Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 574
Filtrar
Más filtros

Tipo del documento
Intervalo de año de publicación
1.
Nature ; 584(7821): 403-409, 2020 08.
Artículo en Inglés | MEDLINE | ID: mdl-32760000

RESUMEN

The tuatara (Sphenodon punctatus)-the only living member of the reptilian order Rhynchocephalia (Sphenodontia), once widespread across Gondwana1,2-is an iconic species that is endemic to New Zealand2,3. A key link to the now-extinct stem reptiles (from which dinosaurs, modern reptiles, birds and mammals evolved), the tuatara provides key insights into the ancestral amniotes2,4. Here we analyse the genome of the tuatara, which-at approximately 5 Gb-is among the largest of the vertebrate genomes yet assembled. Our analyses of this genome, along with comparisons with other vertebrate genomes, reinforce the uniqueness of the tuatara. Phylogenetic analyses indicate that the tuatara lineage diverged from that of snakes and lizards around 250 million years ago. This lineage also shows moderate rates of molecular evolution, with instances of punctuated evolution. Our genome sequence analysis identifies expansions of proteins, non-protein-coding RNA families and repeat elements, the latter of which show an amalgam of reptilian and mammalian features. The sequencing of the tuatara genome provides a valuable resource for deep comparative analyses of tetrapods, as well as for tuatara biology and conservation. Our study also provides important insights into both the technical challenges and the cultural obligations that are associated with genome sequencing.


Asunto(s)
Evolución Molecular , Genoma/genética , Filogenia , Reptiles/genética , Animales , Conservación de los Recursos Naturales/tendencias , Femenino , Genética de Población , Lagartos/genética , Masculino , Anotación de Secuencia Molecular , Nueva Zelanda , Caracteres Sexuales , Serpientes/genética , Sintenía
3.
Pituitary ; 27(1): 70-76, 2024 Feb.
Artículo en Inglés | MEDLINE | ID: mdl-38006472

RESUMEN

PURPOSE: Pituitary transposition is a novel surgical approach to access the retroinfundibular space and interpeduncular cistern. Few studies have evaluated post-surgical outcomes, including incidence of hyponatremia, following pituitary transposition. METHODS: This is a retrospective study including 72 patients who underwent endoscopic endonasal surgery involving pituitary transposition for non-pituitary derived tumors over a decade at the University of Pittsburgh Medical Center. Anterior pituitary deficiencies and replacement therapy, tumor pathology and pre-operative serum sodium (Na) were recorded. Na was assessed at postoperative day 1, 3, 5, 7, and 10. Anatomical/surgical parameters included sellar height, sellar access angle to approach the tumor, and cranial extension of the tumor above the sellar floor (B) compared to the height of the gland (A) (B/A). T-test (normally distributed variables) and Wilcoxon rank-sum test (not-normally distributed) were applied for mean comparison. Logistic regression analyzed correlations between anatomical/surgical parameters and postoperative hyponatremia. RESULTS: 55.6% of patients developed post-operative transient hyponatremia. Two patients (5%) developed severe hyponatremia (sodium level < 120 mmol/L). Eleven (15.3%) patients required desmopressin replacement immediately post-operatively, and 2 other patients needed desmopressin after discharge and after sodium nadir developed. Hyponatremia was inversely associated with sellar access angle (p = 0.02) and the tumor cranial extension above the sellar floor showing a trend towards significance (p = 0.09). CONCLUSION: More than half of patients who had pituitary transposition developed transient hyponatremia. Hyponatremia was more common in those with narrower sellar access angle and smaller cranial extension of the tumor above the sellar floor. Anatomical/surgical parameters may allow risk-stratification for post-operative hyponatremia following pituitary transposition.


Asunto(s)
Hiponatremia , Neoplasias , Enfermedades de la Hipófisis , Neoplasias Hipofisarias , Humanos , Hiponatremia/epidemiología , Hiponatremia/etiología , Estudios Retrospectivos , Incidencia , Desamino Arginina Vasopresina/uso terapéutico , Base del Cráneo/patología , Sodio , Neoplasias Hipofisarias/patología
4.
Pituitary ; 2024 Jul 24.
Artículo en Inglés | MEDLINE | ID: mdl-39046590

