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PRIMARY OBJECTIVE: To evaluate the accuracy of an innovative machine-learning-powered near-infrared spectroscopy (mNIRS)-based bio-optical sensitivity parameters, namely specific tissue optical index (STOI) and intracranial tissue optical index (ITOI) for effective triaging of patients with suspected traumatic brain injury (TBI) across different age-groups to facilitate timely intervention and curtail the silent epidemic. RESEARCH DESIGN: Prospective, observational, double-blinded, cross-sectional single-center. METHODS: A total of 240 subjects suspected with TBI and recommended for head CT scan were enrolled. Findings of CT were compared with the bio-optical sensitivity parameters (STOI+ITOI) generated by the mNIRS system to detect intracranial hemorrhages (ICHs). STATISTICAL SOFTWARE USED: SPSS (IBM VERSION 21.0) RESULTS: Bio-optical sensitivity parameters (STOI+ITOI) analysis of 1288 scanned lobes showed high specificity of 97% (CI 95-98%), sensitivity of 96% (CI 92-99%), and accuracy of 97% (CI 96-98%) across all ages, maintaining robust performance for detecting subdural, epidural, subarachnoid hemorrhages, and contusions. Also, the reliability in the diagnosis of ICH was evidenced by Youden's index of 0.93 and positive and negative likelihood ratios of 29.13 and 0.04, respectively. CONCLUSION: The mNIRS-based STOI+ITOI proves to be an effective triage tool for TBI, exhibiting superior diagnostic performance across all age-groups.
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ABSTRACT: The prevalence of sexual abuse in competitive sports is increasing worldwide and requires a united call to action. The underreporting of such abuses gained media attention resulting from recent high-profile cases. In this article, we report the results of a systematic literature review, identifying root causes of underreporting sexual abuse in competitive sports. We identify that biases and conflicts of interest work against effective reporting of abuse by athletes at the individual, organizational, and cultural levels. We offer conflict of interest and bias mitigation approaches from the social science, law, business, research, and diagnostic error literature that may apply. Competitive sports organizations may use this analysis to identify barriers and improve the effective reporting of sexual abuse.
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Conflito de Interesses , Delitos Sexuais , Esportes , Humanos , Atletas , Viés , Delitos Sexuais/estatística & dados numéricosRESUMO
X-linked retinoschisis (XLR) is a rare medical condition that involves in the splitting of neurosensory layers and the impairment of vision in the retina. In majority of the XLR cases, pathogenic variants in Retinoschisin 1 (RS1) gene have been implicated in males with an early age of onset during early childhood. In the present study, we have recruited two North Indian families having multiple affected male members, who were diagnosed with XLR. The entire protein-coding region of RS1 was screened by PCR-Sanger sequencing and two recurrent pathogenic variants (p.I81N and p.R102Q) were unraveled. The in vitro study of these variants demonstrated the aggregation of mutant RS1 within the endoplasmic reticulum. Furthermore, mutant forms of this protein showed significant intracellular retention, which was evident by the absence of retinoschisin protein fractions in the extracellular media. These inferences were also supported by extensive bioinformatics analysis of the mutants, which showed dramatic conformational changes in the local structure of retinoschisin. Thus, our study suggests that the identified pathogenic variants interfere with proper protein folding, leading to anomalous structural changes ultimately resulting in intracellular retention of retinoschisin within the retina.
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Retinosquise , Pré-Escolar , Masculino , Humanos , Retinosquise/diagnóstico , Retinosquise/genética , Retinosquise/metabolismo , Mutação de Sentido Incorreto/genética , Retina/patologia , Dobramento de Proteína , Índia , Proteínas do Olho/genéticaRESUMO
Due to modern medical advancements, greater proportions of the population will continue to age with longer life spans. Increased life span, however, does not always correlate with improved health span, and may result in an increase in aging-related diseases and disorders. These diseases are often attributed to cellular senescence, in which cells become disengaged from the cell cycle and inert to cell death. These cells are characterized by a proinflammatory secretome. The proinflammatory senescence-associated secretory phenotype, although part of a natural function intended to prevent further DNA damage, creates a microenvironment suited to tumor progression. This microenvironment is most evident in the gastrointestinal tract (GI), where a combination of bacterial infections, senescent cells, and inflammatory proteins can lead to oncogenesis. Thus, it is important to find potential senescence biomarkers as targets of novel therapies for GI diseases and disorders including cancers. However, finding therapeutic targets in the GI microenvironment to reduce the risk of GI tumor onset may also be of value. This review summarizes the effects of cellular senescence on GI aging, inflammation, and cancers, and aims to improve our understanding of these processes with a goal of enhancing future therapy.
