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1.
BMC Geriatr ; 22(1): 436, 2022 05 18.
Artículo en Inglés | MEDLINE | ID: mdl-35585524

RESUMEN

BACKGROUND: Older patients are at increased risk of falling and of serious morbidity and mortality resulting from falls. The ability to accurately identify older patients at increased fall risk affords the opportunity to implement interventions to reduce morbidity and mortality. Geriatricians are trained to assess older patients for fall risk. If geriatricians can accurately predict fallers (as opposed to evaluating for individual risk factors for falling), more aggressive and earlier interventions could be employed to reduce falls in older adult fallers. However, there is paucity of knowledge regarding the accuracy of geriatrician fall risk predictions. This study aims to determine the accuracy of geriatricians in predicting falls. METHODS: Between October 2018 and November 2019, a convenience sample of 100 subjects was recruited from an academic geriatric clinic population seeking routine medical care. Subjects performed a series of gait and balance assessments, answered the Stay Independent Brochure and were surveyed about fall incidence 6-12 months after study entry. Five geriatricians, blinded to subjects and fall outcomes, were provided the subjects' data and asked to categorize each as a faller or non-faller. No requirements were imposed on the geriatricians' use of the available data. These predictions were compared to predictions of an examining geriatrician who performed the assessments and to fall outcomes reported by subjects. RESULTS: Kappa values for the 5 geriatricians who used all the available data to classify participants as fallers or non-fallers compared with the examining geriatrician were 0.42 to 0.59, indicating moderate agreement. Compared to screening tools' mean accuracy of 66.6% (59.6-73.0%), the 5 geriatricians had a mean accuracy for fall prediction of 67.4% (57.3-71.9%). CONCLUSIONS: This study adds to the scant knowledge available in the medical literature regarding the abilities of geriatricians to accurately predict falls in older patients. Studies are needed to characterize how geriatrician assessments of fall risk compare to standardized assessment tools.


Asunto(s)
Marcha , Geriatras , Anciano , Humanos , Incidencia
2.
Chemistry ; 27(11): 3708-3721, 2021 Feb 19.
Artículo en Inglés | MEDLINE | ID: mdl-32885487

RESUMEN

The synthesis of structurally diverse heterocycles for chemical space exploration was achieved via the cascade reactions of indigo with propargylic electrophiles. New pyrazinodiindolodione, naphthyridinedione, azepinodiindolone, oxazinoindolone and pyrrolodione products were prepared in one pot reactions by varying the leaving group (-Cl, -Br, -OMs, -OTs) or propargyl terminal functionality (-H, -Me, -Ph, -Ar). Mechanistic and density functional theory studies revealed that the unsaturated propargyl moiety can behave as an electrophile when aromatic terminal substitutions are made, and therefore competes with leaving group substitution for new outcomes. Selected products from the cascade reactions were investigated for their absorption and fluorescence properties, including transient absorption spectroscopy. This revealed polarity dependent excited state relaxation pathways, fluorescence, and triplet formation, thus highlighting these reactions as a means to access diverse functional materials rapidly.

3.
J Org Chem ; 86(13): 9163-9180, 2021 Jul 02.
Artículo en Inglés | MEDLINE | ID: mdl-34153182

RESUMEN

The deprotection of chiral 1,2-bis(tosylamides) to their corresponding 1,2-diamines is mostly unsuccessful under standard conditions. In a new methodology, the use of Mg/MeOH with sufficient steric additions allows the facile synthesis of 1,2-diamines in 78-98% yields. These results are rationalized using density functional theory and the examination of inner and outer-sphere reduction mechanisms.

