Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 35
Filtrar
Más filtros












Base de datos
Intervalo de año de publicación
1.
J Clin Diagn Res ; 10(8): AF07-9, 2016 Aug.
Artículo en Inglés | MEDLINE | ID: mdl-27656428

RESUMEN

INTRODUCTION: Stress can cause harmful effects in the body that induce a wide range of biochemical and behavioural changes. As anti-stress drugs are routinely used to combat stress hence study is needed to assess the contraindication of these drugs in the physiological systems. AIM: To investigate the effect of alprazolam on restrained stress induced alteration of serum cortisol, and antioxidant vitamin levels in male albino rats. MATERIALS AND METHODS: Adult male albino rats (body weight 175-225g) were divided into four groups of six animals in each. Group I (control), kept undisturbed in the metabolic cage throughout the 42 days experimental period. Group II (stress) rats were kept in a wire mesh restrainer for 6 hr/day for 42 days. Group III (stress+ withdrawal) rats were stressed for 21 days and withdrawal of stress for remaining 21 days (total 42 days). Group IV (stress + alprazolam) rats were only stressed for 21 days and treated with drug alprazolam (5mg/kg body weight, intraperitoneal) in continuation with stress for remaining 21 days (total period is 42 days). At the end of 42 days all the rats were sacrificed and serum cortisol, vitamin C and E levels were estimated. RESULTS: Group II (stressed) showed a significant increase in serum cortisol level with concomitant decrease of serum vitamin C and E levels. Group III (withdrawal) and Group IV (+alprazolam) rats showed significant reduction of serum cortisol along with subsequent increase of serum vitamin C and E concentrations. CONCLUSION: Results indicate a possible antioxidant effect of alprazolam on restrained stress induced alteration of serum cortisol and antioxidant vitamin levels.

2.
Oncogene ; 33(6): 794-803, 2014 Feb 06.
Artículo en Inglés | MEDLINE | ID: mdl-23318454

RESUMEN

Aberrant expression of the oncogenic Kirsten-Ras (Ki-Ras) and interferon-stimulated gene 15 (ISG15) pathways is common in breast and other cancers. However, whether these dysregulated pathways cooperate to promote malignancy is not known. This study links Ki-Ras and ISG15 in a previously unidentified regulatory loop that may underlie malignant transformation of mammary cells. We show that oncogenic Ki-Ras regulates the expression of the ISG15 pathway (free ISG15 and ISG15 conjugates), and ISG15, in turn, stabilizes Ki-Ras protein by inhibiting its targeted degradation via lysosomes in breast cancer cells. Disruption of this loop by silencing either Ki-Ras or the ISG15 pathway restored the disrupted cellular architecture, a hallmark feature of most cancer cells. We also demonstrate that ISG15 and UbcH8 (ISG15-specific conjugating enzyme) shRNAs reversed Ki-Ras mutation-associated phenotypes of cancer cells, such as increased cell proliferation, colony formation, anchorage-independent growth in soft agar, cell migration, and epithelial-mesenchymal transition. As UbcH8-silenced breast cancer cells are devoid of ISG15 conjugates but have free ISG15, our results using UbcH8-silenced cells suggest that ISG15 conjugates, and not free ISG15, contributes to oncogenic Ki-Ras transformation. We have thus identified the conjugated form of ISG15 as a critical downstream mediator of oncogenic Ki-Ras, providing a potential mechanistic link between ISG15 and Ki-Ras-mediated breast tumorigenesis. Our findings, which show that inhibition of the ISGylation reverses the malignant phenotypes of breast cancer cells expressing oncogenic Ki-Ras, support the development of ISG15 conjugation inhibitors for treating breast and also other cancers expressing oncogenic Ki-Ras.


Asunto(s)
Neoplasias de la Mama/genética , Transformación Celular Neoplásica/genética , Citocinas/metabolismo , Genes ras , Ubiquitinas/metabolismo , Proteínas ras/genética , Animales , Autofagia/genética , Neoplasias de la Mama/metabolismo , Neoplasias de la Mama/patología , Procesos de Crecimiento Celular/genética , Línea Celular Tumoral , Transformación Celular Neoplásica/metabolismo , Citocinas/genética , Femenino , Expresión Génica , Humanos , Ratones , Mutación , Células 3T3 NIH , Ubiquitinas/genética , Proteínas ras/metabolismo
3.
Kathmandu Univ Med J (KUMJ) ; 11(42): 162-4, 2013.
Artículo en Inglés | MEDLINE | ID: mdl-24096226

RESUMEN

Variations of venous pattern in the arm are common. In this case report, we present a variation of axillary artery and vein. During routine educational dissections of axillary region, it was observed that a fenestrated axillary vein was perforated by a variant axillary artery in right arm of an old male cadaver. The axillary artery which was fenestrated through axillary vein had only two branches arising from its second part and no branches from its remaining distal parts. The branches are thoraco-acromial (usual) and another large collateral (unusual) branch. This collateral branch is the origin of several important arteries as the subscapular, circumflex scapular, posterior circumflex humeral and lateral thoracic arteries. We propose to name this artery as collateral axillary arterial trunk. The course of this collateral axillary arterial trunk and its branches and also clinical significance of this variation are discussed in the paper.


