Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 45
Filtrar
Más filtros










Base de datos
Intervalo de año de publicación
1.
Plant Biol (Stuttg) ; 21(5): 844-853, 2019 Sep.
Artículo en Inglés | MEDLINE | ID: mdl-30927480

RESUMEN

Environmental cadmium (Cd) sources have increased in mangrove sediments in recent decades, inducing cellular damage to many plants. Avicennia schaueriana is abundant in mangrove sites and has been subject to Cd contamination. The possible effects of Cd toxicity and the structural and physiological disturbances to this plant were studied. Can this plant express early cellular tolerance mechanisms to such metal contamination? Seedlings of A. schaueriana were collected from sites of their natural occurrence, placed in plastic pots containing nutrient solution for 60 days, and subsequently exposed to increasing Cd concentrations for 5 days under experimental conditions. The anatomical, ultrastructural and physiological changes induced by Cd were analysed. Cd accumulated mainly in the root system and in pneumatophores, stems and leaves, induced differential accumulation of mineral nutrients, but did not induce necrosis or changes in leaf anatomy. However, there was a decrease in starch grains and an increase in deposited electron-dense material in the cortex and vascular bundles. Cd induced both increases in calcium (Ca) content in shoots and Ca oxalate crystal precipitation in leaf mesophyll and was detected in crystals and in the secretion of salt glands. Our observations and experimental results provide evidence of Cd tolerance in A. schaueriana. As a new feature, despite the clear cellular physiological disorders, this plant is able to eliminate Cd through leaf salt glands and immobilise it in Ca crystals, representing fast mechanisms for Cd exclusion and complexation in leaves in heavy metal coastal polluted marine ecosystems.


Asunto(s)
Avicennia/efectos de los fármacos , Cadmio/toxicidad , Hojas de la Planta/metabolismo , Avicennia/metabolismo , Avicennia/ultraestructura , Cadmio/metabolismo , Calcio/metabolismo , Microscopía Electrónica de Transmisión , Raíces de Plantas/metabolismo , Tallos de la Planta/metabolismo , Plantones/efectos de los fármacos , Plantones/metabolismo , Plantones/ultraestructura
2.
J Biochem ; 130(5): 687-93, 2001 Nov.
Artículo en Inglés | MEDLINE | ID: mdl-11686932

RESUMEN

Mitochondrial ATP synthase (F(1)F(o)-ATPase) is regulated by an intrinsic ATPase inhibitor protein. In the present study, we investigated the structure-function relationship of the yeast ATPase inhibitor by amino acid replacement. A total of 22 mutants were isolated and characterized. Five mutants (F17S, R20G, R22G, E25A, and F28S) were entirely inactive, indicating that the residues, Phe17, Arg20, Arg22, Glu25, and Phe28, are essential for the ATPase inhibitory activity of the protein. The activity of 7 mutants (A23G, R30G, R32G, Q36G, L37G, L40S, and L44G) decreased, indicating that the residues, Ala23, Arg30, Arg32, Gln36, Leu37, Leu40, and Leu44, are also involved in the activity. Three mutants, V29G, K34Q, and K41Q, retained normal activity at pH 6.5, but were less active at pH 7.2, indicating that the residues, Val29, Lys34, and Lys41, are required for the protein's action at higher pH. The effects of 6 mutants (D26A, E35V, H39N, H39R, K46Q, and K49Q) were slight or undetectable, and the residues Asp26, Glu35, His39, Lys46, and Lys49 thus appear to be dispensable. The mutant E21A retained normal ATPase inhibitory activity but lacked pH-sensitivity. Competition experiments suggested that the 5 inactivated mutants (F17S, R20G, R22G, E25A, and F28S) could still bind to the inhibitory site on F(1)F(o)-ATPase. These results show that the region from the position 17 to 28 of the yeast inhibitor is the most important for its activity and is required for the inhibition of F(1), rather than binding to the enzyme.


