RESUMEN
In order to address serious concerns over public health, water scarcity and groundwater pollution in Jordan, the expansion of decentralized wastewater treatment and reuse (DWWT&R) systems to small communities is one of the goals defined by the Jordan government in the "Water Strategy 2009-2022". This paper evaluates the general potential of decentralized wastewater system solutions to be applied in a selected area of the Lower Jordan Rift Valley in Jordan. For the study area, the connection degree to sewer systems was calculated as 67% (5% in the rural sector and 75% in the urban sector). The annual wastewater production available for DWWT&R in the rural sector of the investigation area was calculated to be nearly 3.8 million m(3) at the end of 2007. The future need of wastewater treatment and reuse facilities of the rural sector was estimated to be increasing by 0.11 million m(3) year(-1), with an overall potential of new treatment capacity of nearly 15,500 population equivalents (pe) year(-1). The overall potential for implementing DWWT&R systems in the urban sector was estimated as nearly 25 million m(3) of wastewater in 2007. The future need of wastewater treatment and reuse facilities required for the urban sector was estimated to be increasing at a rate of 0.12 million pe year(-1). Together with the decision makers and the stakeholders, a potential map with three regions has been defined: Region 1 with existing central wastewater infrastructure, Region 2 with already planned central infrastructure and Region 3 with the highest potential for implementing DWWT&R systems.
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Eliminación de Residuos Líquidos/métodos , Demografía , Contaminación Ambiental , Predicción , Humanos , Jordania , Política , Densidad de Población , Crecimiento Demográfico , Salud Pública , Población Rural , Purificación del Agua/métodos , Abastecimiento de Agua/normasRESUMEN
PURPOSE: To evaluate the progression of keratoconus in 932 eyes of 659 patients through visual, refractive and topographic data after intracorneal ring segment (ICRS) implantation. METHODS: Retrospective review of 659 patients who underwent ICRS (Intacs®) implantation for keratoconus between September 1997 and November 2017. Demographics, preoperative and postoperative uncorrected visual acuity (UCVA) and best-corrected visual acuity (BCVA) in LogMAR, corneal topography parameters (thinnest pachymetry, Kmax), central corneal pachymetry and total follow-up time were evaluated. Statistical analysis was performed using IBM SPSS Statistics 24.0 for windows. RESULTS: Nine hundred and thirty-two eyes of 659 patients, with a mean age of 30.41 years (range 11-76 years), were evaluated. Mean total follow up time was 3.02 years. Forty-one eyes had a total follow up of over 10 years. Both UCVA and BCVA improved significantly after ICRS implantation (P<0.01). Only 18 eyes (2.66% of eyes of patients under 35 years of age) were found to have progression of keratoconus based on postoperative topographic data (Mean age 23.00 years, 55.6% female, total follow-up 2 to 10 years) CONCLUSION: ICRS implantation showed long-term improvement and stability in visual and topographic results in a large case series of patients with keratoconus. Only a minimal rate of progression was detected in young patients. However, further prospective studies need to be conducted to better define predictability of postoperative visual outcomes and progression.
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Sustancia Propia/cirugía , Queratocono/cirugía , Procedimientos Quirúrgicos Oftalmológicos , Implantación de Prótesis , Adolescente , Adulto , Anciano , Niño , Paquimetría Corneal , Sustancia Propia/patología , Topografía de la Córnea , Progresión de la Enfermedad , Femenino , Estudios de Seguimiento , Humanos , Queratocono/diagnóstico , Queratocono/epidemiología , Queratocono/patología , Masculino , Persona de Mediana Edad , Procedimientos Quirúrgicos Oftalmológicos/efectos adversos , Procedimientos Quirúrgicos Oftalmológicos/instrumentación , Procedimientos Quirúrgicos Oftalmológicos/métodos , Procedimientos Quirúrgicos Oftalmológicos/estadística & datos numéricos , Prótesis e Implantes/efectos adversos , Implantación de Prótesis/efectos adversos , Implantación de Prótesis/métodos , Implantación de Prótesis/estadística & datos numéricos , Refracción Ocular , Estudios Retrospectivos , Resultado del Tratamiento , Agudeza Visual , Adulto JovenRESUMEN
We describe a case series of four eyes of four keratoconus patients with extruded intracorneal ring segments (ICRS) in whom donor corneal tissue was used to substitute for the extruded ICRS in an attempt to preserve its effect. In all patients, the extruded intracorneal ring was removed through the exposed area. Donor corneal tissue (tailored to the size and shape of the ICRS) was inserted into the empty ICRS tunnel and fixed in place using 10-0 nylon sutures. At three months follow-up, all patients had a healed graft and displayed a stable Kmax, best corrected visual acuity (BCVA) and corneal topography comparable to the preoperative values. Replacing extruded intracorneal rings with donor tissue grafts in keratoconus patients appears to be a promising technique in preserving the effect of the corneal ring and possibly in treating primary keratoconus with donor tissue segments. Refinement of the technique, longer follow-up, and a larger study population is warranted.