Asunto(s)
Arteria Axilar/anatomía & histología , Vena Axilar/anatomía & histología , Cadáver , Disección , Humanos , Masculino
4.
Insect Mol Biol ; 21(4): 446-55, 2012 Aug.
Artículo en Inglés | MEDLINE | ID: mdl-22690671

RESUMEN

Deformed wing virus (DWV) is a serious pathogen of the honey bee, Apis mellifera L., vectored by the parasitic mite Varroa destructor. The virus is associated with wing deformity in symptomatic bees, and premature death and reduced colony performance in asymptomatic bees. In the present study we reduced DWV infection by feeding both first instar larvae and adult A. mellifera with a double-stranded (ds) RNA construct, DWV-dsRNA, which is specific to DWV in DWV-inoculated bees, by mixing it with their food. We showed that feeding DWV to larvae causes wing deformity in adult bees in the absence of varroa mites and decreases survival rates of adult bees relative to bees not fed DWV. Feeding larvae with DWV-dsRNA in advance of inoculation with virus reduced the DWV viral level and reduced wing deformity relative to larvae fed DWV or DWV with green fluorescent protein-dsRNA (probably a result of RNA silencing), but did not affect survival to the adult stage. Feeding DWV-dsRNA did not affect larval survival rates, which suggests that dsRNA is non-toxic to larvae. Feeding adult workers with DWV-dsRNA in advance of inoculation with virus increased their longevity and reduced DWV concentration relative to controls.


Asunto(s)
Abejas/virología , Virus de Insectos/efectos de los fármacos , Larva/virología , ARN Bicatenario/administración & dosificación , Animales , Abejas/efectos de los fármacos , Abejas/genética , Ingestión de Alimentos , Larva/efectos de los fármacos , Varroidae , Alas de Animales/virología
5.
Work ; 38(3): 291-9, 2011.
Artículo en Inglés | MEDLINE | ID: mdl-21447889

RESUMEN

OBJECTIVE: Increasing awareness of the high physical cost associated with lifting has led to the redesign of these tasks, incorporating manual handling devices and consequently pushing and pulling. Little research has focused on muscle activity responses to pushing and pulling, the current study therefore investigated these responses to further the understanding of risk of injury, informing ergonomics intervention strategies. METHODS: A laboratory study was undertaken to determine the effect of three push/pull techniques and two loads (250 and 500 kg) on muscle activation in nine muscles, distributed through the upper and lower body. Unloaded forward and backward walking were used as control conditions for lower limb muscle activation. PARTICIPANTS: Thirty-six healthy male volunteers participated in the study. Subjects were required to manoeuvre a loaded pallet jack at a velocity of 0.45-0.55 statures. RESULTS: The muscles of the shoulders and upper extremity were affected to a greater degree by technique and load changes than those of the lower limbs. Further, high levels of erector spinae activation were recorded across all six experimental conditions. CONCLUSIONS: Each technique displayed a unique muscle activation profile, indicating that alternating between techniques may reduce early onset of fatigue. Further understanding of muscle activation during pushing and pulling is necessary.


Asunto(s)
Músculo Esquelético/fisiología , Esfuerzo Físico/fisiología , Análisis y Desempeño de Tareas , Adulto , Fenómenos Biomecánicos/fisiología , Electromiografía , Humanos , Masculino , Adulto Joven
6.
J Biol Chem ; 276(44): 40652-8, 2001 Nov 02.
Artículo en Inglés | MEDLINE | ID: mdl-11546768

RESUMEN

DNA topoisomerase II (TOP2) cleavable complexes represent an unusual type of DNA damage characterized by reversible TOP2-DNA cross-links and DNA double strand breaks. Many antitumor drugs and physiological stresses are known to induce TOP2 cleavable complexes leading to apoptotic cell death and genomic instability. However, the molecular mechanism(s) for repair of TOP2 cleavable complexes remains unclear. In the current studies, we show that TOP2 cleavable complexes induced by the prototypic TOP2 poison VM-26 are proteolytically degraded by the ubiquitin/26 S proteasome pathway. Surprisingly the TOP2beta isozyme is preferentially degraded over TOP2alpha isozyme. In addition, transcription inhibitors such as 5,6-dichlorobenzimidazole riboside and camptothecin can substantially block VM-26-induced TOP2beta degradation. These results are consistent with a model in which the repair of TOP2beta cleavable complexes may involve transcription-dependent proteolysis of TOP2beta to reveal the protein-concealed double strand breaks.