RESUMEN

PURPOSE: The COVID-19 pandemic caused significant disruption to the surgical care of patients. The aim of this study was to analyze the impact of the pandemic on endoscopic endonasal surgery (EES) for patients with a pituitary adenoma. METHODS: Patients from 2015 to 2022 that had EES for a pituitary adenoma were included in this study. Patients were separated into pre-COVID (January 2015-March 2020) and COVID (March 2020-September 2022) groups. Univariate analysis was done using chi-square, fisher exact tests, and t-tests to compare groups. RESULTS: This study included 492 patients that had EES for their pituitary adenoma. There were 314 patients in the pre-COVID group and 178 patients in the COVID group. Patients in the COVID group had a higher risk analysis index (RAI) frailty score (15 ± 10 pre-COVID vs. 20 ± 9 COVID, P < 0.001) and a higher American Society of Anesthesiology (ASA) physical status score (3 or 4) (72.0% pre-COVID vs. 81.9% COVID, P = 0.02). There were significantly more macroadenoma cases (87.6% pre-COVID vs. 94.4% COVID, P = 0.02) and extrasellar surgical approaches (45.2% pre-COVID vs. 61.2% COVID, P < 0.001) during COVID. There was no significant difference in length of stay (LOS) and readmission rates between groups. CONCLUSIONS: Patients that presented during the pandemic tended to be more frail, have more comorbidities, and require additional extrasellar surgical approaches. Despite changes in clinical presentation and operative management, the LOS and readmission rate remained stable during COVID, supporting the safety of this procedure during the recent pandemic.

5.
Neurosurg Focus ; 56(4): E3, 2024 04.
Artículo en Inglés | MEDLINE | ID: mdl-38560934

RESUMEN

OBJECTIVE: Although keyhole transorbital approaches are gaining traction, their indications have not been adequately studied comparatively. In this study the authors have defined them also as transwing approaches-meaning that they use the different facies of the sphenoid wing for cranial entry-and sought to compare the four major ones: 1) lateral orbitocraniotomy through a lateral canthal incision (LatOrb); 2) modified orbitozygomatic approach through a palpebral incision (ModOzPalp); 3) modified orbitozygomatic approach through an eyebrow incision (ModOzEyB); and 4) supraorbital craniotomy through an eyebrow incision (SupraOrb), coupled with its expanded version (SupraTransOrb). METHODS: Cadaveric dissections were performed at the neuroanatomy lab. To delineate the skull base exposure, four formalin-fixed heads were used, with two sides dedicated to each approach. The outer limits were assessed via image guidance and were mapped and illustrated accordingly. A fifth head was dissected purely endoscopically, just to facilitate an overview of the transwing concept. Qualitative features were also rigorously examined. RESULTS: The LatOrb proves to be more versatile in the middle cranial fossa (MCF), whereas the anterior cranial fossa (ACF) exposure is limited to a small area above the sphenoid ridge. An anterior clinoidectomy is possible; however, the exposure of the roof of the optic canal is suboptimal. The ModOzPalp adequately exposes both the ACF and MCF. Its lateral trajectory allows the inferior to superior view, yet there is restricted access to the medial anterior skull base (olfactory groove). The ModOzEyB also provides extensive exposure of the ACF and MCF, but has a more superior to inferior trajectory compared to the ModOzPalp, making it more appropriate for pathology reaching the medial anterior skull base or even the contralateral side. The anterior clinoidectomy is performed with improved visualization of the optic canal. The SupraOrb provides mainly anterior cranial base exposure, with minimal middle fossa. An anterior clinoidectomy can be performed, but without any direct observation of the superior orbital fissure. Some MCF access can be accomplished if the lateral sphenoid wing is drilled inferiorly, leading to its highly versatile variant, the SupraTransOrb. CONCLUSIONS: All the aforementioned approaches use the sphenoid wing as skull base corridor from a specific orientation point; hence these are designated as transwing approaches. Their peculiarities mandate careful case selection for the effective and safe completion of the surgical goals.


Asunto(s)
Craneotomía , Base del Cráneo , Humanos , Base del Cráneo/cirugía , Base del Cráneo/anatomía & histología , Craneotomía/métodos , Fosa Craneal Media/cirugía , Fosa Craneal Anterior/cirugía , Órbita/cirugía , Cadáver
6.
Neurosurg Focus ; 56(5): E16, 2024 05.
Artículo en Inglés | MEDLINE | ID: mdl-38691858

