ABSTRACT
INTRODUCTION: Sarcoidosis is a multi-systemic disease characterized by non-caseating granulomas. Bone involvement initially considered as rare and described as a peripheral osteitis of the hands and feet, has recently been reported on the axial skeleton. CASE REPORTS: We report 4 clinical observations of sarcoidosis (3 women, 1 man) with axial bone involvement located to the spine (n = 4), pelvic bone (n = 2), scapular bone (n = 2), sternum (n = 1), mandible (n = 1). Sarcoidosis was already diagnosed in 3 cases. Bone pain was the main symptom, related in 3 cases. Magnetic resonance imaging appeared to be the best imaging test Histological bone analysis revealed typical granulomatous lesions (n = 2). Treatment included corticosteroids (n = 4), hydroxychloroquine (n = 2), and methotrexate (n = 2), with a good efficacy on bone pain in symptomatic patients. CONCLUSION: These 4 cases, as well as recent literature, illustrate bone involvement of sarcoidosis on the axial skeleton. It is symptomatic in around 50% of cases but may be a source of significant disability. Differential diagnosis with neoplasm may require bone histological analysis. This condition appears to be responsive to usual treatments for sarcoidosis.
Subject(s)
Bone Diseases/diagnosis , Sarcoidosis/diagnosis , Adult , Bone Diseases/etiology , Diagnosis, Differential , Female , Granuloma/complications , Granuloma/diagnosis , Humans , Magnetic Resonance Imaging , Male , Middle Aged , Osteolysis/diagnosis , Osteolysis/etiology , Sarcoidosis/complications , Spinal Diseases/diagnosis , Spinal Diseases/etiologyABSTRACT
We report for the first time severe acute pancreatitis in a child treated for phenylketonuria (PKU) discovered on neonatal screening. This 2-year-old boy was first hospitalized for bilious vomiting and moderate back pain. Laboratory values included a lipase level of 1.142 U/L, a phenylalanine level of 10mg/dL, and computed tomography revealed Balthazar grade E pancreatitis. Continuous enteral feeding was started on the 3rd day after admission. We observed clinical and biological improvement. Etiologic investigations for pancreatitis returned negative. Despite the severity of the pancreatitis, we did not observe decompensation of the metabolic disease. Specific nutritional management was necessary.
Subject(s)
Pancreatitis/diagnosis , Phenylketonurias/complications , Acute Disease , Child, Preschool , Humans , Male , Pancreatitis/etiologyABSTRACT
BACKGROUND: IL-15 is believed to play a role in the beneficial impact of exercise on muscle energy metabolism. However, previous studies have generally used supraphysiological levels of IL-15 that do not represent contraction-induced IL-15 secretion. METHODS: L6 myotubes were treated acutely (3â¯h) and chronically (48â¯h) with concentrations of IL-15 mimicking circulating (1-10â¯pg/ml) and muscle interstitial (100â¯pg/ml -20â¯ng/ml) IL-15 levels with the aim to better understand its autocrine/paracrine role on muscle glucose uptake and mitochondrial function. RESULTS: Acute exposure to IL-15 levels representing muscle interstitial IL-15 increased basal glucose uptake without affecting insulin sensitivity. This was accompanied by increased mitochondrial oxidative functions in association with increased AMPK pathway and formation of complex III-containing supercomplexes. Conversely, chronic IL-15 exposure resulted in a biphasic effect on mitochondrial oxidative functions and ETC supercomplex formation was increased with low IL-15 levels but decreased with higher IL-15 concentrations. The AMPK pathway was activated only by high levels of chronic IL-15 treatment. Similar results were obtained in skeletal muscle from muscle-specific IL-15 overexpressing mice that show very high circulating IL-15 levels. CONCLUSIONS: Acute IL-15 treatment that mimics local IL-15 concentrations enhances muscle glucose uptake and mitochondrial oxidative functions. That mitochondria respond differently to different levels of IL-15 during chronic treatments indicates that IL-15 might activate two different pathways in muscle depending on IL-15 concentrations. GENERAL SIGNIFICANCE: Our results suggest that IL-15 may act in an autocrine/paracrine fashion and be, at least in part, involved in the positive effect of exercise on muscle energy metabolism.