Asunto(s)
Inhibidores Enzimáticos/metabolismo , Proteínas/metabolismo , Saccharomyces cerevisiae/química , Secuencias de Aminoácidos , Secuencia de Aminoácidos , Sustitución de Aminoácidos , Animales , Unión Competitiva , Bovinos , Inhibidores Enzimáticos/química , Histidina/genética , Humanos , Lisina/genética , Ratones , ATPasas de Translocación de Protón Mitocondriales/antagonistas & inhibidores , Datos de Secuencia Molecular , Mutagénesis , Fenilalanina/genética , Fenilalanina/metabolismo , Proteínas/química , Proteínas/genética , Ratas , Homología de Secuencia de Aminoácido , Relación Estructura-Actividad , Proteína Inhibidora ATPasa
3.
Virchows Arch ; 437(3): 304-13, 2000 Sep.
Artículo en Inglés | MEDLINE | ID: mdl-11037352

RESUMEN

Although usual interstitial pneumonia (UIP)-like IP has been known as the most serious complication of Hermansky-Pudlak syndrome (HPS), its pathologic features and pathogenesis are poorly understood. We investigated biopsied and autopsied lung tissues from five patients who died of UIP-like IP associated with HPS (HPSIP). The salient histopathologic features of HPSIP observed were: (1) alveolar septa displaying florid proliferation of type-2 pneumocytes (2PCs) with characteristic foamy swelling/degeneration; (2) patchy fibrosis with lymphocytic and histiocytic infiltration centered around respiratory bronchioles, occasionally showing constrictive bronchiolitis; and (3) honeycomb change without predilection for the lower lobes or subpleural area. Those peculiar 2PCs were histochemically characterized by the over accumulation of phospholipid, immunohistochemically by a weak positivity for surfactant protein, and ultrastructurally by the presence of numerous giant lamellar bodies that compressed the nucleus with occasional cytoplasmic disruption, together suggesting a form of cellular degeneration with an over accumulation of surfactant (giant lamellar body degeneration). The present study strongly indicates that there is a basic defect in the formation/secretion process of surfactant by the 2PCs in HPS, which may well be the triggering factor for the HPSIP development. Other factors, such as macrophage dysfunction, may be working synergistically for further acceleration of the inflammatory process.


Asunto(s)
Albinismo Oculocutáneo/patología , Enfermedades Pulmonares Intersticiales/patología , Pulmón/patología , Adulto , Albinismo Oculocutáneo/fisiopatología , Femenino , Humanos , Pulmón/fisiopatología , Pulmón/ultraestructura , Enfermedades Pulmonares Intersticiales/fisiopatología , Masculino , Microscopía Electrónica , Persona de Mediana Edad
4.
No To Shinkei ; 52(4): 335-40, 2000 Apr.
Artículo en Japonés | MEDLINE | ID: mdl-10793422

RESUMEN

The authors reported a case of 39-year-old man with incidentally found meningioma whose postoperative WAIS-R scores were improved significantly. He got a minor head injury run in a car collision and showed no neurological findings on admission. Computed tomography revealed no traumatic abnormalities but left frontal convexity meningioma. Total removal of the tumor was performed 3 weeks after the admission. Preoperative verbal IQ, performance IQ, lower full IQ were 105, 95, 100 respectively, and improved to 113, 112, 114 postoperatively. An asymptomatic patient with incidentally found meningioma could have higher brain function disturbances, which could be improved after its resection, therefore we should operate on such a patient more positively.


Asunto(s)
Neoplasias Encefálicas/psicología , Meningioma/psicología , Escalas de Wechsler , Adulto , Neoplasias Encefálicas/cirugía , Humanos , Masculino , Meningioma/cirugía
5.
Int J Lepr Other Mycobact Dis ; 68(3): 258-66, 2000 Sep.
Artículo en Inglés | MEDLINE | ID: mdl-11221087

RESUMEN

This study was conducted to determine if osteoporosis in male leprosy patients is caused by testicular atrophy. Bone volume (BV/TV), trabecular number (TbN), trabecular thickness (TbTh), and trabecular separation (TbSp) were measured in two areas in decalcified paraffin sections of lumbar bones from 29 male leprosy and 6 male nonleprosy autopsy cases. We found significant differences in the average BV/TV measurements among the 7 patients with nodular Leydig cell hyperplasia (BV/TV 12.24%) and the 22 patients without hyperplasia (BV/TV 7.35%) and 6 patients without leprosy (BV/TV 12.98%). Bone volume was maintained in patients with nodular Leydig cell hyperplasia, and we determined no clinical factor other than the Leydig cell hyperplasia that reflected the bone volume. The osteoporosis of male leprosy patients was attributed to secondary gonadal dysfunction due to testicular atrophy, and Leydig cell hyperplasia appears to preserve bone volume.