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Trasplante de Córnea , Remoción de Dispositivos , Queratocono/cirugía , Prótesis e Implantes , Adulto , Estudios de Cohortes , Trasplante de Córnea/métodos , Trasplante de Córnea/estadística & datos numéricos , Femenino , Humanos , Queratocono/epidemiología , Queratocono/patología , Líbano/epidemiología , Masculino , Prótesis e Implantes/efectos adversos , Estudios Retrospectivos , Trasplante Homólogo , Resultado del Tratamiento , Adulto JovenRESUMEN
BACKGROUND: Because of the growing demand for genetic assessment, there is an urgent need for information about what services are appropriate for women with a family history of breast cancer. Our purpose was to compare the psychologic impact and costs of a multidisciplinary genetic and surgical assessment service with those of current service provisions. METHODS: We carried out a prospective randomized trial of surgical consultation with (the trial group) and without (the control group) genetic assessment in 1000 women with a family history of breast cancer. All P: values are from two-sided tests. RESULTS: Although statistically significantly greater improvement in knowledge about breast cancer was found in the trial group (P: =.05), differences between groups in other psychologic outcomes were not statistically significant. Women in both groups experienced statistically significant reductions in anxiety and found attending the clinics to be highly satisfying. An initial specialist genetic assessment cost pound 14.27 (U.S. $22.55) more than a consultation with a breast surgeon. Counseling and genetic testing of affected relatives, plus subsequent testing of family members of affected relatives identified as mutation carriers, raised the total extra direct and indirect costs per woman in the trial group to pound 60.98 (U.S. $96.35) over costs for the control subjects. CONCLUSIONS: There may be little benefit in providing specialist genetics services to all women with a family history of breast cancer. Further investigation of factors that may mediate the impact of genetic assessment is in progress and may reveal subgroups of women who would benefit from specialist genetics services.
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Neoplasias de la Mama/economía , Neoplasias de la Mama/psicología , Pruebas Genéticas/economía , Grupo de Atención al Paciente/economía , Adulto , Ansiedad/etiología , Neoplasias de la Mama/genética , Análisis Costo-Beneficio , Femenino , Humanos , Persona de Mediana Edad , Satisfacción del Paciente , Estudios Prospectivos , Riesgo , GalesRESUMEN
The aim of this study was to determine whether reporting guidelines and computerised form-based reports improve the completeness of histopathological cancer data available for patient management and population cancer registration and to evaluate the acceptability of the intervention. The study was a randomised controlled trial with a split unit design and stratified cluster randomisation. All 16 hospital pathology laboratories in Wales were randomly allocated to report either breast or colorectal resection specimens by computerised form or conventional free text. 1044 reports were analysed in the study arm, 998 in the control arm. Use of pre-defined forms led to a 28.4% (95% confidence interval (CI): 15.7-41.2%) increase in complete reporting of a minimum dataset required for cancer registration and a 24.5% (95% CI: 11.0-38.0%) increase in complete reporting of minimum data required for patient management. Form-based reporting was acceptable to pathologists and preferred by clinicians. In conclusion, guidelines and computerised forms significantly improve the quality of histopathology reporting.
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Neoplasias de la Mama/patología , Neoplasias Colorrectales/patología , Sistemas de Registros Médicos Computarizados , Guías de Práctica Clínica como Asunto , Femenino , Humanos , Patología Quirúrgica/educación , Patología Quirúrgica/normas , Programas InformáticosRESUMEN
The cellular weakening or cytoxic consequences of CAC are intertwined in the most fundamental sense with energy intake, production, storage, and mobilization. The impact of CAC on the HPA axis to increase GCs makes this energy regulatory hormone along with pancreatic hormones a potential major player in the site-specific organ pathologies associated with CAC. Although little is known about the mechanism of CAC neurotoxicity, the hippocampal endangerment model which relies heavily on the cellular weakening, site-specific effect of continuous or chronic, intermittent (withdrawal, binge drinking) elevation of GCs, even less is known about the mechanism of neurotoxicity of activating the ethanol-inducible CYP2E1 system. It is likely that components of both models contribute to the site-specific, CNS neurotoxicity associated with CAC, but this remains largely unresolved.
