 years) were screened for hypothyroidism by capillary whole blood TSH sample.

RESULTS

Thyroid dysfunction was detected in 4.6%, with 50% unscreened since neonatal screening. Parents reported minimal distress by fingerprick screening.

CONCLUSION

DS is associated with an increased prevalence of thyroid dysfunction, particularly in preschool children. Biochemical screening is essential and capillary whole blood TSH sampling for hypothyroidism is feasible, less invasive and acceptable.

Ganglioneuroma: an 'incidentaloma' of childhood

In adults clinically silent adrenal masses can be discovered incidentally in imaging studies. Most of these 'incidentalomas' are benign, non-functioning adenomas. In contradistinction, in infancy and childhood the most common adrenal mass is the neuroblastoma, a malignant neural crest tumour. Four children are described, each with a benign neural crest tumour - ganglioneuroma - incidentally discovered by conventional radiography or sonographic examination. Complete surgical excision resulted in total recovery of all the children.

Metabolic studies of hypoxia-inducible factor stabilisers IOX2, IOX3 and IOX4 (in vitro) for doping control

The transcriptional activator hypoxia-inducible factor (HIF) is a vital arbitrator in the performance of cellular responses lacking oxygen supply in aerobic organisms. Because these compounds are capable of enhancing the organism's capacity for molecular oxygen transport, they possess great potential for abuse as a performance-enhancing agent in sports. A comprehensive study of the metabolic conversion of the most popular HIF stabilisers such as IOX2, IOX3 and IOX4 using equine liver microsomes (in vitro) is reported. The parents and their metabolites were identified and characterised by liquid chromatography-mass spectrometry in negative ionisation mode using a QExactive high-resolution mass spectrometer. Under the current experimental condition, a total of 10 metabolites for IOX2 (three phase I and seven phase II), nine metabolites for IOX3 (four phase I and five phase II) and five metabolites for IOX4 (three phase I and two phase II) were detected. The outcome of the present study is as follows: (1) all the three IOX candidates are prone to oxidation, results in subsequent monohydroxylated, and some dihydroxylated metabolites. (2) Besides oxidation, there is a possibility of hydrolysis and de-alkylation, which results in corresponding carboxylic acid and amide, respectively. (3) The glucuronide and sulphate conjugate of the parent drugs as well as the monohydroxylated analogues were observed in this study. The characterised in vitro metabolites can potentially serve as target analytes for doping control analysis.

Identification of Hypoxia-inducible factor (HIF) stabilizer roxadustat and its possible metabolites in thoroughbred horses for doping control

Hypoxia-inducible factor (HIF) stabilizer belongs to a novel class of pharmacologically active substances, which are capable of inducing the endogenous erythropoietic system. The transcriptional activator HIF has been shown to significantly increase blood hemoglobin and is well set for the treatment of anemia resulting from chronic kidney disease. This research work reports a comprehensive study of the most popular HIF stabilizer roxadustat and its metabolites in thoroughbred horse urine after oral administration. The plausible structures of the detected metabolites were postulated using liquid chromatography-high-resolution mass spectrometry. Under the experimental condition 13 metabolites (7 phase I, 1 phase II, and 5 conjugates of phase I metabolism) were positively detected (M1-M13). The major phase I metabolites identified were formed by hydroxylation. Dealkylated and hydrolyzed phase I metabolites were also observed in this study. In phase II, a glucuronic acid conjugate of roxadustat was detected as the major metabolite. The sulfonic acid conjugates were observed to be formed from phase I metabolites. The characterized in vivo metabolites can potentially serve as target analytes for doping control analysis; hence, the result is an important tool for assessing its use and abuse in competitive sport.

Effect of yoga therapy on anxiety and depressive symptoms and quality-of-life among caregivers of in-patients with neurological disorders at a tertiary care center in India: A randomized controlled trial

CONTEXT

The concerns of caregivers of patients with neurological disorders have been a felt need for a long time, with many of them experiencing significant psychiatric morbidity.

AIMS

This study aimed to find the effect of yoga in reducing anxiety and depression, as well as improving quality-of-life in caregivers of patients with neurological disorders.

SETTINGS AND DESIGN

The study was conducted using a randomized controlled design, with yoga intervention and waitlisted controls.