Subject(s)
AMP-Activated Protein Kinases/metabolism , Cell Respiration/drug effects , Glucose/metabolism , Interleukin-15/pharmacology , Mitochondria/drug effects , Muscle, Skeletal/drug effects , Muscle, Skeletal/metabolism , Animals , Cells, Cultured , Dose-Response Relationship, Drug , Electron Transport/drug effects , Interleukin-15/genetics , Mice , Mice, Transgenic , Mitochondria/metabolism , Oxidation-Reduction , RatsABSTRACT
In 1996, shortly after a locus for hereditary pancreatitis had been mapped to chromosome 7q35, an apparent gain-of-function missense mutation, p.R122H, in the cationic trypsinogen gene (PRSS1) was identified. Thereafter, the search for chronic pancreatitis-associated genetic factors has been largely focused on one form of genetic variation, namely, single nucleotide substitutions (SNSs). Only very recently has another type of genetic variation - copy number variations (CNVs) - been found to cause the disease. First, we identified duplication and triplication of an approximately 605 kb segment on chromosome 7q35 in French white patients with hereditary or idiopathic chronic pancreatitis. These alterations increased the copy number of PRSS1 as well as PRSS2, which encodes anionic trypsinogen. Second, we characterized a hybrid trypsinogen gene, in which exons 1 and 2 were derived from PRSS2 and exons 3 to 5 from PRSS1. Interestingly, this hybrid gene had two independent gain-of-function effects: increased trypsinogen gene copy number and it contained the p.N29I pancreatitis-causing missense mutation. Lastly, we identified two loss-of-function copy number mutations (deletions) in the SPINK1 gene, which encodes pancreatic secretory trypsin inhibitor (PSTI). Particularly, in one family with chronic pancreatitis, deletion of the complete SPINK1 gene was co-inherited with a CFTR missense mutation (p.L997F), revealing another layer of complexity between CNV and SNS interactions in the determination of a given disease phenotype. These findings represent a further demonstration of how studies of CNVs have altered the landscape of genetic research in the past few years and offer a fresh glimpse into the exciting realm of human CNVs.
Subject(s)
Gene Dosage/genetics , Pancreatitis, Chronic/genetics , Gene Duplication , Genome/genetics , Humans , Mutation/genetics , Pancreatitis, Chronic/classification , Trypsinogen/geneticsABSTRACT
Apoptotic leukocytes are endowed with immunomodulatory properties that can be used to enhance hematopoietic engraftment and prevent graft-versus-host disease (GvHD). This apoptotic cell-induced tolerogenic effect is mediated by host macrophages and not recipient dendritic cells or donor phagocytes present in the bone marrow graft as evidenced by selective cell depletion and trafficking experiments. Furthermore, apoptotic cell infusion is associated with TGF-beta-dependent donor CD4+CD25+ T-cell expansion. Such cells have a regulatory phenotype (CD62L(high) and intracellular CTLA-4+), express high levels of forkhead-box transcription factor p3 (Foxp3) mRNA and exert ex vivo suppressive activity through a cell-to-cell contact mechanism. In vivo CD25 depletion after apoptotic cell infusion prevents the apoptotic cell-induced beneficial effects on engraftment and GvHD occurrence. This highlights the role of regulatory T cells in the tolerogenic effect of apoptotic cell infusion. This novel association between apoptosis and regulatory T-cell expansion may also contribute to preventing deleterious autoimmune responses during normal turnover.