Asunto(s)
Cisteína Endopeptidasas/metabolismo , ADN-Topoisomerasas de Tipo II/metabolismo , Complejos Multienzimáticos/metabolismo , Animales , Secuencia de Bases , Cisplatino/farmacología , Cartilla de ADN , ADN-Topoisomerasas de Tipo II/genética , Regulación hacia Abajo/efectos de los fármacos , Inhibidores Enzimáticos/farmacología , Células HeLa , Humanos , Hidrólisis , Cinética , Ratones , Complejo de la Endopetidasa Proteasomal , Tenipósido/farmacología , Inhibidores de Topoisomerasa II , Células Tumorales Cultivadas
7.
Cancer Res ; 61(15): 5926-32, 2001 Aug 01.
Artículo en Inglés | MEDLINE | ID: mdl-11479235

RESUMEN

Camptothecin (CPT) induces down-regulation of topoisomerase I (TOP1) via an ubiquitin/26S proteasome pathway. Studies using a panel of breast and colorectal cancer cell lines as well as primary nontransformed and oncogene-transformed cells have demonstrated that CPT-induced down-regulation exhibits a high degree of heterogeneity. In general, nontransformed cells are much more proficient in CPT-induced TOP1 down-regulation than their transformed counterparts. Among the breast and colorectal cancer cell lines, there was a general correlation between the extent of CPT-induced TOP1 down-regulation and CPT resistance. The breast cancer cell line ZR-75-1, the most sensitive to CPT, was completely defective in CPT-induced TOP1 down-regulation, whereas the breast cancer cell line BT474, the least sensitive to CPT, exhibited effective CPT-induced TOP1 down-regulation. The 26S proteasome inhibitor MG132 was shown to inhibit CPT-induced down-regulation of TOP1 in BT474 cells and selectively sensitized BT474 but not ZR-75-1 cells to CPT-induced cytotoxicity and apoptosis. In the aggregate, these results suggest that CPT-induced down-regulation of TOP1 could be an important parameter for determining CPT sensitivity/resistance in tumor cells. Analysis of the levels of TOP1 cleavable complexes, SUMO-1-TOP1 conjugates, and ubiquitin-TOP1 conjugates in ZR-75-1 and BT474 cells has suggested that the heterogeneity of CPT-induced down-regulation of TOP1 in tumor cells is at least in part attributable to altered regulation of a process(es) downstream from the TOP1 cleavable complex.


Asunto(s)
Camptotecina/farmacología , ADN-Topoisomerasas de Tipo I/metabolismo , Regulación Enzimológica de la Expresión Génica/efectos de los fármacos , Péptido Hidrolasas/metabolismo , Complejo de la Endopetidasa Proteasomal , Ubiquitinas/metabolismo , Animales , Neoplasias de la Mama/tratamiento farmacológico , Neoplasias de la Mama/enzimología , Neoplasias de la Mama/genética , Células CHO , Línea Celular , Neoplasias del Colon/tratamiento farmacológico , Neoplasias del Colon/enzimología , Neoplasias del Colon/genética , Cricetinae , ADN-Topoisomerasas de Tipo I/biosíntesis , ADN-Topoisomerasas de Tipo I/genética , Regulación hacia Abajo/efectos de los fármacos , Regulación hacia Abajo/fisiología , Resistencia a Antineoplásicos/fisiología , Fibroblastos/efectos de los fármacos , Fibroblastos/enzimología , Fibroblastos/fisiología , Regulación Enzimológica de la Expresión Génica/fisiología , Humanos , Células KB/efectos de los fármacos
8.
J Biol Chem ; 275(34): 26066-73, 2000 Aug 25.
Artículo en Inglés | MEDLINE | ID: mdl-10862613