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Senescência Celular , Neoplasias , Humanos , Neoplasias/metabolismo , Inflamação , Trato Gastrointestinal/metabolismo , Microambiente TumoralRESUMO
BACKGROUND: Long-term outcomes of SIRC are not well established. Furthermore, SIRC is only now being considered more frequently for patients with independent risk factors for PSH, such as obesity. As such, the paucity of data on longer-term post-surgical outcomes of SIRC is particularly notable as it pertains to obese patients. METHODS: All patients undergoing cholecystectomy performed by two surgeons at our institution from 2008-2018 were reviewed. Our inclusion criteria were patients who underwent SIRC or multiport laparoscopic cholecystectomy (MPLC) and had at least one month of postoperative follow-up. Patients who underwent additional procedures at the time of cholecystectomy were excluded. Our outcomes of interest were the 30-day POC rate and the long-term PSH rate. Analysis was conducted on an intention-to-treat basis, using logistic regression analysis for POC and time-to-event analysis for PSH. RESULTS: We examined 584 patients who underwent either SIRC (51%) or MPLC (49%). Of the 296 patients who underwent SIRC, 15 (5%) developed a POC and 23 (8%) developed a PSH. Of the 288 patients who underwent MPLC, 11 (4%) developed a POC, and 28 (10%) developed a PSH. Procedure group and obesity was not associated with the risk of POC (p = 0.29, p = 0.21, respectively). Procedure group was not associated with an increased risk of PSH (p = 0.29). Obese patients, however, were 1.94 times more likely to develop PSH compared to non-obese patients overall (p = 0.02). CONCLUSIONS: There is no statistically significant difference in POC and PSH rate following SIRC when compared with MPLC in patients in the same BMI group. Male gender and prior abdominal surgery are risk factors for POC, while advancing age and obesity are risk factors for PSH.
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Colecistectomia Laparoscópica , Procedimentos Cirúrgicos Robóticos , Robótica , Colecistectomia/métodos , Colecistectomia Laparoscópica/efeitos adversos , Colecistectomia Laparoscópica/métodos , Feminino , Humanos , Masculino , Obesidade/complicações , Obesidade/epidemiologia , Estudos Retrospectivos , Procedimentos Cirúrgicos Robóticos/efeitos adversos , Procedimentos Cirúrgicos Robóticos/métodos , Robótica/métodosRESUMO
The present study was focused on the optimization of process parameters and quality characterization of Khaja. A full factorial design 53 was applied using different levels of fat proportions (5-25%), frying temperature (160-200 °C), and frying time (1-5 min). The response optimizer function in Minitab 18 software was used to select five samples with the highest desirability which were then subjected to sensory analysis. The lightness of the samples decreased significantly (P Ë 0.05) from 68.59 to 43.33 whereas, redness increased significantly (P Ë 0.05) from 0.26 to 11.48 with increasing levels of all independent variables. Water activity and moisture content of the samples decreased significantly (P Ë 0.05) from 0.75 to 0.21 and 14.41-1.40%wb respectively, whereas total fat content increased significantly (P Ë 0.05) from 25.05 to 45.7% with increasing levels of independent variables. The hardness of the samples significantly (P Ë 0.05) varied from 60.45 to 7.69 N. The sensory analysis revealed that the sample with 20% fat proportion, fried at 180 °C for 4 min, scored maximum in overall acceptability. The microstructural images revealed the structural damage and formation of pores in fried samples. The fatty acid analysis showed higher saturated fatty acids in market samples than in optimized samples. The results of the study concluded that fat proportion and frying parameters (temperature and time) are crucial for a better understanding of the deep-frying process of Khaja in order to achieve good quality. Supplementary Information: The online version contains supplementary material available at 10.1007/s13197-022-05509-x.
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Bone is a dynamic organ maintained by tightly regulated mechanisms. With old age, bone homeostasis, which is maintained by an intricate balance between bone formation and bone resorption, undergoes deregulation. Oxidative stress-induced DNA damage, cellular apoptosis, and cellular senescence are all responsible for this tissue dysfunction and the imbalance in the bone homeostasis. These cellular mechanisms have become a target for therapeutics to treat age-related osteoporosis. Genetic mouse models have shown the importance of senescent cell clearance in alleviating age-related osteoporosis. Furthermore, we and others have shown that targeting cellular senescence pharmacologically was an effective tool to alleviate age- and radiation-induced osteoporosis. Senescent cells also have an altered secretome known as the senescence associated secretory phenotype (SASP), which may have autocrine, paracrine, or endocrine function. The current review discusses the current and potential pathways which lead to a senescence profile in an aged skeleton and how bone homeostasis is affected during age-related osteoporosis. The review has also discussed existing therapeutics for the treatment of osteoporosis and rationalizes for novel therapeutic options based on cellular senescence and the SASP as an underlying pathogenesis of an aging bone.
