Cross-Reactivity of Pantoprazole with Three Commercial Cannabinoids Immunoassays in Urine.

Pantoprazole is a frequently prescribed proton pump inhibitor (PPI) commonly utilized in the management of gastrointestinal symptoms. Few substances have proved to cause a false-positive cannabinoid urine screen. However, a case of false-positive urine cannabinoid screen in a patient who received a pantoprazole dose has been recently published. The purpose of this study was to determine the potential cross-reactivity of pantoprazole in the cannabinoid immunoassays: Alere Triage® TOX Drug Screen, KIMS® Cannabinoids II and DRI® Cannabinoids Assay. Drug-free urine to which pantoprazole was added up to 12,000 µg/mL produced negative results in the DRI® Cannabinoids and KIMS® Cannabinoids II. Alere Triage® TOX Drug Screen assay gave positive results at pantoprazole concentrations higher than 1,000 µg/mL. Urine samples from 8 pediatric patients were collected at the beginning of their pantoprazole treatment. Alere Triage® TOX Drug Screen assay produced positive test results in all patient samples and KIMS® Cannabinoids II immunoassay produced positive test results in one patient sample. None patient sample gave a false-positive result when analyzed by the DRI® Cannabinoids Assay. Our findings demonstrate that some cannabinoids immunoassays are susceptible to cross-reaction errors resulting from the presence in urine of pantoprazole and the resulting metabolism of the parent drug. Clinicians should be aware of the possibility of false-positive results for cannabinoids after a pantoprazole treatment.

Cross-reactivity of selected benzofurans with commercial amphetamine and ecstasy immunoassays in urine.

AIM: The aim of this study was to perform a cross-reactivity investigation of six benzofurans with immunoassays (IAs) screening tests for amphetamines and ecstasy in urine samples. METHODS: The following benzofuranes were investigated: 5-(2-Methylaminopropyl)Benzofuran (5-MAPB), 5-(2-methylaminopropyl)-2,3-dihydrobenzofuran (5-MAPDB), 5-(2-Aminopropyl)-Benzofuran (5-APB), 5-(2-Aminopropyl)-2,3-dihydrobenzofuran (5-APDB), 5-(2-Ethylaminopropyl)Benzofuran (5-EAPB) and 5-(2-Aminoethyl)-2,3-dihydrobenzofuran (5-AEDB). The study was performed with urine-free spiked samples and authentic urine samples using eight different IAs for amphetamines and ecstasy. Results: All evaluated benzofurans showed cross-reactivity in some of the IAs tested, except for 5-AEDB. Urine samples of an intoxication case involving 5-MAPB, 5-APB and 5-EAPB were also positives in the IAs tested. CONCLUSION: There is an important variability in the cross-reactivity of the IAs for amphetamine and ecstasy caused by benzofurans depending on the immunoassay employed and the tested compounds.

Cross-Reactivity of Chloroquine and Hydroxychloroquine With DRI Amphetamine Immunoassay.

BACKGROUND: Chloroquine and hydroxychloroquine are medical drugs used to treat the chemoprophylaxis of malaria and a second-line anti-inflammatory drug. METHODS: We performed a study of cross-reactivity of chloroquine and hydroxychloroquine in the DRI Amphetamine Assay inspired by a case report of a self-ingestion of chloroquine after a family dispute, that involved the following: (1) an in vitro study with control samples of healthy subjects, (2) an in vivo study with samples of patients with rheumatoid arthritis, and (3) an evaluation of the cross-reactivity of chloroquine and hydroxychloroquine in 3 additional immunoassays. RESULTS: In the case report, the Amphetamine DRI assay resulted positive both at 1000 ng/mL cutoff (1507 and 1137 ng/mL) and at 500 ng/mL cutoff (1178 and 642 ng/mL). Chloroquine urine levels were 103,900 and 100,900 ng/mL at 5 and 9 hours after ingestion. The results with control samples showed a positive cross-reactivity of chloroquine in the DRI Amphetamine Assay (approximately 0.74% and 0.89% at cutoff of 1000 and 500 ng/mL, respectively). Hydroxychloroquine did not cross-react with the DRI Amphetamine Assay up to 1,000,000 ng/mL. In patients treated with chloroquine or hydroxychloroquine, DRI Amphetamine did not produce false-positive results. The comparative assay study showed a positive cross-reactivity of chloroquine in the Emit II Plus Amphetamines Assay with control samples. CONCLUSIONS: Chloroquine can cause false-positive results in the DRI Amphetamine Assay when it is present at high concentrations. Hydroxychloroquine did not produce false-positive results neither in the DRI Amphetamine Assay nor in the others immunoassays evaluated.

