Efficiency of a miniaturized silica monolithic cartridge in reducing matrix ions as demonstrated in the simultaneous extraction of morphine and codeine from urine samples for quantification with liquid chromatography-tandem mass spectrometry (LC-MS/MS).

Presence of matrix ions could negatively affect the sensitivity and selectivity of liquid chromatography-tandem mass spectrometer (LC-MS/MS). In this study, the efficiency of a miniaturized silica monolithic cartridge in reducing matrix ions was demonstrated in the simultaneous extraction of morphine and codeine from urine samples for quantification with LC-MS. The miniaturized silica monolith with hydroxyl groups present on the largely exposed surface area function as a weak cation exchanger for solid phase extraction (SPE). The miniaturized silica cartridge in 1 cm diameter and 0.5 cm length was housed in a 2-ml syringe fixed over a SPE vacuum manifold for extraction. The cleaning effectiveness of the cartridge was confirmed by osmometer, atomic absorption spectrometer, LC-MS and GC-TOFMS. The drugs were efficiently extracted from urine samples with recoveries ranging from 86% to 114%. The extracted analytes, after concentration and reconstitution, were quantified using LC-MS/MS. The limits of detection for morphine and codeine were 2 ng/ml and 1 ng/mL, respectively. The relative standard deviations of measurements ranged from 3% to 12%. The monolithic sorbent offered good linearity with correlation coefficients > 0.99, over a concentration range of 50-500 ng/ml. The silica monolithic cartridge was found to be more robust than the particle-based packed sorbent and also the commercial cartridge with regards to its recyclability and repeated usage with minimal loss in efficiency. Our study demonstrated the efficiency of the miniaturized silica monolith for removal of matrix ions and extraction of drugs of abuse in urinary screening.

G-1-activated membrane estrogen receptors mediate increased contractility of the human myometrium.

Estrogens are key mediators of increased uterine contractility at labor. We sought to determine whether membrane-associated estrogen receptors, such as the recently described seven-transmembrane receptor G protein-coupled receptor 30 (GPR30), mediated some of this effect. Using human myometrium obtained at term cesarean section before or after the onset of labor, we demonstrated the presence of GPR30 mRNA and protein using quantitative RT-PCR and Western blotting. GPR30 receptor was localized to the cell membrane and often colocalized with calveolin-1. Using the specific estrogen membrane receptor agonist G-1 and myometrial explants, we showed that membrane receptor activation led to phosphorylation of MAPK and the actin-modifying small heat shock protein 27. Using myometrial strips incubated with G-1 or vehicle we demonstrated that estrogen membrane receptor activation increased the myometrial contractile response to oxytocin. These data suggest that activation of the plasma membrane estrogen receptor GPR30 likely participates in the physiology of the human myometrium during pregnancy and identifies it as a potential target to modify uterine activity.

Application of silica-based monolith as solid phase extraction cartridge for extracting polar compounds from urine.

The silica monolith with ionizable silanol groups and large surface area was found able to function as an offline cation exchange solid phase extraction (SPE) cartridge for extracting polar analytes. The prepared cartridge was housed in a 2-mL syringe fixed over a SPE vacuum manifold. The unique property of this silica monolithic cartridge was demonstrated by extracting epinephrine, normetanephrine and metanephrine from urine samples. These analytes were chosen as model compounds for testing because of their high hydrophilicity, and being candidates monitored for clinical diagnosis. The extracted analytes, after concentration and reconstitution were then quantitated by high-performance liquid chromatography coupled to mass spectrometer (HPLC/ESI/MS). Multiple reactions monitoring was carried out with transitions: 184-->107, 184-->134 and 198-->148 for analyzing epinephrine, normetanephrine and metanephrine, respectively. The limit of detection was 3 ng/mL for metanephrine and 5 ng/mL for normetanephrine and epinephrine. The relative standard deviations of measurements ranged from 2 to 10%. The sorbent offered good linearity with coefficient of determination (r(2))>0.99, over a concentration range of 20-200 ng/mL. The relative recoveries ranged from 60 to 67%, 55 to 59% and 99 to 105% for epinephrine, normetanephrine and metanephrine, respectively. The prepared cartridge had shown potential and was found robust in extracting the polar analytes repeatedly without any significant loss in efficiency.

Distribution study of orally administered lipoic acid in rat brain tissues.

