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1.
ESMO Open ; 8(4): 101575, 2023 08.
Artículo en Inglés | MEDLINE | ID: mdl-37517365

RESUMEN

The current Response Evaluation Criteria in Solid Tumors for measuring tumor response in osteosarcoma may be sub-optimal, as even responsive bone tumors may show limited change in tumor diameters. This limits the use of traditional imaging assessment tools. Therefore, discerning osteosarcoma response to therapy on magnetic resonance imaging before surgery is often difficult, and it is typically evaluated after surgery by assessing the amount of necrosis in resected surgical specimens. To address these challenges, sodium fluoride (Na18F) positron emission tomography/computed tomography (PET/CT) scans can be utilized to better image bone response to therapy, as, fluoride is avidly taken up by bone. Na18F Response Criteria in Solid Tumors (NAFCIST) has been developed as a novel method to evaluate treatment response using Na18F PET/CT. Current evidence supporting NAFCIST comes from a pilot study that evaluated alpha particle radium-223 in patients with osteosarcoma. In this review, practical guidance for utilizing NAFCIST in the context of bone tumors is illustrated to aid future studies.


Asunto(s)
Neoplasias Óseas , Osteosarcoma , Humanos , Tomografía Computarizada por Tomografía de Emisión de Positrones/métodos , Fluoruro de Sodio/farmacología , Proyectos Piloto , Radioisótopos de Flúor , Neoplasias Óseas/diagnóstico por imagen , Osteosarcoma/diagnóstico por imagen
2.
Pediatr Blood Cancer ; 61(2): 238-44, 2014 Feb.
Artículo en Inglés | MEDLINE | ID: mdl-23997016

RESUMEN

PURPOSE: This non-randomized, patient-access protocol, assessed both safety and efficacy outcomes following liposomal muramyl-tripeptide-phosphatidylethanolamine (L-MTP-PE; mifamurtide) in patients with high-risk, recurrent and/or metastatic osteosarcoma. METHODS: Patients received mifamurtide 2 mg/m(2) intravenously twice-weekly ×12 weeks, then weekly ×24 weeks with and without chemotherapy. Serum concentration-time profiles were collected. Adverse events within 24 hours of drug administration were classified as infusion-related adverse events (IRAE); other AEs and overall survival (OS) were assessed. RESULTS: The study began therapy in January 2008; the last patient completed therapy in October 2012. Two hundred five patients were enrolled; median age was 16.0 years and 146/205 (71%) had active disease. Mifamurtide serum concentrations declined rapidly in the first 30 minutes post-infusion, then in a log-linear manner 2-6 hours post-dose; t1/2 was 2 hours. There were no readily apparent relationships between age and BSA-normalized clearance, half-life, or pharmacodynamic effects, supporting the dose of 2 mg/m(2) mifamurtide across the age range. Patients reported 3,679 IRAE after 7,482 mifamurtide infusions. These were very rarely grade 3 or 4 and most commonly included chills + fever or headache + fatigue symptom clusters. One- and 2-year OS was 71.7% and 45.9%. Patients with initial metastatic disease or progression approximated by within 9 months of diagnosis (N = 40) had similar 2-year OS (39.9%) as the entire cohort (45.9%) CONCLUSIONS: Mifamurtide had a manageable safety profile; PK/PD of mifamurtide in this patient access study was consistent with prior studies. Two-year OS was 45.9%. A randomized clinical trial would be required to definitively determine impact on patient outcomes.


Asunto(s)
Acetilmuramil-Alanil-Isoglutamina/análogos & derivados , Neoplasias Óseas/tratamiento farmacológico , Factores Inmunológicos/farmacología , Recurrencia Local de Neoplasia/tratamiento farmacológico , Osteosarcoma/tratamiento farmacológico , Fosfatidiletanolaminas/farmacología , Acetilmuramil-Alanil-Isoglutamina/administración & dosificación , Acetilmuramil-Alanil-Isoglutamina/farmacocinética , Acetilmuramil-Alanil-Isoglutamina/farmacología , Adolescente , Adulto , Neoplasias Óseas/mortalidad , Neoplasias Óseas/patología , Niño , Preescolar , Efectos Colaterales y Reacciones Adversas Relacionados con Medicamentos , Femenino , Estudios de Seguimiento , Humanos , Factores Inmunológicos/administración & dosificación , Factores Inmunológicos/farmacocinética , Masculino , Persona de Mediana Edad , Clasificación del Tumor , Metástasis de la Neoplasia , Recurrencia Local de Neoplasia/mortalidad , Recurrencia Local de Neoplasia/patología , Osteosarcoma/mortalidad , Osteosarcoma/patología , Fosfatidiletanolaminas/administración & dosificación , Fosfatidiletanolaminas/farmacocinética , Pronóstico , Seguridad , Tasa de Supervivencia , Distribución Tisular , Adulto Joven
3.
Acta Biomater ; 8(12): 4342-8, 2012 Dec.
Artículo en Inglés | MEDLINE | ID: mdl-22846591