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Corticoesteroides/metabolismo , Alcoholismo/metabolismo , Hipocampo/metabolismo , Sistema Hipotálamo-Hipofisario/metabolismo , Sistema Hipófiso-Suprarrenal/metabolismo , Animales , Encéfalo/metabolismo , Encefalopatías/inducido químicamente , Citocromo P-450 CYP2E1 , Sistema Enzimático del Citocromo P-450/metabolismo , Metabolismo Energético , Masculino , Oxidorreductasas N-Desmetilantes/metabolismo , Ratas , Receptores de Glucocorticoides/metabolismoRESUMEN
conservative approach to splenic trauma has been practised in many countries. Haemodynamically stable patients who have been carefully assessed clinically and radiographically may safely be treated non-operatively. In those patients who require surgery the spleen may be preserved by splenorrhaphy or partial splenectomy. This approach has been practised at our hospital and we present our experience over seven years to show that expectant treatment of splenic injury following trauma is safe.
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Bazo/lesiones , Heridas no Penetrantes/terapia , Accidentes de Tránsito , Adulto , Anciano , Anciano de 80 o más Años , Niño , Femenino , Humanos , Imagen por Resonancia Magnética , Masculino , Persona de Mediana Edad , Bazo/diagnóstico por imagen , Bazo/cirugía , Esplenectomía , Ultrasonografía , Heridas no Penetrantes/diagnósticoRESUMEN
Sixty cases of occult carcinoma of the lung are described. A distinction is made between "revealed cases" (23 cases) in which the carcinoma revealed itself within 5 months after the first cytological findings, and true occult carcinomas (37 cases) in which lesions developed within 5 months to 8 years after the first positive cytology. Mean survival in the "revealed cases" was 13 months. It was 51 months for true occult lung carcinomas and 68.5 months for occult carcinomas treated by chemotherapy starting at the time of discovery of malignant cells in the sputum. The method of choice is selective bronchial aspirates and brushings after repeated sputum cytology which allows for localization of the lesion and early surgery.
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Carcinoma de Células Escamosas/patología , Neoplasias Pulmonares/patología , Esputo/citología , Adenocarcinoma/patología , Anciano , Carcinoma/patología , Femenino , Humanos , Neoplasias Pulmonares/diagnóstico , Neoplasias Pulmonares/terapia , Masculino , Persona de Mediana Edad , Factores de TiempoRESUMEN
INTRODUCTION: Angiolymphoid hyperplasia with eosinophilia (HALE) is a rare, benign proliferative vascular disorder of unknown etiology which typically presents as tumor-like nodules of the skin or subcutaneous tissue. It concerns mostly young female adults. We report a case of HALE located on the ear auricle diagnosed by biopsy. The outcome was total regression. OBSERVATION: An 81-year-old male patient presented with a lesion of the whole ear auricle. A diagnosis of HALE was confirmed histologically on biopsy. The evolution was marked by spontaneous and complete regression in 2 months. There was no recurrence after 1 year of follow-up. DISCUSSION: The etiology of this disease remains hypothetical. It poses real diagnostic problems with other types of proliferation, but its main differential diagnosis is Kimura disease. Its treatment has not been codified yet. Spontaneous regression is possible and justifies following the patient from 3 to 6 months, before a possible surgery.