RESUMEN

OBJECTIVE: Numerous studies have investigated the impact of inflammatory factors in cancer, yet few attempts have been made to investigate these markers in skull base chordoma (SBC). Inflammatory values including neutrophil-lymphocyte ratio (NLR), platelet-lymphocyte ratio (PLR), lymphocyte-monocyte ratio (LMR), systemic immune inflammation index (SII), and systemic inflammation response index (SIRI) can serve as prognostic markers in various cancers. This study aimed to determine whether these inflammatory factors influence overall survival (OS) or progression-free survival (PFS) in patients with primary SBC. METHODS: The electronic medical records of patients with primary SBC who underwent resection from 2001 to 2020 were retrospectively reviewed for the associations of sex, age at diagnosis, preoperative steroid use, tumor volume, extent of resection, adjuvant radiation after surgery, tumor metastasis, Ki-67 index, percent homozygous deletion of 9p23 and percent 1p36 loss, and potential prognostic inflammatory markers of NLR, PLR, LMR, SII, and SIRI with the primary outcome measures of OS and PFS. Maximum log-rank statistical tests were used to determine inflammatory marker thresholds for grouping prior to Kaplan-Meier and Cox proportional hazards analysis for OS and PFS of the elucidated groups. RESULTS: The cohort included 115 primary SBC patients. The mean ± SD tumor volume was 23.0 ± 28.0 cm3, 73% of patients received gross-total resection, 40% received postoperative radiation, 25% had local recurrence, and 6% had subsequent metastatic disease (mean follow-up 47.2 months). Univariable Cox analysis revealed that NLR (p < 0.01), PLR (p = 0.04), LMR (p = 0.04), SII (p < 0.01), and SIRI (p < 0.01) were independently associated with PFS. Additionally, NLR (p = 0.05) and SII (p = 0.03) were significant in multivariable Cox analysis of PFS. However, both univariable and multivariable Cox analysis revealed no correlations with OS. CONCLUSIONS: The routine assessment of inflammatory biomarkers such as NLR and SIRI could have prognostic value in postresection SBC patients.


Asunto(s)
Cordoma , Inflamación , Recurrencia Local de Neoplasia , Neoplasias de la Base del Cráneo , Humanos , Masculino , Femenino , Cordoma/cirugía , Cordoma/mortalidad , Neoplasias de la Base del Cráneo/cirugía , Neoplasias de la Base del Cráneo/mortalidad , Persona de Mediana Edad , Adulto , Estudios Retrospectivos , Anciano , Inflamación/sangre , Biomarcadores de Tumor/sangre , Pronóstico , Linfocitos/metabolismo , Neutrófilos , Adulto Joven
7.
Am J Otolaryngol ; 45(4): 104317, 2024.
Artículo en Inglés | MEDLINE | ID: mdl-38729011

RESUMEN

OBJECTIVES: Tegmen and superior semicircular canal defects have been well studied, yet the factors contributing to their onset and progression are widely debated. The clinical utility of intraoperative intracranial pressure measurements has yet to be tested. This report aims to use intraoperative opening pressure and concurrent superior semicircular canal dehiscence (SSCD) to analyze factors influencing disease course and clinical outcomes in patients with tegmen dehiscence. METHODS: A retrospective analysis of 61 patients who underwent tegmen defect repair was performed. Multiple variables of interest including body mass index (BMI), presence of SSCD, presence of dural venous sinus stenosis, opening pressure, and acetazolamide therapy use were recorded. The cohort was divided into those with or without concurrent SSCD and those presenting with or without cerebrospinal fluid (CSF) leak for analysis. RESULTS: A linear relationship between opening pressure and BMI (p = 0.009) was noted; however, intraoperative opening pressure was not associated with disease outcome. Concurrent SSCD was present in 25 % of patients, while 62 % presented with CSF leak. The concurrent SSCD group exhibited higher opening pressure, higher likelihood of having dural sinus stenosis, and higher likelihood of being discharged on acetazolamide. The CSF leak group had higher likelihood of obstructive sleep apnea and persistent symptoms. CONCLUSIONS: In patients undergoing tegmen defect repair, concurrent SSCD suggests increased disease severity. The presence of preoperative CSF leak predicts persistent symptoms following repair. BMI is linearly correlated with intracranial pressure in these patients.


Asunto(s)
Pérdida de Líquido Cefalorraquídeo , Dehiscencia del Canal Semicircular , Canales Semicirculares , Humanos , Masculino , Femenino , Estudios Retrospectivos , Persona de Mediana Edad , Pérdida de Líquido Cefalorraquídeo/etiología , Pérdida de Líquido Cefalorraquídeo/cirugía , Canales Semicirculares/cirugía , Dehiscencia del Canal Semicircular/cirugía , Dehiscencia del Canal Semicircular/complicaciones , Resultado del Tratamiento , Adulto , Índice de Masa Corporal , Anciano , Presión Intracraneal , Complicaciones Posoperatorias/etiología , Acetazolamida
8.
Sensors (Basel) ; 24(15)2024 Jul 27.
Artículo en Inglés | MEDLINE | ID: mdl-39123931

RESUMEN

This paper presents a novel adaptation of the conventional approximate Bayesian computation sequential Monte Carlo (ABC-SMC) sampling algorithm for parameter estimation in the presence of uncertainties, coined combinatorial ABC-SMC. Inference of this type is used in situations where there does not exist a closed form of the associated likelihood function, which is replaced by a simulating model capable of producing artificial data. In the literature, conventional ABC-SMC is utilised to perform inference on continuous parameters. The novel scheme presented here has been developed to perform inference on parameters that are high-dimensional binary, rather than continuous. By altering the form of the proposal distribution from which to sample candidates in subsequent iterations (referred to as waves), high-dimensional binary variables may be targeted and inferred by the scheme. The efficacy of the proposed scheme is demonstrated through application to vibration data obtained in a structural dynamics experiment on a fibre-optic sensor simulated as a finite plate with uncertain boundary conditions at its edges. Results indicate that the method provides sound inference on the plate boundary conditions, which is validated through subsequent application of the method to multiple vibration datasets. Comparisons between appropriate forms of the metric function used in the scheme are also developed to highlight the effect of this element in the schemes convergence.