Asunto(s)
Lepra/patología , Vértebras Lumbares/patología , Osteoporosis/patología , Testículo/patología , Anciano , Densidad Ósea , Histocitoquímica , Humanos , Hiperplasia/patología , Procesamiento de Imagen Asistido por Computador , Lepra/complicaciones , Células Intersticiales del Testículo/patología , Masculino , Persona de Mediana Edad , Osteoporosis/complicaciones , Estadísticas no Paramétricas
6.
J Orthop Sci ; 4(4): 286-92, 1999.
Artículo en Inglés | MEDLINE | ID: mdl-10436276

RESUMEN

In 64 surgically treated herniated lumbar intervertebral discs, we performed histopathological studies of neovascularization in the outermost layer of the herniated mass in various types of hernia. We obtained specimens separately from the capsule tissue covering the herniated mass and the inner tip tissue of the herniated mass for comparison. Histologically, in most cases, the capsule tissue was the outermost layer of the annulus fibrosus or posterior longitudinal ligament, and the inner tip tissue was the nucleus pulposus. In the capsule tissue, newly formed small blood vessels were present in 73.4% of the total cases examined, regardless of the hernia type. However, the frequency and degree of such vessels in the tip tissue were significantly higher in hernias that perforated the posterior longitudinal ligament than in those that did not. When the intervertebral disc herniates, new blood vessels proliferate in the capsule of the hernial tissue. At the stage when the hernial capsule tissue is still present, these vessels were observed to have difficulty reaching the inner tip portion. These findings suggest that when the nucleus pulposus portion of the herniated mass perforates the posterior longitudinal ligament, it may be subject to a stronger neovascularization reaction.


Asunto(s)
Desplazamiento del Disco Intervertebral/patología , Vértebras Lumbares , Neovascularización Patológica/patología , Adolescente , Adulto , Anciano , Anciano de 80 o más Años , Técnicas de Cultivo , Femenino , Humanos , Inmunohistoquímica , Desplazamiento del Disco Intervertebral/cirugía , Imagen por Resonancia Magnética , Masculino , Persona de Mediana Edad , Pronóstico , Sensibilidad y Especificidad , Índice de Severidad de la Enfermedad
7.
Acta Med Okayama ; 51(5): 279-83, 1997 Oct.
Artículo en Inglés | MEDLINE | ID: mdl-9359926

RESUMEN

A study was conducted to examine the relationship of testicular atrophy to bone metabolism in male leprosy patients. The study consisted of 31 leprosy patients (mean age: 62.0 years) and 31 healthy control men (mean age: 60.0 years). Measurements were made of their serum levels of free testosterone (FT), estradiol (E2), luteinizing hormone (LH) and 25-hydroxyvitamin D (25 OHD). Bone mineral density (BMD) was measured at radial sites and the lumbar vertebral bodies (L2-L4) by dual-energy X-ray absorptiometry using a Hologic QDR-2000 densitometer. FT and E2 levels were significantly lower and LH levels higher in leprosy patients than in controls. This represents a primary hypogonadal pattern. A value of 7.20 pg/ml of FT ( = Mean - 1 SD of control) was used as a cut off value, and the subjects were subdivided into a hypogonadal group (HG) and a non hypogonadal group (non-HG). When the subjects were compared for differences in age, age at onset of disease, duration of disease, body mass index and BMD, only the duration of disease and BMD were significantly different between the two groups. Furthermore, BMD of the forearm significantly correlated with FT levels (r = 0.689, P < 0.0001). Low BMD may be due to orchitis and testicular atrophy.