RESUMEN

Topoisomerase I-mediated DNA damage induced by camptothecin has been shown to induce rapid small ubiquitin-related modifier (SUMO)-1 conjugation to topoisomerase I. In the current study, we show that topoisomerase II-mediated DNA damage induced by teniposide (VM-26) results in the formation of high molecular weight conjugates of both topoisomerase IIalpha and IIbeta isozymes in HeLa cells. Immunological characterization of these conjugates suggests that both topoisomerase IIalpha and IIbeta isozymes are conjugated to SUMO-1. The involvement of SUMO-1/UBC9 in the modification of topoisomerase II isozymes is also supported by the demonstration of physical interaction between topoisomerase II and SUMO-1/UBC9. Surprisingly, ICRF-193, which does not induce topoisomerase II-mediated DNA damage but traps topoisomerase II into a circular clamp conformation, is also shown to induce similar SUMO-1 conjugation to topoisomerase II isozymes. In addition, we show that both oxidative and heat shock stresses, which can cause protein damage, rapidly increase nuclear SUMO-1 conjugates. These studies raise the question on whether SUMO-1 conjugation to topoisomerases is an indirect result of a DNA damage response or a direct result because of protein conformational changes.


Asunto(s)
ADN-Topoisomerasas de Tipo II/metabolismo , Ligasas/metabolismo , Electroforesis en Gel de Poliacrilamida , Inhibidores Enzimáticos/farmacología , Células HeLa , Humanos , Isoenzimas/metabolismo , Unión Proteica , Conformación Proteica , Transducción de Señal , Tenipósido/farmacología , Ubiquitina-Proteína Ligasas
9.
Proc Natl Acad Sci U S A ; 97(8): 4046-51, 2000 Apr 11.
Artículo en Inglés | MEDLINE | ID: mdl-10759568

RESUMEN

Ubiquitin/26S proteasome-dependent degradation of topoisomerase I (TOP1) has been suggested to be a unique repair response to TOP1-mediated DNA damage. In the current study, we show that treatment of mammalian cells or yeast cells expressing human DNA TOP1 with camptothecin (CPT) induces covalent modification of the TOP1 by SUMO-1/Smt3p, a ubiquitin-like protein. This conclusion is based on the following observations: (i) Mammalian DNA TOP1 conjugates induced by CPT were cross-reactive with SUMO-1/Smt3p-specific antibodies both in yeast expressing human DNA TOP1 as well as mammalian cells. (ii) The formation of TOP1 conjugates was shown to be dependent on UBC9, the E2 enzyme for SUMO-1/Smt3p. (iii) TOP1 physically interacts with UBC9. (iv) Ubc9 mutant yeast cells expressing human DNA TOP1 was hypersensitive to CPT, suggesting that UBC9/SUMO-1 may be involved in the repair of TOP1-mediated DNA damage.


Asunto(s)
Daño del ADN , Reparación del ADN , ADN-Topoisomerasas de Tipo I/metabolismo , Proteínas de Saccharomyces cerevisiae , Enzimas Ubiquitina-Conjugadoras , Ubiquitinas/metabolismo , Células HeLa , Humanos , Ligasas/metabolismo , Unión Proteica , Proteínas Represoras/metabolismo , Proteína SUMO-1 , Saccharomyces cerevisiae/enzimología , Saccharomyces cerevisiae/genética , Saccharomyces cerevisiae/metabolismo , Proteínas Modificadoras Pequeñas Relacionadas con Ubiquitina
10.
Br J Ophthalmol ; 84(4): 437-8, 2000 Apr.
Artículo en Inglés | MEDLINE | ID: mdl-10729307

RESUMEN

AIMS: To assess the effectiveness of enucleation or evisceration in relieving pain from painful blind eyes. METHODS: 24 patients with intractable ocular pain underwent enucleation or evisceration with or without an orbital implant. RESULTS: Complete pain relief was achieved in all patients at an average time of 3 months (range 1-15 months). Seven patients required further medical or surgical treatment in addition to removal of the globe. CONCLUSION: Enucleation and evisceration were effective in relieving ocular pain in all patients with a painful blind eye in our study. However, complications of surgery and orbital implants can cause recurrent pain.


