RESUMEN
PURPOSE: To study the correlations of genetic variants of telbivudine phosphorylase kinases and telbivudine plasma concentration with creatine kinase elevation in chronic hepatitis B patients who received telbivudine. METHODS: An observational study was performed in China chronic hepatitis B patients receiving telbivudine therapy at 600 mg once daily. Plasma concentration was measured 12 h after taking telbivudine using ultra-performance liquid chromatography-tandem mass spectrometry and SNPs located in RRM2B, TK2, and NME4 was detected by MALDI-TOF mass spectrometry. All statistical analyses were performed with R 4.3.1 and all graphs were drawn by Origin 2023b and P value < 0.05 was considered statistically significant. RESULTS: A total of 140 patients receiving telbivudine therapy were recruited with a median plasma concentration of 952.49 (781.07-1238.98) ng/mL. The value of plasma concentration was proportional to the grade of creatine kinase elevation and the best telbivudine plasma concentration threshold to discriminate the grade 3/4 CK elevation was 1336.61 ng/mL. Multivariate analysis revealed that plasma concentration and rs3826160 were the independent risk factor of telbivudine-induced creatine kinase elevation. Patients with TC and CC genotype in rs3826160 not only had a higher incidence of creatine kinase elevation but also a higher plasma concentration than TT genotype carriers. CONCLUSION: Chronic hepatitis B patients with TC and CC genotype in rs3826160 have high telbivudine plasma concentration are at risk of elevated creatine kinase.
Asunto(s)
Antivirales , Creatina Quinasa , Hepatitis B Crónica , Polimorfismo de Nucleótido Simple , Telbivudina , Humanos , Telbivudina/uso terapéutico , Hepatitis B Crónica/tratamiento farmacológico , Hepatitis B Crónica/sangre , Hepatitis B Crónica/genética , Femenino , Masculino , Adulto , Antivirales/uso terapéutico , Antivirales/farmacocinética , Antivirales/sangre , Persona de Mediana Edad , Creatina Quinasa/sangre , Timidina Fosforilasa/genética , Timidina/análogos & derivados , Timidina/uso terapéutico , Timidina/farmacocinética , Timidina QuinasaRESUMEN
Despite the tremendous advancements made in cell tracking, in vivo imaging and volumetric analysis, it remains difficult to accurately quantify the number of infused cells following stem cell therapy, especially at the single cell level, mainly due to the sensitivity of cells. In this study, we demonstrate the utility of both liquid scintillator counter (LSC) and accelerator mass spectrometry (AMS) in investigating the distribution and quantification of radioisotope labeled adipocyte derived mesenchymal stem cells (AD-MSCs) at the single cell level after intravenous (IV) transplantation. We first show the incorporation of 14C-thymidine (5 nCi/ml, 24.2 ng/ml) into AD-MSCs without affecting key biological characteristics. These cells were then utilized to track and quantify the distribution of AD-MSCs delivered through the tail vein by AMS, revealing the number of AD-MSCs existing within different organs per mg and per organ at different time points. Notably, the results show that this highly sensitive approach can quantify one cell per mg which effectively means that AD-MSCs can be detected in various tissues at the single cell level. While the significance of these cells is yet to be elucidated, we show that it is possible to accurately depict the pattern of distribution and quantify AD-MSCs in living tissue. This approach can serve to incrementally build profiles of biodistribution for stem cells such as MSCs which is essential for both research and therapeutic purposes.
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Radioisótopos de Carbono , Rastreo Celular , Espectrometría de Masas , Células Madre Mesenquimatosas/metabolismo , Radiofármacos , Timidina , Animales , Radioisótopos de Carbono/farmacocinética , Radioisótopos de Carbono/farmacología , Xenoinjertos , Humanos , Masculino , Trasplante de Células Madre Mesenquimatosas , Ratones , Ratones Endogámicos BALB C , Ratones Desnudos , Radiofármacos/farmacocinética , Radiofármacos/farmacología , Timidina/farmacocinética , Timidina/farmacologíaRESUMEN
The gut microbiota metabolizes drugs and alters their efficacy and toxicity. Diet alters drugs, the metabolism of the microbiota, and the host. However, whether diet-triggered metabolic changes in the microbiota can alter drug responses in the host has been largely unexplored. Here we show that dietary thymidine and serine enhance 5-fluoro 2'deoxyuridine (FUdR) toxicity in C. elegans through different microbial mechanisms. Thymidine promotes microbial conversion of the prodrug FUdR into toxic 5-fluorouridine-5'-monophosphate (FUMP), leading to enhanced host death associated with mitochondrial RNA and DNA depletion, and lethal activation of autophagy. By contrast, serine does not alter FUdR metabolism. Instead, serine alters E. coli's 1C-metabolism, reduces the provision of nucleotides to the host, and exacerbates DNA toxicity and host death without mitochondrial RNA or DNA depletion; moreover, autophagy promotes survival in this condition. This work implies that diet-microbe interactions can alter the host response to drugs without altering the drug or the host.