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Envelhecimento/fisiologia , Osso e Ossos/fisiologia , Osteoporose/tratamento farmacológico , Osteoporose/etiologia , Poli(ADP-Ribose) Polimerase-1/fisiologia , Animais , Osso e Ossos/fisiopatologia , Senescência Celular , Dano ao DNA , Epigênese Genética , Instabilidade Genômica , Humanos , Mitocôndrias/genética , Mitocôndrias/metabolismo , Osteoporose/fisiopatologia , Hormônio Paratireóideo/metabolismo , Telômero/fisiologiaRESUMO
BACKGROUND: Papaya fruit is highly nutritive, but very fragile, and thus has a limited shelf life. Drying is essential to preserve it for longer durations. In this work, osmotic dehydration (OD) with and without ultrasound (US) was applied to papaya slices as a pretreatment in conjugation with vacuum (VD) and convective air drying (AD). Drying was carried out in a novel dryer. Moisture content, drying time, water activity, total color change, total phenolic content, radical scavenging activity, texture, and Fourier-transform infrared (FTIR) spectrums were evaluated for fresh and dried papaya slices. RESULTS: It was observed that US-assisted osmotic dehydration (USOD) followed by VD had the lowest drying time with highest retention of phenols and antioxidants as compared to other drying techniques. Higher phenols and antioxidants in US-pretreated samples were attributed to the release of trapped intra-cellular polyphenols by cavitation. However, the color characteristics and texture of OD pretreatment followed by convective AD slices were found to be better. Color retention could be due to carotenoid preservation, which would be degraded in other treatments, whereas lower brittleness was associated with lower pectin. Infrared spectroscopy confirmed the retention of phytochemicals and antioxidants in dried papaya slices that were subjected to pretreatment. CONCLUSION: Pretreatment before drying enhances the end product quality of dried papaya slices. The results of this study highlight that USOD-VD is effective for nutrition preservation while OD-AD is suitable for preserving physical characteristics. © 2020 Society of Chemical Industry.
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Carica/química , Dessecação/métodos , Conservação de Alimentos/métodos , Ultrassom/métodos , Antioxidantes/química , Dessecação/instrumentação , Conservação de Alimentos/instrumentação , Frutas/química , Osmose , Compostos Fitoquímicos/química , Polifenóis/química , Ultrassom/instrumentação , VácuoRESUMO
Bone atrophy and its related fragility fractures are frequent, late side effects of radiotherapy in cancer survivors and have a detrimental impact on their quality of life. In another study, we showed that parathyroid hormone 1-34 and anti-sclerostin antibody attenuates radiation-induced bone damage by accelerating DNA repair in osteoblasts. DNA damage responses are partially regulated by the ubiquitin proteasome pathway. In the current study, we examined whether proteasome inhibitors have similar bone-protective effects against radiation damage. MG132 treatment greatly reduced radiation-induced apoptosis in cultured osteoblastic cells. This survival effect was owing to accelerated DNA repair as revealed by γH2AX foci and comet assays and to the up-regulation of Ku70 and DNA-dependent protein kinase, catalytic subunit, essential DNA repair proteins in the nonhomologous end-joining pathway. Administration of bortezomib (Bzb) reversed the loss of trabecular bone structure and strength in mice at 4 wk after focal radiation. Histomorphometry revealed that Bzb significantly increased the number of osteoblasts and activity in the irradiated area and suppressed the number and activity of osteoclasts, regardless of irradiation. Two weeks of Bzb treatment accelerated DNA repair in bone-lining osteoblasts and thus promoted their survival. Meanwhile, it also inhibited bone marrow adiposity. Taken together, we demonstrate a novel role of proteasome inhibitors in treating radiation-induced osteoporosis.-Chandra, A., Wang, L., Young, T., Zhong, L., Tseng, W.-J., Levine, M. A., Cengel, K., Liu, X. S., Zhang, Y., Pignolo, R. J., Qin, L. Proteasome inhibitor bortezomib is a novel therapeutic agent for focal radiation-induced osteoporosis.