4.
Sensors (Basel) ; 21(10)2021 May 17.
Artículo en Inglés | MEDLINE | ID: mdl-34067644

RESUMEN

Falls among the elderly population cause detrimental physical, mental, financial problems and, in the worst case, death. The increasing number of people entering the higher risk age-range has increased clinicians' attention to intervene. Clinical tools, e.g., the Timed Up and Go (TUG) test, have been created for aiding clinicians in fall-risk assessment. Often simple to evaluate, these assessments are subject to a clinician's judgment. Wearable sensor data with machine learning algorithms were introduced as an alternative to precisely quantify ambulatory kinematics and predict prospective falls. However, they require a long-term evaluation of large samples of subjects' locomotion and complex feature engineering of sensor kinematics. Therefore, it is critical to build an objective fall-risk detection model that can efficiently measure biometric risk factors with minimal costs. We built and studied a sensor data-driven convolutional neural network model to predict older adults' fall-risk status with relatively high sensitivity to geriatrician's expert assessment. The sample in this study is representative of older patients with multiple co-morbidity seen in daily medical practice. Three non-intrusive wearable sensors were used to measure participants' gait kinematics during the TUG test. This data collection ensured convenient capture of various gait impairment aspects at different body locations.


Asunto(s)
Accidentes por Caídas , Equilibrio Postural , Accidentes por Caídas/prevención & control , Anciano , Fenómenos Biomecánicos , Humanos , Aprendizaje Automático , Estudios Prospectivos , Medición de Riesgo , Estudios de Tiempo y Movimiento
5.
J Org Chem ; 84(17): 11228-11239, 2019 09 06.
Artículo en Inglés | MEDLINE | ID: mdl-31369270

RESUMEN

The nucleophilic addition of organomagnesium and organolithium species to the cheap and robust natural dye indigo led to desymmetrization of the heterocyclic nucleus via a Grignard addition-dehydration procedure. Twenty-seven diversely functionalized [1H,3'H]-3-substituted 2,2'-diindol-3'-ones were synthesized by this methodology, with several showing submicromolar inhibition and exquisite selectivity against P. falciparum parasites (3D7 and Dd2 strains) in vitro. This work demonstrates the utility of indigo dye as a highly versatile scaffold for the synthesis of structurally diverse, bioactive heterocycles.


Asunto(s)
Antimaláricos/química , Antimaláricos/síntesis química , Halógenos/química , Carmin de Índigo/química , Indoles/química , Indoles/síntesis química , Antimaláricos/farmacología , Técnicas de Química Sintética , Indicadores y Reactivos/química , Indoles/farmacología , Plasmodium falciparum/efectos de los fármacos
6.
Org Biomol Chem ; 16(33): 6006-6016, 2018 08 22.
Artículo en Inglés | MEDLINE | ID: mdl-30083677

RESUMEN

The base-initiated alkylation of the abundant natural dye indigo 1 with ring-strained electrophiles results in the unprecedented, one-pot synthesis of functionalised dihydropyrazino[1,2-a:4,3-a']diindoles, dihydroepoxy[1,5]oxazocino[5,4-a:3,2-b']diindoles, and dihydrodiazepino[1,2-a:4,3-a']diindoles, resulting from intramolecular ring opening-expansion cyclisation processes of their parent oxiranes and aziridines. Regiochemical and stereochemical aspects of the reactions are reported together with integrated mechanistic proposals. This new indigo cascade chemistry should have broad applicability in the synthesis of chemical architectures, not readily-accessible by other means. The three-step synthesis of the useful synthetic precursor (R)-2-(chloromethyl)-1-tosylaziridine 14 is also described. Initial biological activity investigations into these new 2,2'-dindolyl-based heterocyclic derivatives revealed potent, selective antiplasmodial activity in vitro for several isolated structures, with IC50 values as low as 76.6 nM for (±)-8, while demonstrating low human cell toxicity.

7.
Nat Prod Rep ; 32(11): 1562-83, 2015 Nov.
Artículo en Inglés | MEDLINE | ID: mdl-26282828

RESUMEN

Recently identified natural atropisomeric compounds with potential medicinal applications are presented. The ability of natural receptors to possess differential binding between atropisomers is an important factor when considering active and inactive atropisomeric drugs, and has required the development of new techniques for atropselective synthesis of desired targets. Advances in this field therefore have significant relevance to modern pharmaceutical and medicinal chemistry. The atropisomeric natural products discussed include hibarimicinone, flavomannins, talaromannins, viriditoxin, rugulotrosin A, abyssomicin C, marinopyrroles, dixiamycins, streptorubin B, ustiloxins A-F, haouamine A, bisnicalaterines, and tedarene B, all of which show significant potential as leads in antibiotic, antiviral and anticancer studies. The importance for the development of common practices regarding atropisomer recognition and classification is also emphasized.