Asunto(s)
Caenorhabditis elegans/efectos de los fármacos , Floxuridina/toxicidad , Interacciones Alimento-Droga , Microbioma Gastrointestinal/efectos de los fármacos , Serina/farmacología , Animales , Caenorhabditis elegans/microbiología , Caenorhabditis elegans/fisiología , Suplementos Dietéticos , Escherichia coli/efectos de los fármacos , Escherichia coli/metabolismo , Floxuridina/farmacocinética , Ácido Fólico/metabolismo , Microbioma Gastrointestinal/fisiología , Timidina/análogos & derivados , Timidina/metabolismo , Timidina/farmacocinética , Timidina/farmacología , Nucleótidos de Uracilo/metabolismo , Nucleótidos de Uracilo/farmacocinéticaRESUMEN
PURPOSE: In oncology, positron emission tomography imaging using dedicated tracers as biomarkers may assist in early evaluation of therapy efficacy. Using 3'-deoxy-3'-[18F]fluorothymidine ([18F]FLT), we investigated the early effects of chemotherapeutic treatment on cancer cell proliferation in a BRAF-mutated colorectal cancer xenograft model. PROCEDURES: Colo205 subcutaneously inoculated animals underwent 90-min dynamic imaging before and 24 h after treatment with vehicle (control), cetuximab (resistant) or irinotecan (sensitive). Total distribution volume was quantified from dynamic data, and standardized uptake values as well as tumor-to-blood ratios were calculated from static images averaged over the last 20 min. In vivo imaging data was correlated with ex vivo proliferation and thymidine metabolism proteins. RESULTS: All imaging parameters showed a significant post-treatment decrease from [18F]FLT baseline uptake for the irinotecan group (p ≤ 0.001) as compared with the cetuximab and vehicle group and correlated strongly with each other (p ≤ 0.0001). In vivo data were in agreement with Ki67 staining, showing a significantly lower percentage of Ki67-positive cells in the irinotecan group as compared with other groups (p ≤ 0.0001). Tumor expression of thymidine kinase 1 phosphorylated on serine 13, thymidylate synthase, and thymidine phosphorylase remained unaffected, while thymidine kinase 1 expression was, surprisingly, significantly higher in irinotecan-treated animals (p ≤ 0.01). In contrast, tumor ATP levels were lowest in this group. CONCLUSIONS: [18F]FLT positron emission tomography was found to be a suitable biomarker of early tumor response to anti-proliferative treatment, with static imaging not being inferior to full compartmental analysis in our xenograft model. The dynamics of thymidine kinase 1 protein expression and protein activity in low ATP environments merits further investigation.
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Biomarcadores de Tumor/metabolismo , Neoplasias Colorrectales/tratamiento farmacológico , Neoplasias Colorrectales/metabolismo , Didesoxinucleósidos/química , Timidina/química , Adenosina Trifosfato/metabolismo , Animales , Línea Celular Tumoral , Didesoxinucleósidos/farmacocinética , Modelos Animales de Enfermedad , Femenino , Inmunohistoquímica , Cinética , Ratones Desnudos , Reproducibilidad de los Resultados , Timidina/farmacocinética , Timidina Quinasa/metabolismoRESUMEN
BACKGROUND AND AIMS: Hepatitis B virus (HBV) covalently closed circular DNA (cccDNA), a mini-chromosome essential for HBV replication, is supposed to be resistant to nucleos(t)ide analogue treatment. We investigated the effect of long-term nucleos(t)ide analogue treatment on cccDNA. METHODS: Among 129 patients who had been enrolled in previous international nucleos(t)ide analogue clinical trials and had liver biopsies at baseline and one year after treatment, we recruited 43 patients on long-term continuous treatment for 72 to 145months for a third liver biopsy. Serum HBV DNA, hepatitis B surface antigen (HBsAg) levels, total intrahepatic HBV DNA (ihHBV DNA), cccDNA, HBV pregenomic RNA (pgRNA) as well as histologic changes were examined. RESULTS: At the time of the third biopsy, serum HBV DNA levels were undetectable in all but one patient. The median levels of HBsAg, ihHBV DNA, and cccDNA were 2.88logIU/ml, 0.03copies/cell, and 0.01copies/cell, respectively. Compared to baseline levels, there was reduction of HBsAg levels by 0.54log (71.46%), ihHBV DNA levels by 2.81log (99.84%), and cccDNA levels by 2.94log (99.89%), with 49% having cccDNA levels below the detection limit. One patient had undetectable HBsAg. The median pgRNA level, measured only in the third biopsy, was 0.021copies/cell, with 40% of patients having undetectable pgRNA. CONCLUSIONS: Long-term nucleos(t)ide analogue treatment induced marked depletion of cccDNA in the majority of patients while serum HBsAg levels, though reduced, were detectable in all but one patient. Whether cccDNA depletion is sustained and associated with better patient outcome requires further study. LAY SUMMARY: It is generally presumed that a form of hepatitis B virus DNA, called covalently closed circular DNA (cccDNA), which hides inside the nuclei of liver cells of patients with chronic hepatitis B, cannot be reduced by antiviral treatment. The present study showed that with prolonged treatment (median period 126months), cccDNA can be markedly reduced, with 49% of liver biopsies having undetectable cccDNA. This suggests that viral replication capacity would be very low after prolonged antiviral treatment.