RESUMEN

Finite element models of tissue engineering scaffolds are powerful tools to understand scaffold function, including how external mechanical signals deform the scaffold at the meso- and microscales. Fiber geometry is needed to inform finite element models of fiber-based tissue engineering scaffolds; however, the accuracy and utility of these models may be limited if they are informed by non-hydrated geometries. Scanning electron microscopy and confocal microscopy, coupled with Fourier analysis of the resulting images, were used to quantify how hydration alters fiber geometry in electrospun collagen and polycaprolactone (PCL) scaffolds. The results also quantify how image size affects fiber geometry. Hydration is demonstrated to increase fiber tortuosity, defined as the ratio of actual fiber length:end-to-end fiber length. For collagen scaffolds, hydration increased the mean tortuosity from 1.05 to 1.21, primarily from large ∼2- to 10-fold) increases in smaller (<40µm) wavelength amplitudes. For PCL fibers, the mean tortuosity increased from 1.01 to only 1.04, primarily from modest ∼2-fold) increases in larger (>100µm) wavelength amplitudes. The results demonstrate that mechanical simulations of electrospun scaffolds should be informed with hydrated scaffold geometries of at least 200µm scale, in order to capture geometrical effects associated with fiber straightening.


Asunto(s)
Colágeno/química , Poliésteres/química , Ingeniería de Tejidos , Andamios del Tejido/química , Análisis de Elementos Finitos
4.
J Biomech ; 43(16): 3183-90, 2010 Dec 01.
Artículo en Inglés | MEDLINE | ID: mdl-20723899

RESUMEN

Engineered skin must be mechanically strong to facilitate surgical application and prevent damage during the early stages of engraftment. However, the evolution of structural properties during culture, the relative contributions of the epidermis and dermis, and any correlation with tissue morphogenesis are not well known. These aspects are investigated by assessing the mechanical properties of engineered skin (ES) and engineered dermis (ED) during a 21-day culture period, including correlations with cellular metabolism, cellular organization and epidermal differentiation. During culture, the epidermis differentiates and begins to cornify, as evidenced by immunostaining and surface electrical capacitance. Tensile testing reveals that the ultimate tensile strength and linear stiffness increase linearly with time for ES, but are relatively unchanged for ED. ES strength correlates significantly with epidermal differentiation (p < 0.001) and a composite strength model indicates that strength is largely determined by the epidermis. These data suggest that strategies to improve ES biomechanics should target the dermis. Additionally, time-dependant changes in average ES strength and percent elongation can be used to set upper bound limits on mechanical stimulation profiles to avoid tissue damage.


Asunto(s)
Epidermis/fisiología , Fenómenos Fisiológicos de la Piel , Ingeniería de Tejidos/métodos , Fenómenos Biomecánicos , Diferenciación Celular , Proliferación Celular , Supervivencia Celular , Dermis/citología , Dermis/crecimiento & desarrollo , Dermis/fisiología , Células Epidérmicas , Epidermis/crecimiento & desarrollo , Humanos , Trasplante de Piel , Estrés Mecánico , Resistencia a la Tracción , Andamios del Tejido , Cicatrización de Heridas
5.
Drugs Today (Barc) ; 46(5): 327-37, 2010 May.
Artículo en Inglés | MEDLINE | ID: mdl-20517534

RESUMEN

Mifamurtide, also known as liposomal muramyl tripeptide phosphatidyl ethanolamine (L-MTP-PE), has been approved for the treatment of osteosarcoma in Europe. Mifamurtide's rational drug design employs MTP-PE for macrophage activation in a multilamellar liposome drug carrier, containing the synthetic phospholipids 1-palmitoyl-2-oleoyl phosphatidyl choline (POPC) and 1,2-dioleoyl phosphatidyl serine (OOPS). Although the drug is not cytotoxic towards normal or tumor cells in vitro, immune activation against osteosarcoma lung metastases in vivo accounts for mifamurtide's antiosteosarcoma effects. Phosphatidyl serine-containing lipids signal macrophage cells that have "flipped phosphatidyl serine" to the outer membrane after apoptosis (e.g., after damage of tumor cells from chemotherapy); thus, both mifamurtide's active and inactive ingredients target immune cells in the lungs. Mifamurtide administration has resulted in 8% and 13% improvement in 6- and 5-year overall survivals, when added to chemotherapy in nonmetastatic and metastatic patients with osteosarcoma, respectively. The short-term toxicities of mifamurtide (fever, headache, flu-like symptoms and rigors) are reduced or eliminated using ibuprofen (200 mg) as premedication for the first infusion; an algorithm for pre- and postmedication is presented. To date, no long-term side effects of mifamurtide have been reported. Compassionate access programs based in two major cancer centers (MD Anderson and Memorial Sloan-Kettering), have recently provided this potentially life-saving drug in North America. The experience with mifamurtide provides an outstanding example of successful cooperation among regulatory bodies and agencies, the pharmaceutical industry and pediatric oncologists to improve cancer care and outcomes for children and young people with a rare sarcoma.