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Bortezomib/farmacologia , Osteoporose/tratamento farmacológico , Inibidores de Proteassoma/farmacologia , Lesões por Radiação/tratamento farmacológico , Protetores contra Radiação/farmacologia , Células 3T3 , Animais , Apoptose/efeitos dos fármacos , Apoptose/efeitos da radiação , Remodelação Óssea/efeitos dos fármacos , Remodelação Óssea/efeitos da radiação , Linhagem Celular , Sobrevivência Celular/efeitos dos fármacos , Reparo do DNA/efeitos dos fármacos , Humanos , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Transgênicos , Osteoblastos/efeitos dos fármacos , Osteoblastos/patologia , Osteoblastos/efeitos da radiação , Osteoporose/metabolismo , Osteoporose/patologia , Lesões por Radiação/metabolismo , Lesões por Radiação/patologia , Microtomografia por Raio-XRESUMO
PURPOSE OF REVIEW: We review cell senescence in the context of age-related bone loss by broadly discussing aging mechanisms in bone, currently known inducers and markers of senescence, the senescence-associated secretory phenotype (SASP), and the emerging roles of senescence in bone homeostasis and pathology. RECENT FINDINGS: Cellular senescence is a state of irreversible cell cycle arrest induced by insults or stressors including telomere attrition, oxidative stress, DNA damage, oncogene activation, and other intrinsic or extrinsic triggers and there is mounting evidence for the role of senescence in aging bone. Cellular aging also instigates a SASP that exerts detrimental paracrine and likely systemic effects. With aging, multiple cell types in the bone microenvironment become senescent, with osteocytes and myeloid cells as primary contributors to the SASP. Targeting undesired senescent cells may be a favorable strategy to promote bone anabolic and anti-resorptive functions in aging bone, with the possibility of improving bone quality and function with normal aging and/or disease.
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Senescência Celular/efeitos dos fármacos , Osteoporose/tratamento farmacológico , Osteoporose/fisiopatologia , Senescência Celular/fisiologia , Humanos , Osteoporose/etiologiaRESUMO
Osteoarthritis (OA) is the most common joint disease, characterized by progressive destruction of the articular cartilage. The surface of joint cartilage is the first defensive and affected site of OA, but our knowledge of genesis and homeostasis of this superficial zone is scarce. EGFR signaling is important for tissue homeostasis. Immunostaining revealed that its activity is mostly dominant in the superficial layer of healthy cartilage but greatly diminished when OA initiates. To evaluate the role of EGFR signaling in the articular cartilage, we studied a cartilage-specific Egfr-deficient (CKO) mouse model (Col2-Cre EgfrWa5/flox). These mice developed early cartilage degeneration at 6 mo of age. By 2 mo of age, although their gross cartilage morphology appears normal, CKO mice had a drastically reduced number of superficial chondrocytes and decreased lubricant secretion at the surface. Using superficial chondrocyte and cartilage explant cultures, we demonstrated that EGFR signaling is critical for maintaining the number and properties of superficial chondrocytes, promoting chondrogenic proteoglycan 4 (Prg4) expression, and stimulating the lubrication function of the cartilage surface. In addition, EGFR deficiency greatly disorganized collagen fibrils in articular cartilage and strikingly reduced cartilage surface modulus. After surgical induction of OA at 3 mo of age, CKO mice quickly developed the most severe OA phenotype, including a complete loss of cartilage, extremely high surface modulus, subchondral bone plate thickening, and elevated joint pain. Taken together, our studies establish EGFR signaling as an important regulator of the superficial layer during articular cartilage development and OA initiation.
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Artrite Experimental/metabolismo , Cartilagem Articular/metabolismo , Receptores ErbB/metabolismo , Osteoartrite/metabolismo , Animais , Artrite Experimental/patologia , Artrite Experimental/prevenção & controle , Células Cultivadas , Condrócitos/metabolismo , Condrócitos/patologia , Condrogênese , Receptores ErbB/deficiência , Receptores ErbB/genética , Humanos , Masculino , Camundongos , Camundongos Knockout , Osteoartrite/patologia , Osteoartrite/prevenção & controle , Proteoglicanas/metabolismo , Transdução de SinaisRESUMO
Huntington's disease (HD) is a devastating illness and at present there is no disease modifying therapy or cure for it; and management of the disease is limited to a few treatment options for amelioration of symptoms. Recently, we showed that the administration of bezafibrate, a pan-PPAR agonist, increases the expression of PGC-1α and mitochondrial biogenesis, and improves phenotype and survival in R6/2 transgenic mouse model of HD. Since the R6/2 mice represent a 'truncated' huntingtin (Htt) mouse model of HD, we tested the efficacy of bezafibrate in a 'full-length' Htt mouse model, the BACHD mice. Bezafibrate treatment restored the impaired PPARγ, PPARδ, PGC-1α signaling pathway, enhanced mitochondrial biogenesis and improved antioxidant defense in the striatum of BACHD mice. Untreated BACHD mice show robust and progressive motor deficits, as well as late-onset and selective neuropathology in the striatum, which was markedly ameliorated in the BACHD mice treated with bezafibrate. Our data demonstrate the efficacy of bezafibrate in ameliorating both neuropathological features and disease phenotype in BACHD mice, and taken together with our previous studies with the R6/2 mice, highlight the strong therapeutic potential of bezafibrate for treatment of HD.