9.
Reprod Biol Endocrinol ; 21(1): 14, 2023 Feb 01.
Artículo en Inglés | MEDLINE | ID: mdl-36721176

RESUMEN

BACKGROUND: Acromegaly is a disease of growth hormone excess that results in enlargement of extremities, abnormal glucose and lipid metabolism, and gonadal disruption. Manifestations of the disease are insidious and typically lead to a diagnostic delay of 7-10 years. Classically the polycystic ovary syndrome (PCOS) phenotype is described in women with irregular menses, clinical or biochemical evidence of androgen excess, and/or multiple ovarian follicles on pelvic ultrasonography. Women with acromegaly may present with some or all of these symptoms. Our objective was to evaluate the prevalence of PCOS in patients with acromegaly and to determine if diagnosis of PCOS results in a delay in diagnosing acromegaly. METHODS: Using patient databases at two academic health centers, we identified 97 premenopausal women aged 18-49 years old presenting with acromegaly. Data were collected regarding pelvic sonography and reproductive history, including the diagnosis of PCOS. Patients carrying the diagnosis of PCOS before their diagnosis of acromegaly were identified and the remaining patients were screened using the Rotterdam criteria to identify additional patients meeting the criteria for PCOS prior to their diagnosis of acromegaly. RESULTS: Mean age of the population (n = 97) at the time of diagnosis of acromegaly was 33.4 ± 7.5 years (SD). Thirty-three percent of patients (n = 32) either carried a diagnosis of PCOS or met diagnostic criteria for PCOS before their diagnosis of acromegaly. In the subset of patients in whom data on symptom onset were available, those who met criteria for PCOS were diagnosed with acromegaly a median of 5 years [4, 9] after the onset of symptoms compared to 2 years [0.92, 3] (p = 0.006) in the patients who did not meet criteria for PCOS. CONCLUSIONS: Our data demonstrate a high prevalence of signs and symptoms of PCOS in reproductive-aged women with acromegaly and a longer time to diagnosis in women who meet the clinical criteria for PCOS. As screening for acromegaly is relatively simple and done with measurement of a random, non-fasting IGF-1 level that can be drawn at any time during the menstrual cycle, screening patients with PCOS for acromegaly may lessen the delay in diagnosis for reproductive-aged women with this disease.


Asunto(s)
Acromegalia , Síndrome del Ovario Poliquístico , Femenino , Humanos , Acromegalia/complicaciones , Acromegalia/diagnóstico , Diagnóstico Tardío , Síndrome del Ovario Poliquístico/complicaciones , Síndrome del Ovario Poliquístico/diagnóstico , Síndrome del Ovario Poliquístico/epidemiología , Reproducción , Estudios Retrospectivos , Adulto
10.
Pediatr Blood Cancer ; : e30358, 2023 Jun 22.
Artículo en Inglés | MEDLINE | ID: mdl-37347686

RESUMEN

BACKGROUND: Chordomas are rare tumors arising from the skull base and spine, with approximately 20 pediatric chordoma cases in the Unitedn States per year. The natural history and optimal treatment of pediatric chordomas, especially poorly differentiated and dedifferentiated subtypes, is incompletely understood. Herein, we present findings from our first National Cancer Institute (NCI) chordoma clinic and a retrospective analysis of published cases of pediatric poorly differentiated chordomas (PDC) and dedifferentiated chordomas (DC). METHODS: Patients less than 40 years old with chordoma were enrolled on the NCI Natural History and Biospecimens Acquisitions Study for Children and Adults with Rare Solid Tumors protocol (NCT03739827). Chordoma experts reviewed patient records, evaluated patients, and provided treatment recommendations. Patient-reported outcomes, biospecimens, and volumetric tumor analyses were collected. A literature review for pediatric PDC and DC was conducted. RESULTS: Twelve patients (median age: 14 years) attended the clinic, including four patients with active disease and three patients with PDC responsive to systemic therapy. Consensus treatment, management, and recommendations were provided to patients. Literature review returned 45 pediatric cases of PDC or DC with variable treatments and outcomes. CONCLUSIONS: A multidisciplinary expert clinic was feasible and successful in improving understanding of pediatric chordoma. While multimodal approaches have all been employed, treatment for PDC has been inconsistent and a recommended standardized treatment approach has not been defined. Centralized efforts, inclusive of specialized chordoma-focused clinics, natural history studies, and prospective analyses will help in the standardization of care for this challenging disease.

