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1.
Rheumatol Int ; 41(4): 707-714, 2021 04.
Artículo en Inglés | MEDLINE | ID: mdl-33559727

RESUMEN

OBJECTIVES: We sought to gain insight into the prevalence of COVID-19 and the impact stringent social distancing (shielding) has had on a large cohort of rheumatology (RD) follow-up patients from a single large UK centre. METHODS: We linked COVID-19-related deaths, screening and infection rates to our RD population (1.2.20-1.5.20) and audited active rheumatology follow-up patients through survey data communicated via a linked mobile phone SMS message. We assessed epidemiology, effect of stringent social distancing (shielding) and quality of life (HRQoL) by Short Form 12 (SF12). RESULTS: There were 10,387 active follow-up patients, 7911 had linked mobile numbers. 12/10,387 RD patients died from COVID-19 (0.12%); local population 4131/7,415,149 (0.12%). For patients with mobile phones, 1693/7911 (21%) responded and of these, 1605 completed the SF12. Inflammatory arthritis predominated 1174/1693 (69%); 792/1693 (47%) were shielding. Advice on shielding/distancing was followed by 1372/1693(81%). 61/1693 (4%) reported COVID-19 (24/61 shielding); medication distribution was similar in COVID and non-COVID patients. Mental SF12 (MCS) but not physical (PCS) component scores were lower in COVID (60) vs. non-COVID (1545), mean differences: MCS, - 3.3; 95% CI - 5.2 to - 1.4, P < 0.001; PCS, - 0.4; 95% CI, - 2.1 to 1.3). In 1545 COVID-negative patients, those shielding had lower MCS (- 2.1; 95% CI - 2.8 to - 1.4) and PCS (- 3.1, 95% CI - 3.7 to - 2.5), both P < 0.001. CONCLUSIONS: Our full RD cohort had no excess of COVID deaths compared to the general local population. Our survey data suggest that shielding adversely affects both mental and physical health in RD. These data broaden our understanding of shielding, indicating need for further study.


Asunto(s)
COVID-19/epidemiología , Recolección de Datos/métodos , Distanciamiento Físico , Reumatología , SARS-CoV-2 , Anciano , COVID-19/mortalidad , COVID-19/prevención & control , Femenino , Humanos , Masculino , Persona de Mediana Edad , Prevalencia
2.
Osteoporos Int ; 32(1): 1-6, 2021 Jan.
Artículo en Inglés | MEDLINE | ID: mdl-33146750

RESUMEN

The COVID-19 pandemic has resulted in huge disruption to healthcare provision, including to dual-energy X-ray absorptiometry (DXA) imaging. Increased waiting lists for DXA from the pandemic mean potential long and uncertain delays in treatment for osteoporosis. To address these increased waiting lists, we propose a rapid, simple, one-stop algorithm incorporating medication use (aromatase inhibitor, corticosteroid) and clinical risk stratification supplementing a standard FRAX assessment. Our pragmatic algorithm produces a recommendation to treat empirically, image with DXA, or observe. If applied, we model a significant reduction in DXA scan requirements with a corresponding reduction in treatment delays for those awaiting DXA. We estimate this will reduce DXA scan numbers by about 50%, whilst pragmatically ensuring those with the highest clinical need correctly receive treatment without delay. This algorithm will help many clinicians including general practitioners/family physicians prioritise DXA when they may not always have the expertise to make this judgement based on clinical information alone. Although we have used UK guidelines as an example, this approach is flexible enough for adaptation by other countries based on their local guidelines, licensing, prescribing requirements, and DXA waiting list times. There are some limitations to our proposal. However, it represents one way of managing the uncertainty of the current COVID-19 pandemic.


Asunto(s)
Absorciometría de Fotón , COVID-19 , Toma de Decisiones Clínicas/métodos , Osteoporosis/diagnóstico por imagen , Algoritmos , Inhibidores de la Aromatasa/efectos adversos , Glucocorticoides/efectos adversos , Humanos , Fracturas Osteoporóticas/diagnóstico por imagen , Pandemias , Medición de Riesgo , Factores de Riesgo , Teléfono , Listas de Espera
3.
Plant Biol (Stuttg) ; 18(4): 627-37, 2016 Jul.
Artículo en Inglés | MEDLINE | ID: mdl-26849835

