RESUMEN
Spastic paraparesis has been described to occur in 13.7% of PSEN1 mutations and can be the presenting feature in 7.5%. In this paper, we describe a family with a particularly young onset of spastic paraparesis due to a novel mutation in PSEN1 (F388S). Three affected brothers underwent comprehensive imaging protocols, two underwent ophthalmological evaluations and one underwent neuropathological examination after his death at age 29. Age of onset was consistently at age 23 with spastic paraparesis, dysarthria and bradyphrenia. Pseudobulbar affect followed with progressive gait problems leading to loss of ambulation in the late 20s. Cerebrospinal fluid levels of amyloid-ß, tau and phosphorylated tau and florbetaben PET were consistent with Alzheimer's disease. Flortaucipir PET showed an uptake pattern atypical for Alzheimer's disease, with disproportionate signal in posterior brain areas. Diffusion tensor imaging showed decreased mean diffusivity in widespread areas of white matter but particularly in areas underlying the peri-Rolandic cortex and in the corticospinal tracts. These changes were more severe than those found in carriers of another PSEN1 mutation, which can cause spastic paraparesis at a later age (A431E), which were in turn more severe than among persons carrying autosomal dominant Alzheimer's disease mutations not causing spastic paraparesis. Neuropathological examination confirmed the presence of cotton wool plaques previously described in association with spastic parapresis and pallor and microgliosis in the corticospinal tract with severe amyloid-ß pathology in motor cortex but without unequivocal disproportionate neuronal loss or tau pathology. In vitro modelling of the effects of the mutation demonstrated increased production of longer length amyloid-ß peptides relative to shorter that predicted the young age of onset. In this paper, we provide imaging and neuropathological characterization of an extreme form of spastic paraparesis occurring in association with autosomal dominant Alzheimer's disease, demonstrating robust diffusion and pathological abnormalities in white matter. That the amyloid-ß profiles produced predicted the young age of onset suggests an amyloid-driven aetiology though the link between this and the white matter pathology remains undefined.
RESUMEN
Alveolar capillary dysplasia with misalignment of pulmonary veins (ACD/MPV) is a rare neonatal lung disease with fatal outcome. Typically, respiratory symptoms present in the first 24 hours of life and patients die within the neonatal period. Atypical, delayed clinical presentations and/or longer survival have also been reported. Here, we studied the clinicopathologic relationship of ACD/MPV by examining 16 cases of ACD/MPV, focusing on atypical features. Based on the presence of diffuse vs. focal/patchy ACD/MPV histopathologic changes, we divided the cases into classic and nonclassic pathology groups. MPV was found in all ACD/MPV. Ten of 16 cases exhibited classic diffuse abnormalities, while 6 of 16 had a nonclassic focal/patchy distribution. However, among 7 patients with atypical clinical features, only 2 had nonclassic pathology, while 4 out of 9 clinically typical cases had nonclassic ACD/MPV pathology. Marked intrapulmonary aberrant arteriovenous vessels were present in all atypical cases. In conclusion, clinical presentation is not always correlated with histopathology in ACD/MPV. Atypical ACD/MPV should be suspected in any infants with fulminant pulmonary hypertension. Abnormal pulmonary veins and aberrant intraseptal vessels are the most important clues for diagnosis. Additional studies are needed for further elucidation of diagnostic histological criteria of atypical ACD/MPV and to explore its pathogenesis.