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Proteína Huntingtina/genética , Doença de Huntington/tratamento farmacológico , PPAR delta/biossíntese , PPAR gama/biossíntese , Coativador 1-alfa do Receptor gama Ativado por Proliferador de Peroxissomo/biossíntese , Animais , Bezafibrato/administração & dosagem , Corpo Estriado/efeitos dos fármacos , Corpo Estriado/patologia , Modelos Animais de Doenças , Humanos , Doença de Huntington/genética , Doença de Huntington/patologia , Camundongos , Camundongos Transgênicos , Mitocôndrias/efeitos dos fármacos , Mitocôndrias/genética , Biogênese de Organelas , PPAR delta/genética , PPAR gama/genética , Coativador 1-alfa do Receptor gama Ativado por Proliferador de Peroxissomo/antagonistas & inibidores , Coativador 1-alfa do Receptor gama Ativado por Proliferador de Peroxissomo/genética , Transdução de Sinais/efeitos dos fármacosRESUMO
Focal radiotherapy for cancer patients has detrimental effects on bones within the radiation field and the primary clinical signs of bone damage include the loss of functional osteoblasts. We reported previously that daily injection of parathyroid hormone (PTH, 1-34) alleviates radiation-induced osteopenia in a preclinical radiotherapy model by improving osteoblast survival. To elucidate the molecular mechanisms, we irradiated osteoblastic UMR 106-01 cells and calvarial organ culture and demonstrated an anti-apoptosis effect of PTH1-34 on these cultures. Inhibitor assay indicated that PTH exerts its radioprotective action mainly through protein kinase A/ß-catenin pathway. γ-H2AX foci staining and comet assay revealed that PTH efficiently promotes the repair of DNA double strand breaks (DSBs) in irradiated osteoblasts via activating the ß-catenin pathway. Interestingly, Wnt3a alone also blocked cell death and accelerated DNA repair in primary osteoprogenitors, osteoblastic and osteocytic cells after radiation through the canonical signaling. Further investigations revealed that both Wnt3a and PTH increase the amount of Ku70, a core protein for initiating the assembly of DSB repair machinery, in osteoblasts after radiation. Moreover, down-regulation of Ku70 by siRNA abrogated the prosurvival effect of PTH and Wnt3a on irradiated osteoblasts. In summary, our results identify a novel role of PTH and canonical Wnt signaling in regulating DSB repair machinery and apoptosis in osteoblasts and shed light on using PTH1-34 or Wnt agonist as possible therapy for radiation-induced osteoporosis.
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Apoptose/efeitos dos fármacos , Reparo do DNA/efeitos dos fármacos , Osteoblastos/efeitos dos fármacos , Hormônio Paratireóideo/farmacologia , Protetores contra Radiação/farmacologia , Animais , Animais Recém-Nascidos , Antígenos Nucleares/genética , Antígenos Nucleares/metabolismo , Apoptose/efeitos da radiação , Diferenciação Celular , Linhagem Celular Tumoral , Proteínas Quinases Dependentes de AMP Cíclico/genética , Proteínas Quinases Dependentes de AMP Cíclico/metabolismo , Quebras de DNA de Cadeia Dupla/efeitos dos fármacos , Quebras de DNA de Cadeia Dupla/efeitos da radiação , Reparo do DNA/efeitos da radiação , Proteínas de Ligação a DNA/genética , Proteínas de Ligação a DNA/metabolismo , Regulação da Expressão Gênica , Autoantígeno Ku , Osteoblastos/citologia , Osteoblastos/efeitos da radiação , Osteócitos/citologia , Osteócitos/efeitos dos fármacos , Osteócitos/efeitos da radiação , Ratos , Proteínas Recombinantes/farmacologia , Transdução de Sinais , Crânio/citologia , Crânio/efeitos dos fármacos , Crânio/efeitos da radiação , Técnicas de Cultura de Tecidos , Proteína Wnt3A/metabolismo , Proteína Wnt3A/farmacologia , Raios X , beta Catenina/genética , beta Catenina/metabolismoRESUMO
BACKGROUND: We recently sensed an increase in the frequency of groin hematoma after inguinal hernia repair (IHR) at our institution. The aim of this study was to provide a more updated assessment of the risk factors inherent to this complication. METHODS: We performed a case-control study of all adult patients (age ≥ 18 y) who developed a groin hematoma after IHR at our institution between 2003 and 2015. Univariate and multivariable analyses were performed to assess for independent predictors for groin hematoma. RESULTS: A total of 96 patients (among 6608 IHR) developed a groin hematoma, (60 were observed, 36 required intervention). The hematoma frequency increased from our previous study (1.4 % versus 0.9%, P < 0.01). Mean age was 64.6 y (range: 18-92), and 84.3% were men. There was no significant difference in the laterality, type, or technique of IHR between cases and controls. Univariate analysis (odds ratio [95% confidence interval], P) identified warfarin usage (3.5, [1.6-6.4], P < 0.01), valvular heart disease (11.6, [2.6-51.3], P < 0.01), atrial fibrillation (2.6, [1.2-5.5], P = 0.01), hypertension (2.03, [1.1-3.6], P = 0.02), recurrent hernia (3.7, [1.4-9.7], P < 0.01), and coronary artery disease (2.1, [1.0-4.4 ], P = 0.05) as significant preoperative factors. The proportion of patients on warfarin decreased since our prior report (31% versus 42%, P = 0.20). On multivariable regression, warfarin and recurrent hernia were independent predictors of hematoma development. CONCLUSIONS: Independent risk factors for the development of groin hematoma after IHR included warfarin use and recurrent hernia. Careful consideration for anticoagulation and surgical hypervigilance remains prudent in all patients undergoing IHR and especially those with recurrence.