RESUMEN

The diversity and abundance of culturable microbiome members of the rice phyllosphere was investigated using cv. Pusa Punjab Basmati 1509. Both diversity and species richness of bacteria were significantly higher in plants in pots in a semi-controlled environment than those in fields. Application of fertilisers reduced both diversity and species richness in field-grown plants under a conventional flooded system of rice intensification (SRI) and in dry-seeded rice (DSR) modes. Sequence analyses of 16S rDNA of culturable bacteria, those selected after amplified ribosomal DNA restriction analysis (ARDRA), showed the dominance of α-proteobacteria (35%) and actinobacteria (38%); Pantoea, Exiguobacterium and Bacillus were common among the culturable phyllospheric bacteria. About 34% of 83 culturable bacterial isolates had higher potential (>2 µg·ml(-1) ) for indole acetic acid production in the absence of tryptophan. Interestingly, the phyllosphere bacterial isolates from the pot experiment had significantly higher potential for nitrogen fixation than isolates from the field experiment. Enrichment for cyanobacteria showed both unicellular forms and non-heterocystous filaments under aerobic as well as anaerobic conditions. PCR-DGGE analysis of these showed that aerobic and anaerobic conditions as well as the three modes of cultivation of rice in the field strongly influenced the number and abundance of phylotypes. The adaptability and functional traits of these culturable microbiome members suggest enormous diversity in the phyllosphere, including potential for plant growth promotion, which was also significantly influenced by the different methods of growing rice.


Asunto(s)
Bacterias/genética , Cianobacterias/genética , Microbiota , Oryza/microbiología , Componentes Aéreos de las Plantas/microbiología , Bacterias/aislamiento & purificación , Cianobacterias/aislamiento & purificación , ADN Bacteriano/genética , ADN Ribosómico/genética , Ácidos Indolacéticos/metabolismo , Nitrógeno/metabolismo , Fijación del Nitrógeno , Filogenia , Análisis de Secuencia de ADN
4.
J Colloid Interface Sci ; 395: 64-7, 2013 Apr 01.
Artículo en Inglés | MEDLINE | ID: mdl-23369799

RESUMEN

Preparation and characterization of epitaxial growth of ZnO nanotip arrays are essential for field emission applications due to its high emission rate of electron and fast electron-transfer rate. At first, nanocrystalline ITO thin films were prepared on glass substrates by ion-beam sputter deposition (IBSD) method. ZnO seed layer was prepared on the ITO coated glass substrates by IBSD at room temperature, and then, ZnO nanotip arrays were epitaxially grown on the as-prepared ZnO seed layer coated ITO/Glass substrates by hydrothermal method. The surface morphology study confirmed that the ZnO nanotip array films were epitaxially grown on ITO/Glass substrates, and it clearly showed the formation of well-aligned ZnO nanotip arrays on ITO/Glass substrate. The as-prepared samples were annealed at different temperatures (100, 150 and 270°C). After annealing, the surface morphology of ZnO nanotip arrays did not show any remarkable change. X-ray diffraction pattern of ZnO nanotip array films prepared on ITO/Glass showed a main peak at 2θ=34.3°, which corresponds to (002) plane. The photoluminescence spectra showed the strong intensity of UV emission and weak intensity of green emission. The J-V characteristic of Ag/NPB/PMMA/ZnO/ITO showed good rectification behavior.

5.
Int J Surg Case Rep ; 3(1): 3-5, 2012.
Artículo en Inglés | MEDLINE | ID: mdl-22288028

RESUMEN

INTRODUCTION: Tendo achilles (TA) ruptures are commonly encountered in orthopaedic practice. These can be managed operatively or conservatively depending on various factors like patient age, activity levels, co morbidities, patient expectations and surgeon preference. They are usually treated in plaster cast immobilisation if managed conservatively. CASE REPORT: We present a case of fatal pulmonary embolism following conservatively managed Tendo achilles (TA) rupture in a young man treated as an orthopaedic outpatient. DISCUSSION: There are no current clear guidelines on venous thromboembolism (VTE) prophylaxis in conservatively managed outpatients with cast immobilisation. CONCLUSION: Our case report highlights the importance of recognition of this aspect of patient management and reviews the current literature available on this debatable topic.