Subject(s)
Apoptosis/immunology , Spleen/cytology , Spleen/immunology , T-Lymphocytes, Regulatory/immunology , Transforming Growth Factor beta/metabolism , Adoptive Transfer , Animals , Bone Marrow Transplantation/immunology , Dendritic Cells/immunology , Forkhead Transcription Factors/genetics , Graft Survival/immunology , Graft vs Host Disease/prevention & control , Immune Tolerance , In Vitro Techniques , Macrophages/immunology , Male , Mice , Mice, Inbred BALB C , Mice, Inbred C57BL , Mice, Transgenic , RNA, Messenger/genetics , Receptors, Interleukin-2/metabolismABSTRACT
Cell fusions produce multinucleate syncytia that are crucial to the structure of essential tissues in many organisms [1-5]. In humans the entire musculature, much of the placenta, and key cells in bones and blood are derived from cell fusion. Yet the developmental fusion of cell membranes has never been directly observed and is poorly understood. Similarity between viral fusion proteins and recently discovered cellular proteins implies that both cell-cell and virus-cell fusion may occur by a similar mechanism [6-8]. Paradoxically, however, fusion of enveloped viruses with cells involves an opening originating as a single pore [9-11], whereas electron microscopy studies of cell-cell fusion describe simultaneous breakdown of large areas of membrane [12, 13]. Here, we have shown that developmental cell fusion is indeed consistent with initiation by a virus-like, pore-forming mechanism. We examined live cell fusions in the epithelia of Caenorhabditis elegans embryos by a new method that integrates multiphoton, confocal, and electron microscopy. The fusion aperture always originated at a single point restricted to the apical adherens junction and widened slowly as a radial wavefront. The fusing membranes dispersed by vesiculation, rather than simple unfolding of the conjoined double bilayer. Thus, in these cells fusion appears to require two specialized sequential processes: formation of a unique primary pore and expansion of the opening by radial internalization of the interacting cell membranes.
Subject(s)
Caenorhabditis elegans/embryology , Epithelial Cells/ultrastructure , Animals , Caenorhabditis elegans/cytology , Caenorhabditis elegans/genetics , Cell Fusion , Giant Cells/ultrastructure , Intercellular Junctions/ultrastructure , Microscopy, Electron , MorphogenesisABSTRACT
Methotrexate (MTX) is one of the most widely used drugs for the treatment of childhood acute lymphoblastic leukemia (ALL) and is commonly given in high doses. However, the rationale for high-dose MTX (HDMTX) has been challenged recently. To determine whether higher MTX polyglutamate (MTXPG) concentrations in ALL blasts translate into greater antileukemic effects, 150 children with newly diagnosed ALL were randomized to initial treatment with either HDMTX (1,000 mg/m2 intravenously over 24 h) or lower-dose MTX (30 mg/m2 by mouth every 6 h x 6). ALL blasts accumulated higher concentrations of MTXPG and long-chain MTXPG (MTXPGLC) after HDMTX (P < 0.00001). Of 101 patients evaluable for peripheral blast cytoreduction, MTXPG concentrations were higher in patients whose blast count decreased within 24 h (P = 0.005) and in those who had no detectable circulating blasts within 4 days (P = 0.004). The extent of inhibition of de novo purine synthesis in ALL blasts was significantly related to the blast concentration of MTXPGLC (IC95% = 483 pmol/10(9) blasts). The percentage of patients with 44-h MTXPGLC exceeding the IC95% was greater after HDMTX (81%) than LDMTX (46%, P < 0.0001). These data indicate that higher blast concentrations of MTXPG are associated with greater antileukemic effects, establishing a strong rationale for HD-MTX in the treatment of childhood ALL.
