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1.
Phys Rev Lett ; 128(7): 072501, 2022 Feb 18.
Artículo en Inglés | MEDLINE | ID: mdl-35244436

RESUMEN

The differential cross sections of the Σ^{-}p→Λn reaction were measured accurately for the Σ^{-} momentum (p_{Σ}) ranging from 470 to 650 MeV/c at the J-PARC Hadron Experimental Facility. Precise angular information about the Σ^{-}p→Λn reaction was obtained for the first time by detecting approximately 100 reaction events at each angular step of Δcosθ=0.1. The obtained differential cross sections show a slightly forward-peaking structure in the measured momentum regions. The cross sections integrated for -0.7≤cosθ≤1.0 were obtained as 22.5±0.68 [statistical error(stat.)] ±0.65 [systematic error(syst.)] mb and 15.8±0.83(stat)±0.52(syst) mb for 470

2.
Phys Rev Lett ; 120(13): 132505, 2018 Mar 30.
Artículo en Inglés | MEDLINE | ID: mdl-29694189

RESUMEN

We report on the first observation of γ rays emitted from an sd-shell hypernucleus, _{Λ}^{19}F. The energy spacing between the ground state doublet, 1/2^{+} and 3/2^{+} states, of _{Λ}^{19}F is determined to be 315.5±0.4(stat)_{-0.5}^{+0.6}(syst) keV by measuring the γ-ray energy of the M1(3/2^{+}→1/2^{+}) transition. In addition, three γ-ray peaks are observed and assigned as E2(5/2^{+}→1/2^{+}), E1(1/2^{-}→1/2^{+}), and E1(1/2^{-}→3/2^{+}) transitions. The excitation energies of the 5/2^{+} and 1/2^{-} states are determined to be 895.2±0.3(stat)±0.5(syst) and 1265.6±1.2(stat)_{-0.5}^{+0.7}(syst) keV, respectively. It is found that the ground state doublet spacing is well described by theoretical models based on existing s- and p-shell hypernuclear data.

3.
Epidemiol Infect ; 144(5): 952-61, 2016 Apr.
Artículo en Inglés | MEDLINE | ID: mdl-26470913

RESUMEN

Shiga-toxin-producing Escherichia coli (STEC) infections usually cause haemolytic uraemic syndrome (HUS) equally in male and female children. This study investigated the localization of globotriaosylceramide (Gb3) in human brain and kidney tissues removed from forensic autopsy cases in Japan. A fatal case was used as a positive control in an outbreak of diarrhoeal disease caused by STEC O157:H7 in a kindergarten in Urawa in 1990. Positive immunodetection of Gb3 was significantly more frequent in female than in male distal and collecting renal tubules. To correlate this finding with a clinical outcome, a retrospective analysis of the predictors of renal failure in the 162 patients of two outbreaks in Japan was performed: one in Tochigi in 2002 and the other in Kagawa Prefecture in 2005. This study concludes renal failure, including HUS, was significantly associated with female sex, and the odds ratio was 4·06 compared to male patients in the two outbreaks. From 2006 to 2009 in Japan, the risk factor of HUS associated with STEC infection was analysed. The number of males and females and the proportion of females who developed HUS were calculated by age and year from 2006 to 2009. In 2006, 2007 and 2009 in adults aged >20 years, adult women were significantly more at risk of developing HUS in Japan.


Asunto(s)
Brotes de Enfermedades , Infecciones por Escherichia coli/epidemiología , Síndrome Hemolítico-Urémico/epidemiología , Escherichia coli Shiga-Toxigénica/fisiología , Adolescente , Adulto , Factores de Edad , Anciano , Anciano de 80 o más Años , Encéfalo/microbiología , Niño , Preescolar , Diarrea/epidemiología , Diarrea/microbiología , Infecciones por Escherichia coli/complicaciones , Femenino , Síndrome Hemolítico-Urémico/microbiología , Humanos , Lactante , Recién Nacido , Japón/epidemiología , Riñón/microbiología , Masculino , Persona de Mediana Edad , Insuficiencia Renal/epidemiología , Insuficiencia Renal/microbiología , Estudios Retrospectivos , Factores de Riesgo , Factores Sexuales , Trihexosilceramidas/análisis , Adulto Joven
4.
Phys Rev Lett ; 115(22): 222501, 2015 Nov 27.
Artículo en Inglés | MEDLINE | ID: mdl-26650298