Asunto(s)
Acetilmuramil-Alanil-Isoglutamina/análogos & derivados , Factores Inmunológicos/uso terapéutico , Osteosarcoma/tratamiento farmacológico , Fosfatidiletanolaminas/uso terapéutico , Acetilmuramil-Alanil-Isoglutamina/efectos adversos , Acetilmuramil-Alanil-Isoglutamina/farmacología , Acetilmuramil-Alanil-Isoglutamina/uso terapéutico , Neoplasias Óseas/tratamiento farmacológico , Neoplasias Óseas/inmunología , Ensayos Clínicos como Asunto , Diseño de Fármacos , Humanos , Factores Inmunológicos/efectos adversos , Factores Inmunológicos/farmacología , Liposomas , Osteosarcoma/inmunología , Fosfatidiletanolaminas/efectos adversos , Fosfatidiletanolaminas/farmacología , Sobrevida
6.
Eur Respir J ; 27(3): 585-93, 2006 Mar.
Artículo en Inglés | MEDLINE | ID: mdl-16507860

RESUMEN

Recently, granulocyte-macrophage colony-stimulating factor (GM-CSF) auto-antibodies have been found in many patients with pulmonary alveolar proteinosis (PAP). The present study reports a retrospective case series of patients who used aerosolised GM-CSF in the treatment of idiopathic PAP. Between 1999 and 2003, 12 patients elected to receive aerosolised GM-CSF (250 microg b.i.d. every other week) in lieu of whole-lung lavage or observation. Patient characteristics, pulmonary function tests, arterial blood gas analysis, laboratory values and chest radiographs were extracted from the patient's medical records. Of the six patients tested, all had GM-CSF neutralising antibodies. Additionally, abnormalities in GM-CSF gene expression (one patient), receptor expression (two patients) and ability to upregulate adhesion molecules (one patient) were found. All patients except one had a positive response (mean improvements in arterial oxygen tension, alveolar-arterial oxygen gradient, carbon monoxide diffusing capacity of the lung and forced vital capacity were 17.1 mmHg, 18.4 mmHg, 16.6% pred and 13.5% pred, respectively). Two patients made a complete recovery and were disease free 1 and 2 yrs after discontinuing treatment. Four patients showed complete response to both the initial course or when treated again for recurrence after discontinuation of treatment. One patient required dose escalation (500 microg b.i.d.) with complete response. GM-CSF was well tolerated without late toxicity after median (range) follow-up of 30.5 (3-68) months. In conclusion, aerosolised granulocyte-macrophage colony-stimulating factor is safe and effective in treating pulmonary alveolar proteinosis providing an alternative to whole-lung lavage or subcutaneous granulocyte-macrophage colony-stimulating factor.


Asunto(s)
Factor Estimulante de Colonias de Granulocitos y Macrófagos/administración & dosificación , Proteinosis Alveolar Pulmonar/tratamiento farmacológico , Administración por Inhalación , Adulto , Femenino , Humanos , Masculino , Persona de Mediana Edad , Estudios Retrospectivos
7.
Leukemia ; 19(1): 118-25, 2005 Jan.
Artículo en Inglés | MEDLINE | ID: mdl-15526021