Utilidad de la determinación de la subunidad alfa tras estímulo con TRH como indicador de persistencia y/o recurrencia tumoral en gonadotropinomas / Utility of alpha subunit determination alter thyrotropin-releasing hormone stimulation as an indicator of gonadotropinoma persistente and/or recurrence

Objetivo: Los gonadotropinomas son tumores originados en las células gonadotropas de la hipófisis anterior causales de la síntesis y la secreción de gonadotrofinas (folitropina [FSH] y lutropina [LH]). La mayoría de estos tumores tienen una producción alterada de gonadotropinas y de sus subunidades (folitropina beta, subunidad alfa y, con menos frecuencia, lutropina beta). Los gonadotropinomas pueden presentar una respuesta de la subunidad alfa de las gonadotropinas al estímulo con protirrelina (TRH) que podría diferenciar estos tumores de los no funcionantes. De igual forma, esta prueba podría ser de utilidad tras la cirugía para poderdiscernir los posibles restos tumorales respecto a los cambios posquirúrgicos. Sujetos y método: Se estudió a 24 pacientes intervenidos de macroadenoma hipofisario, de los que 14 fueron diagnosticados de gonadotropinoma en el estudio histológico. Se les practicó la prueba de lasubunidad alfa tras la administración de TRH antes y después de la cirugía.Resultados: En el estudio prequirúrgico el 50% de los gonadotropinomas tuvieron una respuesta positiva a dicha prueba y en el posquirúrgico otro 50%. El 83% de los pacientes con gonadotropinoma presentaban signos de recidiva/persistencia tumoral y/o cambios en laresonancia magnética (RM) de control posquirúrgico; el 83% de estos pacientes (41,6% del total) tuvo una respuesta positiva de la subunidad alfa tras el estímulo con TRH. En el grupo de macroadenomas no gonadotropinomas sólo un 33% tuvo respuesta positiva antes de la cirugía y otro 33%, después. En la RM practicada después de la cirugía, todos mostraban signos radiológicos compatibles con cambios inflamatorios posquirúrgicos o signos de persistencia y/o recidivatumoral. Conclusiones: Dicha prueba podría ser de ayuda en el diagnóstico diferencial de los gonadotropinomas, así como en el seguimiento y la valoración posquirúrgica de estos tumores (AU)

Objective: Gonadotropinomas are adenomas of the gonadotropic cells of the anterior pituitary. These cells produce and secrete gonadotropins (follicle-stimulating hormone and luteinizing hormone). Most of these tumors show altered production of gonadotropins and their subunits (the - FSH, and, less frequently, -LH subunits). The thyrotropin-releasing hormone (TRH) stimulation test could differentiate these tumors from nonfunctioning tumors. Equally, this test could be able to distinguish between postsurgical changes and tumoral remnants after surgery. Subjects and method: We studied 24 patients with pituitary macroadenoma, 14 of who had a histological diagnosis of gonadotroph adenoma. The TRH stimulation test was performed before and after surgery. Results: Both before and after surgery, a positive result to the TRH test was obtained in 50% of gonadotropinomas. Magnetic resonance imaging (MRI)performed after surgery revealed that 83% of the patients with gonadotropinoma had signs of tumoral persistence or recurrence and/or postsurgical changes. Of these patients, 83% (41.6% of the total) showed positive (..) (AU)

Utility of alpha subunit determination after thyrotropin-releasing hormone stimulation as an indicator of gonadotropinoma persistence and/or recurrence.

OBJECTIVE: Gonadotropinomas are adenomas of the gonadotropic cells of the anterior pituitary. These cells produce and secrete gonadotropins (follicle-stimulating hormone and luteinizing hormone). Most of these tumors show altered production of gonadotropins and their subunits (the p-FSH, a and, less frequently, p-LH subunits). The thyrotropin-releasing hormone (TRH) stimulation test could differentiate these tumors from nonfunctioning tumors. Equally, this test could be able to distinguish between postsurgical changes and tumoral remnants after surgery. SUBJECTS AND METHOD: We studied 24 patients with pituitary macroadenoma, 14 of who had a histological diagnosis of gonadotroph adenoma. The TRH stimulation test was performed before and after surgery. RESULTS: Both before and after surgery, a positive result to the TRH test was obtained in 50% of gonadotropinomas. Magnetic resonance imaging (MRI) performed after surgery revealed that 83% of the patients with gonadotropinoma had signs of tumoral persistence or recurrence and/or postsurgical changes. Of these patients, 83% (41.6% of the total) showed positive a subunit stimulation after the TRH test. In the group of non-gonadotropinoma macroadenomas, only 33% had a positive result before surgery and another 33% had a positive result after surgery. In the MRI performed after surgery, all showed tumoral persistence/recurrence or postsurgical inflammatory changes. CONCLUSIONS: This test could be useful in the differential diagnosis of gonadotropinomas as well as in the follow-upand postsurgical evaluation of these tumors.

Study in mono and bilayers of the interaction of hepatitis G virus (GBV-C/HGV) synthetic antigen E2(99-118) with cell membrane phospholipids.

The interaction of the hepatitis G synthetic peptide E2(99-118) with cell membrane phospholipids of different characteristics such as dipalmitoylphosphatidylcholine (DPPC) and dipalmitoylphosphatidylglycerol (DPPG) was studied by Langmuir isotherms. Epifluorescence microscopy and Atomic force microscopy (AFM) was also used to study interactions with DPPC. Compression isotherms of DPPC/E2(99-118) and DPPG/E2(99-118) mixed monolayers showed negative deviation from ideallity consistent with the existence of attractive interactions. The incorporation of the peptide in DPPC monolayer was also confirmed in epifluorescence microscopy and AFM studies. The peptide retarded the formation of DPPC domains and did not let the phospholipid get organized. No important differences in the interactions with DPPC (neutral) or DPPG (anionic) were found, thus suggesting that electrostatics forces do not have a predominant influence in these interactions.