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Hiperplasia Angiolinfoide con Eosinofilia/diagnóstico , Enfermedades del Oído/diagnóstico , Anciano de 80 o más Años , Hiperplasia Angiolinfoide con Eosinofilia/patología , Biopsia , Diagnóstico Diferencial , Pabellón Auricular/patología , Enfermedades del Oído/patología , Humanos , MasculinoRESUMEN
MRP1 is an ABC (or ATP binding cassette) membrane transport protein shown to confer resistance to structurally dissimilar drugs. Studies of MRP1 topology suggested the presence of a hydrophobic N-domain with five potential membrane-spanning domains linked to an MDR1-like core (MSD1-NBD1-L1-MSD2-NBD2) by an intracellular linker domain (L0). MRP1-mediated multidrug resistance is thought to be due to enhanced drug efflux. However, little is known about MRP1-drug interaction and its drug binding site(s). We previously developed several photoreactive probes to study MRP1-drug interactions. In this report, we have used eight MRP1-HA variants that were modified to have hemagglutinin A (HA) epitopes inserted at different sites in MRP1 sequence. Exhaustive in-gel digestion of all IAARh123 photoaffinity-labeled MRP1-HA variants revealed the same profile of photolabeled peptides as seen for wild type MRP1. Photolabeling of the different MRP1-HA variants followed by digestion with increasing concentrations of trypsin or Staphylococcus aureus V8 protease (1:800 to 1:5 w/w) and immunoprecipitation with anti-HA mAb identified two small photolabeled peptides ( approximately 6-7 kDa) from MRP1-HA(574) and MRP1-HA(1222). Based on the location of the HA epitopes in the latter variants together with molecular masses of the two peptides, the photolabeled amino acid residues were localized to MRP1 sequences encoding transmembranes 10 and 11 of MSD1 (Ser(542)-Arg(593)) and transmembranes 16 and 17 of MSD2 (Cys(1205)-Glu(1253)). Interestingly, the same sequences in MRP1 were also photolabeled with a structurally different photoreactive drug, IACI, confirming the significance of transmembranes 10, 11, 16 and 17 in MRP1 drug binding. Taken together, the results in this study provide the first delineation of the drug binding site(s) of MRP1. Furthermore, our findings suggest the presence of common drug binding site(s) for structurally dissimilar drugs.
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Transportadoras de Casetes de Unión a ATP/metabolismo , Preparaciones Farmacéuticas/metabolismo , Transportadoras de Casetes de Unión a ATP/química , Secuencia de Aminoácidos , Sitios de Unión , Western Blotting , Electroforesis en Gel de Poliacrilamida , Células HeLa , Humanos , Datos de Secuencia Molecular , Proteínas Asociadas a Resistencia a Múltiples Medicamentos , Etiquetas de FotoafinidadRESUMEN
Overexpression of the multidrug resistance-associated protein (MRP1) causes multidrug resistance in cultured cells. MRP1 transports a large number of glutathione, glucuronide, and sulfate-conjugated organic anions by an ATP-dependent efflux mechanism. Six other MRP proteins exist (MRP2-7), and mutations in some of these genes cause major pathological conditions in humans. A detailed characterization of the structure and mechanism of action of these proteins requires an efficient expression system from which large amounts of active protein can be obtained. We report the expression of a recombinant MRP1 in the methylotrophic yeast Pichia pastoris. The protein is expressed in the membrane fraction of these cells, as a stable and underglycosylated 165 kDa peptide. Expression levels are very high, and 30 times superior to those seen in multidrug-resistant HeLa/MRP1 transfectants. MRP1 expressed in P. pastoris binds 8-azido[alpha-(32)P]ATP in a Mg(2+)-dependent and EDTA-sensitive fashion, which can be competed by a molar excess of ADP and ATP. Under hydrolysis conditions (at 37 degrees C), orthovanadate induces trapping of the 8-azido[alpha-(32)P]nucleotide in MRP1, which can be further modulated by known MRP1 ligands. MRP1 is also labeled by a photoactive analogue of rhodamine 123 (IAARh123) in P. pastoris/MRP1 membranes, and this can be competed by known MRP1 ligands. Finally, MRP1-positive membrane vesicles show ATP-dependent uptake of LTC(4). Thus, MRP1 expressed in P. pastoris is active and shows characteristics of MRP1 expressed in mammalian cells, including drug binding, ligand-modulated formation of the MRP1-MgADP-P(i) intermediate (ATPase activity), and ATP-dependent substrate transport. The successful expression of catalytically active and transport-competent MRP1 in P. pastoris should greatly facilitate the efficient production and isolation of the wild type or inactive mutants of MRP1, or of other MRP proteins for structural and functional characterization.