RESUMEN

Despite response rates of 30% after high-dose chemotherapy with autologous hematopoietic stem cell transplant, patients with multiple myeloma are not cured. 153Samarium ethylenediaminetetramethylenephosphonate (153Sm-EDTMP; Quadramet) is a short-range, beta-emitting therapeutic radiopharmaceutical with avid skeletal uptake. In total, 12 patients were treated with escalating doses of 153Sm-EDTMP (N=3/group; 6, 12, 19.8, and 30 mCi/kg) and a fixed dose of melphalan (200 mg/m(2)). No dose limiting toxicity was seen. To better standardize the marrow compartment radiation dose, the study was modified such that an additional six patients were treated at a targeted absorbed radiation dose to the red marrow of 40 Gy based on a trace labeled infusion 1 week prior to the therapy. Despite rapid elimination of unbound radiopharmaceutical via kidneys and bladder, no episodes of nephrotoxicity, hemorrhagic cystitis, or delayed radiation nephritis were observed with a median follow-up of 31 months (range 8.5-44). Median times to ANC>0.5 and platelet >20 x 10(6)/l were 12 and 11 days, respectively, with no graft failures. Overall response rate was 94% including seven very good partial responses and five complete responses. Addition of 153Sm EDTMP to melphalan conditioning appears to be safe, well-tolerated and worthy of further study.


Asunto(s)
Antineoplásicos Alquilantes/uso terapéutico , Melfalán/uso terapéutico , Mieloma Múltiple/radioterapia , Mieloma Múltiple/cirugía , Compuestos Organometálicos/administración & dosificación , Compuestos Organofosforados/administración & dosificación , Radioisótopos/administración & dosificación , Trasplante de Células Madre , Acondicionamiento Pretrasplante , Adulto , Anciano , Antineoplásicos Alquilantes/administración & dosificación , Antineoplásicos Alquilantes/farmacocinética , Terapia Combinada , Relación Dosis-Respuesta a Droga , Femenino , Humanos , Masculino , Dosis Máxima Tolerada , Melfalán/administración & dosificación , Melfalán/farmacocinética , Persona de Mediana Edad , Mieloma Múltiple/tratamiento farmacológico , Samario , Distribución Tisular
8.
Acta Paediatr Suppl ; 93(445): 78-84; discussion 84-5, 2004 May.
Artículo en Inglés | MEDLINE | ID: mdl-15176727

RESUMEN

Significant differences exist between the European and North American treatment protocols for Wilms' tumor and neuroblastoma. There are variations in biopsy technique, timing and extent of initial surgery, chemotherapy protocols and dosage routines, as well as the type of salvage therapy. With the consolidation of the two major North American study groups into a single entity (Children's Oncology Group), the European and North American study groups represent the only remaining large-scale venues for treatment comparison. It is important to study and understand the variation in treatment protocols in order to maintain an open forum of scientific investigation that will lead to improving the care and outcome of children with cancer. It is anticipated that the unification of the North American groups will lead to greater interest and scientific cooperation with the European study group. This paper will serve as a forum for such a discussion at a local level.


Asunto(s)
Neoplasias Renales/diagnóstico , Neoplasias Renales/terapia , Neuroblastoma/diagnóstico , Neuroblastoma/terapia , Tumor de Wilms/diagnóstico , Tumor de Wilms/terapia , Protocolos Clínicos , Europa (Continente) , Humanos , América del Norte
9.
J Burn Care Rehabil ; 25(1): 67-70, 2004.
Artículo en Inglés | MEDLINE | ID: mdl-14726741

RESUMEN

We have seen an alarming increase in the incidence of pediatric palm burns associated with gas fireplaces. The increasing popularity of these units places more children at risk. Medical records of patients under the age of 5 years who sustained hand burns from contact with the glass enclosure of gas fireplaces from 1996 through 2002 were reviewed. Thirty-nine patients were identified, with a mean age of 12.8 months. A 15-fold increase in incidence was observed. Thirty-three patients suffered superficial second-degree burns that were treated conservatively. Twenty-one percent of children developed significant wound complications requiring intensive therapy including extension splinting or surgery. Pediatric burns resulting from palmar contact with the glass enclosures of gas fireplaces have emerged as an avoidable new danger within the home. Although most of these injuries heal with conservative treatment alone, many require surgery or other intensive management to regain acceptable function.


Asunto(s)
Quemaduras/etiología , Traumatismos de la Mano/etiología , Accidentes Domésticos , Quemaduras/epidemiología , Quemaduras/cirugía , Preescolar , Combustibles Fósiles , Vidrio , Traumatismos de la Mano/epidemiología , Traumatismos de la Mano/cirugía , Humanos , Incidencia , Lactante , Trasplante de Piel , Férulas (Fijadores)
10.
Curr Cancer Drug Targets ; 3(4): 239-50, 2003 Aug.
Artículo en Inglés | MEDLINE | ID: mdl-12871055