Asunto(s)
Productos Biológicos/química , Antibacterianos/química , Antibacterianos/farmacología , Productos Biológicos/farmacología , Compuestos Bicíclicos Heterocíclicos con Puentes/química , Estructura Molecular , Estereoisomerismo
8.
Ophthalmology ; 121(10): 1885-91, 2014 Oct.
Artículo en Inglés | MEDLINE | ID: mdl-24953794

RESUMEN

OBJECTIVE: To determine whether rituximab, a monoclonal antibody against the B-lymphocyte antigen CD20, is effective in the treatment of refractory noninfectious scleritis. DESIGN: Prospective, dose-ranging, randomized, double-masked phase I/II clinical trial. PARTICIPANTS: Twelve patients with noninfectious scleritis refractory to systemic corticosteroid and ≥1 other systemic immunosuppressive agent were enrolled from January 2007 to March 2010. INTERVENTION: Subjects were randomly assigned to 500 (n = 5) or 1000 mg (n = 7) dosing arms of rituximab intravenous infusions (500 or 1000 mg), given at study days 1 and 15. Initial responders with breakthrough inflammation after study week 24 were offered treatment with an additional cycle of 2 open-label rituximab 1000 mg infusions. MAIN OUTCOME MEASURES: Primary outcomes were reduction of inflammation, as measured with a validated scleritis disease grading scale (SGS) and reduction in corticosteroid dose by ≥50%. Patients were characterized as responders to study therapy if ≥1 of these endpoints showed improvement and neither showed evidence of worsening. Secondary outcomes were improvement in visual acuity, reduction in pain, and improvement in patient and physician-reported global health assessment. RESULTS: Of 12 enrolled patients, 9 met the SGS endpoint at or before week 24, and 4 additionally were able to reduce corticosteroid dose by ≥50%. With regard to secondary outcome measures, 11 and 9 patients showed improvement in patient and physician global health scores, respectively, and 7 patients had reduction in pain. Of 9 initial responders, 7 experienced breakthrough inflammation after 24 weeks and were treated with a second cycle of rituximab infusions. Four patients had significant objective or subjective worsening within 8 weeks of receiving rituximab; this event was averted in subsequent patients by treatment with peri-infusional oral corticosteroid. No other significant adverse events were noted. No differences in efficacy, toxicity, or likelihood of retreatment were noted between the dosing arms. CONCLUSIONS: Rituximab was effective treatment for 9 of 12 enrolled patients with refractory, noninfectious scleritis at 24 weeks, although 7 required reinfusion with rituximab to maintain inflammatory control. The treatment was well-tolerated, and peri-infusional inflammatory exacerbations were managed successfully with oral corticosteroids. Further long-term studies are warranted to determine the safety and efficacy of rituximab in treating noninfectious scleritis and other ocular inflammatory diseases.


Asunto(s)
Anticuerpos Monoclonales de Origen Murino/administración & dosificación , Factores Inmunológicos/administración & dosificación , Escleritis/tratamiento farmacológico , Adulto , Relación Dosis-Respuesta a Droga , Femenino , Humanos , Infusiones Intravenosas , Masculino , Persona de Mediana Edad , Estudios Prospectivos , Rituximab , Índice de Severidad de la Enfermedad , Adulto Joven
9.
Retina ; 34(8): 1666-74, 2014 Aug.
Artículo en Inglés | MEDLINE | ID: mdl-24743642