Subject(s)
Antimetabolites, Antineoplastic/administration & dosage , Methotrexate/analogs & derivatives , Methotrexate/administration & dosage , Polyglutamic Acid/analogs & derivatives , Precursor Cell Lymphoblastic Leukemia-Lymphoma/drug therapy , Adolescent , Antimetabolites, Antineoplastic/adverse effects , Antimetabolites, Antineoplastic/pharmacokinetics , Bone Marrow/pathology , Child , Child, Preschool , Female , Humans , Infant , Male , Methotrexate/adverse effects , Methotrexate/metabolism , Methotrexate/pharmacokinetics , Polyglutamic Acid/metabolism , Precursor Cell Lymphoblastic Leukemia-Lymphoma/blood , Precursor Cell Lymphoblastic Leukemia-Lymphoma/metabolism , Purines/biosynthesis , Stomatitis/chemically inducedABSTRACT
Two methods for the sampling and analysis of tar produced from wood pyrolysis were compared. The first method used a conventional cold-trapping technique in solvent-filled impingers followed by liquid injection. The second one is a new application of multibed solid-phase adsorbent (SPA) tubes followed by thermal desorption (TD). Both methods are based on gas chromatography (GC) coupled with mass spectrometry (MS). Quantification was performed with a well reproducible GC-MS method with three internal deuterated standards. The SPA/TD method offers several advantages. No solvent is required, the detection levels are improved, and gas chromatography separation is easier. Moreover, sampling time is reduced from about 1h (for the conventional cold-trapping technique in impingers) to a few seconds. No discrimination was observed between the two sampling methods for the 10 quantified compounds (aromatic compounds from benzene to phenanthrene and phenols) except for benzene.
Subject(s)
Gas Chromatography-Mass Spectrometry/methods , Tars/chemistry , Gas Chromatography-Mass Spectrometry/instrumentation , Hydrocarbons, Aromatic/analysis , Hydrocarbons, Aromatic/chemistry , Reproducibility of ResultsABSTRACT
PTK787/ZK 222584 (PTK/ZK) is an oral angiogenesis inhibitor targeting vascular endothelial growth factor (VEGF) receptor tyrosine kinases, including VEGFR-1/Flt-1, VEGFR-2/KDR, VEGFR-3/Flt-4, the platelet-derived growth factor receptor tyrosine kinase and the c-kit protein tyrosine kinase. The objective of this Phase I study was to evaluate the safety, tolerability, biologic activity and pharmacologic profile of PTK/ZK administered orally, twice daily, on a continuous dosing schedule in patients with primary refractory or relapsed acute myeloid leukemia (AML), secondary AML, poor-prognosis de novo AML or advanced myelodysplastic syndrome (MDS). Acute myeloid leukemia patients for whom PTK/ZK monotherapy was ineffective could receive PTK/ZK combined with standard induction chemotherapy. Sixty-three patients received PTK/ZK at doses of 500-1000 mg orally b.i.d. Safety and pharmacokinetic data were collected. Responses were evaluated according to standard bone marrow and peripheral blood criteria. At 1000 mg b.i.d., dose-limiting toxicities of lethargy, hypertension, nausea, emesis and anorexia were observed. Other adverse events related to PTK/ZK were dizziness, weakness, fatigue, diarrhea and pruritus; these were generally mild and reversible. Pharmacokinetic data showed that steady state was reached by day 14, there was no accumulation with repeat dosing and there was no significant increase in exposure at steady state beyond the maximum tolerated dose (MTD). Complete remission was observed in five of 17 AML patients treated with PTK/ZK combined with chemotherapy. In conclusion, the MTD of PTK/ZK is 750 mg orally b.i.d. The drug is generally well tolerated and can be given in combination with chemotherapy for patients with MDS and AML.
Subject(s)
Antineoplastic Combined Chemotherapy Protocols/therapeutic use , Leukemia, Myeloid/drug therapy , Myelodysplastic Syndromes/drug therapy , Phthalazines/therapeutic use , Protein Kinase Inhibitors/therapeutic use , Pyridines/therapeutic use , Acute Disease , Adult , Aged , Aged, 80 and over , Antineoplastic Combined Chemotherapy Protocols/pharmacology , Cell Proliferation/drug effects , Cohort Studies , Dose-Response Relationship, Drug , Drug Therapy, Combination , Female , Humans , Leukemia, Myeloid/diagnosis , Male , Middle Aged , Myelodysplastic Syndromes/diagnosis , Phthalazines/administration & dosage , Phthalazines/adverse effects , Phthalazines/pharmacology , Protein Kinase Inhibitors/administration & dosage , Protein Kinase Inhibitors/adverse effects , Protein Kinase Inhibitors/pharmacology , Pyridines/administration & dosage , Pyridines/adverse effects , Pyridines/pharmacology , Receptor Protein-Tyrosine Kinases/antagonists & inhibitors , Treatment Outcome , Vascular Endothelial Growth Factor Receptor-2/antagonists & inhibitorsABSTRACT
Olive stones (OS) were submitted to hydrothermal carbonisation (HTC) in order to evaluate the possibility of producing high added-value products, mainly furfural (FU) and 5-hydroxymethylfurfural (5-HMF) on one hand and hydrochars and carbons on the other hand. Temperature (160-240 °C), residence time (1-8 h), initial pH (1-5.5) and liquid/solid ratio (4-48 w/w) were systematically varied in order to study the main products and to optimise FU production. FU production yield up to 19.9 %, based on the hemicellulose content, was obtained. Other minor, but valuable, compounds such as 5-methylfurfural (5-MF) and some phenolic compounds were also produced. The hydrochar was carbonised at 900 °C, and the resultant carbon material was highly ultramicroporous with a peak of pore size distribution centred on 0.5 nm and a surface area as high as 1065 m2 g-1, typical of most carbon molecular sieves.