Asunto(s)
Síndrome de Circulación Fetal Persistente/patología , Alveolos Pulmonares/anomalías , Venas Pulmonares/anomalías , Autopsia , Femenino , Edad Gestacional , Humanos , Masculino , Síndrome de Circulación Fetal Persistente/mortalidad , Pronóstico , Alveolos Pulmonares/patología , Estudios RetrospectivosRESUMEN
Invadopodia, cancer cell protrusive structures with associated proteolytic activity, provide cancer cells with the ability to remodel the extracellular matrix. Invadopodia facilitate invasive migration and their formation correlates with cancer cell invasiveness and metastatic potential. The unambiguous identification of invadopodia is an important step to undergo studies on invadopodia regulatory inputs, functional outputs, as well as the prevalence and significance of invadopodia for cancer cells and human tumors. The adaptor protein TKS5 is a known invadopodia regulatory protein, which is necessary for invadopodia formation and activity. TKS5 is highly enriched at invadopodia and, unlike other commonly used invadopodia markers, it does not accumulate significantly in other types of cellular protrusions. However, the use of TKS5 as a marker of invadopodia has not been generalized, in part due to the availability of suitable antibodies against the human protein. We have evaluated two commercial antibodies raised against human TKS5. Here, we detail protocols for the detection of invadopodia-associated TKS5 in human cells in culture and in paraffin-embedded archived tumor surgical specimens using commercial antibodies. These methods should facilitate the identification and study of human invadopodia. â¢TKS5 staining identifies invadopodia in human cancer cell lines and archived surgical tumor specimens.
RESUMEN
In this article, using human pancreatic cancer cell lines and tumor specimens, we analyze the expression and localization of the invadopodia-related proteins TKS5 and Cortactin. Specifically, we present data on: a) TKS5 expression and localization by immunofluorescence in human pancreatic tumors, b) Cortactin expression by western blotting in various human pancreatic adenocarcinoma cell lines, c) TKS5 and Cortactin localization at invadopodia in BxPC-3 pancreatic adenocarcinoma cells, and d) TKS5 and Cortactin localization by co-immunofluorescence in human pancreatic cancer specimens. Data presented here is related to and supportive of the research article by Chen et al., "TKS5-positive invadopodia-like structures in human tumor surgical specimens" (Chen et al., 2019), where interpretation of the research data presented here is available.
Asunto(s)
Sarcoma Histiocítico/diagnóstico , Neoplasias Peritoneales/diagnóstico , Ascitis/etiología , Biomarcadores de Tumor , Errores Diagnósticos , Resultado Fatal , Hemorragia Gastrointestinal/etiología , Hepatitis C Crónica/complicaciones , Histiocitos/patología , Sarcoma Histiocítico/complicaciones , Sarcoma Histiocítico/metabolismo , Sarcoma Histiocítico/patología , Humanos , Masculino , Persona de Mediana Edad , Neoplasias Peritoneales/química , Neoplasias Peritoneales/complicaciones , Neoplasias Peritoneales/patología , Peritonitis/diagnósticoRESUMEN
Invadopodia, cancer cell protrusions with proteolytic activity, are functionally associated with active remodeling of the extracellular matrix. Here, we show that the invadopodia-related protein TKS5 is expressed in human pancreatic adenocarcinoma lines, and demonstrate that pancreatic cancer cells depend on TKS5 for invadopodia formation and function. Immunofluorescence staining of human pancreatic cancer cells reveals that TKS5 is a marker of mature and immature invadopodia. We also analyze the co-staining patterns of TKS5 and the commonly used invadopodia marker Cortactin, and find only partial co-localization of these two proteins at invadopodia, with a large fraction of TKS5-positive invadopodia lacking detectable levels of Cortactin. Whereas compelling evidence exist on the role of invadopodia as mediators of invasive migration in cultured cells and in animal models of cancer, these structures have never been detected inside human tumors. Here, using antibodies against TKS5 and Cortactin, we describe for the first time structures strongly resembling invadopodia in various paraffin-embedded human tumor surgical specimens from pancreas and other organs. Our results strongly suggest that invadopodia are present inside human tumors, and warrants further investigation on their regulation and occurrence in surgical specimens, and on the value of TKS5 antibodies as pathological research and diagnostic tools.