RESUMEN

The energy spacing between the spin-doublet bound state of _{Λ}^{4}He(1^{+},0^{+}) was determined to be 1406±2±2 keV, by measuring γ rays for the 1^{+}→0^{+} transition with a high efficiency germanium detector array in coincidence with the ^{4}He(K^{-},π^{-})_{Λ}^{4}He reaction at J-PARC. In comparison to the corresponding energy spacing in the mirror hypernucleus _{Λ}^{4}H, the present result clearly indicates the existence of charge symmetry breaking (CSB) in ΛN interaction. By combining the energy spacings with the known ground-state binding energies, it is also found that the CSB effect is large in the 0^{+} ground state but is vanishingly small in the 1^{+} excited state, demonstrating that the ΛN CSB interaction has spin dependence.

5.
Reproduction ; 147(5): 615-25, 2014 May.
Artículo en Inglés | MEDLINE | ID: mdl-24713393

RESUMEN

The process of germ cell development is under the tight control of various signaling pathways, among which the PI3K-Akt-mTOR pathway is of critical importance. Previous studies have demonstrated sex-specific roles for several components of this pathway. In the current study, we aimed to evaluate the role of Rheb, a member of the small GTPase superfamily and a critical component for mTORC1 activation, in male and female gametogenesis. The function of Rheb in development and the nervous system has been extensively studied, but little is known about its role in the germ line. We have exploited genetic approaches in the mouse to study the role of Rheb in the germ line and have identified an essential role in spermatogenesis. Conditional knockout (cKO) of Rheb in the male germ line resulted in severe oligoasthenoteratozoospermia and male sterility. More detailed phenotypic analyses uncovered an age-dependent meiotic progression defect combined with subsequent abnormalities in spermiogenesis as evidenced by abnormal sperm morphology. In the female, however, germ-cell specific inactivation of Rheb was not associated with any discernible abnormality; these cKO mice were fertile with morphologically unremarkable ovaries, normal primordial follicle formation, and subsequent follicle maturation. The absence of an abnormal ovarian phenotype is striking given previous studies demonstrating a critical role for the mTORC1 pathway in the maintenance of primordial follicle pool. In conclusion, our findings demonstrate an essential role of Rheb in diverse aspects of spermatogenesis but suggest the existence of functionally redundant factors that can compensate for Rheb deficiency within oocytes.


Asunto(s)
Proteínas de Unión al GTP Monoméricas/fisiología , Neuropéptidos/fisiología , Oogénesis/fisiología , Espermatogénesis/fisiología , Animales , Femenino , Fertilidad/genética , Fertilidad/fisiología , Masculino , Ratones , Ratones Noqueados , Modelos Animales , Proteínas de Unión al GTP Monoméricas/deficiencia , Proteínas de Unión al GTP Monoméricas/genética , Neuropéptidos/deficiencia , Neuropéptidos/genética , Proteína Homóloga de Ras Enriquecida en el Cerebro , Transducción de Señal/genética , Transducción de Señal/fisiología , Serina-Treonina Quinasas TOR/fisiología
6.
Transplant Proc ; 49(1): 78-83, 2017.
Artículo en Inglés | MEDLINE | ID: mdl-28104164