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Antivirales , Virus de la Hepatitis B , Hepatitis B Crónica , Hígado , Adenina/administración & dosificación , Adenina/análogos & derivados , Adenina/farmacocinética , Antivirales/administración & dosificación , Antivirales/farmacocinética , Biopsia/métodos , ADN Circular/análisis , ADN Viral/sangre , Femenino , Virus de la Hepatitis B/efectos de los fármacos , Virus de la Hepatitis B/genética , Hepatitis B Crónica/tratamiento farmacológico , Hepatitis B Crónica/virología , Humanos , Lamivudine/administración & dosificación , Lamivudine/farmacocinética , Hígado/patología , Hígado/virología , Masculino , Persona de Mediana Edad , Nucleósidos/farmacología , Organofosfonatos/administración & dosificación , Organofosfonatos/farmacocinética , Evaluación de Resultado en la Atención de Salud , Telbivudina , Timidina/administración & dosificación , Timidina/análogos & derivados , Timidina/farmacocinética , Tiempo , Replicación Viral/efectos de los fármacosRESUMEN
A scintillation image of tritium fixed in a melt-on scintillator was obtained using a charged-coupled device (CCD) imager, and a linear relationship was observed between the intensity of the scintillation image and the radioactivity of tritium. In a [3H]thymidine uptake experiment, a linear correlation between the intensity of the CCD image and the dilution ratio of cells was confirmed. Scintillation imaging has the potential for use in direct observation of tritium radioactivity distribution.
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Radiofármacos/farmacocinética , Conteo por Cintilación/instrumentación , Timidina/farmacocinética , Tritio/farmacocinética , Animales , Partículas beta , Células PC12 , Ratas , Conteo por Cintilación/métodosRESUMEN
PURPOSE: 4'-[Methyl-(11)C]-thiothymidine (4DST) has been developed as an in vivo cell proliferation marker based on its DNA incorporation mechanism. This study evaluated the potential of 4DST PET/CT for imaging cellular proliferation in advanced clear cell renal cell carcinoma (RCC), compared with FDG PET/CT. Both 4DST and FDG uptake were compared with biological findings based on surgical pathology. METHODS: Five patients (3 men and 2 women; mean (±SD) age 64.8 ± 11.0 years) with a single RCC (mean diameter: 9.3 ± 3.2 cm) were examined by PET/CT using 4DST and FDG. The dynamic emission scan of 4DST for RCC over 35 min followed by a static emission scan of the body for 4DST and FDG. Then we compared the maximum standardized uptake value (SUVmax) of 20 areas of RCC on both 4DST and FDG images with (1) the Ki-67 index of cellular proliferation (2) Fuhrman grade system for nuclear grade (G) in RCC and (3) pathological phosphorylated grade of mammalian target of rapamycin (pmTOR). RESULTS: All patient cases showed clear uptake of FDG and 4DST in RCC tumors, with mean 4DST SUVmax of 7.3 ± 2.2 (range 4.3-9.4) and mean FDG SUVmax of 6.0 ± 2.8 (range 3.4-10.4). The correlation coefficient between SUVmax and Ki-67 index was higher with 4DST (r = 0.61) than with FDG (r = 0.43). Tumor 4DST uptake (G0: 1.4, G2: 2.6, G2 5.6, G4: 5.7) and tumor FDG uptake (G0: 1.8, G2: 2.9, G2 3.7, G4: 4.1) were both related to Fuhrman grade system. The 4DST uptake increased as the pmTOR grade increases (G0: 3.1, G1: 4.8, G2: 4.7, G3: 6.2); in contrast FDG uptake was unrelated to pmTOR grade (G0: 2.8, G2: 4.0, G2 3.3, G4: 3.6). CONCLUSION: A higher correlation with the proliferation of RCC was observed for 4DST than for FDG. The 4DST uptake exhibits the possibility to predict pmTOR grade, indicating that 4DST has potential for the evaluation of therapeutic effect with mTOR inhibitor in patients with RCC.
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Radioisótopos de Carbono/farmacocinética , Carcinoma de Células Renales/diagnóstico por imagen , Fluorodesoxiglucosa F18/farmacocinética , Neoplasias Renales/diagnóstico por imagen , Tomografía Computarizada por Tomografía de Emisión de Positrones , Timidina/farmacocinética , Anciano , Femenino , Humanos , Masculino , Persona de Mediana Edad , Radiofármacos/farmacocinéticaRESUMEN
BACKGROUND: Current approved nucleoside therapies for genital herpes simplex virus (HSV) infections are effective but improved therapies are needed for treatment of both acute and recurrent diseases. METHODS: The effects of N-methanocarbathymidine were evaluated and compared to acyclovir using guinea pig models of acute and recurrent infection. For acute disease following intravaginal inoculation of 10(6 )pfu HSV-2 (MS strain), animals were treated intraperitoneally beginning 24 h post-infection, and the effects on disease severity, vaginal virus replication, subsequent recurrences, and latent virus loads were evaluated. For evaluation of recurrent infection, animals were treated for 21 days beginning 14 days after infection and disease recurrence and recurrent shedding were evaluated. RESULTS: Treatment of the acute disease with N-methanocarbathymidine significantly reduced the severity of acute disease and decreased acute vaginal virus shedding more effectively than acyclovir. Significantly, none of the animals developed visible disease in the high-dose N-methanocarbathymidine group and this was the only group in which the number of days with recurrent virus shedding was reduced. Treatment of recurrent disease was equivalent to acyclovir when acyclovir was continuously supplied in the drinking water. CONCLUSION: N-methanocarbathymidine was effective as therapy for acute and recurrent genital HSV-2 disease in the guinea pig models.