6.
Eur J Trauma Emerg Surg ; 37(5): 519-24, 2011 Oct.
Artículo en Inglés | MEDLINE | ID: mdl-26815424

RESUMEN

PURPOSE: We present our case series on the use of flexible locked intramedullary nails in the management of metacarpal fractures. METHODS: This was a prospective study over a period of 2 years of all patients with metacarpal fractures with 100% displacement or rotational deformity operated by the flexible locked intramedullary nails from January 2008 to April 2010 at Queen Elizabeth Hospital, Gateshead, UK RESULTS: Twenty-six patients with fractures of metacarpal neck and shaft were included in the study. All fractures went on to union by an average of 6.3 weeks with full metacarpophalangeal joint movement and grip strength. CONCLUSION: In our experience, this device helps to achieve good functional results with minimal soft tissue disruption and complications in the management of unstable metacarpal fractures.

7.
Oncogene ; 28(8): 1053-62, 2009 Feb 26.
Artículo en Inglés | MEDLINE | ID: mdl-19137022

RESUMEN

The chromodomain helicase DNA-binding proteins (CHDs) are known to affect transcription through their ability to remodel chromatin and modulate histone deacetylation. In an effort to understand the functional role of the CHD2 in mammals, we have generated a Chd2 mutant mouse model. Remarkably, the Chd2 protein appears to play a critical role in the development, hematopoiesis and tumor suppression. The Chd2 heterozygous mutant mice exhibit increased extramedullary hematopoiesis and susceptibility to lymphomas. At the cellular level, Chd2 mutants are defective in hematopoietic stem cell differentiation, accumulate higher levels of the chromatin-associated DNA damage response mediator, gamma H2AX, and exhibit an aberrant DNA damage response after X-ray irradiation. Our data suggest a direct role for the chromatin remodeling protein in DNA damage signaling and genome stability maintenance.


Asunto(s)
Daño del ADN , Proteínas de Unión al ADN/fisiología , Hígado/patología , Linfoma/patología , Transducción de Señal , Animales , Diferenciación Celular , Células Cultivadas , Cromatina/genética , Cromatina/metabolismo , Feto , Células Madre Hematopoyéticas/metabolismo , Heterocigoto , Histonas/genética , Histonas/metabolismo , Hígado/metabolismo , Linfoma/genética , Linfoma/metabolismo , Ratones , Ratones Noqueados , Rayos X
8.
Parasitology ; 134(Pt 6): 777-87, 2007 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-17306059

RESUMEN

In this study, cDNA microarray analysis of a closely related species, Leishmania major, was used as a screening tool to compare antimonial-resistant and susceptible clinical isolates of Leishmania donovani in order to to identify candidate genes on the basis of antimony resistance. Clinically confirmed resistant isolate 39 and sensitive isolate 2001 were used in this study. Many differentially regulated genes were identified whose expression levels differ in sodium antimony gluconate (SAG)-treated patients. Interestingly, genes on the array, showing changes in expression of over 2-fold revealed the identity of ABC transporters, which are known determinants of drug resistance in laboratory mutants. The functionality of the transporters was validated by flow cytometry which, being biologically informative, provides direct clues to gene function. The results suggest that isolate 39 could have developed resistance by an increased multidrug resistance protein (MRP)-like pump. This study provides preliminary clues to the role of a thiol-dependent efflux system in antimonial resistant clinical isolates of Leishmania donovani.


Asunto(s)
Gluconato de Sodio Antimonio , Resistencia a Medicamentos/genética , Genes Protozoarios/genética , Leishmania donovani/efectos de los fármacos , Leishmania donovani/genética , Leishmaniasis Visceral/parasitología , Análisis de Secuencia por Matrices de Oligonucleótidos , Transportadoras de Casetes de Unión a ATP/genética , Animales , Gluconato de Sodio Antimonio/farmacología , Northern Blotting , Biología Computacional , Citometría de Flujo , Perfilación de la Expresión Génica , Regulación de la Expresión Génica , Humanos , Leishmania donovani/metabolismo , Leishmania major/efectos de los fármacos , Leishmania major/genética , Leishmania major/metabolismo , Compuestos de Sulfhidrilo/metabolismo
9.
Bioorg Med Chem ; 14(18): 6414-9, 2006 Sep 15.
Artículo en Inglés | MEDLINE | ID: mdl-16766192

RESUMEN

A novel conjugate of melatonin 2 and alpha-lipoic acid 4 has been prepared using DCC mediated coupling. The conjugate named melatoninolipoamide has been assigned its structure 1 on the basis of spectral analysis (UV, IR, NMR, and EI-MS). Pulse radiolysis studies of the conjugate were carried out in aqueous solutions with both oxidizing and reducing radicals. The results indicate that the melatonin moiety of the conjugate reacts preferably with oxidizing radicals and the lipoic acid moiety exhibits preferential reaction with reducing radicals. The in vitro radioprotection ability of 1 was examined by gamma-radiation induced lipid peroxidation in liposomes and hemolysis of erythrocytes, and compared the results with those of melatonin and alpha-lipoic acid. The studies suggest that the conjugate can be explored as a probable radioprotector.