RESUMEN

BACKGROUND: Previously, we explored the histopathologic characteristics of medullary ray injury (MRI) inducing interstitial fibrosis and tubular atrophy (IF/TA) to determine its etiologies, which include calcineurin inhibitor (CNI) toxicity and urologic complications. However, we did not examine the effects of these etiologies on long-term kidney allograft prognosis, because biopsy timing differed among cases. AIM: We examined the influence of early MRI on kidney allograft prognosis using protocol biopsies taken within a 3-month time frame. METHODS: We defined early MRI as tubular degeneration with interstitial edema or mild fibrosis localized to the medullary ray. We divided 53 protocol biopsies into 2 groups, with and without early MRI. Early MRI+ cases with isometric vacuolization were classified as CNI toxicity; those with Tamm-Horsfall protein in the interstitium and a thyroidlike appearance were classified as urinary tract system abnormalities; remaining cases were classified as "others." We compared changes in serum levels of creatinine (sCr) over 3 years and fibrosis extent at 1 year. RESULTS: The sCr levels were significantly higher in the MRI+ group than the MRI- group at 3 years (P = .024). Examining the 3 MRI+ subgroups, only the MRI+ urinary tract system abnormalities group had significantly high sCr levels compared to the MRI- group (P = .019). The MRI+ group showed significant signs of IF/TA at 1 year. CONCLUSIONS: Early MRI after kidney transplantation was significantly more likely to develop IF/TA at 1 year and had higher sCr levels at 3 years. In such cases, intervention might preserve graft function over the long term.


Asunto(s)
Rechazo de Injerto/patología , Trasplante de Riñón/efectos adversos , Riñón/patología , Adulto , Biopsia , Creatinina/sangre , Femenino , Fibrosis/patología , Humanos , Masculino , Persona de Mediana Edad
7.
Radiat Prot Dosimetry ; 168(1): 61-71, 2016 Jan.
Artículo en Inglés | MEDLINE | ID: mdl-25669653

RESUMEN

Since diagnostic reference levels (DRLs) for children are not currently established in Japan, the authors determined local DRLs for the full range of paediatric CT examinations in a single tertiary care children's hospital. A retrospective review of 4801 CT performance records for paediatric patients (<15 y old) who had undergone CT examinations from 2008 to 2011 was conducted. The most frequent examinations were of the head (52 %), followed by cardiac (15 %), temporal bone (9 %), abdomen (7 %), chest (6 %) and others (11 %). Approximately one-third of children received two or more CT scans. The authors' investigation showed that mean CTDIvol and DLP for head, chest and abdomen increased as a function of age. Benchmarking of the results showed that CTDIvol, DLP and effective dose for chest and abdomen examinations in this hospital were below average, whereas those for the head tended to be at or slightly above average of established DRL values from five countries. The results suggest that CT examinations as performed in a tertiary children's hospital in Japan are well optimised.


Asunto(s)
Pediatría , Tomografía Computarizada por Rayos X/normas , Adolescente , Niño , Preescolar , Femenino , Hospitales Pediátricos , Humanos , Lactante , Japón , Masculino , Dosis de Radiación , Radiometría , Valores de Referencia , Estudios Retrospectivos , Centros de Atención Terciaria
8.
Biochim Biophys Acta ; 950(3): 303-12, 1988 Sep 07.
Artículo en Inglés | MEDLINE | ID: mdl-2844259

RESUMEN

The trpE gene of Thermus thermophilus HB8 was cloned by complementation of an Escherichia coli tryptophan auxotroph. The E. coli harboring the cloned gene produced the anthranilate synthase I, which was heat-stable and enzymatically active at higher temperature. The nucleotide sequence of the trpE gene and its flanking regions was determined. The trpE gene was preceded by an attenuator-like structure and followed by the trpG gene, with a short gap between them. No other gene essential for tryptophan biosynthesis was observed after the trpG gene. The amino-acid sequences of the T. themophilus anthranilate synthase I and II deduced from the nucleotide sequence were compared with those of other organisms.


Asunto(s)
Antranilato Sintasa/genética , Clonación Molecular , Genes Bacterianos , Genes , Operón , Thermus/genética , Secuencia de Aminoácidos , Secuencia de Bases , Enzimas de Restricción del ADN , Escherichia coli/genética , Prueba de Complementación Genética , Isoenzimas/genética , Datos de Secuencia Molecular , Homología de Secuencia de Ácido Nucleico , Thermus/enzimología , Triptófano/biosíntesis
9.
Biochim Biophys Acta ; 912(2): 178-84, 1987 Apr 08.
Artículo en Inglés | MEDLINE | ID: mdl-3828357

RESUMEN

The amino-acid sequence of a tetrameric manganese superoxide dismutase from Thermus thermophilus HB8 has been determined. The protein was cleaved with cyanogen bromide (BrCN) into four peptides and their alignment was deduced through the fragment of partial cleavage with BrCN and the peptides were produced by cleavage of the protein with o-iodosobenzoic acid. Most of the peptides were sequenced by solid phase Edman degradation. Some of the peptides were sequenced by the Edman dansyl method after sub-fragmentation by proteinase digestion. The amino-acid sequence consists of 203 residues corresponding to a subunit molecular weight of 23,144.