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Miembro 1 de la Subfamilia B de Casetes de Unión a ATP/biosíntesis , Miembro 1 de la Subfamilia B de Casetes de Unión a ATP/genética , Adenosina Trifosfato/análogos & derivados , Pichia/genética , Proteínas Recombinantes/biosíntesis , Miembro 1 de la Subfamilia B de Casetes de Unión a ATP/metabolismo , Miembro 1 de la Subfamilia B de Casetes de Unión a ATP/fisiología , Adenosina Trifosfato/metabolismo , Adenosina Trifosfato/fisiología , Azidas/metabolismo , Fraccionamiento Celular , Membrana Celular/metabolismo , Humanos , Radioisótopos de Yodo/metabolismo , Leucotrieno C4/metabolismo , Radioisótopos de Fósforo , Etiquetas de Fotoafinidad/metabolismo , Pichia/citología , Pichia/metabolismo , Plásmidos/biosíntesis , Plásmidos/síntesis química , Unión Proteica/genética , Transporte de Proteínas/genética , Proteínas Recombinantes/genética , Proteínas Recombinantes/metabolismo , Rodamina 123/metabolismo , Tritio , Vanadatos/farmacologíaRESUMEN
The mechanisms of MRP1-drug binding and transport are not clear. In this study, we have characterized the interaction between MRP1 and rhodamine 123 (Rh123) using the photoreactive-iodinated analogue, [(125)I]iodoaryl azido-rhodamine 123 (or IAARh123). Photoaffinity labeling of plasma membranes from HeLa cells transfected with MRP1 cDNA (HeLa-MRP1) with IAARh123 shows the photolabeling of a 190 kDa polypeptide not labeled in HeLa cells transfected with the vector alone. Immunoprecipitation of a 190 kDa photolabeled protein with MRP1-sepcific monoclonal antibodies (QCRL-1, MRPr1, and MRPm6) confirmed the identity of this protein as MRP1. Analysis of MRP1-IAARh123 interactions showed that photolabeling of membranes from HeLa-MRP1 with increasing concentrations of IAARh123 was saturable, and was inhibited with excess of IAARh123. Furthermore, the photoaffinity labeling of MRP1 with IAARh123 was greatly reduced in the presence of excess Leukotreine C(4) or MK571, but to a lesser extent with excess doxorubicin, colchicine or chloroquine. Cell growth assays showed 5-fold and 14-fold increase in the IC(50) of HeLa-MRP1 to Rh123 and the Etoposide VP16 relative to HeLa cells, respectively. Analysis of Rh123 fluorescence in HeLa and HeLa-MRP1 cells with or without ATP suggests that cross-resistance to Rh123 is in part due to reduced drug accumulation in the cytosol of HeLa-MRP1 cells. Mild digestion of purified IAARh123-photolabeled MRP1 with trypsin showed two large polypeptides (approximately 111 and approximately 85 kDa) resulting from cleavage in the linker domain (L1) connecting the multiple-spanning domains MSD0 and MSD1 to MSD2. Exhaustive proteolysis of purified IAARh123-labeled 85 and 111 kDa polypeptides revealed one (6 kDa) and two (approximately 6 plus 4 kDa) photolabeled peptides, respectively. Resolution of total tryptic digest of IAARh123-labeled MRP1 by HPLC showed three radiolabeled peaks consistent with the three Staphylococcus aureus V8 cleaved peptides from the Cleveland maps. Together, the results of this study show direct binding of IAARh123 to three sites that localize to the N- and C-domains of MRP1. Moreover, IAARh123 provides a sensitive and specific probe to study MRP1-drug interactions.
Asunto(s)
Miembro 1 de la Subfamilia B de Casetes de Unión a ATP/química , Rodamina 123/química , Miembro 1 de la Subfamilia B de Casetes de Unión a ATP/metabolismo , Sitios de Unión , Transporte Biológico , Membrana Celular/química , Membrana Celular/metabolismo , Células HeLa , Humanos , Unión Proteica , Rodamina 123/metabolismo , TransfecciónRESUMEN
All consecutive patients with positive blood culture for Candida species over a 6-year period were evaluated to define recent epidemiologic characteristics of candidemia, and to assess the prevalence of late complications. We encountered 106 cases; medical records were available for 99 of them. The rate of candidemia was increasing until 1990, after which it declined. C. albicans was the most common species, but in the last 2 years, C. tropicalis and C. parapsilosis were emerging. Overall mortality rate was 54.5% without significant variation during the study period. Antifungal therapy was withheld in 24/99 cases (24.2%). Decision to withhold treatment was taken in 19/59 cases (32.2%) before the availability of fluconazole in 1990, compared with 5/40 cases (12.5%) afterward (p < 0.05). Follow-up was possible in 35 instances for an average period of 17.1 months (range: 1-48 months); 7 of these individuals, all with transient candidemia, were untreated. None of the survivors developed late complications. These findings demonstrate that candidemia appears to be declining since 1990, with a noticeable decrease in the prevalence of C. albicans but an increase in that of C. tropicalis and C. parapsilosis, that fewer patients are left untreated since fluconazole became available, and that the risk of late complications among the survivors is low.