Asunto(s)
Melatonina/análogos & derivados , Melatonina/química , Protectores contra Radiación/síntesis química , Ácido Tióctico/análogos & derivados , Ácido Tióctico/química , Radicales Libres/química , Melatonina/síntesis química , Estructura Molecular , Oxidación-Reducción , Radiólisis de Impulso/métodos , Protectores contra Radiación/química , Ácido Tióctico/síntesis química
10.
J Obstet Gynaecol ; 24(7): 798-800, 2004 Oct.
Artículo en Inglés | MEDLINE | ID: mdl-15763792

RESUMEN

The aim of this study was to determine the effectiveness of medroxyprogesterone acetate (Depo Provera) in the treatment of menorrhagia attributed to uterine fibroids and to determine whether it reduces fibroid volume. Twenty premenopausal women with menorrhagia attributed to uterine fibroids received Depo Provera (150 mg/month) for 6 months. Control of bleeding was assessed by menstrual diary, haematologic parameters (Hb) and uterine and fibroid size measured sonargraphically. Following a period of 6 months after the initiation of Depo Provera, 30% became amenorrhoeic, 70% noticed improvement in their bleeding pattern and 15% had an increase in their haemoglobin levels. The mean uterine and fibroid volume was also reduced by 48% and 33%, respectively. Medical therapy with Depo Provera with symptomatic fibroids causes significant improvement in bleeding pattern as well as a reduction in fibroid volume.


Asunto(s)
Leiomioma/tratamiento farmacológico , Acetato de Medroxiprogesterona/uso terapéutico , Neoplasias Uterinas/tratamiento farmacológico , Adulto , Femenino , Hemoglobinas/análisis , Humanos , Leiomioma/complicaciones , Leiomioma/diagnóstico por imagen , Menorragia/etiología , Menorragia/terapia , Proyectos Piloto , Premenopausia , Resultado del Tratamiento , Ultrasonografía , Neoplasias Uterinas/complicaciones , Neoplasias Uterinas/diagnóstico por imagen
11.
S Afr Med J ; 93(5): 371-4, 2003 May.
Artículo en Inglés | MEDLINE | ID: mdl-12830602

RESUMEN

OBJECTIVE: To compare the safety and efficacy of misoprostol with that of dinoprostone for the induction of labour at term, or near term. DESIGN: Three hundred and ninety-six women with term pregnancies were randomised to receive either oral or vaginal misoprostol, or dinoprostone. Women who had had a previous caesarean section (CS) or those with a malpresentation or who were parity > or = 5, were excluded. The control group received dinoprostone 1 mg inserted in the posterior fornix and repeated 6-hourly to a maximum of three doses. The study group received either oral misoprostol 20 micrograms 2-hourly to a maximum of four doses (80 micrograms), or vaginal misoprostol 25 micrograms in the posterior fornix with a switch to the oral misoprostol regimen if there was no change in the Bishop's score or no palpable uterine contractions. RESULTS: There was no significant difference in vaginal delivery rate within 24 hours between the groups (58.1% v. 58%, p = 0.633). There were no significant differences in CS rates between the groups; however, more CSs were performed for fetal distress in the misoprostol group than in the dinoprostone group (28% v. 25%). There was a significantly higher incidence of hyperstimulation in the vaginal misoprostol group (21.4%) than in the other two groups (oral misoprostol 16.5%, dinoprostone 8.9%) (p = 0.004). The incidence of meconium staining of liquor was comparable between the groups. CONCLUSIONS: In selected women, the efficacy of misoprostol for the induction of labour at term is similar to that of dinoprostone but misoprostol is associated with a higher incidence of hyperstimulation.