Asunto(s)
Superóxido Dismutasa , Thermus/enzimología , Secuencia de Aminoácidos , Bromuro de Cianógeno , Yodobenzoatos
10.
J Bone Miner Res ; 9(4): 465-72, 1994 Apr.
Artículo en Inglés | MEDLINE | ID: mdl-8030434

RESUMEN

Our previous study provided a novel assay system utilizing devitalized bone slices for study of the differentiation of osteoclast progenitors into preosteoclasts and mature osteoclasts among calvarial cells of mouse embryos. Using this assay system, we examined the effect of phorbol myristate acetate (PMA) on osteoclast formation as assessed by the appearance of tartrate-resistant acid phosphatase (TRAP)-positive cells and bone resorption lacunae. PMA alone was directly unable to induce the appearance of TRAP-positive cells and bone resorption lacunae of calvarial bone cells of mouse embryos. However, PMA markedly stimulated increases in the number of TRAP-positive cells and area of the resorption lacunae of the calvarial cells when the bone cells were primed by 1 alpha,25-(OH)2D3. This stimulatory effect of PMA was dose dependent. H-7, having relatively high affinity for protein kinase C, strongly inhibited in a dose-dependent fashion the stimulatory effect of PMA on the bone resorption of the hormone-primed calvarial cells. We also examined the involvement of prostaglandin in this stimulatory effect of PMA. Indomethacin, a cyclooxygenase inhibitor, markedly abolished the stimulatory effect of PMA on the bone resorption of the calvarial cells. PMA stimulated prostaglandin E2 (PGE2) production by the calvarial cells primed with 1 alpha,25-(OH)2D3 in a dose-dependent fashion. However, the PMA stimulation of the PGE2 production was significantly inhibited by H-7 and also by indomethacin. Furthermore, we observed that the addition of PGE2 to the calvarial cells primed with 1 alpha,25-(OH)2D3 for 1 or 3 days resulted in an increased number of TRAP-positive cells and increased bone resorption.(ABSTRACT TRUNCATED AT 250 WORDS)


Asunto(s)
Calcitriol/farmacología , Osteoclastos/efectos de los fármacos , Acetato de Tetradecanoilforbol/farmacología , 1-(5-Isoquinolinesulfonil)-2-Metilpiperazina , Animales , Calcitriol/administración & dosificación , Diferenciación Celular/efectos de los fármacos , Dinoprostona/metabolismo , Dinoprostona/farmacología , Sinergismo Farmacológico , Embrión de Mamíferos , Técnicas In Vitro , Isoquinolinas/farmacología , Ratones , Ratones Endogámicos ICR , Osteoclastos/citología , Osteoclastos/metabolismo , Piperazinas/farmacología , Cráneo/citología , Cráneo/efectos de los fármacos , Cráneo/metabolismo , Células Madre/efectos de los fármacos , Acetato de Tetradecanoilforbol/administración & dosificación
11.
Gene ; 245(1): 185-91, 2000 Mar 07.
Artículo en Inglés | MEDLINE | ID: mdl-10713459

RESUMEN

The necdin gene is expressed predominantly in postmitotic neurons and encodes a growth suppressor that interacts with the transcription factors E2F1 and p53. Human necdin gene (NDN) is maternally imprinted and located in Prader-Willi syndrome deletion region 15q11.2-q12. We isolated an NDN homologous sequence from a human genomic DNA library. The homologous sequence is overall 83% identical with necdin cDNA sequence, and possesses a short poly(A) stretch at the 3' end and direct repeats at both ends. Expression of the homologous sequence, which lacks a 5' promoter sequence, was undetected in cultured human cell lines. We mapped this sequence to chromosome 12q14-q21.1 by fluorescence in situ hybridization. These characteristics of the NDN-homologous sequence are consistent with those of processed pseudogenes. The information about the necdin pseudogene in the human genome will be useful for genetic studies on NDN-associated neurogenic disorders.