RESUMEN

PURPOSE: To study the clinical features and incidence rate of ocular complications in patients with punctate inner choroidopathy. METHODS: This is a retrospective cohort study conducted in a single-center academic practice setting. Patients diagnosed with punctate inner choroidopathy at the Wilmer Eye Institute, Johns Hopkins University from 1984 to 2012 were identified. Demographics and clinical features including the presence of choroidal neovascularization (CNV) and structural complications were collected. Main outcome measures, including visual impairment and incidence rate of ocular complications, were analyzed. RESULTS: Thirty-one patients (59 eyes) were included in the study. Follow-up data were available for 24 patients (47 eyes) with a mean follow-up time of 3.4 years (range, 2 months to 8.7 years). In the affected eyes with follow-up, the incidence rate of visual impairment to 20/50 or worse was 0.06 per eye-year (EY) (95% confidence interval, 0.022/EY-0.114/EY). The incidence rate of visual loss to 20/200 or worse was 0.006/EY (95% confidence interval, 0.0001/EY-0.034/EY). Thirty-six eyes (77%) had an ultimate visual acuity of 20/40 or better. All of the 13 patients with more than ≥ 3 years of follow-up had a visual acuity of ≥ 20/40 in at least 1 eye at 3 years after presentation. Two thirds of the follow-up patients (67%) on immunomodulatory drug therapy did not have new or recurrent CNV. However, this was not a statistically significant difference. Three eyes with follow-up had recurrence of CNV for an incidence rate of 0.04/EY (95% confidence interval, 0.008/EY-0.12/EY). Two eyes developed new CNV during follow-up for an incidence rate of 0.02/EY (95% confidence interval, 0.002/EY-0.066/EY). CONCLUSION: The visual prognosis in most cases of punctate inner choroidopathy is very good. The incidence rate of new CNV and recurrent CNV was 0.02/EY and 0.04/EY, respectively.


Asunto(s)
Neovascularización Coroidal/diagnóstico , Neovascularización Coroidal/epidemiología , Coroiditis/complicaciones , Personas con Daño Visual/estadística & datos numéricos , Administración Oral , Adulto , Inhibidores de la Angiogénesis/uso terapéutico , Coroiditis/diagnóstico , Coroiditis/tratamiento farmacológico , Femenino , Glucocorticoides/uso terapéutico , Humanos , Inmunosupresores/uso terapéutico , Incidencia , Masculino , Persona de Mediana Edad , Coroiditis Multifocal , Prevalencia , Estudios Retrospectivos , Factor A de Crecimiento Endotelial Vascular/antagonistas & inhibidores , Trastornos de la Visión/diagnóstico , Trastornos de la Visión/epidemiología , Agudeza Visual/fisiología , Adulto Joven
10.
Ocul Immunol Inflamm ; : 1-7, 2024 Jul 16.
Artículo en Inglés | MEDLINE | ID: mdl-39012757

RESUMEN

PURPOSE: To evaluate the efficacy of topical interferon alpha-2b (tIFN a2b) and subcutaneous pegylated interferon alpha-2a (peg-IFN a2a) in the treatment of refractory pseudophakic (PME) and uveitic (UME) macular edema. METHODS: Retrospective case series of patients with PME or UME that was non-responsive to conventional therapies. Topical IFN a2b drops (1 MIU/ml) were commenced four times a day. Non-responders were offered treatment with subcutaneous peg-IFN a2a starting at 180 mcg weekly. RESULTS: Seven eyes of seven patients (three UME and four PME) were treated with tIFN a2b. Three eyes had complete ME resolution with tIFN treatment after a mean of 2.66 weeks (range 1-4 weeks) and no recurrence after a mean total course of 11.33 weeks (range 5-20 weeks). Two cases (both PME) had partial responses to tIFN treatment and two cases (both UME) failed to respond. Of the four eyes that incompletely responded to tIFN (treatment range 6 weeks to 4 months), three were treated with peg-IFN a2a, which invariably led to complete and sustained ME resolution. Adverse effects from topical treatment were mild and consisted mainly of superficial irritation. Adverse effects of subcutaneous treatment included nausea, vomiting, anorexia, and leukopenia, though none limited treatment. CONCLUSIONS: Topical IFNa-2b appears safe and effective in isolation or in conjunction with topical steroids for the treatment of inflammatory macular edema (IME) in about half of patients in our small series. All partial and non-responders had complete disease resolution with systemic IFN. Topical IFN a2b should be considered in patients with refractory IME.