11.
Pituitary ; 26(2): 221-226, 2023 Apr.
Artículo en Inglés | MEDLINE | ID: mdl-36930352

RESUMEN

PURPOSE: Acromegaly is a disorder characterized by IGF-1 excess due to autonomous GH secretion. In individuals without acromegaly, IGF-1 is not only influenced by GH secretion but is also sensitive to other factors including nutritional status, as evidenced by the inverted U-shaped association between BMI and IGF-1; in low-weight individuals (BMI < 18.5 kg/m2) and those who are obese, IGF-1 levels may be frankly low. It is not known if this same relationship between BMI and IGF-1 is also observed in acromegaly. METHODS: Retrospective study including patients who underwent resection of a pituitary adenoma (n = 197) for either acromegaly (n = 32) or a nonfunctioning adenoma (NFPA, n = 165) at a large academic medical center between 1/1/2015 and 5/31/2021. RESULTS: Median BMI in acromegaly was 30.8 kg/m2 (range 20.9-42.6 kg/m2). Percent upper limit of normal (%ULN) IGF-1 was 228.2% [159.0, 271.4] in acromegaly versus 32.2% [18.5, 50] in NFPA (p < 0.0001). There was a significant positive association between BMI and %ULN IGF-1 (R = 0.35, p < 0.05) in acromegaly. In contrast, there was no association between BMI and %ULN IGF-1 in the NFPA group as a whole (p = 0.22), but a significant inverse association between BMI and %ULN IGF-1 in NFPA patients with a BMI ≥ 35 kg/m2 (rho = - 0.39, p = 0.02). CONCLUSION: In contrast to individuals without acromegaly, BMI is significantly and positively associated with IGF-1 in acromegaly across the weight spectrum. Future studies are needed to determine if obese patients with acromegaly experience more significant symptoms related to their disease, or if patients with a low BMI may require different diagnostic criteria.


Asunto(s)
Acromegalia , Adenoma , Hormona de Crecimiento Humana , Humanos , Acromegalia/cirugía , Estudios Retrospectivos , Índice de Masa Corporal , Factor I del Crecimiento Similar a la Insulina , Adenoma/complicaciones , Adenoma/cirugía , Obesidad
12.
Pituitary ; 26(4): 461-473, 2023 Aug.
Artículo en Inglés | MEDLINE | ID: mdl-37389776

RESUMEN

BACKGROUND: Surgical resection is the main treatment for symptomatic nonfunctioning pituitary adenomas (NFPA). We aimed to analyze the impact of surgical approach, completeness of resection, and postoperative radiotherapy on long-term progression-free survival (PFS) of NFPA, using individual patient data (IPD) meta-analysis. METHODS: An electronic literature searched was conducted on PubMed, EMBASE, and Web of Science from database inception to 6 November 2022. Studies describing the natural history of surgically resected NFPA, with provision of Kaplan-Meier curves, were included. These were digitized to obtain IPD, which was pooled in one-stage and two-stage meta-analysis to determine hazard ratios (HRs) and 95%CIs of gross total resection (GTR) versus subtotal resection (STR), and postoperative radiotherapy versus none. An indirect analysis of single-arm data between endoscopic endonasal (EES) and microscopic transsphenoidal (MTS) surgical technique was also performed. RESULTS: Altogether, eleven studies (3941 patients) were retrieved. PFS was significantly lower in STR than GTR (shared-frailty HR 0.32, 95%CI 0.27-0.39, p < 0.001). Postoperative radiotherapy significantly improved PFS compared to no radiotherapy (shared-frailty HR 0.20, 95%CI 0.15-0.26, p < 0.001), including in the subgroup of patients with STR (shared-frailty HR 0.12, 95%CI 0.08-0.18, p < 0.001). Similar PFS was observed between EES and MTS (indirect HR 1.09, 95%CI 0.92-1.30, p = 0.301). CONCLUSIONS: This systematic review and patient-level meta-analysis provides a robust prognostication of surgically treated NFPA. We reinforce current guidelines stating that GTR should be the standard of surgical resection. Postoperative radiotherapy is of considerable benefit, especially for patients with STR. Surgical approach does not significantly affect long-term prognosis. REGISTRATION: PROSPERO CRD42022374034.