Asunto(s)
Maduración Cervical/efectos de los fármacos , Misoprostol/uso terapéutico , Oxitócicos/uso terapéutico , Adulto , Parto Obstétrico/métodos , Dinoprostona/uso terapéutico , Femenino , Humanos , Recién Nacido , Complicaciones del Trabajo de Parto , Embarazo , Resultado del Embarazo , Embarazo Prolongado/efectos de los fármacos , Estudios Prospectivos , Resultado del Tratamiento
12.
J Hazard Mater ; 98(1-3): 117-26, 2003 Mar 17.
Artículo en Inglés | MEDLINE | ID: mdl-12628781

RESUMEN

Investigations on the adsorption of ammonium dinitramide (NH(4)N(NO(2))(2)) (ADN) from aqueous solutions on powdered activated charcoal (PAC) were carried out in order to find out an effective and easier method of separating ADN from aqueous solutions. The effectiveness of PAC in the selective adsorption of ADN from aqueous solutions of ADN (ADN-F) and ADN in presence of sulfate (SO(4)(2-)) and nitrate (NO(3)(-)) ions (ADN-PS) was examined and compared using batch and column methods. The adsorption process follows both Langmuir and Freundlich adsorption isotherms and the isotherm parameters for the models were determined. The observed data favor the formation of monolayer adsorption. The adsorption capacities were found to be 63.3, 119, 105.3 and 82 mg of ADN per g of PAC for ADN-F (batch), ADN-PS (batch), ADN-F (column) and ADN-PS (column), respectively. Break-through curves for ADN-F and ADN-PS were obtained for the optimization of separation of ADN from aqueous solutions. Elution curves were generated for the desorption of ADN from PAC using hot water as eluent.


Asunto(s)
Nitritos/farmacocinética , Compuestos de Amonio Cuaternario/farmacocinética , Adsorción , Carbón Orgánico , Modelos Teóricos , Espectroscopía Infrarroja Corta
13.
Toxicol Pathol ; 29 Suppl: 147-54, 2001.
Artículo en Inglés | MEDLINE | ID: mdl-11695551

RESUMEN

The p53 tumor suppressor gene has been shown to be critical in preventing cancer in humans and mice. We have generated and extensively characterized p53-deficient mice lacking one (p53+/-) or both (p53-/-) p53 alleles. The p53-deficient mice are much more susceptible to an array of different tumor types than their wild-type (p53+/+) littermates. The enhanced tumor susceptibility of the p53+/- mice has made them one of several transgenic mouse models that are being considered as substitutes for standard 2-year rodent carcinogenicity assays. In order to fully exploit this model, it will be important to understand some of the basic biological and molecular mechanisms that underlie its enhanced tumor susceptibility. With this in mind, we have explored the fate of the remaining wild-type p53 allele in spontaneously arising p53+/- tumors and have shown that over half of these tumors retain an intact, functional wild-type p53 allele. This suggests that p53 is haploinsufficient for tumor suppression and that mere reduction in p53 dosage is sufficient to promote cancer formation. To support the idea that p53 is indeed a haploinsufficient tumor suppressor, we show here that normal p53+/- cells exhibit reduced parameters of growth control and stress response compared to their p53+/- counterparts. We hypothesize that the reduced p53 dosage in the p53+/- cells provides an environment more conducive to the development of further oncogenic lesions and the initiation of a tumor. Finally, we have assessed p53 loss of heterozygosity (LOH) in carcinogen-induced p53+/- tumors and have found that some agents induce tumors that almost invariably exhibit p53 LOH, whereas other agents induce tumors that often retain the wild-type p53 allele. Our preliminary data suggest that LOH is dependent on both the mechanism of genotoxicity of the agent utilized and the tissue type targeted.


Asunto(s)
Pruebas de Carcinogenicidad/métodos , Carcinógenos/toxicidad , Genes p53 , Mutágenos/toxicidad , Neoplasias Experimentales/inducido químicamente , Alternativas a las Pruebas en Animales , Animales , Dosificación de Gen , Predisposición Genética a la Enfermedad , Genotipo , Pérdida de Heterocigocidad , Ratones , Ratones Noqueados , Ratones Transgénicos , Neoplasias Experimentales/genética
14.
Biochem Biophys Res Commun ; 286(5): 869-74, 2001 Sep 07.
Artículo en Inglés | MEDLINE | ID: mdl-11527379