Subject(s)
Carbon/chemistry , Olea , Furaldehyde/analogs & derivatives , TemperatureABSTRACT
INTRODUCTION: Eosinophilic fasciitis or Shulman's disease is characterized, in its typical form, by palpable thickening of the skin and soft tissues, blood hypereosinophilia and fascia lesions. We hereby report a case of eosinophilic fasciitis in which hypereosinophilia preceded for several months the clinical signs of fasciitis. CASE REPORT: A 64-year-old woman, with a history of Little's syndrome with motor disability, was admitted in internal medicine for eosinophilia. For almost three months, no origin to the eosinophilia was found. The secondary onset of an edema and pain located on four limbs led to the diagnosis of eosinophilic fasciitis. Muscle magnetic resonance imaging was supportive and the muscle histological analysis confirmed the diagnosis of eosinophilic fasciitis. Treatment with steroids induced a rapid normalization of the eosinophilia and edema. CONCLUSION: In this case report, eosinophilia was preceding the clinical cutaneous signs that led to the diagnosis of eosinophilic fasciitis. It is likely to believe that myalgias, frequently found in the onset of eosinophilic fasciitis, may have been hidden by the history of infantile encephalopathy. The diagnosis of eosinophilic fasciitis must be kept in mind of physicians in the investigation of an eosinophilia, even though cutaneous signs are lacking.
Subject(s)
Eosinophilia/diagnosis , Fasciitis/diagnosis , Synovitis/diagnosis , Diagnosis, Differential , Disease Progression , Eosinophilia/pathology , Fasciitis/pathology , Female , Humans , Middle AgedABSTRACT
OBJECTIVE: Women with diabetes may need elective preterm delivery due to pregnancy or diabetes related complications. The aim of this study was to describe the neonatal outcomes arising from elective preterm delivery in diabetic women. METHOD: Suitable patients were identified by the obstetric team at Hull Royal Infirmary Women and Children's Hospital and data was extracted from their case notes. 45 diabetic women with planned preterm delivery were identified within a set time frame, resulting in 48 babies. RESULTS: Of the 48 babies born, 47 survived. 36 out of 48 were delivered via caesarean section. Gestational ages ranged from 29+3 to 36+6 weeks, and 24 out of 48 (50%) had a birth weight greater than the 90th centile for gestational age.34 out of the 48 babies experienced some form of neonatal complication and were admitted to the neonatal unit. The median duration of stay in the neonatal unit was 7 days. 14 of the surviving neonates suffered from respiratory distress, although only 4 required surfactant therapy to regain respiratory function. However, the incidence of serious neonatal complications in those born after 34 weeks was shown to be low. CONCLUSIONS: Elective preterm delivery after 34 weeks had little effect on overall neonatal outcome. Therefore it could be proposed that elective preterm delivery after 34 weeks gestation may be an acceptable option in diabetic women if there are maternal or obstetric complications.