METHODOLOGY

SIXTY CONSENTING CAREGIVERS OF INPATIENTS IN NEUROLOGY WARDS WERE RANDOMIZED INTO TWO GROUPS: Yoga and control. Demographic variables except years of education and length of caretaking were comparable in the two groups, as also baseline scores of anxiety, depression and quality-of-life. A specific yoga module comprising yogāsanas, prāṇāyāma, and chanting was taught to the participants in the yoga group by the researcher. At follow-up 43 patients (yoga n=20 and control group n=23) were available. Two-way repeated measures analysis of variance was used to test the change from pre-test to post-test scores within and between groups. Analysis of covariance was performed to compare the post-test scores between the groups adjusting for education and length of caretaking.

RESULTS

Following one month intervention of yoga therapy, there was a significant (P<0.001) decrease in anxiety and depression scores, as well as improved quality-of-life among the participants in the yoga group as compared with the control group.

CONCLUSION

This study highlights the usefulness of a yoga intervention for caregivers of inpatients with neurological problems. The small sample size and lack of blinding were some of the limitations of this study.

The effect of blood transfusion on central venous oxygen saturation in critically ill patients admitted to a neurointensive care unit

BACKGROUND

Literature suggests poorer outcomes during anaemia as well as following red blood cell transfusion (BT) in brain injured patients. Recently, central venous oxygen saturation (ScvO₂ ) has been proposed as a physiological trigger to guide red BT. In this study, we looked at ScvO₂ changes following BT in patients admitted to a neurointensive care unit (NICU).

STUDY DESIGN

In this prospective, observational study, adult, acutely ill neurological patients of >18 years were recruited. The following parameters were measured before and immediately after transfusion and then at 6, 12, 18 and 24 h after transfusion: haemoglobin (Hb), ScvO₂ and central venous oxygen partial pressure (PcvO₂ ) (blood sampled from central venous catheter). Simultaneously, hemodynamic parameters [central venous pressure (CVP), heart rate (HR), mean arterial pressure (MAP) and systolic blood pressure (SBP)] were also noted.

RESULTS

Data from 70 adult patients were analysed. Following BT, significant improvement was noted in Hb, ScvO₂ and all hemodynamic parameters. The ScvO₂ changes correlated significantly with the number of units of BT (P = 0·039), pre-transfusion Hb (P = 0·010), ScvO₂ (P = 0·001) and PcvO₂ (P = 0·001). When receiver operating characteristic (ROC) curves were drawn, optimum cut-off values of baseline ScvO₂ and Hb to predict the need for transfusion in terms of oxygen delivery were 70% and 8·6 gm dL^-1 respectively.

DISCUSSION

Baseline ScvO₂ <70% appears to be a useful physiological trigger for deciding the need for BT in brain injured patients. Whether improvement in ScvO₂ leads to improvement in regional brain oxygenation needs to be studied.

Active immunization with tumor cells transduced by a novel AAV plasmid-based gene delivery system

Ex vivo genetically engineered cytokine-secreting tumor cell vaccines have been shown to prevent metastatic disease in animal models of lung and breast cancer. Because of the inefficiency of existing modes of gene delivery in transducing primary human tumor cells, it has been difficult to clinically apply this strategy. In this study, liposome-mediated delivery of an adeno-associated virus (AAV)-based plasmid containing the sequence for murine gamma-interferon (gamma-IFN) (pMP6A-mIFN-gamma) was used to generate cytokine-secreting murine tumor cell vaccines. High levels of gamma-IFN and elevated class I major histocompatibility complex expression after transfer of pMP6A-mIFN-gamma into the murine lung cancer cell line, D122, was demonstrated. The efficiency of gene transfer was determined by two different methods and was estimated to be 10-15%. Irradiated gamma-IFN D122 cells generated by this novel gene delivery system (D122/pMP6A-mIFN-gamma) and also by standard retroviral methods (DIF2) were administered as weekly vaccinations by intraperitoneal injection to animals bearing 7-day-old intrafootpad D122 tumors. Hindlimb amputation was performed when footpad diameters reached 7 mm, and lungs were harvested 28 days later. Animals vaccinated with gamma-IFN-secreting D122 cells produced by AAV-based plasmids delivery demonstrated a significant delay in footpad tumor growth when compared with controls and DIF2 cells. Fifty-seven percent of animals vaccinated with D122/pMP6A-mIFN-gamma were free of pulmonary metastases 28 days after amputation, significantly improved from the 0, 7, and 15% observed in animals vaccinated with irradiated parental D122 cells, irradiated D122 cells lipofected with an empty-cassette vector (pMP6A), or DIF2 cells, respectively. These results and the ability to transfer genes with this delivery system to a broad range of tumor types support its use in the generation of cytokine-secreting tumor cell vaccinations for use in clinical trials.