Asunto(s)
Moléculas de Adhesión Celular/genética , Seudogenes/genética , Secuencia de Bases , Northern Blotting , Bandeo Cromosómico , Mapeo Cromosómico , Cromosomas Humanos Par 12/genética , Clonación Molecular , ADN/química , ADN/genética , ADN/aislamiento & purificación , Regulación Neoplásica de la Expresión Génica , Glioma/genética , Glioma/patología , Humanos , Hibridación Fluorescente in Situ , Datos de Secuencia Molecular , Nectinas , Neuroblastoma/genética , Neuroblastoma/patología , ARN Mensajero/genética , Alineación de Secuencia , Análisis de Secuencia de ADN , Células Tumorales Cultivadas
12.
Gene ; 213(1-2): 65-72, 1998 Jun 15.
Artículo en Inglés | MEDLINE | ID: mdl-9630521

RESUMEN

Necdin is a growth suppressor expressed in virtually all postmitotic neurons in the brain. The human necdin gene, NDN, is maternally imprinted and deleted in the Prader-Willi syndrome, a neurobehavioral contiguous gene disorder. Here, we isolated and characterized the human chromosomal necdin gene and its promoter region. The necdin gene is intronless, and it encodes a protein of 321 amino acid residues, four residues shorter than mouse Necdin. By fluorescence in-situ hybridization analysis, the necdin gene was localized to chromosome 15q11.2-q12 within the Prader-Willi syndrome deletion region. CpG islands were found in a region extending from the proximal 5'-flanking sequence to the protein coding region. The 5'-flanking sequence, which lacks canonical TATA and CAAT boxes, possessed a promoter activity in postmitotic neurons derived from murine embryonal carcinoma P19 cells. Methylation in vitro of HhaI CpG sites in the promoter region reduced the transcriptional activity. These results suggest that the necdin gene is silenced through methylation of the CpG island encompassing its promoter region.


Asunto(s)
Genes , Proteínas del Tejido Nervioso/genética , Proteínas Nucleares/genética , Síndrome de Prader-Willi/genética , Eliminación de Secuencia , Secuencia de Aminoácidos , Animales , Secuencia de Bases , Carcinoma Embrionario/patología , Islas de CpG , Metilación de ADN , Femenino , Impresión Genómica , Humanos , Hipotálamo/metabolismo , Hibridación in Situ , Ratones , Datos de Secuencia Molecular , Neuronas/metabolismo , Regiones Promotoras Genéticas , Alineación de Secuencia , Homología de Secuencia , Especificidad de la Especie , Transcripción Genética , Células Tumorales Cultivadas
13.
FEBS Lett ; 249(1): 21-6, 1989 May 22.
Artículo en Inglés | MEDLINE | ID: mdl-2542093

RESUMEN

The nucleotide sequence of a new insertion sequence (IS) in Escherichia coli, IS421, was determined. It is 1340 bp long and contains inverted repeats of 22 bp at its termini. It is flanked by 13 bp direct repeats apparently generated upon insertion. There are two ORFs longer than 200 bp in IS421. One can encode a polypeptide of 371 amino acids (aa) and the other, which is on the other strand, can encode a polypeptide of 102 aa. The C-terminal part of the 371 aa polypeptide shows some homology to that of transposases encoded in some other known IS elements. The copy number of IS421 in chromosomal DNA was 4 for E. coli K-12 and B, and 5 for E. coli C, as determined by the Southern hybridization of restriction fragments.