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Hematoma/epidemiologia , Hérnia Inguinal/cirurgia , Herniorrafia/efeitos adversos , Complicações Pós-Operatórias/epidemiologia , Idoso , Idoso de 80 Anos ou mais , Anticoagulantes , Estudos de Casos e Controles , Feminino , Hematoma/etiologia , Humanos , Masculino , Pessoa de Meia-Idade , Minnesota/epidemiologia , Complicações Pós-Operatórias/etiologia , Fatores de RiscoRESUMO
Combined parathyroid hormone (PTH) and bisphosphonate (alendronate-ALN) therapy has recently been shown to increase bone volume fraction and plate-like trabecular structure beyond either monotherapy. To identify the mechanism through which plate-like structure was enhanced, we used in vivo microcomputed tomography (µCT) of the proximal tibia metaphysis and individual trabecular dynamics (ITD) analysis to quantify connectivity repair (incidences of rod connection and plate perforation filling) and deterioration (incidences of rod disconnection and plate perforation). Three-month-old female, intact rats were scanned before and after a 12 day treatment period of vehicle (Veh, n = 5), ALN (n = 6), PTH (n = 6), and combined (PTH+ALN, n = 6) therapy. Additionally, we used computational simulation and finite element (FE) analysis to delineate the contributions of connectivity repair or trabecular thickening to trabecular bone stiffness. Our results showed that the combined therapy group had greater connectivity repair (5.8 ± 0.5% connected rods and 2.0 ± 0.3% filled plates) beyond that of the Veh group, resulting in the greatest net gain in connectivity. For all treatment groups, increases in bone volume due to thickening (5-31%) were far greater than those due to connectivity repair (2-3%). Newly formed bone contributing only to trabecular thickening caused a 10%, 41%, and 69% increase in stiffness in the ALN, PTH, and PTH+ALN groups, respectively. Moreover, newly formed bone that led to connectivity repair resulted in an additional improvement in stiffness, with the highest in PTH+ALN (by an additional 12%), which was significantly greater than either PTH (5.6%) or ALN (4.5%). An efficiency ratio was calculated as the mean percent increase in stiffness divided by mean percent increase in BV for either thickening or connectivity repair in each treatment. For all treatments, the efficiency ratio of connectivity repair (ALN: 2.9; PTH: 3.4; PTH+ALN: 4.4) was higher than that due to thickening (ALN: 2.0; PTH: 1.7; PTH+ALN: 2.2), suggesting connectivity repair required less new bone formation to induce larger gains in stiffness. We conclude that through rod connection and plate perforation filling PTH+ALN combination therapy improved bone stiffness in a more efficient and effective manner than either monotherapy.