11.
Prim Care ; 51(1): 155-169, 2024 Mar.
Artículo en Inglés | MEDLINE | ID: mdl-38278569

RESUMEN

Infectious endocarditis (IE) is a universally fatal condition if left unmanaged, requiring urgent evaluation and treatment. Fever, new heart murmur, vegetations found by echocardiogram, and bacteremia are the most common symptoms and findings. Blood cultures and echocardiography are obligatory diagnostic modalities and should be used with the modified Duke criteria, the accepted diagnostic aid, when establishing a diagnosis of IE. When IE is suspected, consultations with cardiology, infectious disease, and cardiothoracic surgery teams should be made early. Staphylococci, Streptococci, and Enterococci are common pathogens, necessitating bactericidal antimicrobial therapy. Importantly, up to 50% of patients with IE will require cardiothoracic surgical intervention.


Asunto(s)
Endocarditis , Humanos , Endocarditis/diagnóstico , Endocarditis/terapia , Ecocardiografía , Antibacterianos/uso terapéutico
12.
bioRxiv ; 2024 May 14.
Artículo en Inglés | MEDLINE | ID: mdl-38798486

RESUMEN

Post-stroke hyperglycemia occurs in 30% - 60% of ischemic stroke patients as part of the systemic stress response, but neither clinical evidence nor pre-clinical studies indicate whether post-stroke hyperglycemia affects stroke outcome. Here we investigated this issue using a mouse model of permanent ischemia. Mice were maintained either normoglycemic or hyperglycemic during the interval of 17 - 48 hours after ischemia onset. Post-stroke hyperglycemia was found to increase infarct volume, blood-brain barrier disruption, and hemorrhage formation, and to impair motor recovery. Post-stroke hyperglycemia also increased superoxide formation by peri-infarct microglia/macrophages. In contrast, post-stroke hyperglycemia did not increase superoxide formation or exacerbate motor impairment in p47 phox-/- mice, which cannot form an active superoxide-producing NADPH oxidase-2 complex. These results suggest that hyperglycemia occurring hours-to-days after ischemia can increase oxidative stress in peri-infarct tissues by fueling NADPH oxidase activity in reactive microglia/macrophages, and by this mechanism contribute to worsened functional outcome.

13.
Clin Exp Ophthalmol ; 41(1): 95-108, 2013.
Artículo en Inglés | MEDLINE | ID: mdl-22712598

RESUMEN

The term, ocular toxoplasmosis, refers to eye disease related to infection with the parasite, Toxoplasma gondii. Recurrent posterior uveitis is the typical form of this disease, characterized by unilateral, necrotizing retinitis with secondary choroiditis, occurring adjacent to a pigmented retinochoroidal scar and associated with retinal vasculitis and vitritis. Multiple atypical presentations are also described, and severe inflammation is observed in immunocompromised patients. Histopathological correlations demonstrate focal coagulative retinal necrosis, and early in the course of the disease, this inflammation is based in the inner retina. For typical ocular toxoplasmosis, a diagnosis is easily made on clinical examination. In atypical cases, ocular fluid testing to detect parasite DNA by polymerase chain reaction or to determine intraocular production of specific antibody may be extremely helpful for establishing aetiology. Given the high seroprevalence of toxoplasmosis in most communities, serological testing for T. gondii antibodies is generally not useful. Despite a lack of published evidence for effectiveness of current therapies, most ophthalmologists elect to treat patients with ocular toxoplasmosis that reduces or threatens to impact vision. Classic therapy consists of oral pyrimethamine and sulfadiazine, plus systemic corticosteroid. Substantial toxicity of this drug combination has spurred interest in alternative antimicrobials, as well as local forms of drug delivery. At this time, however, no therapeutic approach is curative of ocular toxoplasmosis.