Lipoic acid (LA), an essential cofactor for mitochondrial enzymes and a natural antioxidant, has been explored for the treatment of Alzheimer's disease. However, lipoic acid distribution in brain has not been investigated via oral dosing in human subjects or animals. Therefore, we aim to investigate the distribution of orally administered LA from systemic circulation into rat brain tissues and understand the transport efficiency of lipoic acid across the blood-brain barrier. Brain and blood samples were obtained from male Lister Hooded rats at pre-defined time points after single and chronic oral dosing of LA at 50 mg/kg. Levels of LA were determined using liquid chromatography tandem mass spectrometry. An equilibrium dialysis method was employed to elucidate LA protein binding in brain and blood tissues. Basal endogenous levels of LA in control rats were found to fluctuate between 0.005 and 0.267 microM in blood and 0-0.024 microM in brain after correction for residual blood volume. Pharmacokinetic profiling demonstrated rapid biphasic elimination of LA in blood and poor distribution into various brain regions with levels ranging from 0.0009 to 0.0072 microM. The in vitro and in vivo LA brain:blood partition ratios were 0.1 and -0.01, respectively. Our results demonstrate for the first time that LA does not cross the blood-brain barrier readily and suggest that the antioxidant effect of LA in brain may not be due to its direct effect in the central nervous system.

Gas chromatography/mass spectrometry in metabolic profiling of biological fluids.

One of the objectives of metabonomics is to identify subtle changes in metabolite profiles between biological systems of different physiological or pathological states. Gas chromatography mass spectrometry (GC/MS) is a widely used analytical tool for metabolic profiling in various biofluids, such as urine and blood due to its high sensitivity, peak resolution and reproducibility. The availability of the GC/MS electron impact (EI) spectral library further facilitates the identification of diagnostic biomarkers and aids the subsequent mechanistic elucidation of the biological or pathological variations. With the advent of new comprehensive two dimensional GC (GC x GC) coupled to time-of-flight mass spectrometry (TOFMS), it is possible to detect more than 1200 compounds in a single analytical run. In this review, we discuss the applications of GC/MS in the metabolic profiling of urine and blood, and discuss its advances in methodologies and technologies.

Modeling Caco-2 permeability of drugs using immobilized artificial membrane chromatography and physicochemical descriptors.

This study evaluates the potential of immobilized artificial membrane (IAM) chromatography, in combination with other physicochemical descriptors for high-throughput absorption profiling during lead optimization. An IAM chromatographic method was developed and validated. Absorption profiles of 32 structurally diverse compounds (acidic, basic, neutral and amphoteric) were then evaluated based on their IAM retention factor (log k'IAM), molecular weight (MW), calculated log P (C log P), polar surface area (PSA), hydrogen bonding capacity (HBD and HBA) and calculated Caco-2 permeability (QPCaco). Using regression and stepwise regression analysis, experimental Caco-2 permeability was correlated against log k'IAM and a combination of various physicochemical variables for quantitative structural-permeability relationship (QSPR) study. For the 32 structurally diverse compounds, log k'IAM correlated poorly with Caco-2 permeability values (R2 = 0.227). Stepwise regression analysis confirmed that Clog, PSA, HBD and HBA parameters are not statistically significant and can be eliminated. Correlation between Caco-2 cell uptake and log k'IAM was enhanced when molecular size factor (MW) was included (R2 = 0.555). The exclusion of 11 compounds (paracellularly and actively transported, Pgp substrates and blocker, and molecules with MW lesser than 200 and greater than 800) improved the correlation between Caco-2 permeability, IAM and MW factors to R2 value of 0.84. The results showed that IAM chromatography can only profile the passive absorption of drug molecules. Finally, it was confirmed in this study that the IAM model can accurately identify the Caco-2 permeability of nontransported Pgp substrates, such as verapamil and ketoconazole, through passive permeation because of their high permeability. IAM chromatography, combined with molecular size factor (MW), is useful for elucidating biopartitioning mechanism of drugs.

Nonhematologic malignancies after allogeneic hematopoietic stem cell transplantation: incidence and molecular monitoring.