Asunto(s)
Elementos Transponibles de ADN , Escherichia coli/genética , Secuencia de Aminoácidos , Secuencia de Bases , Sondas de ADN , Escherichia coli/análisis , Datos de Secuencia Molecular , Hibridación de Ácido Nucleico , Nucleotidiltransferasas/genética , Péptidos/genética , Transposasas
14.
Neuropharmacology ; 41(5): 629-38, 2001 Oct.
Artículo en Inglés | MEDLINE | ID: mdl-11587718

RESUMEN

Functional contribution of the cholinergic pathway between the frontal cortex and basal nucleus of Meynert to micturition reflex was investigated. Male Wistar rats were subjected to bilateral lesion of the basal forebrain by ibotenic acid (IA) injection (7.5 microg/rat on each side) (BF rats). Phosphate buffered saline (PBS) was injected into control rats (sham operated rats; SO rats). Cystometrograms were obtained from conscious BF and SO rats 7-10 days after IA/PBS injection. Bladder capacity (BC) of BF rats was significantly smaller than that of SO rats (approximately 43.7%) and was accompanied by decrease in choline-acetyltransferase activity in the frontal cortices. Oxotremorine M, a muscarinic receptor agonist, increased BC in BF rats, while pirenzepine, an M1 muscarinic receptor antagonist, counteracted the effect of the oxotremorine M-induced increase in BC. Injection of oxotremorine M into the dorsal pontine tegmentum (DPT) reduced BC in BF and SO rats, while injection of pirenzepine had no effect on cystometrograms. These findings indicate that the M1 muscarinic receptor plays a part in the forebrain inhibitory mechanisms involved in the micturition reflex and that muscarinic receptor in the DPT contributes to excitatory control of micturition reflex.


Asunto(s)
Prosencéfalo/fisiología , Receptores Muscarínicos/fisiología , Reflejo/efectos de los fármacos , Vejiga Urinaria/fisiología , Micción/efectos de los fármacos , Animales , Núcleo Basal de Meynert/efectos de los fármacos , Núcleo Basal de Meynert/fisiología , Relación Dosis-Respuesta a Droga , Agonistas de Aminoácidos Excitadores , Ácido Iboténico , Masculino , Agonistas Muscarínicos/farmacología , Oxotremorina/farmacología , Prosencéfalo/efectos de los fármacos , Ratas , Ratas Wistar , Receptor Muscarínico M1 , Reflejo/fisiología , Vejiga Urinaria/efectos de los fármacos , Micción/fisiología
15.
Am J Med Genet ; 76(5): 389-94, 1998 Apr 13.
Artículo en Inglés | MEDLINE | ID: mdl-9556297

RESUMEN

Sclerosing bone dysplasias are diagnosed on the basis of a characteristic pattern of osteosclerosis and clinical manifestations; in many of them, cause and pathogenesis are still unknown. A 33-year-old man had five fractures of the humerus, tibiae, and femur as a result of mild traumatic incidents that occurred between the ages of 18 and 33 years as well as a remnant of rib fractures without apparent trauma on radiographs. His height was 158 cm (-2.2 SD). Radiographic evaluation showed cranial sclerosis, longitudinal striations in the metaphyses of the femur and tibia, fan-like striation in the ilium, metaphyseal widening in the femur and tibia, and sclerosis of the ribs. The blood chemistry findings, including serum calcium, phosphorus, and alkaline phosphatase, were normal. Biopsy from the ilium showed thick trabeculae composed of woven bone. The coexistence of osteopathia striata, cranial sclerosis, metaphyseal undermodeling, and bone fragility has not been recognized previously. Our case appears to represent a new form of sclerosing bone dysplasia.


Asunto(s)
Anomalías Múltiples/diagnóstico , Huesos/anomalías , Fracturas Óseas/etiología , Cráneo/patología , Anomalías Múltiples/diagnóstico por imagen , Adulto , Huesos/diagnóstico por imagen , Fracturas del Fémur/etiología , Peroné/anomalías , Humanos , Húmero/anomalías , Ilion/patología , Masculino , Radiografía , Recurrencia , Esclerosis , Cráneo/diagnóstico por imagen , Tibia/anomalías
16.
J Biochem ; 105(3): 362-6, 1989 Mar.
Artículo en Inglés | MEDLINE | ID: mdl-2732211