Asunto(s)
Proteínas Adaptadoras del Transporte Vesicular/fisiología , Adenocarcinoma/patología , Proteínas de Neoplasias/fisiología , Neoplasias Pancreáticas/patología , Podosomas/fisiología , Adenocarcinoma/química , Adenocarcinoma/cirugía , Adenocarcinoma/ultraestructura , Adulto , Anciano , Línea Celular Tumoral , Cortactina/análisis , Femenino , Técnica del Anticuerpo Fluorescente Directa , Humanos , Masculino , Persona de Mediana Edad , Invasividad Neoplásica , Neoplasias/química , Neoplasias/patología , Neoplasias Pancreáticas/química , Neoplasias Pancreáticas/cirugía , Neoplasias Pancreáticas/ultraestructura , Adhesión en Parafina , Podosomas/química , Podosomas/ultraestructura , Interferencia de ARN , ARN Interferente Pequeño/genéticaRESUMEN
Amyloidosis is a disorder characterized by the deposition of insoluble abnormal proteins in the extracellular space. It may occur as a localized lesion or as a systemic disease involving multiple organs and systems. Localized conjunctival amyloidosis is rare and is less frequently associated with systemic involvement. Although amyloidosis itself is a benign lesion involvement of multiple organs and systems is associated with poor prognosis. Diagnosis of amyloidosis is made on biopsy specimens with Congo red staining for the appearance of apple-green birefringence under polarized light microscopy. Liquid chromatography tandem-mass spectrometry (LC-MS/MS) is much more sensitive in diagnosing amyloidosis and can determine the type of amyloid deposit. Here we reported a case of conjunctival amyloidosis in a 52â¯year-old male patient who was presented with left lower eyelid swelling to our medical center. He has a complicated past medical history of anti-phospholipid antibody syndrome, Buerger's disease (thromboangitis obliterans), and small cell lymphoma (SLL) of the right orbit/eyelid. The patient received radiation to the right orbit to treat SLL with therapy completed one and a half years prior to presentation. Physical examination revealed a firm, raised yellowish colored lesion in the left lower conjunctiva. The conjunctival lesion was biopsied, and tissue sections were examined with Congo red stains and LC-MS/MS analysis. The biopsy showed amyloid deposits without evidence of malignancy, and the type of proteins in the deposit was immunoglobulin light chain (AL) of kappa type. A complete work up was taken for possible systemic involvement of amyloidosis and results were all negative. To our knowledge, this is the first case of localized conjunctival amyloidosis with a history of contralateral orbit/eyelid SLL.
Asunto(s)
Amiloidosis/patología , Enfermedades de la Conjuntiva/patología , Linfoma/patología , Neoplasias Orbitales/patología , Síndrome Antifosfolípido/etiología , Biopsia , Humanos , Linfoma/radioterapia , Linfoma no Hodgkin/radioterapia , Masculino , Persona de Mediana Edad , Órbita/patología , Neoplasias Orbitales/radioterapia , Tromboangitis Obliterante/etiologíaRESUMEN
A 52â¯year-old obese male presented with a moderately differentiated adenocarcinoma of the sigmoid colon. On staging CT, the patient was found to have a cystic lesion in the left retroperitoneum.
Asunto(s)
Adenocarcinoma/patología , Quiste Broncogénico/patología , Neoplasias del Colon/patología , Adenocarcinoma/diagnóstico por imagen , Adenocarcinoma/cirugía , Colon Sigmoide/patología , Colon Sigmoide/cirugía , Neoplasias del Colon/diagnóstico por imagen , Neoplasias del Colon/cirugía , Humanos , Masculino , Persona de Mediana Edad , Espacio Retroperitoneal/patología , Tomografía Computarizada por Rayos XRESUMEN
A 40â¯year old female with no documented medical history presented to the Emergency Department with several days of lethargy and altered mental status. She was found to be anemic, thrombocytopenic, and hypotensive. The patient was found to be in severe metabolic acidosis, became bradycardic, and quickly deteriorated. Clinicians suspected thrombotic thrombocytopenic purpura, and the diagnosis was supported by ADAMTS13 testing. The clinicians attempted to place a Quinton catheter for emergent plasmapheresis, but the patient expired before definitive treatment could be initiated. Autopsy was obtained and revealed a right middle lobe consolidation grossly consistent with lymphoid tissue or tumor.