Asunto(s)
Coriorretinitis , Toxoplasmosis Ocular , Animales , Antiprotozoarios/uso terapéutico , Coriorretinitis/diagnóstico , Coriorretinitis/tratamiento farmacológico , Coriorretinitis/patología , Quimioterapia Combinada , Glucocorticoides/uso terapéutico , Humanos , Pirimetamina/uso terapéutico , Sulfadiazina/uso terapéutico , Toxoplasma/patogenicidad , Toxoplasmosis Ocular/diagnóstico , Toxoplasmosis Ocular/tratamiento farmacológico , Toxoplasmosis Ocular/patología
14.
Clin Exp Ophthalmol ; 41(1): 82-94, 2013.
Artículo en Inglés | MEDLINE | ID: mdl-22594908

RESUMEN

Ocular toxoplasmosis results from retinal infection with the protozoan, Toxoplasma gondii. This parasite, which exists as multiple clonal subpopulations and in three stages, is capable of replication in any nucleated cell of its primary feline or multiple paratenic hosts. Human seroprevalence of toxoplasmosis is high across the globe, but with geographic variation. While prevalence of ocular toxoplasmosis is not well documented, toxoplasmic retinochoroiditis is the commonest form of posterior uveitis in many countries. Correlation of parasite genotype with disease is an important area of new research. Ocular infection with T. gondii often follows ingestion of bradyzoites in undercooked infected meat. Oocysts may survive for an extended period in the environment, and water contaminated with oocysts is an important source in toxoplasmosis epidemics. Ocular toxoplasmosis is preventable by a combination of community activities and personal measures. Public health action is well justified by the considerable burden of congenital and postnatal infections.


Asunto(s)
Salud Pública , Toxoplasmosis Ocular , Animales , Coriorretinitis/epidemiología , Coriorretinitis/parasitología , Salud Global , Humanos , Toxoplasma/patogenicidad , Toxoplasmosis Ocular/epidemiología , Toxoplasmosis Ocular/parasitología
15.
Ocul Immunol Inflamm ; : 1-9, 2023 Mar 09.
Artículo en Inglés | MEDLINE | ID: mdl-36893445

RESUMEN

INTRODUCTION: Currently, little is known regarding bone health surveillance for glucocorticoid-exposed non-infectious uveitis (NIU) patients or their baseline risks of skeletal fragility outcomes. METHODS: Using claims data, we calculated rates of dual-energy x-ray absorptiometry (DXA) screening for glucocorticoid-exposed NIU and rheumatoid arthritis (RA) patients. Separately, we compared risks of skeletal fragility metrics amongst NIU patients, RA patients, and controls, independent of glucocorticoid use. RESULTS: The adjusted hazard ratio (aHR) of NIU patients to have a DXA scan was 0.64 (95% CI, 0.63-0.65; p < .001) compared to RA patients. The aHR for any skeletal fragility outcome amongst NIU patients was 0.97 (p < .02) compared to normal controls, while RA patients had excess risk (aHR, 1.15; p < .001). CONCLUSIONS: NIU patients are 36% less likely to receive a DXA scan after high-dose glucocorticoid exposure compared with RA patients. No elevated risk of osteoporosis for NIU patients was found compared to normal controls.

16.
Curr Opin Ophthalmol ; 23(6): 517-22, 2012 Nov.
Artículo en Inglés | MEDLINE | ID: mdl-23047168

RESUMEN

PURPOSE OF REVIEW: In the present era of highly active antiretroviral therapy (HAART), the challenges that HIV/AIDS patients face with regard to ocular complications has changed immensely; nonetheless, significant ocular morbidity persists. We present an update on these challenges, focusing particularly on the relevant literature from the past 12-18 months. RECENT FINDINGS: Although its incidence has decreased substantially in the HAART era, cytomegalovirus (CMV) retinitis remains an important cause of ocular morbidity and predictor of mortality. Presently, patients with less than 50 CD4 T-cells/µL have an approximately equal risk of developing this potentially blinding ocular complication compared with the pre-HAART era. Less is understood about the current epidemiological considerations of ocular syphilis and HIV; however, patients with HIV may have increased likelihood of posterior syphilitic uveitis. Regarding the neuroretinal disorder associated with HIV, new ophthalmic imaging modalities are helping to uncover potentially associated structural alterations. SUMMARY: Future challenges in the fight against HIV/AIDS-related eye disease will involve identifying additional factors conferring increased risk of CMV retinitis, understanding the scope of ocular syphilis and other eye infections in HIV patients, and furthering our understanding of the structural changes in neuroretinal disorder as an indicator of other end-organ damage.