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Antivirales/farmacología , Herpes Genital/tratamiento farmacológico , Herpes Genital/virología , Herpesvirus Humano 2/efectos de los fármacos , Herpesvirus Humano 2/fisiología , Timidina/análogos & derivados , Esparcimiento de Virus/efectos de los fármacos , Enfermedad Aguda , Animales , Antivirales/farmacocinética , Antivirales/uso terapéutico , Modelos Animales de Enfermedad , Femenino , Cobayas , Recurrencia , Timidina/farmacocinética , Timidina/farmacología , Timidina/uso terapéuticoRESUMEN
BACKGROUND: In order to shed light on the regenerative mechanism of mesenchymal stem cells (MSCs) in vivo, the bio-distribution profile of implanted cells using a stable and long-term tracking method is needed. We herein investigated the bio-distribution of human placental deciduas basalis derived MSCs (termed as PDB-MSCs) in nude mice after intravenous injection by carbon radioisotope labeling thymidine ((14)C-TdR), which is able to incorporate into new DNA strands during cell replication. RESULTS: The proliferation rate and radioactive emission of human PDB-MSCs after labeled with different concentrations of (14)C-TdR were measured. PDB-MSCs labeled with 1 µCi possessed high radioactivity, and the biological characteristics (i.e. morphology, colony forming ability, differentiation capabilities, karyotype and cell cycle) showed no significant changes after labeling. Thus, 1 µCi was the optimal concentration in this experimental design. In nude mice, 1 × 10(6) (14)C-TdR-labeled PDB-MSCs were injected intravenously and the organs were collected at days 1, 2, 3, 5, 30 and 180 after injection, respectively. Radiolabeled PDB-MSCs were found mainly in the lung, liver, spleen, stomach and left femur of the recipient nude mice at the whole observation period. CONCLUSIONS: This work provided solid evidence that (14)C-TdR labeling did not alter the biological characteristics of human placental MSCs, and that this labeling method has potential to decrease the signal from non-infused or dead cells for cell tracking. Therefore, this labeling technique can be utilized to quantify the infused cells after long-term follow-up in pre-clinical studies.
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Radioisótopos de Carbono/farmacocinética , Rastreo Celular/métodos , Células Madre Mesenquimatosas/química , Células Madre Mesenquimatosas/citología , Placenta/citología , Timidina/farmacocinética , Animales , Radioisótopos de Carbono/química , Femenino , Humanos , Células Madre Mesenquimatosas/metabolismo , Ratones , Ratones Desnudos , Embarazo , Timidina/química , Distribución TisularRESUMEN
BACKGROUND & AIMS: This study investigated the antiviral efficacy and safety of telbivudine in combination with pegylated interferon (PegIFN) alpha-2a in chronic hepatitis B (CHB) patients. METHODS: This was a randomized, open-label, multicentre study, in treatment-naïve patients with HBeAg-positive CHB, comparing the efficacy and safety of telbivudine in combination with PegIFN alpha-2a with telbivudine monotherapy and PegIFN alpha-2a monotherapy. The study was terminated early due to increased rates of peripheral neuropathy in the combination-therapy group. RESULTS: Of the 159 patients randomized (from 300 planned) 50 were assigned to combination therapy, 55 to telbivudine, 54 to PegIFN, and 110 (18, 49, and 43, respectively) reached week 24. Peripheral neuropathy occurred in 7/50, 1/54, and 0/54 patients in the three groups of safety populations, respectively. No relationship between the occurrence of peripheral neuropathy and other variables (e.g., pharmacokinetic data, treatment efficacy, ALT levels, creatine kinase elevations) were observed. At week 24, undetectable HBV DNA (<300 copies/ml) was achieved by 71% (12/17), 35% (17/48), and 7% (3/42) of patients, with available data receiving combination therapy, telbivudine monotherapy and PegIFN monotherapy, respectively (p = 0.022 for combination therapy vs. telbivudine; p<0.0001 for combination therapy vs. PegIFN). CONCLUSIONS: Combination therapy carried an increased risk of peripheral neuropathy. Despite the rapid and profound reductions in HBV DNA levels, combination therapy with telbivudine and PegIFN should not be used.