Asunto(s)
Oftalmopatías/cirugía , Enucleación del Ojo , Evisceración del Ojo , Dolor/cirugía , Adolescente , Adulto , Anciano , Anciano de 80 o más Años , Ceguera/complicaciones , Niño , Femenino , Estudios de Seguimiento , Humanos , Masculino , Persona de Mediana Edad , Dolor/etiología , Resultado del Tratamiento
11.
Drug Deliv ; 7(4): 201-7, 2000.
Artículo en Inglés | MEDLINE | ID: mdl-11195426

RESUMEN

The objectives of our study were to prepare a biodegradable polyisobutylcyanoacrylate (PIBCA) colloidal particulate system of pilocarpine, to incorporate it into a Pluronic F127(PF127)-based gel delivery system, and to evaluate its ability to prolong the release of pilocarpine. Polyisobutylcyanoacrylate nanocapsules (PIBCA-NC) of pilocarpine were prepared by interfacial polymerization. Physicochemical characterization of the colloidal dispersion of PIBCA-NC of pilocarpine was performed by measuring drug loading, particle size analysis, and scanning electron microscopy. Results indicated that approximately 13.5% of pilocarpine was loaded onto the PIBCA-NC, the nanocapsules ranged from 370 to 460 nm, the distribution was narrow, and there was no significant effect of stirring speed on particle size. The PIBCA-NC dispersion of 1% pilocarpine alone (I) and after incorporation into the Pluronic F127 gel delivery system (II) were compared against 1% pilocarpine incorporated into a PF127 gel containing 5% methylcellulose (PF127MC) alone (III) by measuring the miotic response in the albino rabbit eye. Statistical analysis indicated a rank-order for both the duration and intensity of miosis of II > III >> I, with all differences being significant (p < 0.05). Thus, it appears that II increases the contact time of pilocarpine with the absorbing tissue in the eye, thereby improving ocular bioavailability. The PIBCA-NC of pilocarpine dispersed in the PF127MC gel delivery system has considerable potential for achieving a prolonged delivery for such drugs as pilocarpine and other more hydrophobic drugs.


Asunto(s)
Cianoacrilatos , Excipientes , Ojo/metabolismo , Mióticos/administración & dosificación , Pilocarpina/administración & dosificación , Poloxámero , Polímeros , Algoritmos , Animales , Área Bajo la Curva , Sistemas de Liberación de Medicamentos , Enbucrilato , Masculino , Microscopía Electrónica de Rastreo , Miosis/inducido químicamente , Mióticos/farmacocinética , Mióticos/farmacología , Pilocarpina/farmacocinética , Pilocarpina/farmacología , Conejos
12.
Ann N Y Acad Sci ; 922: 1-10, 2000.
Artículo en Inglés | MEDLINE | ID: mdl-11193884

RESUMEN

Camptothecin (CPT) class of compounds has been demonstrated to be effective against a broad spectrum of tumors. Their molecular target has been firmly established to be human DNA topoisomerase I (topo I). CPT inhibits topo I by blocking the rejoining step of the cleavage/religation reaction of topo-I, resulting in accumulation of a covalent reaction intermediate, the cleavable complex. The primary mechanism of cell killing by CPT is S-phase-specific killing through potentially lethal collisions between advancing replication forks and topo-I cleavable complexes. Collisions with the transcription machinery have also been shown to trigger the formation of long-lived covalent topo-I DNA complexes, which contribute to CPT cytotoxicity. Two novel repair responses to topo-I-mediated DNA damage involving covalent modifications of topo-I have been discovered. The first involves activation of the ubiquitin/26S proteasome pathway, leading to degradation of topo-I (CPT-induced topo-I downregulation). The second involves SUMO conjugation to topo-I. The potentials roles of these new mechanisms for repair of topo-I-mediated DNA damage in determining CPT sensitivity/resistance in tumor cells are discussed.


Asunto(s)
Antineoplásicos Fitogénicos/farmacología , Camptotecina/farmacología , Animales , Inhibidores Enzimáticos/farmacología , Humanos , Sustancias Intercalantes/farmacología , Inhibidores de Topoisomerasa I
14.
Biochem Pharmacol ; 56(9): 1157-66, 1998 Nov 01.
Artículo en Inglés | MEDLINE | ID: mdl-9802326

RESUMEN

Protoberberines are a new class of organic cations that are dual poisons of topoisomerases I and II. Certain protoberberines exhibit greater in vitro cytotoxicity against cell lines derived from solid tumors than from leukemias. Using a group of seventeen different protoberberine analogs, the structural basis for selective cytotoxicity toward sensitive SF-268 glioblastoma cells as compared with resistant RPMI 8402 lymphoblast cells was explored. The selective cytotoxicity is associated with the presence of an imminium ion and other structural features of protoberberines, and is not shared by drugs such as camptothecin, doxorubicin, vinblastine, and etoposide, which are either equally or more cytotoxic against RPMI 8402 cells than SF-268 cells. The selective cytotoxicity of protoberberines against SF-268 over RPMI 8402 cells is not due to differences in topoisomerase levels or known drug efflux systems such as multidrug resistance (MDR1) and multidrug-resistance protein (MRP). Comparative in vitro studies of the accumulation of coralyne, a fluorescent protoberberine, into sensitive and resistant cells demonstrated a correlation between drug accumulation and selective cytotoxicity. Inhibitors of coralyne uptake included several protoberberine-related compounds. Of these, palmatine, a minimally cytotoxic protoberberine, both inhibited coralyne accumulation and reduced cytotoxicity against SF-268 cells, but not against RPMI 8402 cells. Despite the structural resemblance of protoberberines to catecholamines, our experiments using inhibitors and cells expressing biogenic amine uptake systems have ruled out the involvement of biogenic amine uptake1, uptake2, and vesicular monoamine transport systems. Uptake systems remaining as candidates, supported by preliminary data, include transport via vesicles derived from specialized membrane invaginations and selected carrier-mediated organic amine transport systems.