RESUMEN

The lungs are common sites of involvement by primary and metastatic malignant disease. Patients with malignancies in the lung have limited treatment options and are usually not curable. Numerous investigators have studied the potential of delivering various therapeutic agents directly to the lungs and pulmonary lymphatics by nebulization. Most of the research involves the use of immunomodulatory strategies; a few aerosol studies of chemotherapy and gene therapy have also been conducted. Most of these studies have been conducted in animal models. A few human trials have also been completed. Results suggest that aerosol therapies have the potential to shrink pulmonary metastases of selected histologies, and that survival in selected patients with metastatic renal cell cancer may be prolonged. The approach to therapy of cancer in the lungs holds promise as a means to avoid systemic toxicity and obtain an improved therapeutic effect. Research is currently underway to address issues of local versus systemic toxicity, optimal drug delivery and selection of optimal drugs and schedules including outpatient aerosol therapy. Future issues in design of aerosol cancer treatment include identifying effective combinations of agents, schedules, and use of aerosol therapy at home as adjuvant therapy.


Asunto(s)
Antineoplásicos/administración & dosificación , Neoplasias Pulmonares/tratamiento farmacológico , Administración por Inhalación , Aerosoles , Animales , Ensayos Clínicos como Asunto/estadística & datos numéricos , Citocinas/administración & dosificación , Citocinas/genética , Humanos , Neoplasias Pulmonares/genética
11.
J Exp Biol ; 205(Pt 14): 2053-65, 2002 Jul.
Artículo en Inglés | MEDLINE | ID: mdl-12089209

RESUMEN

A previous study provided evidence that the adaptive strategy used by the teleost fish Bostrichthys sinensis (sleeper) for detoxifying ammonia during extended periods of air exposure was to synthesize and store glutamine, primarily in the muscle, accompanied by an increase in glutamine synthetase (GSase) activity in liver. The aim of the present study was to assess the effect on GSase expression in various tissues of exposure of B. sinensis to exogenous ammonia. Exogenous ammonia increases internal ammonia concentrations in fish, mimicking environmental situations such as air exposure that preclude loss of ammonia across the gills, and thus triggering alternative mechanisms for ammonia detoxification. The results reveal relatively high levels of GSase activity, not only in liver but also, unexpectedly, in muscle, and even higher levels in intestine and, in particular, stomach. Exposure to ammonia results in significant increases in GSase activity, GSase protein and GSase mRNA levels in all of these tissues except stomach. The amino acid sequences of GSases from liver and stomach deduced from the cDNA sequences are essentially identical and are >97 % identical to the amino acid sequences of GSases from Gulf toadfish (Opsanus beta) and marble goby (Oxyeleotris marmoratus).


Asunto(s)
Cloruro de Amonio/farmacología , Expresión Génica/efectos de los fármacos , Glutamato-Amoníaco Ligasa/genética , Perciformes/metabolismo , Secuencia de Aminoácidos , Animales , Secuencia de Bases , ADN Complementario/química , Glutamato-Amoníaco Ligasa/química , Glutamato-Amoníaco Ligasa/metabolismo , Intestinos/enzimología , Hígado/enzimología , Datos de Secuencia Molecular , Músculos/enzimología , ARN Mensajero/análisis , Alineación de Secuencia , Estómago/enzimología
12.
Int Immunopharmacol ; 2(2-3): 333-44, 2002 Feb.
Artículo en Inglés | MEDLINE | ID: mdl-11811936

RESUMEN

This is the first report of aerosol interleukin 2 (IL-2) liposome administration to individuals with immune deficiency. Parenteral IL-2 therapy has shown beneficial effects in some patients with cancer, common variable immunodeficiency (CVID), and human immunodeficiency virus (HIV) but is problematic because of side effects including fever and malaise as well as local swelling (delayed type hypersensitivity like reaction) after each subcutaneous IL-2 injection. Provision of an IL-2:human albumin liposome formulation via the aerosol route had few side effects in a recent clinical trial in cancer patients. Details of good manufacturing practice (GMP) synthesis and analysis of IL-2 liposomes (N= 6 lots) made without albumin carrier protein and placebo liposomes (three lots) are presented. After centrifugation, IL-2 was closely associated with the liposome pellet (99%). Mean diameter of liposomes was 1.1 microm. Patient acceptance, safety, toxicity, and immune effects of IL-2 liposomes were studied in individuals with primary immune deficiency (N = 15) and subsequently, a larger cohort of patients with hepatitis C. Experience in the immune deficient patients is the subject of this report. Placebo liposomes (12 weeks) and IL-2 liposomes (12 weeks) were provided using a nebulizer. Aerosol placebo liposomes and IL-2 liposomes were well tolerated. No changes in chest X-ray or pulmonary function were seen. Since biologic activity of aerosol IL-2 liposomes has been seen in viral disease (hepatitis C), additional studies of aerosol IL-2 liposomes in individuals with hepatitis C and HIV are planned.