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Hepatitis B Crónica/tratamiento farmacológico , Interferón-alfa/efectos adversos , Enfermedades del Sistema Nervioso Periférico/etiología , Polietilenglicoles/efectos adversos , Timidina/análogos & derivados , Adulto , Antivirales/efectos adversos , Antivirales/farmacocinética , ADN Viral/análisis , Portadores de Fármacos , Quimioterapia Combinada , Femenino , Salud Global , Antígenos e de la Hepatitis B/inmunología , Virus de la Hepatitis B/genética , Virus de la Hepatitis B/inmunología , Hepatitis B Crónica/metabolismo , Hepatitis B Crónica/virología , Humanos , Incidencia , Interferón-alfa/farmacocinética , Masculino , Enfermedades del Sistema Nervioso Periférico/diagnóstico , Enfermedades del Sistema Nervioso Periférico/epidemiología , Polietilenglicoles/farmacocinética , Proteínas Recombinantes/efectos adversos , Proteínas Recombinantes/farmacocinética , Telbivudina , Timidina/efectos adversos , Timidina/farmacocinéticaRESUMEN
BACKGROUND: During cerebral inflammation uracil nucleotides leak to the extracellular medium and activate glial pyrimidine receptors contributing to the development of a reactive phenotype. Chronically activated microglia acquire an anti-inflammatory phenotype that favors neuronal differentiation, but the impact of these microglia on astrogliosis is unknown. We investigated the contribution of pyrimidine receptors to microglia-astrocyte signaling in a chronic model of inflammation and its impact on astrogliosis. METHODS: Co-cultures of astrocytes and microglia were chronically treated with lipopolysaccharide (LPS) and incubated with uracil nucleotides for 48 h. The effect of nucleotides was evaluated in methyl-[3H]-thymidine incorporation. Western blot and immunofluorescence was performed to detect the expression of P2Y6 receptors and the inducible form of nitric oxide synthase (iNOS). Nitric oxide (NO) release was quantified through Griess reaction. Cell death was also investigated by the LDH assay and by the TUNEL assay or Hoechst 33258 staining. RESULTS: UTP, UDP (0.001 to 1 mM) or PSB 0474 (0.01 to 10 µM) inhibited cell proliferation up to 43 ± 2% (n = 10, P <0.05), an effect prevented by the selective P2Y6 receptor antagonist MRS 2578 (1 µM). UTP was rapidly metabolized into UDP, which had a longer half-life. The inhibitory effect of UDP (1 mM) was abolished by phospholipase C (PLC), protein kinase C (PKC) and nitric oxide synthase (NOS) inhibitors. Both UDP (1 mM) and PSB 0474 (10 µM) increased NO release up to 199 ± 20% (n = 4, P <0.05), an effect dependent on P2Y6 receptors-PLC-PKC pathway activation, indicating that this pathway mediates NO release. Western blot and immunocytochemistry analysis indicated that P2Y6 receptors were expressed in the cultures being mainly localized in microglia. Moreover, the expression of iNOS was mainly observed in microglia and was upregulated by UDP (1 mM) or PSB 0474 (10 µM). UDP-mediated NO release induced apoptosis in astrocytes, but not in microglia. CONCLUSIONS: In LPS treated co-cultures of astrocytes and microglia, UTP is rapidly converted into UDP, which activates P2Y6 receptors inducing the release of NO by microglia that causes astrocyte apoptosis, thus controlling their rate of proliferation and preventing an excessive astrogliosis.
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Apoptosis/fisiología , Astrocitos/fisiología , Microglía/metabolismo , Óxido Nítrico/metabolismo , Receptores Purinérgicos P2/metabolismo , Animales , Animales Recién Nacidos , Apoptosis/efectos de los fármacos , Astrocitos/efectos de los fármacos , Ciclo Celular/efectos de los fármacos , Proliferación Celular/efectos de los fármacos , Células Cultivadas , Técnicas de Cocultivo , Inhibidores Enzimáticos/farmacología , Regulación de la Expresión Génica/efectos de los fármacos , Proteína Ácida Fibrilar de la Glía/metabolismo , Lipopolisacáridos/farmacología , Microglía/efectos de los fármacos , Ratas , Ratas Wistar , Timidina/farmacocinética , Factores de Tiempo , Tritio/farmacocinética , Nucleótidos de Uracilo/metabolismo , Nucleótidos de Uracilo/farmacologíaRESUMEN
The objectives of this study were to evaluate the safety, tolerability and pharmacokinetics (PK) of BMS-986001 as a single oral dose in healthy male subjects. Sixty-four healthy male subjects were randomized to receive a single dose of BMS-986001 or placebo in this single-blind, placebo-controlled, sequential ascending-dose study. There were eight treatment groups (10, 30, 100, 300, 600, and 900 mg fed; and 100 and 300 mg fasted) of eight subjects each (BMS-986001 n = 6/placebo n = 2). BMS-986001 was well tolerated, with no serious adverse events (AEs), deaths, or discontinuations due to AEs reported. AEs were experienced by 14.6% of subjects receiving BMS-986001; however, these did not appear to be dose related and were not considered to be related to study drug. BMS-986001 was rapidly absorbed and exhibited a linear dose-exposure relationship across the dose range studied. PK appeared similar whether administered with or without food. Administration of BMS-986001 as a single dose was generally safe and well tolerated. A linear dose-exposure relationship was seen across all doses studied, with no apparent food effect. Further clinical development is warranted.
Asunto(s)
Fármacos Anti-VIH/farmacocinética , Interacciones Alimento-Droga , Inhibidores de la Transcriptasa Inversa/farmacocinética , Timidina/análogos & derivados , Adulto , Fármacos Anti-VIH/efectos adversos , Fármacos Anti-VIH/sangre , Fármacos Anti-VIH/orina , Relación Dosis-Respuesta a Droga , Ayuno/metabolismo , Voluntarios Sanos , Humanos , Masculino , Persona de Mediana Edad , Inhibidores de la Transcriptasa Inversa/efectos adversos , Inhibidores de la Transcriptasa Inversa/sangre , Inhibidores de la Transcriptasa Inversa/orina , Método Simple Ciego , Timidina/efectos adversos , Timidina/sangre , Timidina/farmacocinética , Timidina/orina , Adulto JovenRESUMEN
Telbivudine is a nucleoside analogue that has been approved for the treatment of chronic hepatitis B virus (HBV) infection in adults at 600 mg/day. We conducted a phase I, open-label, first-in-pediatrics study to investigate the safety and pharmacokinetics of a single dose of telbivudine in HBV-infected children and adolescents. Eligible patients were enrolled sequentially from older to younger groups, with evaluation of safety and available pharmacokinetic data after each stratum. Adolescent patients (>12 to 18 years) received a single dose of 600 mg telbivudine as an oral solution, while children aged 2 to 12 years received a single dose of 15 or 25 mg/kg of body weight up to a maximum of 600 mg. Telbivudine was well tolerated; all adverse events were mild, and none occurred in more than one patient. The plasma telbivudine concentration-versus-time profiles in adolescents given 600 mg were similar to the mean profile of healthy adults receiving the same oral dose. Children aged 2 to <6 and 6 to 12 years receiving a single 15-mg/kg dose showed similar plasma exposures. To predict the steady-state exposure, plasma concentration-versus-time profiles for patients aged 2 to 12 years (15 mg/kg) and >12 to 18 years (600 mg) were fitted to a two-compartment 1st-order, microconstant, lag time, 1st-order elimination pharmacokinetic (PK) model. This analysis predicted the following dosages to mimic exposures in healthy adults receiving 600 mg/day: 20 mg/kg/day for children 2 to 12 years and 600 mg/day for adolescents. Studies are ongoing to evaluate the efficacy of the recommended dose in pediatric patients. (This study has been registered at ClinicalTrials.gov under registration no. NCT00907894.).