Asunto(s)
Lepra/complicaciones , Osteoporosis/etiología , Testículo/patología , Anciano , Atrofia , Densidad Ósea , Estradiol/sangre , Humanos , Hormona Luteinizante/sangre , Masculino , Persona de Mediana Edad , Testosterona/sangre
8.
Acta Paediatr Jpn ; 39(1): 10-7, 1997 Feb.
Artículo en Inglés | MEDLINE | ID: mdl-9124041

RESUMEN

The long-term follow-up of chronic hyperinsulinemic seizures, epileptogenesis and other neurological complications in five patients who were treated with conservative therapy followed by pancreatectomy during the neonatal period and infancy, who were confirmed to have diffuse nesidioblastosis are described. The reaction pattern of the C-peptide (CPR) suppression test and its relation to the final extent of pancreatectomy was examined in four patients. The chronological change in electro-encephalography (EEG) and its epileptogenesis was also examined in each patient during hyperinsulinemic hypoglycemia, and during normoglycemia in a long-term post-pancreatectomy follow-up. All patients demonstrated several types of hypoglycemic seizures, ranging from apnea, erratic seizures, evolving to generalized/unilateral tonic-clonic or tonic seizures, myoclonic seizures and EEG abnormalities. Four of five patients still suffered from epilepsy at the age of 4-22 years. The reaction pattern of the CPR suppression test showed dichotomy, with a hyper-reactive pattern in two patients who required total pancreatectomy to control hypoglycemia, and a suppression pattern in two other patients treated with 90-95% pancreatectomy. Neonatal onset and subsequent myoclonic seizures were ominous signs of epileptogenesis to various types of intractable epilepsy and other neurological sequelae. A prompt diagnosis and pancreatectomy of a sufficient extent at the first operation are essential. The CPR suppression test may be useful for a prompt diagnosis and selection of the extent of pancreatectomy.


Asunto(s)
Péptido C , Pancreatectomía , Enfermedades Pancreáticas/cirugía , Pruebas de Función Pancreática , Análisis Químico de la Sangre , Epilepsia/etiología , Femenino , Humanos , Hiperinsulinismo/etiología , Hipoglucemia/etiología , Lactante , Recién Nacido , Masculino , Enfermedades Pancreáticas/fisiopatología , Estudios Prospectivos
12.
Surg Neurol ; 47(1): 28-31, 1997 Jan.
Artículo en Inglés | MEDLINE | ID: mdl-8986161

RESUMEN

BACKGROUND: Down's syndrome's association with malignancies such as leukemia is well known, but its association with brain tumor appears to be rare. We reviewed such rare cases of Down's syndrome and intracranial germ-cell tumor. CASE REPORT: A 10-year-old boy with Down's syndrome and intracranial germinoma located in the left basal ganglia is reported. The patient presented with right hemiparesis and was treated with a combination of surgery, chemotherapy with cisplatin and etoposide, and irradiation. CONCLUSIONS: We speculate that the percentage of germ-cell tumors is high among Down syndrome patients with brain tumors and that the most common site is the basal ganglia.


Asunto(s)
Ganglios Basales , Neoplasias Encefálicas/complicaciones , Síndrome de Down/complicaciones , Germinoma/complicaciones , Ganglios Basales/patología , Neoplasias Encefálicas/patología , Niño , Síndrome de Down/patología , Germinoma/patología , Humanos , Masculino
13.
Brain Tumor Pathol ; 14(1): 59-62, 1997.
Artículo en Inglés | MEDLINE | ID: mdl-9384804

RESUMEN

This report concerns a 64-year-old woman with a lymphoplasmacyte-rich meningioma. Radiographically and macroscopically, the tumor had the appearance of an ordinary meningioma. Components of the meningothelial cells were positively immunostained for epithelial membrane antigen. The results of immunohistochemical assays with the antibodies to surface markers of lymphocytes L26 and UCHL-1 indicated that the lymphoplasmacellular proliferation was not neoplastic but probably represented an immune reaction of the host.