Asunto(s)
Antineoplásicos/farmacología , Berberina/análogos & derivados , Inhibidores Enzimáticos/farmacología , Glioblastoma/tratamiento farmacológico , Inhibidores de Topoisomerasa I , Inhibidores de Topoisomerasa II , Berberina/metabolismo , Alcaloides de Berberina/metabolismo , Aminas Biogénicas/metabolismo , Glioblastoma/patología , Humanos , Relación Estructura-Actividad , Células Tumorales Cultivadas
15.
J Pharm Sci ; 87(10): 1190-5, 1998 Oct.
Artículo en Inglés | MEDLINE | ID: mdl-9758675

RESUMEN

The overall objective of this study was to develop Pluronic F127 (PF127)-containing formulations of pilocarpine hydrochloride (PHCL) which can be used for sustained-release ocular delivery of PHCL. The PF127 formulations of PHCL containing methylcellulose (MC) or hydroxypropyl methylcellulose (HPMC) as an additive had previously exhibited the slowest dissolution rates and released the drug the slowest in vitro. This study was performed to assess the in vivo performance of these two formulations using miosis in the albino rabbit eye produced by PHCL as a measure of ocular bioavailability. The PF127MC formulation (20 microL) had a significantly greater intensity of miosis compared to the same volume of an isotonic solution of PHCL. The duration and the intensity of the miotic response increased significantly as the instilled volume of the PF127MC gel formulation increased. The miotic response, expressed as % bioactivity by assigning a value of 100% to the 20 microL PF127MC treatment, was increased as the volume instilled was reduced from 60 to 20 microL. However, no difference in bioactivity between the 60 and 100 microL volumes was observed. In addition, the 100 microL volumes of both the PF127MC and PF127HPMC gel formulations exhibited bioactivity equivalent to 20 microL of an isotonic PHCL solution. Thus, for a given instilled concentration, the larger the volume instilled the greater the amount of drug present in tear fluid and thus the higher the concentration delivered to the iris sphincter muscle and hence the greater the miotic response. However, the fraction of the dose reaching the iris sphincter muscle was greater for the smaller instilled volume. On the basis of these findings and previous in vitro results, the PF127 formulations of PHCL having MC or HPMC as an additive showed considerable potential as sustained-release ocular delivery systems for PHCL. This conclusion was based upon their ability to provide a substantial prolongation of drug action and an improvement in the ocular bioavailability of pilocarpine compared to conventional eye drops and previously utilized PF127 formulations of PHCL. It appears that ocular bioavailability can be increased more readily by altering both the rheological characteristics of the delivery system and by using a smaller dose volume.


Asunto(s)
Preparaciones de Acción Retardada , Ojo , Pilocarpina/administración & dosificación , Poloxámero/administración & dosificación , Animales , Área Bajo la Curva , Disponibilidad Biológica , Portadores de Fármacos , Evaluación de Medicamentos , Masculino , Miosis , Modelos Biológicos , Pilocarpina/farmacocinética , Conejos
16.
J Pharm Sci ; 87(2): 226-30, 1998 Feb.
Artículo en Inglés | MEDLINE | ID: mdl-9519158

RESUMEN

The overall objective of this study was to develop pluronic F127 (PF127)-containing formulations of pilocarpine hydrochloride (PHCL) suitable for controlled-release ocular delivery of PHCL. Various aqueous formulations were evaluated containing 1% w/v PHCL and 25% w/v PF127 alone or with one of the following additives present: poly(ethylene glycol) 4600 (PEG), poly(vinylpyrrolidone) 10,000 (PVP), poly(vinyl alcohol) 10,000 (PVA), methylcellulose 15 cP (MC), and hydroxypropyl methylcellulose 80-120 cP (HPMC). The in vitro dissolution of the PF127 formulations and the pilocarpine release profiles from them were obtained simultaneously at 34 degrees C and room temperature using a membraneless in vitro model. It was observed that the PEG- and PVP-containing PF127 formulations of PHCL dissolved the quickest and released the drug at a significantly faster rate than the control PF127 formulation, which had no additive present. The PF127 formulations of PHCL containing MC or HPMC exhibited the slowest dissolution rates and released the drug the slowest. The same rank order was observed at each temperature for the dissolution and PHCL release profiles of each formulation. On the basis of the in vitro results, the PF127 formulations of PHCL containing MC or HPMC as an additive showed potential for use as controlled-release ocular delivery systems for PHCL.