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Antivirales/farmacocinética , Hepatitis B Crónica/tratamiento farmacológico , Timidina/análogos & derivados , Administración Oral , Adolescente , Adulto , Antivirales/sangre , Antivirales/uso terapéutico , Niño , Preescolar , Esquema de Medicación , Cálculo de Dosificación de Drogas , Femenino , Hepatitis B Crónica/sangre , Hepatitis B Crónica/virología , Humanos , Masculino , Telbivudina , Timidina/sangre , Timidina/farmacocinética , Timidina/uso terapéuticoRESUMEN
OBJECTIVE: To investigate the safety, tolerability, pharmacokinetics, and antiviral activity of BMS-986001 (a nucleoside reverse transcriptase inhibitor) in treatment-experienced, HIV-1-infected subjects not exposed to antiretroviral treatment in the previous 3 months. METHODS: Thirty-two HIV-1-infected subjects were randomized (3:1) to receive BMS-986001 or placebo once daily for 10 days in this double-blind, placebo-controlled, dose-escalating monotherapy phase IIa study. There were 4 treatment groups (100, 200, 300, and 600 mg, all once daily) of 8 subjects each (BMS-986001, n = 6/placebo n = 2). RESULTS: BMS-986001 was generally well tolerated, with no discontinuations due to adverse events and no deaths occurring. Adverse events were experienced by 22 of 24 BMS-986001-treated subjects and did not seem to be dose related. The majority were mild and considered unrelated or unlikely to be related to the study drug. The pharmacokinetics of BMS-986001 were dose proportional. Median decrease in plasma HIV-1 RNA from baseline to day 11 was 0.97, 1.15, 1.28, and 1.15 log10 copies/mL for BMS-986001 at 100, 200, 300, and 600 mg, respectively. Plasma area under the curve correlated with the antiviral activity of BMS-986001, indicating that area under the curves produced by 100-600 mg doses were on the upper end of the exposure-response curve. One subject with a single thymidine analog mutation at baseline responded well to BMS-986001. CONCLUSIONS: Administration of BMS-986001 for 10 days resulted in substantial decreases in plasma HIV-1 RNA levels for all dose groups and was generally well tolerated. These data support continued clinical development of BMS-986001 at a dose of 100 mg, once daily or greater. TRIAL REGISTRATION: EUDRACT Number 2008-004810-29.
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Fármacos Anti-VIH/uso terapéutico , Infecciones por VIH/tratamiento farmacológico , VIH-1/efectos de los fármacos , Inhibidores de la Transcriptasa Inversa/uso terapéutico , Timidina/análogos & derivados , Adolescente , Adulto , Fármacos Anti-VIH/efectos adversos , Fármacos Anti-VIH/farmacocinética , Recuento de Linfocito CD4 , Relación Dosis-Respuesta a Droga , Esquema de Medicación , Femenino , Infecciones por VIH/virología , Humanos , Masculino , Persona de Mediana Edad , Placebos , ARN Viral/sangre , Inhibidores de la Transcriptasa Inversa/efectos adversos , Inhibidores de la Transcriptasa Inversa/farmacocinética , Timidina/efectos adversos , Timidina/farmacocinética , Timidina/uso terapéutico , Carga Viral/efectos de los fármacos , Adulto JovenRESUMEN
The nucleoside analogue 4-thiothymidine has shown great potential in vitro as a photosensitiser for the photodynamic therapy of numerous cancer cell lines. However, the limited penetrating power of UV-A radiation, to which it responds, raises doubts as to its practical usefulness in clinical applications. We addressed this issue by studying the penetration extent of topical thiothymidine and the antiproliferative effect of its combination with UV-A radiation on ex vivo basal cell carcinoma (BCC) and squamous cell carcinoma (SCC) skin cancer biopsies, and normal skin. Our results show that both the intralesional concentration of the drug and the intensity of UV-A radiation are sufficient to activate the molecule and cause extensive death by apoptosis of the malignant cells. Normal skin biopsies were not significantly affected by the treatment.