RESUMEN

The trpE gene of Clostridium thermocellum, a moderately thermophilic and absolutely anaerobic bacterium, was cloned by its ability to complement growth of an Escherichia coli tryptophan auxotroph (trpE) deficient in anthranilate synthase I. The nucleotide sequence of trpE and its flanking region was determined. The trpE gene overlapped at the termination codon with a putative initiation codon of trpG (trp[G]D), as deduced from the amino acid sequence homology with anthranilate synthase II of Serratia marcescens. S1-nuclease mapping of the trpE transcript produced in E. coli cells suggested that the promoter of C. thermocellum was utilized by E. coli. The amino acid sequence of anthranilate synthase I of C. thermocellum predicted from the nucleotide sequence is more similar to that of an extremely thermophilic bacterium, Thermus thermophilus HB8, than that of mesophilic bacteria.


Asunto(s)
Clonación Molecular , Clostridium/genética , ADN Bacteriano/genética , Genes Bacterianos , Secuencia de Aminoácidos , Secuencia de Bases , Medios de Cultivo , Datos de Secuencia Molecular , Transcripción Genética
17.
Brain Res ; 853(1): 81-92, 2000 Jan 17.
Artículo en Inglés | MEDLINE | ID: mdl-10627311

RESUMEN

In the present study we investigated the effect of (+/-)-1-(3, 4-dimethoxyphenyl)-2-(4-diphenylmethylpiperazinyl) ethanol dihydrochloride (tamolarizine), a calcium entry blocker, on place learning impairment in rats with damage selective to the hippocampal CA1 subfield induced by transient forebrain ischemia. Tamolarizine was administered (40 mg/kg) immediately after 15-min brain ischemia. Place learning was tested in a task in which the rat was required to alternatively visit two places located diametrically opposite each other in an open field. The ischemia+saline group showed severe learning impairment in this task; their performance level was significantly inferior to that of the sham-operated group through the test period (30 days). Although the ischemia+tamolarizine group showed slight impairment of place learning during the course of this test, they later reached almost the same performance level as the sham-operated group. Selective neuronal loss in the CA1 subfield was much less in the ischemia+tamolarizine group than in the ischemia+saline group. These results indicate that tamolarizine treatment protects the hippocampus from ischemic brain damage and ameliorates place learning impairment.


Asunto(s)
Bloqueadores de los Canales de Calcio/farmacología , Ataque Isquémico Transitorio/tratamiento farmacológico , Discapacidades para el Aprendizaje/prevención & control , Piperazinas/farmacología , Prosencéfalo/efectos de los fármacos , Conducta Espacial/efectos de los fármacos , Animales , Conducta Animal/efectos de los fármacos , Recuento de Células/efectos de los fármacos , Estimulación Eléctrica , Electrodos Implantados , Hipocampo/efectos de los fármacos , Hipocampo/patología , Ataque Isquémico Transitorio/complicaciones , Aprendizaje/efectos de los fármacos , Aprendizaje/fisiología , Discapacidades para el Aprendizaje/etiología , Masculino , Actividad Motora/efectos de los fármacos , Prosencéfalo/irrigación sanguínea , Prosencéfalo/fisiopatología , Ratas , Ratas Wistar , Autoestimulación , Conducta Espacial/fisiología
18.
J Control Release ; 53(1-3): 137-43, 1998 Apr 30.
Artículo en Inglés | MEDLINE | ID: mdl-9741921

RESUMEN

Antisense oligonucleotides with base sequences complementary to a specific RNA can, after binding to intracellular mRNA, selectively modulate the expression of a gene. However, these molecules are poorly stable in biological fluids and are characterized by a low intracellular penetration. In view of using oligonucleotides as active molecules, the development of polymeric particulate carriers was considered. Oligonucleotides were associated with biodegradable polyalkylcyanoacrylate nanoparticles through the formation of ion pairs between the negatively charged oligonucleotides and hydrophobic cations. Oligonucleotides bound to these nanoparticles were found to be protected from nuclease attack in cell culture media and their cellular uptake was increased as the result of the capture of nanoparticles by an endocytotic/phagocytotic pathway. The in vivo pharmacokinetic profile of oligonucleotides free or associated with nanoparticles has been investigated after intravenous administration to mice and the stability of these molecules has been evaluated by original methodology based on the use of polyacrylamide gel electrophoresis (PAGE) followed by multichannel radioactivity counting. Stability in vivo in the plasma and in the liver was shown to be improved when the oligonucleotides were adsorbed onto the nanoparticles. These results obtained both in vitro and in vivo open exciting perspectives for the specific delivery of oligonucleotides to the liver, thus considering this approach for the treatment of liver diseases (e.g. liver metastasis or hepatitis).