Asunto(s)
Linfocitos/patología , Neoplasias Meníngeas/patología , Meningioma/patología , Femenino , Humanos , Inmunohistoquímica , Inmunofenotipificación , Imagen por Resonancia Magnética , Neoplasias Meníngeas/diagnóstico por imagen , Meningioma/diagnóstico por imagen , Persona de Mediana Edad , Mucina-1/análisis , Tomografía Computarizada por Rayos X
15.
Jpn J Med Sci Biol ; 48(1): 71-8, 1995 Feb.
Artículo en Inglés | MEDLINE | ID: mdl-7666596

RESUMEN

Seroepizootiological study of hantavirus infection among 393 urban rats (Rattus norvegicus) captured in six regions in Japan during the period from 1990 to 1994 was carried out by the indirect fluorescent antibody (IFA) test and Western blot (WB). Fifteen out of 393 (3.8%) rat sera were antibody-positive by IFA, i.e., Tokyo Port (12.8%, 6/47), Shimizu Port (5.7%, 2/35), Otaru Port (1.5%, 1/65) and Nagoya City (3.6%, 6/167). In two other regions, i.e., Kasai Seaside Park and Haneda Airport, rat sera were antibody-negative. One serum with a lower IFA titer, 1:64, from Otaru Port was confirmed to be antibody-positive by WB, while two sera from Shimizu Port (IFA titer, 1:32 and 1:64) were not. In Nagoya City, one out of four sera (IFA titer, 1:32) and one of two sera (IFA titer, 1:64) were also confirmed to be antibody-positive by WB. Continuous hantavirus infection among rats in Tokyo Port, Shimizu Port and Nagoya City and the existence of hantavirus among rats in Otaru Port were demonstrated.


Asunto(s)
Infecciones por Hantavirus/veterinaria , Ratas/virología , Enfermedades de los Roedores/epidemiología , Animales , Anticuerpos Antivirales/sangre , Técnica del Anticuerpo Fluorescente , Infecciones por Hantavirus/epidemiología
17.
Acta Neuropathol ; 88(4): 389-93, 1994.
Artículo en Inglés | MEDLINE | ID: mdl-7839834

RESUMEN

We report the pathological findings of the skeletal muscle and peripheral nerves from a male 14-months-old thoroughbred horse showing idiopathic knuckling. The affected animal, when in staining position, presented knuckling at the fetlock joint of both forelegs, and dragged both fore- and hindlegs when attempting forward movement. The skeletal muscles demonstrated neurogenic atrophy characterized by the scattering of single angular fibers, groups consisting of five to ten angular fibers, and multiple fascicles of atrophic and hypertrophic fibers. The severity of changes tended to be a distal gradient. While there was no evidence of fiber loss on light microscopy, a diffuse scattering of myelin ovoid, Wallerian-like degeneration and onion-bulb formations were observed in almost all peripheral nerves collected. The characteristic features in electron microscope were swollen axons, which contained accumulations of organelles, especially degenerative mitochondria and neurofilamanets. Onion-bulb formations were frequently found and were associated with Schwann cell processes and occasional collagen pockets. Other prominent feature were Büngner bands which contained myelin debris and regenerating axons or sprouts. These findings suggested that the nature of this disease was a disturbance in axonal transport and were indicative of a distal axonopathy.


Asunto(s)
Enfermedades de los Caballos/patología , Cojera Animal/patología , Hipotonía Muscular/veterinaria , Enfermedades del Sistema Nervioso Periférico/veterinaria , Animales , Caballos , Cojera Animal/etiología , Masculino , Hipotonía Muscular/etiología , Hipotonía Muscular/patología , Enfermedades del Sistema Nervioso Periférico/complicaciones , Enfermedades del Sistema Nervioso Periférico/patología , Nervio Tibial/patología
18.
Masui ; 42(7): 1002-8, 1993 Jul.
Artículo en Japonés | MEDLINE | ID: mdl-8394470

RESUMEN

The authors evaluated the cumulative dose response of pipecuronium under isoflurane anesthesia, and the efficacy as well as safety of priming principle in 52 patients who underwent elective surgery. The ED95 of pipecuronium was 34.24 +/- 5.34 micrograms.kg-1 in 10 patients and 70 micrograms.kg-1 (not equal to ED95 x 2) was used as total dose (T). The 42 patients were divided to receive either no prime or, 5%, 10%, 15% or 20% of T as a prime followed 5 minutes later by the remaining (intubating) dose. The muscle weakness in awake patients was determined after the priming doses by examining several clinical symptoms and by evaluating the effect of intubating doses on neuromuscular blockade. The priming using 10% of T provided rapid intubating conditions. However, the priming dose caused a significant incidence of symptoms of muscle weakness. Therefore, the priming principle should be used with caution.