RESUMEN

Activation of the extracellular-signal-responsive kinase (ERK 1/2) by MAP kinase/ERK kinase (MEK1/2) following ischemia/reperfusion in the brain has been associated with cell death since inhibition of MEK1/2 provides neuroprotection in cerebral ischemia injury. Since inflammation has been implicated in ischemic brain injury, the present study investigated whether MEK1/2 modifies expression of two key inflammatory cytokines, IL-1beta and TNFalpha, that have been shown to exacerbate ischemic brain injury. A mouse model of transient cerebral ischemia was deployed to test the effect of selective MEK1/2 inhibitor (SL327) on infarct size and cytokine expression. SL327 (100 mg/kg, i.p.) administered 15 min prior to ischemia resulted in 64% reduction in infarct size over controls (n = 8, P < 0.01). Under the same condition, SL327 significantly reduced peak expression of IL-1beta mRNA (59% reduction compared to vehicle, P < 0.01, n = 4) but not TNF-alpha mRNA. A parallel reduction in IL-1beta protein (67%, P < 0.05, n = 6) was also observed using ELISA analysis. These data suggest that the neuroprotective effect of MEK1/2 inhibition may be mediated by suppression of IL-1beta. The study also demonstrates for the first time that these two cytokines are differentially regulated by kinase mediated signaling pathways.


Asunto(s)
Isquemia Encefálica/metabolismo , Interleucina-1/metabolismo , Quinasas de Proteína Quinasa Activadas por Mitógenos/antagonistas & inhibidores , Proteínas Serina-Treonina Quinasas/antagonistas & inhibidores , ARN/metabolismo , Factor de Necrosis Tumoral alfa/metabolismo , Aminoacetonitrilo/análogos & derivados , Animales , Encéfalo/metabolismo , Inhibidores Enzimáticos/farmacología , Ensayo de Inmunoadsorción Enzimática , MAP Quinasa Quinasa 1 , Sistema de Señalización de MAP Quinasas , Masculino , Ratones , Ratones Endogámicos C57BL , Inhibidores de Proteasas/farmacología , ARN Mensajero/metabolismo , Reacción en Cadena de la Polimerasa de Transcriptasa Inversa , Transducción de Señal
15.
Knee ; 8(2): 129-33, 2001 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-11337239

RESUMEN

A total of 62 arthroscopic meniscal repairs (60 knees in 59 patients) over a 5-year period were evaluated retrospectively to assess outcome and to identify factors that might improve future clinical results. The overall success rate was 66.1%. Early repair within 3 months of sustaining the tear gave better results (91%) than if carried out later (58%). Suture repair alone yielded better results (78%) than meniscal arrows or a T-fix device (56%). Healing rates of atraumatic meniscus tears were much lower than for traumatic tears (42 vs. 73%). The isolated atraumatic medial meniscal tear appeared to do particularly poorly (33% healing) and may be better treated by meniscectomy.


Asunto(s)
Artroscopía/métodos , Meniscos Tibiales/cirugía , Lesiones de Menisco Tibial , Adolescente , Adulto , Niño , Femenino , Humanos , Masculino , Persona de Mediana Edad , Estudios Retrospectivos , Factores de Tiempo , Resultado del Tratamiento
16.
J Ethnopharmacol ; 71(3): 425-35, 2000 Aug.
Artículo en Inglés | MEDLINE | ID: mdl-10940579

RESUMEN

The possible antioxidant effects of crude extract and a purified aqueous fraction of Asparagus racemosus against membrane damage induced by the free radicals generated during gamma-radiation were examined in rat liver mitochondria. gamma-Radiation, in the dose range of 75-900 Gy, induced lipid peroxidation as assessed by the formation of thiobarbituric acid reactive substances (TBARS) and lipid hydroperoxides (LOOH). Using an effective dose of 450 Gy, antioxidant effects of A. racemosus extract were studied against oxidative damage in terms of protection against lipid peroxidation, protein oxidation, depletion of protein thiols and the levels of the antioxidant enzyme, superoxide dismutase. An active fraction consisting of polysaccharides (termed as P3) was effective even at a low concentration of 10 microg/ml. Both the crude extract as well as the P3 fraction significantly inhibited lipid peroxidation and protein oxidation. The antioxidant effect of P3 fraction was more pronounced against lipid peroxidation, as assessed by TBARS formation, while that of the crude extract was more effective in inhibiting protein oxidation. Both the crude extract and P3 fraction also partly protects against radiation-induced loss of protein thiols and inactivation of superoxide dismutase. The inhibitory effects of these active principles, at the concentration of 10 microg/ml, are comparable to that of the established antioxidants glutathione and ascorbic acid. Hence our results indicate that extracts from A. racemosus have potent antioxidant properties in vitro in mitochondrial membranes of rat liver.