Asunto(s)
Neoplasias Pulmonares/patología , Linfoma de Células B de la Zona Marginal/patología , Proteína ADAMTS13/sangre , Adulto , Autopsia , Femenino , Humanos , Púrpura Trombocitopénica Trombótica/diagnósticoRESUMEN
A 34-year old male with a giant condyloma acuminatum of the anus secondary to HIV infection presented to the emergency department with a persistent nose bleed lasting 2-3days, acute anemia, thrombocytopenia, and coagulopathy. The patient also had significant hepatosplenomegaly and elevated liver enzymes which were a new finding since the patient's last hospitalization 1-2month prior to the current admission. A bone marrow biopsy showed diffuse infiltration by carcinoma with neuroendocrine features. The patient quickly developed multi-organ injury, decompensated, and died. An autopsy was obtained which established the diagnosis of small cell carcinoma of the liver.
Asunto(s)
Trastornos de la Coagulación Sanguínea/patología , Neoplasias de la Médula Ósea/secundario , Infecciones por VIH/complicaciones , Fallo Hepático/patología , Pancitopenia/patología , Carcinoma Pulmonar de Células Pequeñas/patología , Neoplasias del Bazo/secundario , Adulto , Autopsia , Trastornos de la Coagulación Sanguínea/etiología , Neoplasias de la Médula Ósea/etiología , Resultado Fatal , Infecciones por VIH/virología , VIH-1/patogenicidad , Humanos , Fallo Hepático/etiología , Neoplasias Pulmonares/etiología , Neoplasias Pulmonares/patología , Masculino , Pancitopenia/etiología , Carcinoma Pulmonar de Células Pequeñas/etiología , Neoplasias del Bazo/etiologíaRESUMEN
Foregut duplication cysts are extremely rare congenital malformations. Herein we report a case of 73 year old male with a left upper quadrant abdominal lesion identified on CT scan.
Asunto(s)
Quistes/diagnóstico por imagen , Epitelio/diagnóstico por imagen , Estómago/diagnóstico por imagen , Anciano , Humanos , Masculino , Manejo de Especímenes , Estómago/anomalías , Tomografía Computarizada por Rayos XRESUMEN
T cell immunoglobulin and ITIM domain (TIGIT) and CD226 emerge as a novel T cell cosignaling pathway in which CD226 and TIGIT serve as costimulatory and coinhibitory receptors, respectively, for the ligands CD155 and CD112. In this study, we describe CD112R, a member of poliovirus receptor-like proteins, as a new coinhibitory receptor for human T cells. CD112R is preferentially expressed on T cells and inhibits T cell receptor-mediated signals. We further identify that CD112, widely expressed on antigen-presenting cells and tumor cells, is the ligand for CD112R with high affinity. CD112R competes with CD226 to bind to CD112. Disrupting the CD112R-CD112 interaction enhances human T cell response. Our experiments identify CD112R as a novel checkpoint for human T cells via interaction with CD112.