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Carcinoma Basocelular/tratamiento farmacológico , Carcinoma de Células Escamosas/tratamiento farmacológico , Fotoquimioterapia , Fármacos Fotosensibilizantes/uso terapéutico , Neoplasias Cutáneas/tratamiento farmacológico , Timidina/análogos & derivados , Apoptosis , Biopsia , Carcinoma Basocelular/metabolismo , Carcinoma Basocelular/patología , Carcinoma de Células Escamosas/metabolismo , Carcinoma de Células Escamosas/patología , Línea Celular Tumoral , Humanos , Fármacos Fotosensibilizantes/farmacocinética , Piel/metabolismo , Piel/patología , Absorción Cutánea , Neoplasias Cutáneas/metabolismo , Neoplasias Cutáneas/patología , Timidina/farmacocinética , Timidina/uso terapéutico , Rayos UltravioletaRESUMEN
Two kinds of novel thymidine derivatives, N-thymidine-yl-N'-methyl-N'-{N''-[2-sulfanyl-(ethylamino)acetyl]-2-aminoethylsulfanyl-1-hexanamide}-ethanediamine (TMHEA) and N-thymidine-yl-N'-methyl-N'-{N''-[2-sulfanyl-(ethylamino)acetyl]-2-aminoethylsulfanyl-1-hexanamide}-hexanediamine (TMHHA) were prepared and successfully labeled with (99m)Tc in high labeling yields. The in vitro stability and in vivo biodistribution of (99m)Tc-TMHEA and (99m)Tc-TMHHA were investigated and compared. The biodistribution studies indicate that the radiotracer (99m)Tc-TMHEA displays selective tumor uptake, suggesting it is a potential tumor imaging agent.
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Diagnóstico por Imagen , Neoplasias/diagnóstico , Coloración y Etiquetado , Tecnecio/farmacocinética , Timidina/análogos & derivados , 1-Octanol/química , Animales , Ratones , Ratones Endogámicos ICR , Tecnecio/sangre , Tecnecio/química , Timidina/química , Timidina/farmacocinética , Distribución Tisular , Pruebas de Toxicidad , Agua/químicaRESUMEN
UNLABELLED: The effect of an anti-human leukocyte antigen-DR (MHC class II) humanized monoclonal antibody, IMMU-114, against the human to bovine cellular response was investigated. METHODS: Human peripheral mononuclear cells (PBMCs) were cocultured with inactivated self-PBMCs (Self), bovine PBMCs with control antibody (Xeno), or bovine PBMCs with IMMU-114 (IMMU-114). Cellular responses were investigated by thymidine incorporation assay, CFSE (carboxyfluorescein diacetate succinimidyl ester)-mixed lymphocyte reaction, and cytokine production in culture medium. RESULTS: Thymidine incorporation rates at a 1:1 responder to stimulator ratio for Xeno + control antibody, Xeno + IMMU-114, Self + control antibody, and Self + IMMU-114 were 14201.3 ± 1968.4, 513.0 ± 49.5, 952.7 ± 128.7, and 423.3 ± 138.8 cpm, respectively (P = 0.032). Those at a 1:2 ratio were 6518.0 ± 690.1, 896.6 ± 92.9, 1051.0 ± 123.6, and 736.0 ± 35.6 cpm, respectively (P = 0.036). CFSE-mixed lymphocyte reaction demonstrated that the frequencies of CFSE-low, CD4(+), and CD25(+) activating T cells in Self, Xeno, and IMMU-114 were 0.27 ± 0.04%, 3.65 ± 0.53%, and 1.23 ± 0.15%, respectively (P = 0.027). Cytokine production in culture medium indicated that IMMU-114 decreased Th1-type cytokines, including interleukin-2, interferon-γ, and tumor necrosis factor-α. CONCLUSION: IMMU-114 effectively suppresses human to bovine cellular responses. The mechanism involves direct inhibition of the interaction between class II human leukocyte antigen-DR-positive cells and CD4(+) T cells, and indirect suppression of Th1 cytokine production.
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Anticuerpos Monoclonales Humanizados/inmunología , Antígenos HLA-DR/inmunología , Leucocitos Mononucleares/inmunología , Trasplante Heterólogo/inmunología , Animales , Anticuerpos Heterófilos/inmunología , Anticuerpos Monoclonales Humanizados/farmacología , Antígenos Heterófilos/inmunología , Linfocitos T CD4-Positivos/citología , Linfocitos T CD4-Positivos/inmunología , Linfocitos T CD4-Positivos/metabolismo , Bovinos , Células Cultivadas , Técnicas de Cocultivo , Citocinas/inmunología , Citocinas/metabolismo , Antígenos de Histocompatibilidad Clase II/inmunología , Humanos , Terapia de Inmunosupresión/métodos , Leucocitos Mononucleares/citología , Leucocitos Mononucleares/metabolismo , Timidina/farmacocinéticaRESUMEN
UNLABELLED: 4'-[methyl-(11)C]thiothymidine ((11)C-4DST) is a novel radiopharmaceutical that can be used for tumor imaging because of its rapid incorporation into DNA as a substrate for DNA synthesis. The in vivo stability of (11)C-4DST is much greater than that of natural thymidine, because of the presence of a sulfur atom in the 4'-position. Here, we evaluated the tissue kinetics and biodistribution of (11)C-4DST in a rodent tumor and acute sterile inflammation model in comparison with the previously published biodistribution data of 3'-deoxy-3'-(18)F-fluorothymidine ((18)F-FLT), (18)F-FDG, (11)C-choline, (11)C-methionine, and 2 σ-receptor ligands in the same animal model. METHODS: C6 tumor cells were implanted subcutaneously into the right shoulder and turpentine (0.1 mL) was injected intramuscularly into the left hind leg of male Wistar rats 11 d and 24 h, respectively, before the scanning day. The animals were anesthetized with isoflurane, and (11)C-4DST (20-50 MBq) was injected