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Alendronato/farmacologia , Fenômenos Mecânicos , Hormônio Paratireóideo/farmacologia , Tíbia/efeitos dos fármacos , Animais , Fenômenos Biomecânicos/efeitos dos fármacos , Interações Medicamentosas , Feminino , Análise de Elementos Finitos , Tamanho do Órgão/efeitos dos fármacos , Ratos , Ratos Sprague-Dawley , Tíbia/anatomia & histologia , Tíbia/diagnóstico por imagem , Tíbia/fisiologia , Microtomografia por Raio-XRESUMO
Maintaining bone architecture requires continuous generation of osteoblasts from osteoprogenitor pools. Our previous study of mice with epidermal growth factor receptor (EGFR) specifically inactivated in osteoblast lineage cells revealed that EGFR stimulates bone formation by expanding the population of mesenchymal progenitors. EGFR ligands are potent regulators for the osteoprogenitor pool, but the underlying mechanisms are largely unknown. Here we demonstrate that activation of EGFR increases the number of osteoprogenitors by promoting cell proliferation and suppressing either serum depletion-induced or TNFα-induced apoptosis mainly through the MAPK/ERK pathway. Mouse calvarial organ culture revealed that EGF elevated the number of proliferative cells and decreased the number of apoptotic cells, which led to increased osteoblasts. Microarray analysis of MC3T3 cells, an osteoprogenitor cell line, revealed that EGFR signaling stimulates the expression of MCL1, an antiapoptotic protein, and a family of EGR transcription factors (EGR1, -2, and -3). The up-regulation of MCL1 and EGR2 by EGF was further confirmed in osteoprogenitors close to the calvarial bone surface. Overexpression of NAB2, a co-repressor for EGRs, attenuated the EGF-induced increase in osteoprogenitor number. Interestingly, knocking down the expression of EGR2, but not EGR1 or -3, resulted in a similar effect. Using inhibitor, adenovirus overexpression, and siRNA approaches, we demonstrate that EGFR signaling activates the MAPK/ERK pathway to stimulate the expression of EGR2, which in turn leads to cell growth and MCL1-mediated cell survival. Taken together, our data clearly demonstrate that EGFR-induced EGR2 expression is critical for osteoprogenitor maintenance and new bone formation.
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Proliferação de Células , Proteína 2 de Resposta de Crescimento Precoce/metabolismo , Receptores ErbB/metabolismo , Osteoblastos/metabolismo , Transdução de Sinais , Animais , Animais Recém-Nascidos , Apoptose , Linhagem Celular , Sobrevivência Celular , Proteína 2 de Resposta de Crescimento Precoce/genética , Receptores ErbB/genética , Perfilação da Expressão Gênica , Immunoblotting , Sistema de Sinalização das MAP Quinases , Camundongos , Proteína de Sequência 1 de Leucemia de Células Mieloides , Análise de Sequência com Séries de Oligonucleotídeos , Técnicas de Cultura de Órgãos , Osteoblastos/citologia , Proteínas Proto-Oncogênicas c-bcl-2/genética , Proteínas Proto-Oncogênicas c-bcl-2/metabolismo , Interferência de RNA , Reação em Cadeia da Polimerase Via Transcriptase Reversa , Crânio/citologia , Crânio/metabolismoRESUMO
The epidermal growth factor receptor (EGFR) is an essential player in the development of multiple organs during embryonic and postnatal stages. To understand its role in epiphyseal cartilage development, we generated transgenic mice with conditionally inactivated EGFR in chondrocytes. Postnatally, these mice exhibited a normal initiation of cartilage canals at the perichondrium, but the excavation of these canals into the cartilage was strongly suppressed, resulting in a delay in the formation of the secondary ossification center (SOC). This delay was accompanied by normal chondrocyte hypertrophy but decreased mineralization and apoptosis of hypertrophic chondrocytes and reduced osteoclast number at the border of marrow space. Immunohistochemical analyses demonstrated that inactivation of chondrocyte-specific EGFR signaling reduced the amounts of matrix metalloproteinases (MMP9, -13, and -14) and RANKL (receptor activator of NF-κB ligand) in the hypertrophic chondrocytes close to the marrow space and decreased the cartilage matrix degradation in the SOC. Analyses of EGFR downstream signaling pathways in primary epiphyseal chondrocytes revealed that up-regulation of MMP9 and RANKL by EGFR signaling was partially mediated by the canonical Wnt/ß-catenin pathway, whereas EGFR-enhanced MMP13 expression was not. Further biochemical studies suggested that EGFR signaling stimulates the phosphorylation of LRP6, increases active ß-catenin level, and induces its nuclear translocation. In line with these in vitro studies, deficiency in chondrocyte-specific EGFR activity reduced ß-catenin amount in hypertrophic chondrocytes in vivo. In conclusion, our work demonstrates that chondrocyte-specific EGFR signaling is an important regulator of cartilage matrix degradation during SOC formation and epiphyseal cartilage development and that its actions are partially mediated by activating the ß-catenin pathway.