Asunto(s)
Aerosoles/administración & dosificación , Síndromes de Inmunodeficiencia/terapia , Interleucina-2/administración & dosificación , Administración por Inhalación , Adolescente , Adulto , Aerosoles/síntesis química , Aerosoles/farmacología , Aerosoles/normas , Niño , Preescolar , Estudios Cruzados , Método Doble Ciego , Femenino , Humanos , Síndromes de Inmunodeficiencia/sangre , Interleucina-2/síntesis química , Interleucina-2/fisiología , Interleucina-2/normas , Liposomas/administración & dosificación , Liposomas/síntesis química , Liposomas/farmacología , Liposomas/normas , Activación de Linfocitos/efectos de los fármacos , Masculino , Persona de Mediana Edad
13.
Nurse Educ Today ; 21(6): 423-33, 2001 Aug.
Artículo en Inglés | MEDLINE | ID: mdl-11466005

RESUMEN

Almost 6% of Britain's population are of black or minority ethnic origin. There is increasing recognition that the health needs of such groups are not adequately met within the current health care system. One factor in reducing health inequalities is for health professionals to become culturally aware in order to serve these communities effectively. This literature review focuses on pre-registration nursing programmes that address cultural sensitivity as part of basic training. The studies were selected by a computerized search of a number of databases and a hand search of selected nursing journals. The papers were reviewed under the following headings: setting, programme design, conceptual framework, curricula content, student assessment, and course evaluation. The programmes presented were undertaken predominantly in the USA. Either few programmes exist in the UK, or the programme details have not been published. Although, in the UK, cultural sensitivity training appears in its infancy, there are positive signs of change.


Asunto(s)
Diversidad Cultural , Educación en Enfermería/métodos , Curriculum , Humanos
14.
Comp Biochem Physiol A Mol Integr Physiol ; 129(2-3): 527-39, 2001 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-11423323

RESUMEN

The purpose of this study was to determine if carbamoyl phosphate synthetase III (CPSase III) and related urea cycle enzyme activities in skeletal muscle tissue of juvenile rainbow trout (Oncorhynchus mykiss) increase during short- or long-term exercise, in parallel with changes in whole-body urea excretion rates. Urea excretion was elevated by 65% in fish that swam at high-speed (50 cm/s) vs. low-speed (20 cm/s) over a 2-h period, with no significant changes in CPSase III, ornithine transcarbamoylase or glutamine synthetase activities in muscle tissue. Fish that swam for 4 days at high-speed had higher rates of ammonia excretion and GSase activity in muscle and liver tissue relative to low-speed swimmers. Calculations showed that 47-53% of excreted urea, theoretically could be accounted for by total muscle CPSase III activity in juvenile and adult trout. The data indicate that increases in the rate of urea excretion during short-term high intensity exercise are not linked to higher activities of urea cycle enzymes in muscle tissue, but this does not rule out the possibility of increased flux through muscle CPSase III and related enzymes. Furthermore, these results indicate that urea cycle enzyme activities in skeletal muscle tissue can account for a significant portion of total urea excretion in juvenile and adult trout.


Asunto(s)
Ligasas de Carbono-Nitrógeno/metabolismo , Hígado/enzimología , Músculo Esquelético/enzimología , Nitrógeno/metabolismo , Oncorhynchus mykiss/fisiología , Animales , Enzimas , Femenino , Glutamato-Amoníaco Ligasa/metabolismo , Masculino , Ornitina Carbamoiltransferasa/metabolismo , Condicionamiento Físico Animal , Urea/metabolismo
15.
J Exp Biol ; 204(Pt 9): 1605-14, 2001 May.
Artículo en Inglés | MEDLINE | ID: mdl-11398749