Subject(s)
Cesarean Section , Diabetes, Gestational/therapy , Labor, Induced , Pregnancy in Diabetics/therapy , Premature Birth , Respiratory Distress Syndrome, Newborn/epidemiology , Adult , Birth Weight , Delivery, Obstetric , Diabetes Mellitus, Type 1 , Diabetes Mellitus, Type 2 , England/epidemiology , Female , Gestational Age , Humans , Infant, Newborn , Infant, Premature , Intensive Care Units, Neonatal , Length of Stay/statistics & numerical data , Pregnancy , Pulmonary Surfactants/therapeutic use , Retrospective Studies , Young AdultABSTRACT
Allopurinol is used to prevent hyperuricemia in newly diagnosed patients with acute lymphoblastic leukemia (ALL). Although allopurinol has been shown to inhibit de novo purine synthesis (DNPS) in fibroblasts in vitro, this effect has not been assessed in ALL lymphoblasts. We assessed DNPS in ALL lymphoblasts in 46 consecutive patients with ALL. DNPS was determined by 14C-formate incorporation in purine bases both at diagnosis (n = 46) and 44h after MTX therapy +/- allopurinol (n = 31). The 27 patients who had received no allopurinol prior to the diagnostic bone marrow aspirate had significantly higher rates of DNPS (median, 102 fmol new purines/nmol total purines/h) compared to the 12 patients who had received more than one dose of allopurinol (100 mg/m2 orally) (median, 2.3 fmol/nmol/h; P < 0.001); the seven patients who received one dose of allopurinol had intermediate rates of DNPS (median, 58.5 fmol/nmol/h). Among patients who were evaluable for MTX effects at 44h (n = 31), the percent inhibition of DNPS was greater in the eight patients who received concomitant allopurinol (median, 100% inhibition) compared to the 23 patients who received only methotrexate therapy (median, 89% inhibition, P = 0.03). These data indicate that allopurinol suppresses may contribute to the decrease in circulating blasts in patients with newly diagnosed acute leukemias.
Subject(s)
Antineoplastic Combined Chemotherapy Protocols/therapeutic use , Lymphocytes/drug effects , Precursor Cell Lymphoblastic Leukemia-Lymphoma/drug therapy , Purines/biosynthesis , Adolescent , Allopurinol/administration & dosage , Analysis of Variance , Antimetabolites, Antineoplastic/administration & dosage , Bone Marrow/metabolism , Bone Marrow/pathology , Child , Child, Preschool , Humans , Infant , Linear Models , Lymphocytes/metabolism , Methotrexate/administration & dosage , Precursor Cell Lymphoblastic Leukemia-Lymphoma/metabolism , Precursor Cell Lymphoblastic Leukemia-Lymphoma/pathologyABSTRACT
High pressures under the feet of diabetic patients with neuropathy are associated with the development of plantar ulceration. The aim of management is the reduction of such stresses with orthoses and insoles. An American hosiery manufacturer has developed socks designed to reduce stress on athletes' feet, and we report a preliminary evaluation of this technique in the reduction of elevated plantar pressure in 27 neuropathic diabetic patients. With a computerized optical pedobarograph, three footsteps on each side were recorded under three conditions: 1) barefoot, 2) wearing the patients' own hosiery, and 3) wearing experimental patented padded hosiery. The patients' own hosiery did not have a significant effect on plantar pressure, but the experimental hosiery reduced both peak forefoot pressure and the area under the time-pressure curve (P less than .001) by a mean of 26 and 29%, respectively. We conclude that the experimental hosiery is effective in reducing vertical pressures under the diabetic foot and, in conjunction with established orthotic techniques, may be a useful addition to the treatment of the diabetic patient at risk for foot ulceration.