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Candidiasis/epidemiología , Fungemia/epidemiología , Adulto , Anciano , Anciano de 80 o más Años , Antifúngicos/uso terapéutico , Candida/aislamiento & purificación , Candidiasis/tratamiento farmacológico , Candidiasis/microbiología , Femenino , Estudios de Seguimiento , Fungemia/tratamiento farmacológico , Fungemia/microbiología , Hospitales de Enseñanza , Humanos , Lactante , Masculino , Michigan/epidemiología , Persona de Mediana Edad , Prevalencia , Especificidad de la Especie , Encuestas y CuestionariosRESUMEN
Alternative splicing plays an important role in the expression of genetic information. Among the best understood alternative splicing factors are transformer and transformer-2, which regulate sexual differentiation in Drosophila. Like the Drosophila genes, the recently identified mammalian homologues are subject to alternative splicing. Using an antibody directed against the major human transformer-2 beta isoform, we show that it has a widespread expression in the rat brain. Pilocarpine-induced neuronal activity changes the alternative splicing pattern of the human transformer-2-beta gene in the brain. After neuronal stimulation, a variant bearing high similarity to a male-specific Drosophila tra-2179 isoform is switched off in the hippocampus and is detectable in the cortex. In addition, the ratio of another short RNA isoform (htra2-beta2) to htra2-beta1 is changed. Htra2-beta2 is not translated into protein, and probably helps to regulate the relative amounts of htra2-beta1 to beta3. We also observe activity-dependent changes in alternative splicing of the clathrin light chain B, c-src and NMDAR1 genes, indicating that the coordinated change of alternative splicing patterns might contribute to molecular plasticity in the brain.
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Empalme Alternativo/fisiología , Química Encefálica/fisiología , Proteínas del Tejido Nervioso , Proteínas Nucleares/genética , Proteínas de Unión al ARN , Secuencia de Aminoácidos , Animales , Anticuerpos , Corteza Cerebral/química , Clatrina/genética , Regulación de la Expresión Génica/efectos de los fármacos , Regulación de la Expresión Génica/fisiología , Genes src/fisiología , Hipocampo/química , Humanos , Masculino , Datos de Secuencia Molecular , Agonistas Muscarínicos/farmacología , Neuronas/química , Neuronas/fisiología , Proteínas Nucleares/inmunología , Proteínas Nucleares/metabolismo , Fosforilación , Pilocarpina/farmacología , ARN Mensajero/análisis , Ratas , Ratas Wistar , Receptores de N-Metil-D-Aspartato/genética , Ribonucleasas , Factores de Empalme Serina-ArgininaRESUMEN
A 58-year-old man who had had three laparotomies for gastric surgery, developed a painful mass in the abdominal wall scar. Radiology confirmed bone formation in the scar. The bone was excised and the wound repaired. Histology confirmed metaplastic mature bone formation. This case draws the attention to the clinical condition of bone formation in midline scars. Clinically, it should be differentiated from scar recurrence following surgery for abdominal malignancy.