Asunto(s)
Sistemas de Liberación de Medicamentos/métodos , Excipientes/química , Mióticos/administración & dosificación , Pilocarpina/administración & dosificación , Poloxaleno/química , Polietilenglicoles/química , Química Farmacéutica , Preparaciones de Acción Retardada , Derivados de la Hipromelosa , Análisis de los Mínimos Cuadrados , Metilcelulosa/análogos & derivados , Metilcelulosa/química , Mióticos/química , Soluciones Oftálmicas , Pilocarpina/química , Povidona/química , Reología , Viscosidad
17.
J Biol Chem ; 272(39): 24159-64, 1997 Sep 26.
Artículo en Inglés | MEDLINE | ID: mdl-9305865

RESUMEN

Topoisomerase I (TOP1) relaxes superhelical DNA through a breakage/rejoining reaction in which the active site tyrosine links covalently to a 3' phosphate at the break site as a transient intermediate. The antitumor drug camptothecin (CPT) and its analogs inhibit the rejoining step of the breakage/rejoining reaction, which traps the enzyme in covalent linkage with DNA (the cleavable complex). Little is known about the fate of cellular TOP1 trapped in the cleavable complex. We have analyzed TOP1 in mammalian cell lines treated with CPT. When CPT-treated cells were lysed with either SDS or alkali and analyzed by Western blotting, greater than 90% of the TOP1 was linked to DNA. Nuclease treatment of the cell lysate to remove the covalently linked DNA from TOP1 revealed a distinct ladder of higher molecular weight bands having properties indicative of multi-ubiquitin (Ub) conjugates of TOP1. Approximately 5-10% of TOP1 was present as these conjugates within minutes of CPT treatment. Consistent with ubiquitination, TOP1 was not modified in ts85 cells at the restrictive temperature for its thermolabile ubiquitin-activating enzyme (E1). Because conjugation with ubiquitin can mark proteins for destruction by the 26S proteasome, we analyzed TOP1 protein levels during prolonged CPT treatment. TOP1 protein levels were reduced to about 25% during CPT treatments of 2-4 h resulting from increased destruction, with the half-life dropping from 10-16 h down to 1-2 h. The destruction of TOP1, like the formation of Ub-TOP1 conjugates, was not observed in ts85 cells at the restrictive temperature. The destruction of TOP1 was also prevented in cells treated with MG-132 and lactacystin, specific inhibitors of the 26S proteasome. Finally, the multi-Ub conjugates of TOP1 were observed whether or not aphidicolin was included in cotreatment with CPT, indicating that replication fork activity was not involved in making TOP1 a substrate for ubiquitination. These results demonstrate that independent of DNA replication, the TOP1 cleavable complex is ubiquitinated and destroyed in cells treated with antitumor drugs that block the religation step of the TOP1 reaction.


Asunto(s)
Antineoplásicos Fitogénicos/farmacología , Camptotecina/farmacología , Inhibidores Enzimáticos/farmacología , Inhibidores de Topoisomerasa I , Ubiquitinas/farmacología , Animales , Cisteína Endopeptidasas/metabolismo , Ratones , Complejos Multienzimáticos/metabolismo , Complejo de la Endopetidasa Proteasomal , Células Tumorales Cultivadas
18.
J Assoc Physicians India ; 42(11): 885-7, 1994 Nov.
Artículo en Inglés | MEDLINE | ID: mdl-7868492