Asunto(s)
Moléculas de Adhesión Celular/inmunología , Subunidad beta del Receptor de Interleucina-2/metabolismo , Receptores de Superficie Celular/inmunología , Linfocitos T/inmunología , Secuencia de Aminoácidos , Animales , Antígenos de Diferenciación de Linfocitos T/metabolismo , Moléculas de Adhesión Celular/genética , Moléculas de Adhesión Celular/metabolismo , Puntos de Control del Ciclo Celular/inmunología , Línea Celular Tumoral , Células Dendríticas/inmunología , Células HEK293 , Humanos , Ligandos , Activación de Linfocitos , Ratones , Modelos Moleculares , Datos de Secuencia Molecular , Nectinas , Filogenia , Receptores de Antígenos de Linfocitos T/metabolismo , Receptores de Superficie Celular/genética , Receptores de Superficie Celular/metabolismo , Receptores Virales/genética , Receptores Virales/inmunología , Receptores Virales/metabolismo , Proteínas Recombinantes de Fusión/genética , Proteínas Recombinantes de Fusión/inmunología , Proteínas Recombinantes de Fusión/metabolismo , Homología de Secuencia de Aminoácido , Transducción de Señal , Linfocitos T/citologíaRESUMEN
BACKGROUND: The objective of this study was to review the efficacy of intracranial packing as a means of tamponade for life-threatening intraoperative hemorrhage that was refractory to more common techniques for achieving hemostasis. METHODS: Neuroimaging and hospital records were reviewed for the seven adult patients who had experienced life-threateningly severe hemorrhage during intracranial surgery and in whom packing was used to control the bleeding. All packing was left in place at the time of closure and was removed when the patient's condition was considered safe for a second operation. RESULTS: Hemorrhage was successfully halted in all seven patients, and all survived their operations. Six were discharged from the hospital, but one patient with severe parenchymal injury from trauma and multiple medical comorbidities died on postoperative Day 2 after supportive care was withdrawn. Four had an improved Glasgow Outcome Scale (GOS) score at the time of last follow-up, and two of these improved from dependent to independent living. There were no postoperative intracranial or wound infections. CONCLUSION: Intracranial packing to tamponade severe intracranial hemorrhage can be a lifesaving neurosurgical maneuver. LEVEL OF EVIDENCE: Therapeutic study, level V.
Asunto(s)
Lesiones Encefálicas/complicaciones , Endotaponamiento/métodos , Mortalidad Hospitalaria/tendencias , Hemorragias Intracraneales/cirugía , Complicaciones Intraoperatorias/terapia , Procedimientos Neuroquirúrgicos/efectos adversos , Adolescente , Adulto , Lesiones Encefálicas/diagnóstico , Endotaponamiento/mortalidad , Femenino , Escala de Coma de Glasgow , Humanos , Hemorragias Intracraneales/etiología , Hemorragias Intracraneales/mortalidad , Hemorragias Intracraneales/fisiopatología , Complicaciones Intraoperatorias/diagnóstico , Complicaciones Intraoperatorias/mortalidad , Masculino , Persona de Mediana Edad , Procedimientos Neuroquirúrgicos/métodos , Medición de Riesgo , Muestreo , Índice de Severidad de la Enfermedad , Tasa de Supervivencia , Resultado del Tratamiento , Adulto JovenRESUMEN
The medical records of all children in whom packing was used to control severe intracranial hemorrhage were reviewed. Eight children, with ages ranging from newborn to 4 years, met the inclusion criteria and all survived. Five were victims of severe closed head trauma, 2 had received penetrating cranial injuries, and 1 developed severe bleeding while undergoing surgery for a malignant tumor in the posterior fossa. Blood loss at the time of removal of the packing was minimal in 7 patients and was surgically controllable in the other. Packing is a simple, efficient, and safe maneuver which can very often halt intracranial bleeding that is considered to be otherwise uncontrollable, and can thereby limit the consequences of prolonged or repeated periods of hypotension and possible exsanguination.
Asunto(s)
Endotaponamiento/métodos , Hemorragias Intracraneales/cirugía , Complicaciones Intraoperatorias/cirugía , Neoplasias Encefálicas/complicaciones , Neoplasias Encefálicas/cirugía , Preescolar , Endotaponamiento/efectos adversos , Traumatismos Cerrados de la Cabeza/complicaciones , Traumatismos Cerrados de la Cabeza/cirugía , Traumatismos Penetrantes de la Cabeza/complicaciones , Traumatismos Penetrantes de la Cabeza/cirugía , Humanos , Lactante , Recién Nacido , Hemorragias Intracraneales/etiología , Complicaciones Intraoperatorias/etiología , Resultado del TratamientoRESUMEN
BACKGROUND: This study investigated how the B7-H5 protein, a new member of the B7 family, is expressed in normal human pancreas tissues and examined its expression changes in pancreatic cancer. METHODS: In this analysis, B7-H5 expression was examined by immunohistochemical staining of frozen specimens from patients undergoing pancreatic resection. RESULTS: Membranous B7-H5 protein was expressed on normal ductal epithelium within the pancreas. Other cell types from the normal pancreas, such as acinar cells and islet cells, did not express B7-H5. In adenocarcinoma, B7-H5 staining was decreased or absent. Interestingly, B7-H5 expression in intraductal papillary mucinous neoplasms varied with grade. No B7-H5 expression was found with other cancer types such as neuroendocrine tumors, but normal ducts adjacent to tumors were highly positive. CONCLUSIONS: The findings showed that B7-H5 expression was restricted to ductal cells in the normal pancreas and the expression was downregulated in pancreatic adenocarcinomas. In addition, the findings showed that B7-H5 expression changes within different stages of dysplasia. The study suggests that loss of the B7-H5 signal may contribute to immune evasion of pancreatic adenocarcinoma. However future studies are needed.