Assuntos
Condrócitos/metabolismo , Receptores ErbB/metabolismo , Lâmina de Crescimento/embriologia , Via de Sinalização Wnt/fisiologia , Animais , Colagenases/biossíntese , Colagenases/genética , Receptores ErbB/genética , Matriz Extracelular/genética , Matriz Extracelular/metabolismo , Regulação da Expressão Gênica no Desenvolvimento , Regulação Enzimológica da Expressão Gênica , Lâmina de Crescimento/metabolismo , Proteína-6 Relacionada a Receptor de Lipoproteína de Baixa Densidade/genética , Proteína-6 Relacionada a Receptor de Lipoproteína de Baixa Densidade/metabolismo , Camundongos , Camundongos Knockout , Fosforilação/fisiologia , Ligante RANK/genética , Ligante RANK/metabolismo , beta Catenina/genética , beta Catenina/metabolismoRESUMO
There is substantial evidence that impairment of peroxisome proliferator-activated receptor (PPAR)-γ-coactivator 1α (PGC-1α) levels and activity play an important role in Huntington's disease (HD) pathogenesis. We tested whether pharmacologic treatment with the pan-PPAR agonist bezafibrate would correct a deficiency of PGC-1α and exert beneficial effects in a transgenic mouse model of HD. We found that administration of bezafibrate in the diet restored levels of PGC-1α, PPARs and downstream genes to levels which occur in wild-type mice. There were significant improvements in phenotype and survival. In the striatum, astrogliosis and neuronal atrophy were attenuated and numbers of mitochondria were increased. Bezafibrate treatment prevented conversion of type I oxidative to type II glycolytic muscle fibers and increased the numbers of muscle mitochondria. Finally, bezafibrate rescued lipid accumulation and apparent vacuolization of brown adipose tissue in the HD mice. These findings provide strong evidence that treatment with bezafibrate exerts neuroprotective effects which may be beneficial in the treatment of HD.
Assuntos
Bezafibrato/farmacologia , Doença de Huntington/tratamento farmacológico , Mitocôndrias/efeitos dos fármacos , Fármacos Neuroprotetores/farmacologia , Transativadores/metabolismo , Tecido Adiposo Marrom/efeitos dos fármacos , Tecido Adiposo Marrom/ultraestrutura , Animais , Bezafibrato/administração & dosagem , Corpo Estriado/patologia , Dieta , Modelos Animais de Doenças , Gliose/patologia , Doença de Huntington/genética , Doença de Huntington/metabolismo , Doença de Huntington/patologia , Camundongos , Camundongos Transgênicos , Mitocôndrias/metabolismo , Mitocôndrias/ultraestrutura , Mitocôndrias Musculares/efeitos dos fármacos , Mitocôndrias Musculares/ultraestrutura , Fibras Musculares Esqueléticas/efeitos dos fármacos , Fibras Musculares Esqueléticas/metabolismo , Fibras Musculares Esqueléticas/ultraestrutura , Neurônios/patologia , Fármacos Neuroprotetores/administração & dosagem , Estresse Oxidativo , PPAR gama/agonistas , PPAR gama/metabolismo , Coativador 1-alfa do Receptor gama Ativado por Proliferador de Peroxissomo , Fenótipo , Transdução de Sinais/efeitos dos fármacos , Transdução de Sinais/genética , Taxa de Sobrevida , Fatores de Transcrição , Ativação Transcricional , Vacúolos/ultraestruturaRESUMO
Huntington's disease (HD) is a prototypical dominantly inherited neurodegenerative disorder characterized by progressive cognitive deterioration, psychiatric disturbances, and a movement disorder. The genetic cause of the illness is a CAG repeat expansion in the huntingtin gene, which leads to a polyglutamine expansion in the huntingtin protein. The exact mechanism by which mutant huntingtin causes HD is unknown, but it causes abnormalities in gene transcription as well as both mitochondrial dysfunction and oxidative damage. Because the penetrance of HD is complete with CAG repeats greater than 39, patients can be diagnosed well before disease onset with genetic testing. Longitudinal studies of HD patients before disease onset have shown that subtle cognitive and motor deficits occur as much as 10 years before onset, as do reductions in glucose utilization and striatal atrophy. An increase in inflammation, as shown by elevated interleukin-6, occurs approximately 15 years before onset. Detection of these abnormalities may be useful in defining an optimal time for disease intervention to try to slow or halt the degenerative process. Although reducing gene expression with small interfering RNA or short hairpin RNA is an attractive approach, other approaches targeting energy metabolism, inflammation, and oxidative damage may be more easily and rapidly moved into the clinic. The recent PREQUEL study of coenzyme Q10 in presymptomatic gene carriers showed the feasibility of carrying out clinical trials to slow or halt onset of HD. We review both the earliest detectable clinical and laboratory manifestations of HD, as well as potential neuroprotective therapies that could be utilized in presymptomatic HD.