Asunto(s)
Fragilidad , Neoplasias Hipofisarias , Humanos , Neoplasias Hipofisarias/radioterapia , Neoplasias Hipofisarias/cirugía , Supervivencia sin Progresión , Pronóstico , Endoscopía , Resultado del Tratamiento , Estudios Retrospectivos
13.
Nucleic Acids Res ; 49(W1): W654-W661, 2021 07 02.
Artículo en Inglés | MEDLINE | ID: mdl-33744969

RESUMEN

Experiments that are planned using accurate prediction algorithms will mitigate failures in recombinant protein production. We have developed TISIGNER (https://tisigner.com) with the aim of addressing technical challenges to recombinant protein production. We offer three web services, TIsigner (Translation Initiation coding region designer), SoDoPE (Soluble Domain for Protein Expression) and Razor, which are specialised in synonymous optimisation of recombinant protein expression, solubility and signal peptide analysis, respectively. Importantly, TIsigner, SoDoPE and Razor are linked, which allows users to switch between the tools when optimising genes of interest.


Asunto(s)
Proteínas Recombinantes/biosíntesis , Programas Informáticos , Internet , Iniciación de la Cadena Peptídica Traduccional , Señales de Clasificación de Proteína , Proteínas Recombinantes/química , Proteínas Recombinantes/genética , Solubilidad
14.
Adv Exp Med Biol ; 1414: 45-96, 2023.
Artículo en Inglés | MEDLINE | ID: mdl-36520413

RESUMEN

Nitric-oxide dioxygenases (NODs) activate and combine O2 with NO to form nitrate. A variety of oxygen-binding hemoglobins with associated partner reductases or electron donors function as enzymatic NODs. Kinetic and structural investigations of the archetypal two-domain microbial flavohemoglobin-NOD have illuminated an allosteric mechanism that employs selective tunnels for O2 and NO, gates for NO and nitrate, transient O2 association with ferric heme, and an O2 and NO-triggered, ferric heme spin crossover-driven, motion-controlled, and dipole-regulated electron-transfer switch. The proposed mechanism facilitates radical-radical coupling of ferric-superoxide with NO to form nitrate while preventing suicidal ferrous-NO formation. Diverse globins display the structural and functional motifs necessary for a similar allosteric NOD mechanism. In silico docking simulations reveal monomeric erythrocyte hemoglobin alpha-chain and beta-chain intrinsically matched and tightly coupled with NADH-cytochrome b5 oxidoreductase and NADPH-cytochrome P450 oxidoreductase, respectively, forming membrane-bound flavohemoglobin-like mammalian NODs. The neuroprotective neuroglobin manifests a potential NOD role in a close-fitting ternary complex with membrane-bound NADH-cytochrome b5 oxidoreductase and cytochrome b5. Cytoglobin interfaces weakly with cytochrome b5 for O2 and NO-regulated electron-transfer and coupled NOD activity. The mechanistic model also provides insight into the evolution of O2 binding cooperativity in hemoglobin and a basis for the discovery of allosteric NOD inhibitors.


Asunto(s)
Dioxigenasas , Oxidorreductasas , Humanos , Animales , Globinas , Nitratos , Citocromos b , NAD , Óxidos , Oxidación-Reducción , Mamíferos
15.
Adv Exp Med Biol ; 1405: 477-506, 2023.
Artículo en Inglés | MEDLINE | ID: mdl-37452950

RESUMEN

Malignant bone tumors affecting the brain and spine are a rare and exceedingly difficult-to-treat group of diseases. Most commonly consisting of chordoma and chondrosarcoma, these tumors also include giant-cell tumors and osteosarcomas. This chapter will cover the background, epidemiology, genetics, molecular biology, histopathology, radiographic features, clinical manifestations, therapeutic approaches, and clinical management of each entity.


Asunto(s)
Osteosarcoma , Neoplasias de la Médula Espinal , Neoplasias de la Columna Vertebral , Humanos , Neoplasias de la Columna Vertebral/diagnóstico por imagen , Neoplasias de la Columna Vertebral/epidemiología , Neoplasias de la Columna Vertebral/genética , Huesos/patología , Cartílago/patología , Encéfalo/patología
16.
J Biol Chem ; 296: 100186, 2021.
Artículo en Inglés | MEDLINE | ID: mdl-33310705