Asunto(s)
Adenocarcinoma/metabolismo , Biomarcadores de Tumor/metabolismo , Carcinoma Ductal Pancreático/metabolismo , Inmunoglobulinas/metabolismo , Páncreas/metabolismo , Neoplasias Pancreáticas/metabolismo , Adenocarcinoma/patología , Carcinoma Ductal Pancreático/patología , Citometría de Flujo , Regulación Neoplásica de la Expresión Génica , Humanos , Técnicas para Inmunoenzimas , Estadificación de Neoplasias , Páncreas/patología , Neoplasias Pancreáticas/patología , Pronóstico , Células Tumorales CultivadasRESUMEN
5-Fluorouracile, oxaliplatin, irinotecan, and leucovorin (FOLFIRINOX) has not been extensively used in the neoadjuvant setting because of concerns with safety and toxicity. We evaluated our institutional experience with neoadjuvant FOLFIRINOX in borderline resectable pancreatic adenocarcinoma (BRPAC). The primary endpoints were completion of therapy to surgery and negative resection margin (R0) rate. Patients with BRPAC treated with neoadjuvant FOLFIRINOX were retrospectively analyzed. Between August 2011 and September 2013, 20 patients with BRPAC treated with neoadjuvant FOLFIRINOX were identified. Most patients (88.8%) completed FOLFIRINOX therapy and underwent resection. Abutment of venous structures was identified in 13 cases (72.2%), while short segment portal vein encasement in 3 cases (16.6%) with concomitant arterial involvement in 3 cases (16.6%). Isolated superior mesenteric artery abutment was identified in 2 cases (11.2%). Patients received a median of 4 cycles of FOLFIRINOX. There was 1 case of progression. Vascular resection was performed in 9 cases (52.9%). Preoperative radiation therapy was used in 8 patients (44%). All patients underwent margin negative resection (R0). Histopathologic treatment response was evident in 10 cases (58.8%). Neoadjuvant FOLFIRINOX was generally safe and the expected toxicity did not prevent surgery allowing for a high rate of R0 resection.
Asunto(s)
Adenocarcinoma/tratamiento farmacológico , Leucovorina/uso terapéutico , Neoplasias Pancreáticas/tratamiento farmacológico , Complejo Vitamínico B/uso terapéutico , Adenocarcinoma/cirugía , Anciano , Femenino , Humanos , Masculino , Persona de Mediana Edad , Terapia Neoadyuvante , Neoplasias Pancreáticas/cirugía , Estudios Retrospectivos , Resultado del TratamientoRESUMEN
G-protein-coupled receptors (GPCR) are the largest family of cell surface molecules that play important role/s in a number of biological and pathological processes including cancers. Earlier studies have highlighted the importance of Wnt7a signaling via its cognate receptor Frizzled9, a GPCR, in inhibition of cell proliferation, anchorage-independent growth, and reversal of transformed phenotype in non small cell lung cancer primarily through activation of the tumor suppressor, PPARγ. However, the G-protein effectors that couple to this important tumor suppressor pathway have not been identified, and are of potential therapeutic interest. In this study, by using two independent Wnt7a/Frizzled9-specific read-outs, we identify Gα16 as a novel downstream effector of Wnt7a/Frizzled9 signaling. Interestingly, Gα16 expression is severely down-regulated, both at the messenger RNA levels and protein levels, in many non small cell lung cancer cell lines. Additionally, through gene-specific knock-downs and expression of GTPase-deficient forms (Q212L) of Gα16, we also establish Gα16 as a novel regulator of non small cell lung cancer cell proliferation and anchorage-independent cell growth. Taken together, our data not only establish the importance of Gα16 as a critical downstream effector of the non-canonical Wnt signaling pathway but also as a potential therapeutic target for the treatment of non small cell lung cancer.