Asunto(s)
Intubación Intratraqueal , Pipecuronio/administración & dosificación , Procedimientos Quirúrgicos Operativos , Adulto , Anciano , Anestesia por Inhalación , Método Doble Ciego , Femenino , Humanos , Isoflurano , Masculino , Persona de Mediana Edad , Factores de Tiempo
19.
J Clin Anesth ; 3(6): 451-5, 1991.
Artículo en Inglés | MEDLINE | ID: mdl-1760167

RESUMEN

STUDY OBJECTIVE: To evaluate the effects of preanesthetic administration of intramuscular (IM) ranitidine on pH and volume of gastric contents in children. DESIGN: Three randomized treatment groups. SETTING: Central operating rooms at a university hospital. PATIENTS: Forty children age 1 to 10 years undergoing a variety of elective surgical procedures requiring general anesthesia with endotracheal intubation. INTERVENTIONS: IM ranitidine 1 mg/kg (n = 15) or 2 mg/kg (n = 15) was administered 2 hours prior to induction of anesthesia. Ten patients without ranitidine served as the control group. An orogastric tube was inserted into each patient. MEASUREMENTS AND MAIN RESULTS: Gastric fluid pH and volume were measured every hour in the three groups. Plasma ranitidine concentrations were measured in ten patients of the ranitidine-treated groups. The mean volume of gastric fluid at induction of anesthesia was significantly lower in the ranitidine-treated patients (2.4 ml for ranitidine 1 mg/kg, 3.2 ml for ranitidine 2 mg/kg) than in the controls (8.6 ml; p less than 0.05). The mean pH values at induction of anesthesia were significantly higher in the ranitidine-treated patients (4.6 for 1 mg/kg, 6.7 for 2 mg/kg) than in the controls (2.1; p less than 0.05). Dose-dependent plasma ranitidine concentrations were obtained. CONCLUSIONS: Preanesthetic IM ranitidine 1 to 2 mg/kg resulted in a higher pH and lower volume of gastric fluid at the time of induction and in a higher pH during 3 hours of anesthesia. This therapy may be a useful adjunct to premedication for children who have a greater than normal risk of pulmonary aspiration during anesthesia.


Asunto(s)
Ácido Gástrico/metabolismo , Contenido Digestivo/efectos de los fármacos , Medicación Preanestésica , Ranitidina/uso terapéutico , Niño , Preescolar , Relación Dosis-Respuesta a Droga , Determinación de la Acidez Gástrica , Humanos , Concentración de Iones de Hidrógeno , Lactante , Inyecciones Intramusculares , Ranitidina/administración & dosificación , Ranitidina/sangre
20.
Acta Ophthalmol (Copenh) ; 69(2): 256-60, 1991 Apr.
Artículo en Inglés | MEDLINE | ID: mdl-1872148

RESUMEN

A young girl with ocular albinism and the Hermansky-Pudlak syndrome is described. Ocular albinism generally occurs in males. In this condition, the pigmentation of the skin and hair is nearly normal, and the melanin pigment abnormality is limited to the eyeballs. The chief complaints are visual disturbance, nystagmus, and photophobia. A 3-year-old girl was recently brought to our hospital with nystagmus, which she had exhibited since the age of 1 year. Funduscopy resulted in a diagnosis of ocular albinism. Further investigations, specifically, microscopy of her platelets, led us to conclude that she had Hermansky-Pudlak syndrome.


Asunto(s)
Albinismo Oculocutáneo/diagnóstico , Preescolar , Electrorretinografía , Entropión/diagnóstico , Femenino , Angiografía con Fluoresceína , Fondo de Ojo , Humanos , Nistagmo Patológico/diagnóstico , Deficiencia de Almacenamiento del Pool Plaquetario/patología , Agudeza Visual
SELECCIÓN DE REFERENCIAS
DETALLE DE LA BÚSQUEDA
...