RESUMEN

This study was designed to elucidate the strategies adopted by mudskippers to handle endogenous ammonia during aerial exposure in constant darkness. Under these conditions, specimens exhibited minimal locomotory activity, and the ammonia and urea excretion rates in both Periophthalmodon schlosseri and Boleophthalmus boddaerti decreased significantly. As a consequence, ammonia accumulation occurred in the tissues of both species of mudskipper. A significant increase in urea levels was found in the liver of P. schlosseri after 24h of aerial exposure, but no similar increase was seen in the tissues of B. boddaerti. It is unlikely that these two species of mudskipper detoxified ammonia to urea during aerial exposure since B. boddaerti does not possess a complete ornithine-urea cycle (OUC) and, although all the OUC enzymes were present in P. schlosseri, the activity of carbamoyl phosphate synthetase present in the liver mitochondria was too low to render the OUC functional for ammonia detoxification. Peritoneal injection of 15NH4Cl into P. schlosseri showed that this mudskipper was capable of incorporating some of the labelled ammonia into urea in its liver. However, aerial exposure did not affect this capability and did not induce detoxification of the accumulated ammonia to urea. Mudskippers exposed to terrestrial conditions and constant darkness did, however, show significant decreases in the total free amino acid content in the liver and blood, in the case of P. schlosseri and in the muscle of B. boddaerti. No changes in the alanine or glutamine content of the muscle were found in either species. Analyses of the balance between the reduction in nitrogenous excretion and the increase in nitrogenous accumulation further revealed that these two species of mudskipper were capable of reducing their protein and amino acid catabolic rates. Such adaptations constitute the most efficient way to avoid the build-up of internal ammonia, and would render unnecessary the detoxification of ammonia through energetically expensive pathways. This finding may be the first report of a teleost fish showing a reduction in proteolysis and amino acid catabolism in response to aerial exposure.


Asunto(s)
Aire , Aminoácidos/metabolismo , Amoníaco/metabolismo , Oscuridad , Perciformes/metabolismo , Proteínas/metabolismo , Alanina/metabolismo , Aminoácidos/sangre , Cloruro de Amonio/administración & dosificación , Cloruro de Amonio/metabolismo , Animales , Carbamoil-Fosfato Sintasa (Amoniaco)/metabolismo , Carbamoil-Fosfato Sintasa (Glutamina-Hidrolizante)/metabolismo , Glutamina/metabolismo , Inactivación Metabólica , Cinética , Hígado/metabolismo , Mitocondrias Hepáticas/enzimología , Actividad Motora , Músculos/metabolismo , Urea/metabolismo
16.
Cancer ; 91(6): 1166-9, 2001 Mar 15.
Artículo en Inglés | MEDLINE | ID: mdl-11267962

RESUMEN

BACKGROUND: CI-958 is a synthetic intercalating agent of a new chemical class, the benzopyranoindazoles, with promising preclinical activity. Its mechanism of action is thought to be stabilization of the cleavable complex of DNA with topoisomerase II, as well as DNA helicase blockade. It is thought to have less cardiotoxicity than the anthracyclines. Early Phase I studies in adults showed the drug to be well tolerated, making it an attractive agent to pursue in Phase I clinical trials in children. METHODS: Children and adolescents with recurrent solid tumors received CI-958 at an initial dose of 450 mg/m(2) over 2 hours. Dose escalation was performed in a standard fashion in cohorts of three patients until dose limiting toxicity and the maximum tolerated dose were determined. RESULTS: Twenty-one patients were entered on the study. The maximum tolerated dose was found to be 650 mg/m(2). Dose limiting toxicities were Grade 4 neutropenia and Grade 4 hypotension at the dose level of 700 mg/m(2). CONCLUSIONS: The maximum tolerated dose of CI-958 in children and adolescents is 650 mg/m(2). No antitumor activity has been observed.


Asunto(s)
Antineoplásicos/efectos adversos , Indazoles/efectos adversos , Neoplasias/tratamiento farmacológico , Adolescente , Adulto , Factores de Edad , Antineoplásicos/administración & dosificación , Antineoplásicos/farmacología , Niño , Preescolar , Relación Dosis-Respuesta a Droga , Femenino , Humanos , Hipotensión/inducido químicamente , Indazoles/administración & dosificación , Indazoles/farmacología , Infusiones Intravenosas , Masculino , Neutropenia/inducido químicamente
17.
Comp Biochem Physiol B Biochem Mol Biol ; 126(4): 521-35, 2000 Aug.
Artículo en Inglés | MEDLINE | ID: mdl-11026664

RESUMEN

The presence of carbamoyl phosphate synthetase III (CPSase III), catalyzing the first step of the urea cycle in fish, in Atlantic halibut (Hippoglossus hippoglossus L.) yolk-sac larvae and adult white muscle has been established using gel filtration chromatography to separate the CPSase III from the pyrimidine-pathway related CPSase II. The results are consistent with the hypothesis that teleostean fish express urea cycle enzymes during early development and with recent observations of low levels of CPSase III in muscle tissue. The presence of CPSase III in crude extracts could not be established using sensitive assay conditions to discriminate between CPSase III and CPSase II. However, kinetic characterization after chromatographic separation identified each as typical CPSase II and CPSase III activities, respectively. The CPSase III was less sensitive to activation by N-acetyl-L-glutamate and had a higher Km for ammonia than CPSase III found in other species. These results suggest that precise quantitation of low levels of CPSase III in the presence of CPSase II by assaying crude extracts may be difficult unless the enzymes are first separated and the kinetic properties of CPSase III are determined; the results indicate that assaying larval extracts of Atlantic halibut in the presence of uridine triphosphate results in CPSase activity that reflects mostly CPSase III and can, therefore, be used to measure changes in CPSase III activity.