Asunto(s)
Proliferación Celular , Subunidades alfa de la Proteína de Unión al GTP Gq-G11/metabolismo , Inhibidores de Crecimiento/metabolismo , Vía de Señalización Wnt , Carcinoma de Pulmón de Células no Pequeñas/genética , Carcinoma de Pulmón de Células no Pequeñas/metabolismo , Carcinoma de Pulmón de Células no Pequeñas/patología , Línea Celular , Línea Celular Tumoral , Activación Enzimática , Receptores Frizzled/genética , Receptores Frizzled/metabolismo , Subunidades alfa de la Proteína de Unión al GTP Gq-G11/genética , Inhibidores de Crecimiento/genética , Humanos , Immunoblotting , Neoplasias Pulmonares/genética , Neoplasias Pulmonares/metabolismo , Neoplasias Pulmonares/patología , Proteína Quinasa 7 Activada por Mitógenos/metabolismo , Mutación , PPAR gamma/metabolismo , Interferencia de ARN , Receptores Huérfanos Similares al Receptor Tirosina Quinasa/metabolismo , Reacción en Cadena de la Polimerasa de Transcriptasa Inversa , Proteínas Wnt/genética , Proteínas Wnt/metabolismoRESUMEN
Protein-polymer conjugates are widely used in biotechnology and medicine, and new methods to prepare the bioconjugates would be advantageous for these applications. In this report, we demonstrate that bioactive "smart" polymer conjugates can be synthesized by polymerizing from defined initiation sites on proteins, thus preparing the polymer conjugates in situ. In particular, free cysteines, Cys-34 of bovine serum albumin (BSA) and Cys-131 of T4 lysozyme V131C, were modified with initiators for atom transfer radical polymerization (ATRP) either through a reversible disulfide linkage or irreversible bond by reaction with pyridyl disulfide- and maleimide-functionalized initiators, respectively. Initiator conjugation was verified by electrospray-ionization mass spectroscopy (ESI-MS), and the location of the modification was confirmed by muLC-MSMS (tandem mass spectrometry) analysis of the trypsin-digested protein macroinitiators. Polymerization of N-isopropylacrylamide (NIPAAm) from the protein macroinitiators resulted in thermosensitive BSA-polyNIPAAm and lysozyme-polyNIPAAm in greater than 65% yield. The resultant conjugates were characterized by gel electrophoresis and size exclusion chromatography (SEC) and easily purified by preparative SEC. The identity of polymer isolated from the BSA conjugate was confirmed by (1)H NMR, and the polydispersity index was determined by gel permeation chromatography (GPC) to be as low as 1.34. Lytic activities of the lysozyme conjugates were determined by two standard assays and compared to that of the unmodified enzyme prior to polymerization; no statistical differences in bioactivity were observed.
Asunto(s)
Resinas Acrílicas/química , Muramidasa/química , Albúmina Sérica Bovina/química , Cisteína/química , Muramidasa/metabolismo , Espectrometría de Masa por Ionización de ElectrosprayRESUMEN
[reaction: see text] The pH-controlled Sharpless asymmetric aminohydroxylation (AA) of styrenes provides 1-aryl-2-amino ethanols (regioisomer B) with high enantio-, chemo-, and regioselectivity. As existing AA protocols typically give regioisomer A as the major reaction product when using carbamate nitrogen sources, this method is a convenient alternative for the selective production of regioisomer B.