Survivors of allogeneic hematopoietic stem cell transplantation (HSCT) are at a life-long increased risk of secondary nonhematologic malignancies. In 615 adult Chinese allogeneic HSCT patients, nine developed nonhematologic malignancies. The 5-year cumulative incidence was 6.1%, 4.5 times the background cancer incidence. Early-onset (within first 6 months) and late-onset (>3 years) subtypes were observed. Secondary cancers included hepatocellular carcinoma, oral and esophageal squamous cell tumors and lung adenocarcinoma in a female nonsmoker. The spectrum reflected local cancer epidemiology, which was different from Western populations. The pathogenesis might be related to acceleration of pre-existing cancers (early-onset type), or prolonged immunosuppression (late-onset type). DNA chimerism studies showed that all tumors were recipient-derived. In the plasma, DNA in all cases was apparently donor-derived, although aberrantly methylated p15 was detectable in a patient with a p15-methylated secondary cancer, implying that minute quantities of tumor (and therefore recipient) derived DNA might be present.

Expression patterns of cell cycle and apoptosis-related genes in a multidrug-resistant human colon carcinoma cell line.

BACKGROUND: An in vitro multidrug resistance (MDR) system from a human colonic cancer cell line (SW620-MDR) has been established. To further study the mechanisms at molecular level and prevention of multidrug resistance in clinical practice, it was demonstrated that the expressions of several apoptosis-related and cell cycle regulator genes were changed in the cells. METHODS: A multidrug-resistant colonic cell line (SW620-MDR) was established, and the Atlas human cDNA expression array was used for studying the pattern of gene expression in this cell line. Furthermore, Northern hybridization or real-time PCR analysis confirmed the pattern of gene expression. RESULTS: In the SW620-MDR cell line the pro-apoptosis genes, CASP4, BIK, PDCD2, and TACE were expressed with decreased levels, and the antiapoptosis genes CD27-L and IGFBP2 were over-expressed. Furthermore, the cell cycle regulator genes such as CDK6, CCND1, CDC27HS, CDC16HS, Wee1Hu, MAPKK1, and IGFBP6 were expressed with decreased levels in the drug-resistant cell line. CONCLUSIONS: It is worthwhile investigating whether the differentially expressed pattern of the aforementioned genes exists in the drug-resistant cancer specimens, and to further understand their functions in the cancer drug-resistance mechanism.

The importance of needs assessment in planning health promoting schools initiatives: comparison of youth risk behaviours of two districts in Hong Kong.

A needs assessment is recommended to be carried out before planning resource allocation in a community as it could help to identify the needs of the people. This study illustrated the importance of needs assessment in planning health promoting school initiatives by comparing the results of youth risk behaviours surveys conducted at two districts of Hong Kong, namely Tsuen Wan and North District. The findings indicated that the two districts should prioritize their resources in respect to their urgent needs. A higher proportion of students from Tsuen Wan participated in vigorous exercise regularly in comparison to students from North District. Students from North District consumed more vegetable per week and exhibited less depressive symptoms than students from Tsuen Wan. The availability of data on youth risk behaviours of the two districts would provide information for strategic planning and direct decision-making in youth health programmes.

A green health education approach to health promoting schools.

Since the Education Commission of the Hong Kong Special Administrative Region had proposed the educational reform in 2000, there is a new direction for school curriculum development. Lok Wah Catholic Primary School was one of the schools taking the health promoting school approach for educational reform. This paper aims to share information on how the School implemented the "Green Health Education Approach" to create a healthy learning environment for students.

Treatment of postrenal transplantation lymphoproliferative disease manifesting as plasmacytoma with nonmyeloablative hematopoietic stem cell transplantation from the same kidney donor.

Posttransplantation lymphoproliferative disease (PTLD) presenting as an Epstein-Barr-virus (EBV)-related nasal plasmacytoma developed in a renal-allograft recipient 13 years after transplantation. Systemic dissemination occurred despite immunosuppression withdrawal, surgery, irradiation, and chemotherapy. A nonmyeloablative hematopoietic-stem-cell-transplantation (HSCT) with peripheral blood HSC from the kidney donor was performed. With the onset of graft-versus-host disease, resolution of the systemic disease was demonstrated clinically and molecularly by serial quantification of plasma EBV-DNA. Isolated relapse occurred in the central nervous system (CNS), a known tumour sanctuary site, ultimately leading to death. Nonmyeloablative HSCT might be considered a cellular therapy for PTLD, but possible CNS relapse must be effectively tackled.