RESUMEN

The study comprised of 2 groups. In group I sickling test was done in students studying in a school which mainly caters to the educational needs of the backward community. Out of 130 students examined 24 were found to be sicklers. The distribution of this cases among various castes/tribes were as follows--Choudharys (Cd)-13, Gamits (Gt)-4, Dhodhia Patels (DP)-4, Koknis (K)-2 and Koli Patel (KP)-1. In group II, patients admitted in the hospital between Jan '81 to June '82 were studied. The prevalence of sickle cell syndrome was 1.74%. The most common mode of presentation were limb pains and weakness. Hemoglobin values ranged from 3.0 gram% to 12 gms%. 35 cases of HbSS, 149 cases of HbAS and 1 case of Sickle Beta thalassemia were seen. The distribution of the cases amongst the various tribes and castes were as follows-Cd-93, Gt-56, DP-23, KP-7, K-4 and Rathods (R)-2. No cases were found in Anavil Brahmins or Patidar Patels. Clinical and pathological observations included palpable splenomegaly in 54 cases, splenic abscess in 1 case, isothenuria in large number of patients, microscopic hematuria in 6 cases and frank hematuria in 1 case. Osteomyelitis and cholecystitis were seen in one case each.


Asunto(s)
Anemia de Células Falciformes/epidemiología , Adolescente , Anemia de Células Falciformes/sangre , Anemia de Células Falciformes/etnología , Niño , Femenino , Hemoglobina Falciforme/análisis , Humanos , India/epidemiología , Masculino , Prevalencia
19.
Biochemistry ; 33(39): 11868-74, 1994 Oct 04.
Artículo en Inglés | MEDLINE | ID: mdl-7918405

RESUMEN

In order to determine the role of Tyr 766 of Escherichia coli DNA polymerase I in the catalysis of DNA synthesis, we investigated the properties of a Tyr 766-->Ser (Y766S) mutant of the Klenow fragment of E. coli DNA polymerase I. We found that the rates of incorporation of only dTTP but not the other dNTP substrates were affected in the reactions catalyzed by the mutant enzyme, when homopolymeric template-primers were used. The mutant enzyme exhibited a reduced rate of synthesis only with poly(rA)- or poly(dA)-directed reactions. Examination of the ability of the mutant and the wild-type enzymes to bind to dGTP and dTTP, as judged by UV-mediated cross-linking, indicated nearly identical binding efficiencies of both nucleotides. However, the ability of the mutant enzyme to bind to poly(rA).(dT)15 and poly(dA).(dT)15 was found to be significantly reduced as compared to the binding to heteropolymeric DNA. In order to further define the nature of template-mediated restriction on the catalytic activity of the mutant enzyme, its ability to copy DNA templates containing a stretch of AAAAA and ACACA sequences was compared. The results show that DNA synthesis catalyzed by the mutant enzyme is significantly retarded when it encounters the AAAAA region of the template but not the ACACA region. Product analysis of the reaction directed by the two template-primers showed that the mutant enzyme stalls/terminates synthesis upon encountering an AAAAA sequence in the template.(ABSTRACT TRUNCATED AT 250 WORDS)


Asunto(s)
ADN Polimerasa I/metabolismo , ADN/biosíntesis , Desoxirribonucleótidos/metabolismo , Escherichia coli/enzimología , Secuencia de Bases , Aductos de ADN , ADN Polimerasa I/genética , Cartilla de ADN/metabolismo , Nucleótidos de Desoxiguanina/metabolismo , Escherichia coli/genética , Datos de Secuencia Molecular , Mutación , Serina/genética , Especificidad por Sustrato , Nucleótidos de Timina/metabolismo , Tirosina/genética , Rayos Ultravioleta
20.
Otolaryngol Head Neck Surg ; 107(6 Pt 1): 755-7, 1992 Dec.
Artículo en Inglés | MEDLINE | ID: mdl-1470453

RESUMEN

Otolaryngologic manifestations of AIDS have been described in the past. In this study, I had examined 14 adults with nasal obstruction and mouth breathing. Nine patients also reported deafness--unilateral in three of them and bilateral in six. All of them revealed a mass in the nasopharynx, either on the posterior rhinoscopy or the x-ray neck-lateral view. To exclude nasopharyngeal malignancy, all of the patients underwent examination of the nasopharynx while under general anaesthesia and biopsy. The histopathologic diagnosis in every patient was nonspecific, reactive lymphoid hyperplasia, which has been described in the background of HIV infections. Four were already confirmed HIV-positive and 10 were found positive on the HIV antibody test. A strong association was established between seropositivity, adenoid hypertrophy, and secretory otitis media in adults.


Asunto(s)
Tonsila Faríngea/patología , Seropositividad para VIH/complicaciones , Otitis Media con Derrame/complicaciones , Adolescente , Adulto , Femenino , Humanos , Hipertrofia/complicaciones , Masculino , Persona de Mediana Edad , Respiración por la Boca/etiología , Obstrucción Nasal/etiología
SELECCIÓN DE REFERENCIAS
DETALLE DE LA BÚSQUEDA
...