Asunto(s)
Cianoacrilatos , Tionucleótidos/administración & dosificación , Animales , Células Cultivadas , Portadores de Fármacos , Semivida , Riñón/metabolismo , Hígado/metabolismo , Masculino , Ratones , Microesferas , Tamaño de la Partícula , Tionucleótidos/sangre , Tionucleótidos/farmacocinética , Distribución Tisular
19.
Behav Pharmacol ; 2(3): 233-240, 1991 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-11224067

RESUMEN

Drug discrimination training with terguride, a 9, 10-transdihydrogenated derivative of lisuride, was carried out using a two-lever food-reinforced procedure (FR 10) in rats, to investigate its influence on central dopaminergic (DA) and serotonergic (5-HT) functions. The terguride (0.05mg/kg, i.p.) discrimination was established within 64 +/- 5 training sessions (mean +/- S.E.) and was stably maintained thereafter. Higher doses of terguride could not be used for discriminative training due to response disruption. In generalization tests with terguride, drug-appropriate responding increased dose-dependently and reached levels of 45 and 99% at 0.01 and 0.05mg/kg i.p. The D(2) agonist lisuride at low doses and the DA autoreceptor agonist (-)-3-PPP substituted for terguride. The DA agonist apomorphine and the 5-HT agonist 5-MeO-DMT produced dose-dependent but incomplete substitution. The D(1) agonist SKF38393, the DA antagonist haloperidol, the D(2) antagonist sulpiride, the D(1) antagonist SCH23390, the 5-HT(1A) agonist 8-OH-DPAT, the 5-HT(1B) agonist m-CPP and the 5-HT(2) agonist DOI were not generalized. In antagonism tests, sulpride completely blocked the terguride-appropriate response, but SCH23390 and the 5-HT antagonist methysergide did not. These results indicate that discriminative stimulus properties of terguride in rats are mediated primarily by activation of receptors with characteristics similar to those of presynaptic D(2) autoreceptors.

20.
J Neurosurg ; 75(6): 930-4, 1991 Dec.
Artículo en Inglés | MEDLINE | ID: mdl-1682427

RESUMEN

Cell lines resistant to 1-(4-amino-2-methyl-5-pyrimidinyl)methyl-3- (2-chloroethyl)-3-nitrosourea hydrochloride (ACNU) show a high degree of collateral sensitivity to L-asparaginase. The mechanism for this phenomenon was investigated by comparing the nutritional requirements and asparagine synthetase activity of the resistant sublines to those of parent cells. Nine ACNU-resistant sublines were isolated from rat glioma 9L cells after incubation with various concentrations of ACNU in Ham's F-12 medium. The 9L cells grew independently of asparagine, developing well in asparagine-deficient Dulbecco's modified Eagle's medium. In contrast, the growth rates of all nine ACNU-resistant sublines decreased under the same conditions and required the addition of 10(-4) M asparagine for maximum growth. Asparagine synthetase activity in the ACNU-resistant cells was much lower than in the 9L cells, suggesting that the requirement for asparagine in the resistant sublines was due to reduced activity of this enzyme. A growth-inhibition assay showed that the ACNU-resistant sublines were more sensitive to L-asparaginase than 9L cells by up to 2 x 10(5)-fold. These results suggest that L-asparaginase therapy has the potential to become a new approach for treating acquired ACNU resistance.


Asunto(s)
Asparaginasa/farmacología , Glioma/tratamiento farmacológico , Nimustina/uso terapéutico , Animales , Asparagina/farmacología , Aspartatoamoníaco Ligasa/metabolismo , División Celular/efectos de los fármacos , Resistencia a Medicamentos , Glioma/enzimología , Ratas , Células Tumorales Cultivadas/efectos de los fármacos
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