Application of visual basic in high-throughput mass spectrometry-directed purification of combinatorial libraries.

We present an approach to customize the sample submission process for high-throughput purification (HTP) of combinatorial parallel libraries using preparative liquid chromatography electrospray ionization mass spectrometry. In this study, Visual Basic and Visual Basic for Applications programs were developed using Microsoft Visual Basic 6 and Microsoft Excel 2000, respectively. These programs are subsequently applied for the seamless electronic submission and handling of data for HTP. Functions were incorporated into these programs where medicinal chemists can perform on-line verification of the purification status and on-line retrieval of postpurification data. The application of these user friendly and cost effective programs in our HTP technology has greatly increased our work efficiency by reducing paper work and manual manipulation of data.

Treatment of lymphoma relapses after allogeneic hematopoietic stem cell transplantation with intensive chemotherapy followed by infusion of hematopoietic stem cell from the original donor.

Five lymphoma patients relapsed from allogeneic hematopoietic stem cell transplantation (HSCT). Three patients who received myeloablative conditioning had full donor chimerism at relapse, whereas two who received nonmyeloablative conditioning had partially or completely lost the graft. All received mini-BEAM [carmustine (BCNU), etoposide, cytarabine (AraC), melphalan], followed by infusion of HSC (four peripheral blood, one marrow) from the initial donor. Neutropenia and thrombocytopenia were brief, and full donor chimerism was established in all cases. There were four complete and one partial remissions. Graft-versus-host disease occurred in three cases, all with full donor chimerism at relapse. Two patients died subsequently of disease relapse or progression. Another two patients died from fungal infection, one of whom was still in remission at death. One patient had remained in remission 47 months after treatment. Mini-BEAM/HSC is an effective treatment for lymphoma relapses after allogeneic HSCT, but optimal strategies of remission consolidation and prevention of treatment-related complications are needed to improve outcome.

Poor engraftment after allogeneic bone marrow transplantation: role of chimerism analysis in treatment and outcome.

We analyzed the clinical course and risk factors of 18 patients with poor engraftment after allogeneic bone marrow transplantation (BMT), defined as absolute neutrophil count below 0.1 x 10(9)/l 28 days post-BMT. Significant risks associated with non-engraftment included HLA one antigen mismatch, BMT from matched unrelated donor, and a low dose of colony-forming units-granulocyte-macrophage (<10(4)/kg). Examined by a semiquantitative analysis of polymorphic microsatellite markers, donor DNA chimerism on day 28 was found to be predictive of treatment outcome. Seven patients had detectable donor DNA, varying from 43 to 100%. Five of them responded to granulocyte colony-stimulating factor (G-CSF) and achieved engraftment. Two were given further infusions of peripheral blood hematopoietic stem cells (PBSC) from the same donors, resulting in engraftment in one of them. Eleven patients had no detectable donor DNA, and none responded to G-CSF. Autologous regeneration occurred in six of these patients, four after infusion of backup marrow and two spontaneously. The remaining five patients died despite the administration of PBSC from the same or different donors. Regular monitoring of donor DNA chimerism is useful in the management of patients at high risk of poor engraftment.

Helicobacter pylori inhibits activity of cdc2 kinase and delays G2/M to G1 progression in gastric adenocarcinoma cell line.

BACKGROUND: Helicobacter pylori is a bacterial pathogen strongly associated with ulcer diseases and gastric cancer. The bacterial-induced alteration of cell-cycle control in host cells may play a role in the pathogenetic mechanisms. The aims of this study were to define the effect of H. pylori on the G2/M to G1 transition in a gastric cell line. METHODS: Cultured gastric cells, AGS, were synchronized in the S/early G2 phase and treated with intact H. pylori. The cell-cycle distribution of AGS cells was determined by flow cytometry. The activity of cdc2 kinase, as well as of some parameters that affect the kinase activity, was also examined. RESULTS: H. pylori delays cell-cycle progression at the G2/M phase in AGS cells. The G2/M delay was associated with reduced activity of cdc2 kinase. Both down-regulation of cell-cycle regulators (p34cdc2, cyclin B1 and cdc25C) and decreased association between p34cdc2 and cyclin B1 were found to be associated with the activity of cdc2 kinase abated after the H. pylori infection. In addition, the H. pylori-induced G2/M delay required direct contact between the bacteria and host cells. CONCLUSIONS: H. pylori inhibits G2/M to G1 progression and causes a reduction of cell division in gastric epithelial cells.