Asunto(s)
Antioxidantes/farmacología , Mitocondrias Hepáticas/efectos de la radiación , Extractos Vegetales/farmacología , Animales , Asparagus , Femenino , Rayos gamma , Peroxidación de Lípido/efectos de los fármacos , Mitocondrias Hepáticas/efectos de los fármacos , Ratas , Ratas Wistar , Superóxido Dismutasa/metabolismo
17.
Cancer Res ; 60(8): 2273-80, 2000 Apr 15.
Artículo en Inglés | MEDLINE | ID: mdl-10786695

RESUMEN

DNA damage from exposure to environmental chemical carcinogens and failure of repair systems to eliminate these lesions from the genome are considered as the crucial initial steps in the development of various human malignancies. Many cellular proteins are known to play vital roles to overcome the effects of DNA damage. Among such proteins, p53 is known to respond to DNA damage by accumulating in the nucleus and inhibiting cell cycle progression to facilitate DNA repair and the maintenance of genomic stability. In this study, we have investigated the role of p53 protein in modulating nucleotide excision repair of anti-benzo-(a)pyrene-diol-epoxide (BPDE)-DNA adducts and related effects using human fibroblasts with normal (p53-WT) and altered p53 protein (p53Mut and p53-Null). Interestingly, irrespective of the presence or absence of p53, the anti-BPDE dose-dependent p21 protein induction response was qualitatively comparable in all of the three cell lines. However, cells with defective p53 function were deficient for the removal of anti-BPDE-DNA adducts from the overall genome compared to cells with wild-type p53 activity. Strand-specific repair analysis within the individual strands of the p53 gene revealed decreased repair of adducts from the nontranscribed strand in p53-Mut and p53-Null cells. However, the repair of the transcribed strand appeared to be identical in all of the three cell lines. Furthermore, p53-Mut and p53-Null cells were more sensitive than p53-WT cells and displayed increased levels of anti-BPDE-induced apoptosis. Thus, wild-type p53 is required for the efficient global genomic repair of anti-BPDE-induced DNA adducts from the overall genome, but not for transcription-coupled repair of actively transcribed genes. These findings indicate that inefficient DNA repair of potentially cytotoxic and mutagenic lesions from the nontranscribed strand due to the loss of p53, but not the loss of p21, function might be responsible for enhanced cytotoxicity and apoptosis in human cells upon DNA damage.


Asunto(s)
Benzopirenos/toxicidad , Carcinógenos/toxicidad , Daño del ADN/efectos de los fármacos , Reparación del ADN/efectos de los fármacos , Genoma Humano , Proteína p53 Supresora de Tumor/metabolismo , 7,8-Dihidro-7,8-dihidroxibenzo(a)pireno 9,10-óxido/metabolismo , Apoptosis/efectos de los fármacos , Benzopirenos/metabolismo , Carcinógenos/metabolismo , Línea Celular , Supervivencia Celular/efectos de los fármacos , Inhibidor p21 de las Quinasas Dependientes de la Ciclina , Ciclinas/metabolismo , Aductos de ADN/metabolismo , Daño del ADN/genética , Reparación del ADN/genética , ADN de Cadena Simple/efectos de los fármacos , ADN de Cadena Simple/genética , Relación Dosis-Respuesta a Droga , Fibroblastos/citología , Fibroblastos/efectos de los fármacos , Fibroblastos/metabolismo , Genes p53/genética , Humanos , Mutación/genética , Transcripción Genética/efectos de los fármacos , Transcripción Genética/genética , Proteína p53 Supresora de Tumor/genética , Regulación hacia Arriba/efectos de los fármacos
18.
Toxicol In Vitro ; 14(1): 53-9, 2000 Feb.
Artículo en Inglés | MEDLINE | ID: mdl-10699361

RESUMEN

The phenanthroindolizidine plant alkaloids pergularinine (PGL) and tylophorinidine (TPD) isolated from the Indian medicinal herb Pergularia pallida have been evaluated for their biological activity and assessed for the first time employing dihydrofolate reductase (DHFR) (5,6,7,8-THF: NADP(+) oxidoreductase, EC 1.5.1.3) as the probe in the present investigations. The enzyme is a key target in cancer chemotherapy and has been purified from Lactobacillus leichmannii. Cytotoxicity studies showed that both PGL and TPD are potently toxic and inhibited the growth of L. leichmannii cells (IC(50)=45 and 40 microM, respectively). Both the alkaloids significantly inhibited DHFR activity (IC(50)=40 and 32 microM for PGL and TPD, respectively). Alkaloid concentrations greater than 75-95 microM resulted in a complete loss of DHFR activity. Our results are suggestive of the alkaloids as potential antimicrobial and antitumour compounds. Alkaloid binding to DHFR is slow and reversible. Inhibition kinetics revealed K(i) values of 9x10(-6) M and 7x10(-6) M for PGL and TPD, respectively for the enzyme and inhibition in both the cases was a simple linear 'non-competitive' type.