RESUMEN

The substrates O2 and NO cooperatively activate the NO dioxygenase function of Escherichia coli flavohemoglobin. Steady-state and transient kinetic measurements support a structure-based mechanistic model in which O2 and NO movements and conserved amino acids at the E11, G8, E2, E7, B10, and F7 positions within the globin domain control activation. In the cooperative and allosteric mechanism, O2 migrates to the catalytic heme site via a long hydrophobic tunnel and displaces LeuE11 away from the ferric iron, which forces open a short tunnel to the catalytic site gated by the ValG8/IleE15 pair and LeuE11. NO permeates this tunnel and leverages upon the gating side chains triggering the CD loop to furl, which moves the E and F-helices and switches an electron transfer gate formed by LysF7, GlnE7, and water. This allows FADH2 to reduce the ferric iron, which forms the stable ferric-superoxide-TyrB10/GlnE7 complex. This complex reacts with internalized NO with a bimolecular rate constant of 1010 M-1 s-1 forming nitrate, which migrates to the CD loop and unfurls the spring-like structure. To restart the cycle, LeuE11 toggles back to the ferric iron. Actuating electron transfer with O2 and NO movements averts irreversible NO poisoning and reductive inactivation of the enzyme. Together, structure snapshots and kinetic constants provide glimpses of intermediate conformational states, time scales for motion, and associated energies.


Asunto(s)
Dihidropteridina Reductasa/metabolismo , Proteínas de Escherichia coli/metabolismo , Escherichia coli/metabolismo , NADH NADPH Oxidorreductasas/metabolismo , Oxigenasas/metabolismo , Regulación Alostérica , Dihidropteridina Reductasa/química , Escherichia coli/química , Infecciones por Escherichia coli/microbiología , Proteínas de Escherichia coli/química , Humanos , Modelos Moleculares , NADH NADPH Oxidorreductasas/química , Óxido Nítrico/metabolismo , Oxigenasas/química , Conformación Proteica
17.
Muscle Nerve ; 65(2): 247-255, 2022 02.
Artículo en Inglés | MEDLINE | ID: mdl-34738250

RESUMEN

INTRODUCTION/AIMS: While the peripheral nervous system has the inherent ability to recover following injury, results are often unsatisfactory, resulting in permanent functional deficits and disability. Therefore, methods that enhance regeneration are of significant interest. The present study investigates an injectable nerve-tissue-specific hydrogel as a biomaterial for nerve regeneration in a rat nerve crush model. METHODS: Nerve-specific hydrogels were injected into the subepineurial space in both uninjured and crushed sciatic nerves of rats to assess safety and efficacy, respectively. The animals were followed longitudinally for 12 wk using sciatic functional index and kinematic measures. At 12 wk, electrophysiologic examination was also performed, followed by nerve and muscle histologic assessment. RESULTS: When the hydrogel was injected into an uninjured nerve, no differences in sciatic functional index, kinematic function, or axon counts were observed. A slight reduction in muscle fiber diameter was observed in the hydrogel-injected animals, but overall muscle area and kinematic function were not affected. Hydrogel injection following nerve crush injury resulted in multiple modest improvements in sciatic functional index and kinematic function with an earlier return to normal function observed in the hydrogel treated animals as compared to untreated controls. While no improvements in supramaximal compound motor action potential were observed in hydrogel treated animals, increased axon counts were observed on histologic assessment. DISCUSSION: These improvements in functional and histologic outcomes in a rapidly and fully recovering model suggest that injection of a nerve-specific hydrogel is safe and has the potential to improve outcomes following nerve injury.


Asunto(s)
Lesiones por Aplastamiento , Hidrogeles , Animales , Lesiones por Aplastamiento/patología , Compresión Nerviosa , Regeneración Nerviosa/fisiología , Ratas , Roedores , Nervio Ciático/lesiones
18.
J Neurooncol ; 157(2): 207-219, 2022 Apr.
Artículo en Inglés | MEDLINE | ID: mdl-35301638

RESUMEN

PURPOSE: To summarize the clinical features and outcomes of petroclival meningioma patients treated with stereotactic radiosurgery (SRS) as either a primary or an adjuvant modality. METHODS: Relevant articles were retrieved from PubMed, Scopus, Web of Science, and Cochrane. A systematic review and meta-analysis of treatment outcomes comparing primary and adjuvant SRS was conducted. RESULTS: Seven articles comprising 722 cases were included. The mean tumor marginal dose was 13.5 Gy. After SRS, symptoms improved in 28.7%, remained unchanged in 61.3%, and worsened in 10.0% of the cohort. Tumor control was achieved in 94.8% of patients. The mean tumor volume change was -6.4 cm3. The 5-year and 10-year progression-free survival (PFS) rates were 91-100% and 69.6-89.9%, respectively. Overall, 61.9% of patients underwent primary radiosurgery, and 38.1% had adjuvant radiosurgery. Patients who had primary SRS reported higher rates of tumor control (94.3% vs. 88.2%) and fewer SRS-related complications (3.7% vs. 10.3%) than those who received adjuvant SRS (not accounting for microsurgical complications). The functional status of patients who had primary SRS was more likely to improve or remain unchanged, with an effect size of 1.12 (95% CI 1.1-1.25; I2 = 0). Neither group displayed superiority in worsening functional outcomes or tumor control rate. CONCLUSION: SRS of petroclival meningiomas was associated with excellent long-term PFS and local tumor control rates. Primary SRS was highly effective for patients with smaller volume lesions without clinically symptomatic mass effect. In patients who warrant initial resection, adjuvant radiosurgery remains an important modality to prevent regrowth while maintaining postresection function.