Leukaemic relapse of donor origin after allogeneic bone marrow transplantation from a donor who later developed bronchogenic carcinoma.

Donor-derived leukaemia is exceptional after allogeneic bone marrow transplantation (BMT). A woman with chronic myeloid leukaemia received an allogeneic BMT from a human leucocyte antigen-identical brother. The donor, a 50-year-old non-smoker, died of squamous cell bronchogenic carcinoma 1 year later. At 4 years post BMT, the patient became BCR/ABL positive and relapsed with acute myeloid leukaemia, which was shown to be donor-derived cytogenetically and molecularly. Retrospective analysis showed that the donor-leukaemic clone had started to evolve as early as 6 months post BMT. Sequencing of p53 ruled out Li-Fraumeni syndrome. Predisposition to malignancy might be an underlying mechanism of donor-cell leukaemia.

Tyrosine kinase inhibitor STI571 in the treatment of Philadelphia chromosome-positive leukaemia failing myeloablative stem cell transplantation.

Eight patients with Philadelphia chromosome-positive (Ph(+)) leukaemia relapsing from stem cell transplantation (SCT) (one syngeneic and seven allogeneic) were treated with the tyrosine kinase inhibitor STI571. Five patients relapsing as chronic myeloid leukaemia (CML) in chronic phase achieved a complete haematological response, with complete and major cytogenetic responses occurring in four and one cases, respectively. One patient became negative for BCR/ABL in the bone marrow. Three patients relapsed as acute leukaemia (two CML in myeloblastic crisis and one Ph(+) acute lymphoblastic leukaemia), all of whom achieved haematological and cytogenetic responses. One patient also became BCR/ABL negative. However, pancytopenia and graft-versus-host disease led to cessation of treatment in the remaining two cases, which was followed by disease recurrence refractory to further STI treatment. Our results showed that Ph(+) leukaemic relapses after SCT might respond well to STI571 therapy.

Preparation and characterization of immunogens for antibody production against metanephrine and normetanephrine.

A two-step zero-length cross-linking procedure using active esters was successfully adopted for conjugating metanephrine (MN) and normetanephrine (NM) to bovine serum albumin (BSA). The protein was activated with water-soluble 1-ethyl-3-(3-dimethylaminopropyl) carbodiimide (EDC) in the presence of N-hydroxysulfosuccimide (sulfo-NHS), leading to the formation of active N-succinimidyl esters of some glutamic and aspartic acid carboxyls. The pertinence of this reaction for the coupling of these haptens to carboxylate groups was confirmed via reaction with a model compound, 2-hydroxybenzoic acid, and subsequent characterization using atmospheric pressure chemical ionization mass spectrometry (APCI-MS). Matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF-MS) was used for the quantitative assessment of the hapten/protein ratios of these conjugates. This technique of conjugate characterization demonstrated greater resolution in molecular weight determination compared to nondenaturing polyacrylamide gel electrophoresis (native PAGE). Preliminary results from enzyme-linked immunosorbent assay (ELISA) and inhibition ELISA procedures using test antisera confirmed that the synthesized immunogens were highly antigenic and elicited specific antibody responses in BALB/c mice against the haptens.

Exploring the recognized bio-mimicry materials for gas sensing.

This study was undertaken to synthesize peptides that are partially similar to the binding sites of human olfactory receptor protein. First, a putative 3-D model structure of human olfactory receptor protein (P30953) was modeled using a molecular simulation method. The computer docking simulation was then performed to determine the most plausible binding sites between the model structure and target gases, trimethylamine, ammonia, acetic acid, and o-xylene. According to the simulation result, a series of polypeptide sequences, horp61 for TMA, horp103 for o-xylene, horp109 for ammonia, and horp193 for acetic acid as recognized molecules were designed for gas sensing purposes. Preparing these peptides as corresponding gas sensing probes, the results showed a high relative sensitivity response of 6.7 for TMA (probe horp61), 5.1 for o-xylene (probe horp103), 11 for ammonia (probe horp109), and 28 for acetic acid (probe horp193), respectively. These results indicate that peptide mimicking of binding domain on olfactory receptor opens a new window and offers a novel strategy for the further development of recognized materials for gas sensing.