Asunto(s)
Alcaloides , Antibacterianos/farmacología , Antineoplásicos Fitogénicos/farmacología , Antagonistas del Ácido Fólico/farmacología , Isoquinolinas/farmacología , Tetrahidrofolato Deshidrogenasa/metabolismo , Antibacterianos/aislamiento & purificación , Antineoplásicos Fitogénicos/aislamiento & purificación , División Celular/efectos de los fármacos , India , Isoquinolinas/aislamiento & purificación , Lactobacillus/efectos de los fármacos , Plantas Medicinales/química
19.
J Neurosci Methods ; 90(1): 37-46, 1999 Aug 01.
Artículo en Inglés | MEDLINE | ID: mdl-10517272

RESUMEN

We describe a head-stage, with precision microtranslators for the chronic placement of micro-wire electrodes in the neocortex, that minimizes compressive damage to the brain. The head-stage has a diameter of 5.8 mm and allows six electrodes, separated by 450 microm on a hexagonal grid, to be individually and continuously positioned throughout a depth of approximately 3 mm. Suction is used to transiently support the dura against a curved array of tubes that guide and stabilize the electrodes as a means to prevent compression of the neocortex as the electrodes breach the dura. With this headstage we recorded extracellular signals in a rat immediately after surgery. Single-unit waveforms at a given electrode position were stable for at least several hours in the freely behaving animal and were obtained throughout the depth of the neocortex for at least 2 months. Electrophysiological records and histological examination showed that the upper layers of the neocortex were intact and minimally damaged after the implantation.


Asunto(s)
Electrodos Implantados , Microelectrodos , Neocórtex/fisiología , Animales , Femenino , Miniaturización , Ratas , Ratas Long-Evans , Vacio
20.
Bioorg Med Chem ; 7(6): 1105-10, 1999 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-10428380

RESUMEN

Beta-carboline-benzoquinolizidine plant alkaloid deoxytubulosine (DTB) was evaluated and assessed for the first time for its biochemical and biological activity employing the biomarker dihydrofolate reductase (DHFR) (5,6,7,8-tetrahydrofolate: NADP+ oxidoreductase, EC 1.5.1.3) as the probe enzyme, a key target in cancer chemotherapy. DHFR, employed in the present investigations was purified from Lactobacillus leichmannii. DTB, isolated from the Indian medicinal plant Alangium lamarckii was demonstrated to exhibit potent cytotoxicity. The alkaloid potently inhibited the cell growth of L. leichmannii and the cellular enzyme activity of DHFR (IC50=40 and 30 microM for the cell growth and enzyme inhibitions, respectively). DTB concentrations >75 microM resulted in a total loss of the DHFR activity, thus suggesting that the beta-carboline-benzoquinolizidine plant alkaloid is a promising potential antitumor agent. Our results are also suggestive of its potential antimicrobial activity. DTB binding to DHFR appears to be slow and reversible. Inhibition kinetics revealed that DHFR has a Ki value of 5x10(-6) M for DTB and that the enzyme inhibition is a simple linear 'non-competitive' type.


Asunto(s)
Antagonistas del Ácido Fólico/farmacología , Inhibidores de Crecimiento/farmacología , Plantas Medicinales/química , Quinolizinas/farmacología , Tetrahidrofolato Deshidrogenasa/metabolismo , Tubercidina/farmacología , Alcaloides/aislamiento & purificación , Alcaloides/farmacología , Antibacterianos/farmacología , Antineoplásicos Fitogénicos/farmacología , Unión Competitiva , Antagonistas del Ácido Fólico/aislamiento & purificación , Inhibidores de Crecimiento/química , India , Lactobacillus/efectos de los fármacos , Magnoliopsida/química , Quinolizinas/aislamiento & purificación , Tetrahidrofolato Deshidrogenasa/efectos de los fármacos , Tubercidina/aislamiento & purificación
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