Asunto(s)
Carbamoil-Fosfato Sintasa (Amoniaco)/metabolismo , Peces/metabolismo , Urea/metabolismo , Animales , Carbamoil-Fosfato Sintasa (Amoniaco)/química , Cromatografía en Gel , Embrión no Mamífero/enzimología , Peces/embriología , Peces/crecimiento & desarrollo , Riñón/enzimología , Hígado/enzimología , Músculos/enzimología , Tiburones/metabolismo
18.
Anticancer Drugs ; 11(7): 555-63, 2000 Aug.
Artículo en Inglés | MEDLINE | ID: mdl-11036958

RESUMEN

The lung is a common site of both metastases and primary neoplasia. This phase I study was designed to test the feasibility and toxicity of administering interleukin (IL)-2 liposomes by aerosol to patients with pulmonary metastases. The goal was to test whether IL-2 liposomes could be given by aerosol using biologically effective but non-toxic doses in an outpatient setting. Liposomes containing IL-2 or placebo (buffer) were synthesized and mixed to provide a constant lipid dose, and were nebulized using a Puritan twin jet nebulizer and a standard compressor. The liposome-containing mist was inhaled for about 20 min 3 times a day in order to selectively stimulate immune function within the lung and to avoid systemic toxicity. The dose chosen was based on canine efficacy and toxicity studies that used bronchoalveolar lavage to demonstrate increased cell numbers and activation of mononuclear cells after inhalation of nebulized IL-2 liposomes. Nine patients were treated in three cohorts of three patients at 1.5, 3.0 and 6.0 x 10(6) IU of IL-2 3 times a day. No significant toxicity was observed. We conclude that the delivery of IL-2 liposomes by inhalation is well tolerated. Further studies of inhalational IL-2 liposomes to determine efficacy as an anti-cancer therapy are warranted.


Asunto(s)
Interleucina-2/administración & dosificación , Neoplasias Pulmonares/tratamiento farmacológico , Neoplasias Pulmonares/secundario , Administración por Inhalación , Adulto , Esquema de Medicación , Estudios de Factibilidad , Femenino , Humanos , Interleucina-2/efectos adversos , Liposomas , Neoplasias Pulmonares/sangre , Masculino , Persona de Mediana Edad , Receptores de Interleucina-2/sangre , Espirometría
20.
Structure ; 8(5): 505-14, 2000 May 15.
Artículo en Inglés | MEDLINE | ID: mdl-10801492

RESUMEN

BACKGROUND: Cyanase is an enzyme found in bacteria and plants that catalyzes the reaction of cyanate with bicarbonate to produce ammonia and carbon dioxide. In Escherichia coli, cyanase is induced from the cyn operon in response to extracellular cyanate. The enzyme is functionally active as a homodecamer of 17 kDa subunits, and displays half-site binding of substrates or substrate analogs. The enzyme shows no significant amino acid sequence homology with other proteins. RESULTS: We have determined the crystal structure of cyanase at 1.65 A resolution using the multiwavelength anomalous diffraction (MAD) method. Cyanase crystals are triclinic and contain one homodecamer in the asymmetric unit. Selenomethionine-labeled protein offers 40 selenium atoms for use in phasing. Structures of cyanase with bound chloride or oxalate anions, inhibitors of the enzyme, allowed identification of the active site. CONCLUSIONS: The cyanase monomer is composed of two domains. The N-terminal domain shows structural similarity to the DNA-binding alpha-helix bundle motif. The C-terminal domain has an 'open fold' with no structural homology to other proteins. The subunits of cyanase are arranged in a novel manner both at the dimer and decamer level. The dimer structure reveals the C-terminal domains to be intertwined, and the decamer is formed by a pentamer of these dimers. The active site of the enzyme is located between dimers and is comprised of residues from four adjacent subunits of the homodecamer. The structural data allow a conceivable reaction mechanism to be proposed.


Asunto(s)
Liasas de Carbono-Nitrógeno/química , Escherichia coli/enzimología , Modelos Moleculares , Sitios de Unión , Dominio Catalítico , Cristalografía por Rayos X/métodos , Dimerización , Datos de Secuencia Molecular , Estructura Cuaternaria de Proteína , Estructura Terciaria de Proteína , Homología de Secuencia de Aminoácido , Sincrotrones
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