Mapping the ligand binding pocket of the human muscarinic cholinergic receptor Hm1: contribution of tyrosine-82

The ligand binding pocket of many G protein-coupled receptors is thought to be located within the core formed by their seven transmembrane domains (TMDs). Previous results suggested that muscarinic antagonists bind to a pocket located toward the extracellular region of the TMDs, primarily at TMDs 2, 3, 6, and 7. Tyrosine-82 (Y82) is located in TMD2 only one helical turn from the presumed membrane surface of Hm1, whereas a phenylalanine (F124) is found in the equivalent position of the closely related Hm3. In order to determine the contribution of Y82 to Hm1 ligand binding and selectivity versus Hm3, we constructed the point mutation Y82 F of Hm1 and measured binding affinities of various ligands, with 3H-N-methylscopolamine (3H-NMS) as the tracer. The Hm1 wild-type receptor and the Y82F mutant were transfected into human embryonic kidney U293 cells. Whereas the affinities of NMS, carbachol, and atropine were either unchanged (carbachol) or enhanced by less than twofold (atropine and NMS), the affinity of the Hm1-selective pirenzepine was reduced threefold by the Y82F mutation. These changes parallel affinity differences of Hm1 and Hm3, indicating that the Y82 F mutation affects the binding pocket and that Y82 contributes to the binding selectivity among closely related muscarinic receptors.

Regional cerebral tissue oxygen saturation changes following blood transfusion in neuro-intensive care unit patients - a pilot observational study

BACKGROUND

Although central venous oxygen saturation (ScvO₂ ) is used to decide on red blood cell (RBC) transfusion, whether its improvement is associated with parallel improvement in cerebral oxygenation is not adequately studied. This study looked at changes in regional cerebral tissue oxygen saturation (rSO₂ ) following RBC transfusion in neuro-intensive care unit (ICU) patients.

METHODS

In this prospective observational pilot study, rSO₂ was measured in adult neuro-ICU patients before RBC transfusion, at the end and at 6, 12, 18 and 24 h after RBC transfusion. rSO₂ measurements were taken using cerebral oximetry on both sides of the hemicraniums. Haemoglobin, central venous pressure, ScvO₂ and temperature were recorded during the study period. Arterial oxygen content, central venous oxygen content and cerebral fractional oxygen extraction were calculated. Mann Whitney U test was used to study the changes in variables at baseline and at 24 h following RBC transfusion. Friedman's test was used to study changes in parameters from baseline to 24 h post-transfusion. A P value of <0·05 was considered to be significant.

RESULTS

The data from 13 subjects were analysed. rSO₂ increased significantly following RBC transfusion on both sides of the brain (P = 0·002, P = 0·007), with a corresponding decrease in cerebral fractional oxygen extraction (P = 0·001, P = 0·007).

CONCLUSIONS

RBC transfusion increased rSO₂ significantly on both sides of the brain. As patients' outcomes were not studied, whether this increase in regional cerebral oxygen saturation is beneficial or if it is because of excess DO₂ is still unclear. Further studies are required to clarify this issue.

Separation of ephedrine and pseudoephedrine enantiomers using a polysaccharide-based chiral column: A normal phase liquid chromatography-high-resolution mass spectrometry approach

Chiral considerations are found to be very much relevant in various aspects of forensic toxicology and pharmacology. In forensics, it has become increasingly important to identify the chirality of doping agents to avoid legal arguments and challenges to the analytical findings. The scope of this study was to develop an liquid chromatography-mass spectrometry (LCMS) method for the enantiomeric separation of typical illicit drugs such as ephedrines (ie, 1S,2R(+)-ephedrine and 1R,2S(-)-ephedrine) and pseudoephedrine (ie, R,R(-)-pseudoephedrine and S,S(+)-pseudoephedrine) by using normal phase chiral liquid chromatography-high-resolution mass spectrometry technique. Results show that the Lux i-amylose-1 stationary phase has very broad and balancing-enantio-recognition properties towards ephedrine analogues, and this immobilized chiral stationary phase may offer a powerful tool for enantio-separation of different types of pharmaceuticals in the normal phase mode. The type of mobile phase and organic modifier used appear to have dramatic influences on separation quality. Since the developed method was able to detect and separate the enantiomers at very low levels (in pico grams), this method opens easy access for the unambiguous identification of these illicit drugs and can be used for the routine screening of the biological samples in the antidoping laboratories.