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Cicatriz/complicaciones , Laparotomía/efectos adversos , Osificación Heterotópica/etiología , Diagnóstico Diferencial , Humanos , Masculino , Metaplasia/diagnóstico , Metaplasia/etiología , Persona de Mediana Edad , Miositis Osificante/diagnóstico , Miositis Osificante/patología , Osificación Heterotópica/diagnósticoRESUMEN
Tumor cells overcome cytotoxic drug pressure by the overexpression of either or both transmembrane proteins, the P-glycoprotein (P-gp) and the multidrug resistance protein (MRP). The MRP has been shown to mediate the transport of cytotoxic natural products, in addition to glutathione-, glucuronidate-, and sulfate-conjugated cell metabolites. However, the mechanism of MRP drug binding and transport is at present not clear. In this study, we have used a photoreactive quinoline-based drug, N-(hydrocinchonidin-8'-yl)-4-azido-2-hydroxybenzamide (IACI), to show the photoaffinity labeling of the 190 kDa protein in membranes from the drug resistant SCLC H69/AR cells. The photoaffinity labeling of the 190 kDa protein by IACI was saturable and specific. The identity of the IACI-photolabeled protein as the MRP was confirmed by immunoprecipitation with the monoclonal antibody QCRL-1. Furthermore, a molar excess of leukotriene C(4), doxorubicin, colchicine, and other quinoline-based drugs, including MK571, inhibited the photoaffinity labeling of the MRP. Drug transport studies showed lower IACI accumulation in MRP-expressing cells which was reversed by depleting ATP levels in H69/AR cells. Mild digestion of the purified IACI-photolabeled MRP with trypsin showed two large polypeptides ( approximately 111 and approximately 85 kDa). The 85 kDa polypeptide which contains the QCRL-1 and MRPm6 monoclonal antibody epitopes corresponds to the C-terminal half of the MRP (amino acids approximately 900-1531) containing the third multiple spanning domain (MSD3) and the second nucleotide binding site. The 111 kDa polypeptide which contains the epitope sequence of the MRPr1 monoclonal antibody encodes the remainder of the MRP sequence (amino acids 1-900) containing the MSD1 and MSD2 plus the first nucleotide binding domain. Cleveland maps of purified IACI-labeled 85 and 111 kDa polypeptides revealed 6 kDa and approximately 6 plus 4 kDa photolabeled peptides, respectively. In addition, resolution of the exhaustively digested IACI-photolabeled MRP by HPLC showed two major and one minor radiolabeled peaks that eluted late in the gradient (60 to 72% acetonitrile). Taken together, the results of this study show direct binding of IACI to the MRP at physiologically relevant sites. Moreover, IACI photolabels three small peptides which localize to the N- and C-halves of the MRP. Finally, IACI provides a sensitive and specific probe for studying MRP-drug interactions.
Asunto(s)
Transportadoras de Casetes de Unión a ATP/metabolismo , Azidas/metabolismo , Benzamidas/metabolismo , Alcaloides de Cinchona/metabolismo , Resistencia a Múltiples Medicamentos , Proteínas de Neoplasias/metabolismo , Etiquetas de Fotoafinidad/metabolismo , Transportadoras de Casetes de Unión a ATP/antagonistas & inhibidores , Transportadoras de Casetes de Unión a ATP/química , Azidas/química , Benzamidas/química , Unión Competitiva , Alcaloides de Cinchona/química , Humanos , Proteínas Asociadas a Resistencia a Múltiples Medicamentos , Proteínas de Neoplasias/química , Fragmentos de Péptidos/química , Fragmentos de Péptidos/metabolismo , Unión Proteica , Células Tumorales Cultivadas/química , Células Tumorales Cultivadas/metabolismoRESUMEN
B lymphocyte stimulator (BLyS; also known as TNFSF20, BAFF, TALL-1, zTNF4, and THANK), a tumor necrosis factor ligand family member, has recently been identified as a factor that promotes expansion and differentiation of the B cell population, leading to increases in serum immunoglobulin levels. Here, pharmacokinetic parameters for BLyS administered i.v. and s.c. to mice are described, and the effects of different dosing regimens on serum and salivary immunoglobulin levels as well as splenic cell populations are reported. The pharmacokinetics of BLyS following i.v. injection are monophasic with a half-life of 160 min, a clearance of 0.22 ml/min-kg, and a volume of distribution of 53 ml/kg. Systemic administration of BLyS to mice resulted in increased serum IgG, IgA, IgM, and IgE and salivary IgA as well as splenic B cell population expansion and differentiation. The i.v. and s.c. routes of administration were pharmacologically equivalent, even though s.c. bioavailability of BLyS is only 25%. BLyS (s.c.) dramatically elevated serum IgG and IgA levels, and the duration of the responses after cessation of treatment (t(1/2) = 4.4 and 1.3 days, respectively) are similar to the half-lives of endogenous IgG and IgA in mice. The IgM response is more modest than that of IgG and IgA but lasts longer (t(1/2) = 7.0 days) than the half-life of endogenous IgM. A linear pharmacodynamic response was identified between days of dosing x log(dose), and increases in serum IgG, IgA, and IgM indicating that the response is more sensitive to the duration of dosing than to the cumulative dose. The implications of these findings for therapeutic administration of BLyS are discussed.