intravenously. A dynamic PET scan was performed for 60 min with either the shoulder or hind leg region in the field of view. The animals were sacrificed, and a biodistribution study was performed. RESULTS: (11)C-4DST showed the highest tumor uptake (standardized uptake value, 4.93) of all radiopharmaceuticals tested. Its tumor-to-muscle concentration ratio (12.7) was similar to that of (18)F-FDG (13.2). The selectivity of (11)C-4DST for tumor as compared with acute inflammation was high (37.7), comparable to that of the σ-ligand (18)F-FE-SA5845 and much higher than that of (18)F-FDG (3.5). Rapidly proliferating tissues (tumor and bone marrow) showed a steadily increasing uptake. In inflamed muscle, (11)C-4DST showed relatively rapid washout, and tracer concentrations in inflamed and noninflamed muscle were not significantly different at intervals greater than 40 min. Competition of endogenous thymidine for (11)C-4DST uptake in target tissues was negligible, in contrast to competition for (18)F-FLT uptake. Thus, pretreatment of animals with thymidine phosphorylase was not required before PET with (11)C-4DST. CONCLUSION: In our rodent model, (11)C-4DST showed high tumor uptake (sensitivity) and high tumor selectivity. The different kinetics of (11)C-4DST in rapidly proliferating and inflammatory tissue may allow distinction between tumor and acute inflammation in a clinical setting. These promising results for (11)C-4DST warrant further investigation in PET studies in patients with various types of tumors.
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Inflamación/diagnóstico por imagen , Neoplasias/diagnóstico por imagen , Radiofármacos , Timidina/análogos & derivados , Animales , Médula Ósea/diagnóstico por imagen , Interpretación Estadística de Datos , Masculino , Músculo Esquelético/diagnóstico por imagen , Tomografía de Emisión de Positrones , Radiofármacos/farmacocinética , Ratas , Ratas Wistar , Timidina/farmacocinética , Distribución TisularRESUMEN
INTRODUCTION: Uncontrolled proliferation is a fundamental characteristic of cancer, and consequently, imaging of tumor proliferative status finds interest clinically both as a diagnostic tool and for evaluation of response to treatment. Positron emission tomography (PET) radiotracers based on a nucleoside core, such as 3'-[18F]fluoro-3'-deoxythymidine ([18F]FLT), have been extensively studied for this purpose. However, [18F]FLT suffers from poor DNA incorporation leading to occasional poor correlation of [18F]FLT tumor uptake with other proliferation indicators such as Ki-67 immunostaining. METHODS: N3-((1-(2-[18F]fluoroethyl)-1H-[1,2,3]-triazol-4-yl)methyl)thymidine ([18F]2) and N3-((1-(2-[18F]fluoroethyl)-1H-[1,2,3]-triazol-4-yl)methyl)-4'-thio-ß-thymidine ([18F]3) were synthesized by click chemistry from [18F]fluoroethyl azide and by direct nucleophilic substitution of a tosylate precursor. Metabolic stability and phosphorylation potential of the radiotracers were evaluated in vitro and compared to [18F]FLT. Further, metabolic stability and biodistribution analysis of [18F]2 and [18F]3 were evaluated in vivo. RESULTS: Stable isotope standards and radiochemistry precursors were synthesized by modification of existing literature procedures. [18F]2 and [18F]3 were synthesized in a radiochemical yield of 8%-12% (end of synthesis, non-decay corrected). Both nucleosides were stable to metabolic degradation by thymidine phosphorylase, and in vivo stability analysis showed only one metabolite for [18F]3. No phosphorylation of [18F]2 could be detected in HCT116 cell homogenates, and in the same assay, only minor (â¼8%) phosphorylation of [18F]3 was observed. Biodistribution in Balb/c mice indicated rapid clearance for [18F]2 and [18F]3 to a lesser extent. CONCLUSIONS: The favorable biodistribution and metabolic profile of [18F]3 warrant further investigation as a next-generation PET proliferation marker.
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Timidina/síntesis química , Animales , Proliferación Celular , Técnicas de Química Sintética , Química Clic , Estabilidad de Medicamentos , Radioisótopos de Flúor , Células HCT116 , Humanos , Masculino , Ratones , Tomografía de Emisión de Positrones , Trazadores Radiactivos , Radioquímica , Estándares de Referencia , Timidina/metabolismo , Timidina/farmacocinética , Timidina Quinasa/metabolismoRESUMEN
Patients failing antiretroviral treatment for extended periods of time are at risk of accumulating HIV drug resistance mutations (DRMs), which negatively influences second-line treatment. This retrospective study assessed the rate of DRM accumulation among South African patients with continued virological failure. Serial genotypic resistance testing was performed and DRMs were scored according to the 2009 IAS-USA list. Among 43 patients, 38 (88.4%) harbored ≥1 DRM. The median time between two sequential resistance tests was 5 months (IQR: 3-10). Thymidine analogue mutations accumulated at a rate of 0.07 mutation per month of drug exposure, which is faster than previously reported. Routine virological monitoring should be implemented in resource-limited settings to preserve susceptibility to second-line regimens.