Asunto(s)
Infecciones Oportunistas Relacionadas con el SIDA/etiología , Retinitis por Citomegalovirus/etiología , Infecciones por VIH/etiología , Infecciones Oportunistas Relacionadas con el SIDA/diagnóstico , Infecciones Oportunistas Relacionadas con el SIDA/tratamiento farmacológico , Terapia Antirretroviral Altamente Activa , Recuento de Linfocito CD4 , Linfocitos T CD4-Positivos/inmunología , Retinitis por Citomegalovirus/diagnóstico , Retinitis por Citomegalovirus/tratamiento farmacológico , Infecciones por VIH/diagnóstico , Infecciones por VIH/tratamiento farmacológico , Humanos , Incidencia , Sífilis/diagnóstico , Sífilis/tratamiento farmacológico , Sífilis/etiología , Agudeza Visual
17.
Antioxidants (Basel) ; 11(12)2022 Dec 15.
Artículo en Inglés | MEDLINE | ID: mdl-36552674

RESUMEN

Both genetic and environmental factors increase risk for Parkinson's disease. Many of the known genetic factors influence α-synuclein aggregation or degradation, whereas most of the identified environmental factors produce oxidative stress. Studies using in vitro approaches have identified mechanisms by which oxidative stress can accelerate the formation of α-synuclein aggregates, but there is a paucity of evidence supporting the importance of these processes over extended time periods in brain. To assess this issue, we evaluated α-synuclein aggregates in brains of three transgenic mouse strains: hSyn mice, which overexpress human α-synuclein in neurons and spontaneously develop α-synuclein aggregates; EAAT3-/- mice, which exhibit a neuron-specific impairment in cysteine uptake and resultant neuron-selective chronic oxidative stress; and double-transgenic hSyn/EAAT3-/- mice. Aggregate formation was evaluated by quantitative immunohistochemistry for phosphoserine 129 α-synuclein and by an α-synuclein proximity ligation assay. Both methods showed that the double transgenic hSyn/EAAT3-/- mice exhibited a significantly higher α-synuclein aggregate density than littermate hSyn mice in each brain region examined. Negligible aggregate formation was observed in the EAAT3-/- mouse strain, suggesting a synergistic rather than additive interaction between the two genotypes. A similar pattern of results was observed in assessments of motor function: the pole test and rotarod test. Together, these observations indicate that chronic, low-grade neuronal oxidative stress promotes α-synuclein aggregate formation in vivo. This process may contribute to the mechanism by which environmentally induced oxidative stress contributes to α-synuclein pathology in idiopathic Parkinson's disease.

18.
Prog Neurobiol ; 202: 102070, 2021 07.
Artículo en Inglés | MEDLINE | ID: mdl-33951536

RESUMEN

Oxidative stress and α-synuclein aggregation both drive neurodegeneration in Parkinson's disease, and the protein kinase c-Abl provides a potential amplifying link between these pathogenic factors. Suppressing interactions between these factors may thus be a viable therapeutic approach for this disorder. To evaluate this possibility, pre-formed α-synuclein fibrils (PFFs) were used to induce α-synuclein aggregation in neuronal cultures. Exposure to PFFs induced oxidative stress and c-Abl activation in wild-type neurons. By contrast, α-synuclein - deficient neurons, which cannot form α-synuclein aggregates, failed to exhibit either oxidative stress or c-Abl activation. N-acetyl cysteine, a thiol repletion agent that supports neuronal glutathione metabolism, suppressed the PFF - induced redox stress and c-Abl activation in the wild-type neurons, and likewise suppressed α-synuclein aggregation. Parallel findings were observed in mouse brain: PFF-induced α-synuclein aggregation in the substantia nigra was associated with redox stress, c-Abl activation, and dopaminergic neuronal loss, along with microglial activation and motor impairment, all of which were attenuated with oral N-acetyl cysteine. Similar results were obtained using AAV-mediated α-synuclein overexpression as an alternative means of driving α-synuclein aggregation in vivo. These findings show that α-synuclein aggregates induce c-Abl activation by a redox stress mechanism. c-Abl activation in turn promotes α-synuclein aggregation, in a feed-forward interaction. The capacity of N-acetyl cysteine to interrupt this interaction adds mechanistic support its consideration as a therapeutic in Parkinson's disease.