Subject(s)
Clothing , Diabetic Neuropathies/therapy , Foot , Female , Humans , Male , Neural Conduction , Perception , PressureABSTRACT
OBJECTIVE: To investigate the role of limited joint mobility (LJM) in causing abnormal foot pressures and foot ulceration. RESEARCH DESIGN AND METHODS: The subjects were recruited from a general diabetes clinic where patients were screened for neuropathy, retinopathy, and elevated plantar foot pressure. Sixty-four patients in five groups were matched by age and sex in the following groups: group 1, patients with LJM and neuropathy; group 2, nonneuropathic diabetic patients with LJM; group 3, patients with neuropathy and no LJM; group 4, diabetic control subjects; and group 5, nondiabetic control subjects. Joint mobility was assessed in the foot at subtalar and metatarsophalangeal joints; plantar foot pressures were assessed by optical pedobarography and neuropathic status by a Biothesiometer and electrophysiology. RESULTS: Joint mobility was reduced at both sites in groups 1 and 2 compared with groups 3, 4, and 5 (P less than 0.001). Plantar foot pressures were significantly higher in groups 1 and 2 compared with groups 3, 4, and 5 (P less than 0.001). No differences in plantar foot pressures were observed between groups 1 and 2. There were strong correlations between plantar foot pressures and joint mobility in the foot (r = -0.7, P less than 0.001). Previous foot ulceration was present in 65% of patients in group 1, none in group 2, and 5% in group 3. CONCLUSIONS: 1) LJM may be a major factor in causing abnormally high plantar foot pressures, 2) abnormal plantar foot pressures alone do not lead to foot ulceration, and 3) LJM contributes to foot ulceration in the susceptible neuropathic foot.
Subject(s)
Ankle Joint/physiopathology , Diabetic Neuropathies/physiopathology , Foot Diseases/physiopathology , Metatarsophalangeal Joint/physiopathology , Skin Ulcer/physiopathology , Diabetic Neuropathies/complications , Diabetic Retinopathy/complications , Diabetic Retinopathy/physiopathology , Electrophysiology , Evaluation Studies as Topic , Female , Foot , Foot Diseases/etiology , Gait/physiology , Humans , Male , Metacarpophalangeal Joint/physiopathology , Middle Aged , Pressure , Range of Motion, Articular , Skin Ulcer/etiologyABSTRACT
BMS-911543, a promising anticancer agent, exhibited time-dependent and dose-dependent nonlinear pharmacokinetics (PKs) in its first-in-human (FIH) study. Initial physiologically based pharmacokinetic (PBPK) modeling efforts using CYP1A2-mediated clearance kinetics were unsuccessful; however, further model analysis revealed that CYP1A2 time-dependent inhibition (TDI) and perhaps other factors could be keys to the nonlinearity. Subsequent experiments in human liver microsomes showed that the compound was a time-dependent inhibitor of CYP1A2 and were used to determine the enzyme inactivation parameter values. In addition, a rat tissue distribution study was conducted and human plasma samples were profiled to support the refinement of the PBPK model. It was concluded that the interplay between four BMS-911543 properties, namely, low solubility, saturation of the metabolizing enzyme CYP1A2, CYP1A2 TDI, and CYP1A2 induction likely resulted in the time-dependent and dose-dependent nonlinear PKs. The methodology of PBPK model-guided unmasking of compound properties can serve as a general practice for mechanistic understanding of a new compound's disposition.
ABSTRACT
BACKGROUND AND OBJECTIVES: Carbamazepine is among those drugs that have been considered to have a narrow therapeutic plasma concentration range, that is, a narrow therapeutic index. Although the US Food and Drug Administration has approved new generic products based on standard single-dose bioequivalence studies, several state formularies, including the New Jersey Drug Utilization Review Council, have recently established additional criteria for acceptance of bioequivalence of narrow therapeutic index drugs, limiting the use of some approved generic drugs in specific states. To further validate the adequacy of single-dose studies for the determination of bioequivalence of narrow therapeutic index drugs, a multiple-dose study was conducted that more closely reflected therapeutic use. METHODS: A single-center, multiple-dose, randomized, open-label, 2-way crossover bioequivalence study was conducted in 32 fasting volunteers at steady state. Subjects received the test and reference products as a 200 mg carbamazepine tablet 3 times a day in a crossover fashion. Concentrations of carbamazepine and carbamazepine-10,11-epoxide in plasma were measured by a validated specific HPLC method. RESULTS: A total of 28 subjects completed the study. Pharmacokinetic parameters and measures of fluctuation for both products at steady state were similar, with 90% and 95% confidence intervals falling within 90% and 110%. CONCLUSION: The multiple-dose study provided reliable safety and bioequivalence data under rigorous statistical conditions and confirmed bioequivalence of test and reference products determined by a single-dose study.