Asunto(s)
Neoplasias Meníngeas , Meningioma , Radiocirugia , Neoplasias de la Base del Cráneo , Estudios de Seguimiento , Humanos , Neoplasias Meníngeas/complicaciones , Neoplasias Meníngeas/radioterapia , Neoplasias Meníngeas/cirugía , Meningioma/complicaciones , Meningioma/radioterapia , Meningioma/cirugía , Radiocirugia/efectos adversos , Estudios Retrospectivos , Neoplasias de la Base del Cráneo/complicaciones , Neoplasias de la Base del Cráneo/radioterapia , Neoplasias de la Base del Cráneo/cirugía , Resultado del Tratamiento
19.
PLoS Comput Biol ; 17(10): e1009461, 2021 10.
Artículo en Inglés | MEDLINE | ID: mdl-34610008

RESUMEN

Recombinant protein production is a key process in generating proteins of interest in the pharmaceutical industry and biomedical research. However, about 50% of recombinant proteins fail to be expressed in a variety of host cells. Here we show that the accessibility of translation initiation sites modelled using the mRNA base-unpairing across the Boltzmann's ensemble significantly outperforms alternative features. This approach accurately predicts the successes or failures of expression experiments, which utilised Escherichia coli cells to express 11,430 recombinant proteins from over 189 diverse species. On this basis, we develop TIsigner that uses simulated annealing to modify up to the first nine codons of mRNAs with synonymous substitutions. We show that accessibility captures the key propensity beyond the target region (initiation sites in this case), as a modest number of synonymous changes is sufficient to tune the recombinant protein expression levels. We build a stochastic simulation model and show that higher accessibility leads to higher protein production and slower cell growth, supporting the idea of protein cost, where cell growth is constrained by protein circuits during overexpression.


Asunto(s)
Codón Iniciador/genética , Codón de Terminación/genética , Proteínas Recombinantes/química , Proteínas Recombinantes/genética , Mutación Silenciosa/genética , Biología Computacional
20.
Pituitary ; 25(3): 508-519, 2022 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-35467273

RESUMEN

PURPOSE: To review our institutional experience with the surgical management of prolactinomas through the endoscopic endonasal approach with specific focus on cavernous sinus invasion. METHODS: Clinical and radiographic data were collected retrospectively from the electronic medical record of 78 consecutive patients with prolactinomas undergoing endoscopic endonasal resection from 2002 to 2019. Immediate and late post-operative remission were defined as prolactin < 20 ng/mL within 14 days and 1-year of surgery without adjuvant therapy, respectively. Cavernous sinus invasion was quantified by Knosp score. RESULTS: A total of 78 patients with prolactinoma, 59% being male, underwent surgical resection with a mean age of 37 ± 13 years. Indications for surgery were medication resistance in 38 patients (48.7%), medication intolerance in 11 (14.1%), and patient preference in 29 (37.2%). Patients with Knosp 0-2 achieved higher immediate remission rates (83.8%) compared to patients with Knosp 3 (58.8%) and Knosp 4 (41.7%) patients (p = 0.003). Long-term remission rates were 48.7% and increased to 71.8% when combined with adjuvant treatments. Knosp 4 prolactinomas had significantly higher tumor volumes, higher preoperative prolactin levels, higher recurrence rates, higher rates of adjuvant therapy utilization, and were more likely to have failed dopamine agonist therapy compared to other tumor grades (p < 0.05). We encountered 18 complications in our series, and no cerebrospinal fluid leaks. CONCLUSION: The endoscopic endonasal approach is a safe and effective modality that can be employed in properly selected patients with invasive prolactinomas. It is associated with improved control and remission rates despite cavernous sinus invasion, though at a lower rate than without invasion.


Asunto(s)
Seno Cavernoso , Neoplasias Hipofisarias , Prolactinoma , Adulto , Seno Cavernoso/patología , Seno Cavernoso/cirugía , Femenino , Humanos , Masculino , Persona de Mediana Edad , Neoplasias Hipofisarias/patología , Neoplasias Hipofisarias/cirugía , Prolactina , Prolactinoma/tratamiento farmacológico , Prolactinoma/patología , Prolactinoma/cirugía , Estudios Retrospectivos , Resultado del Tratamiento , Adulto Joven
SELECCIÓN DE REFERENCIAS
DETALLE DE LA BÚSQUEDA