Asunto(s)
Enfermedad de Parkinson , alfa-Sinucleína , Animales , Cisteína , Dopamina , Neuronas Dopaminérgicas/metabolismo , Ratones , Oxidación-Reducción , Enfermedad de Parkinson/tratamiento farmacológico , Sustancia Negra/metabolismo , alfa-Sinucleína/metabolismo
19.
World J Surg ; 34(11): 2757-64, 2010 Nov.
Artículo en Inglés | MEDLINE | ID: mdl-20628742

RESUMEN

BACKGROUND: Systemic inflammatory response syndrome (SIRS) is a syndrome that reflects the widespread activation of inflammatory pathways. The goal of this study was to find whether the presence or absence of SIRS on emergency surgical admissions is related to the subsequent clinical outcome in terms of in-hospital interventions, length of stay, and mortality. METHODS: The presence of SIRS at admission, final diagnosis of the underlying disease, treatments, and clinical outcomes were prospectively recorded for 1 month. Comparisons of interventions and outcomes were performed between SIRS+ vs. SIRS- patients. In patients with SIRS, the contribution of each positive criterion was evaluated with regards to mortality. RESULTS: A total of 179 patients were recruited. The prevalence of SIRS at admission was 35.2%. SIRS+ patients required less diagnostic procedures compared with SIRS- (28.6% vs. 34.5%) but had more therapeutic interventions (39.7% vs. 16.4%), surgical interventions (33.3% vs. 3.4%), intensive treatments (11.1% vs. 0.9%; p < 0.05), longer hospital stay (median 6 days vs. 2 days), and more frequent deaths (11.1% vs. 2.6%). SIRS+ patients with four positive criteria had more surgical interventions, intensive treatments, and fatal outcomes compared with the others. Of importance the most influent factor was the respiratory rate followed by the white cell count and the heart rate/temperature. CONCLUSIONS: Patients with SIRS at admission apparently receive more interventions, have longer length of stay, and increased mortality than those patients without SIRS. These findings require separate validation in a larger cohort study.


Asunto(s)
Síndrome de Respuesta Inflamatoria Sistémica/diagnóstico , Síndrome de Respuesta Inflamatoria Sistémica/terapia , Adulto , Anciano , Anciano de 80 o más Años , Femenino , Humanos , Tiempo de Internación , Masculino , Auditoría Médica , Persona de Mediana Edad , Síndrome de Respuesta Inflamatoria Sistémica/etiología , Síndrome de Respuesta Inflamatoria Sistémica/mortalidad , Resultado del Tratamiento , Adulto Joven
20.
Adv Neurobiol ; 23: 169-185, 2019.
Artículo en Inglés | MEDLINE | ID: mdl-31667809

RESUMEN

It has been known for over 50 years that brain has significant glycogen stores, but the physiological function of this energy reserve remains uncertain. This uncertainty stems in part from several technical challenges inherent in the study of brain glycogen metabolism, and may also stem from some conceptual limitations. Factors presenting technical challenges include low glycogen content in brain, non-homogenous labeling of glycogen by radiotracers, rapid glycogenolysis during postmortem tissue handling, and effects of the stress response on brain glycogen turnover. Here, we briefly review aspects of glycogen structure and metabolism that bear on these technical challenges, and discuss ways these can be overcome. We also highlight physiological aspects of glycogen metabolism that limit the conditions under which glycogen metabolism can be useful or advantageous over glucose metabolism. Comparisons with glycogen metabolism in skeletal muscle provide an additional perspective on potential functions of glycogen in brain.


Asunto(s)
Encéfalo/metabolismo , Glucógeno/metabolismo , Glucogenólisis
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