Subject(s)
Analgesics, Non-Narcotic/administration & dosage , Analgesics, Non-Narcotic/pharmacokinetics , Carbamazepine/administration & dosage , Carbamazepine/pharmacokinetics , Adult , Analgesics, Non-Narcotic/adverse effects , Analgesics, Non-Narcotic/blood , Carbamazepine/adverse effects , Carbamazepine/blood , Chromatography, High Pressure Liquid , Cross-Over Studies , Drug Administration Schedule , Humans , Male , Reference Values , Therapeutic Equivalency , Time FactorsABSTRACT
Phenylpropanolamine (PPA) is contained in about 106 products, over half of which are available over-the-counter (OTC). Most are cough/cold remedies; nine are OTC diet aids. More than nine million Americans were using OTC diet aids in 1981, making PPA the fifth most used drug in the United States, responsible for over $200 million in revenues. The safety of PPA remains controversial. Although most controlled studies indicate minimal pressor effects with recommended doses, adverse drug reactions (ADRs) continue to be documented. Since 1965, 142 ADRs have been reported in 85 studies, 69% of these in North America. Many such cases may go unrecognized. About two thirds of all ADRs occurred in females and in patients under 30. Of ADRs attributed to legitimately sold PPA products, 85% occurred after consumption of OTC products versus only 15% after prescription drugs. The PPA product often contained combination ingredients, or PPA was consumed along with additional drugs. An overdose of PPA was taken in about a third of the cases. After ingestion of non-overdose amounts, 82% of the ADRs were severe. The most frequent side effects involved symptoms compatible with acute hypertension, with severe headache the most common complaint. Twenty-four intracranial hemorrhages, eight seizures, and eight deaths (most due to stroke) were associated with PPA ingestion. We have summarized these data in an effort to alert clinicians to the prevalence of usage of PPA products and the potential for adverse effects. In patients who present with elevated blood pressure or signs of acute hypertension, especially hypertensive encephalopathy of undetermined origin, we recommend inquiry about recent ingestion of PPA-containing diet aids and cough/cold products and suggest having such patients remain upright rather than supine.
Subject(s)
Phenylpropanolamine/adverse effects , Drug Combinations , Drug Interactions , Humans , Phenylpropanolamine/administration & dosage , StereoisomerismABSTRACT
Cancer chemotherapy doses are empirical in that the majority are administered at a fixed dose (mg/m2 or mg/kg). One reason for this is the intrinsic sensitivity of the tumour or host cells to one particular chemotherapy agent is unknown. Therefore, the likelihood of response or toxicity is unpredictable a priori. This contrasts with antimicrobial chemotherapy where sensitivity (minimum inhibitory concentration) can be determined for a specific bacterium. The pharmacokinetics of cancer chemotherapy agents is also highly variable between patients. In addition, the small therapeutic index of these drugs, combined with the lack of good surrogate markers of toxicity or response, adds to the empiricism of the administration of cancer chemotherapy. In the past few years, numerous studies have established good relationships between systemic exposure to cancer chemotherapy and both response and toxicity. These relationships have been used to individualise chemotherapy dose administration a priori and a posteriori. Some examples of drugs which are individualised based on their pharmacokinetics are methotrexate, busulfan and carboplatin. Other examples of antineoplastic agents which may eventually be individualised based on their pharmacokinetics are mercaptopurine, fluorouracil, etoposide and teniposide, topotecan and suramin. New strategies are being investigated to improve the therapeutic index of cancer chemotherapy agents such as biomodulation, pharmacogenetics, circadian administration and the modification of drug scheduling. Pharmacokinetic studies have also played a major role in these areas. Thus, despite the empiricism associate with cancer chemotherapy administration, some progress has been made and shown to have an impact on outcome. However, more studies are needed to improve cancer chemotherapy administration.