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1.
Curationis ; 47(1): e1-e8, 2024 May 06.
Artículo en Inglés | MEDLINE | ID: mdl-38708759

RESUMEN

BACKGROUND:  Globally, enrolled nurses (ENs) are embarking on an educational journey to become registered nurses (RNs) in order to enhance their knowledge and career opportunities. However, their aspiration is not without challenges. In Namibia, the experiences of these nurses have not been extensively researched. OBJECTIVES:  This study aims to explore and describe the experiences and challenges of ENs undertaking a Bachelor of Nursing Science at the University of Namibia. METHOD:  A qualitative, exploratory, descriptive and contextual research strategy was followed as the basis of conducting the study. A sample of 15 nursing students was purposively selected from the target population of 73 nursing students. This sample size was determined by the saturation of data as reflected in repeating themes. The collected data were analysed thematically using an inductive approach. RESULTS:  Three main themes subsequently emerged from the study: ENs' positive experiences advancing in the Bachelor of Nursing Science (BNSc) programme; nurses' negative experiences advancing in the BNSc programme; and recommendations to ensure effective advancement in the BNSc programmeConclusion: The findings of this study revealed that ENs positively experience becoming a RN when it comes to self-development; however, they have negative experiences such as not receiving exemptions for prior learning and having to learn a new curriculum.Contribution: These findings may be used by the Faculty of Health Sciences, School of Nursing and Public Health management in order to develop targeted interventions and ongoing strategies during their curriculum review cycles to ensure positive student experiences and success within the programme.


Asunto(s)
Bachillerato en Enfermería , Investigación Cualitativa , Estudiantes de Enfermería , Humanos , Namibia , Bachillerato en Enfermería/estadística & datos numéricos , Bachillerato en Enfermería/normas , Bachillerato en Enfermería/métodos , Estudiantes de Enfermería/estadística & datos numéricos , Estudiantes de Enfermería/psicología , Femenino , Adulto , Masculino , Enfermeras y Enfermeros/estadística & datos numéricos , Enfermeras y Enfermeros/psicología , Enfermeras y Enfermeros/normas , Curriculum/tendencias , Curriculum/normas
2.
Curationis ; 47(1): 1-8, 2024. tables
Artículo en Inglés | AIM (África) | ID: biblio-1554038

RESUMEN

Background: Globally, enrolled nurses (ENs) are embarking on an educational journey to become registered nurses (RNs) in order to enhance their knowledge and career opportunities. However, their aspiration is not without challenges. In Namibia, the experiences of these nurses have not been extensively researched. Objectives: This study aims to explore and describe the experiences and challenges of ENs undertaking a Bachelor of Nursing Science at the University of Namibia. Method: A qualitative, exploratory, descriptive and contextual research strategy was followed as the basis of conducting the study. A sample of 15 nursing students was purposively selected from the target population of 73 nursing students. This sample size was determined by the saturation of data as reflected in repeating themes. The collected data were analysed thematically using an inductive approach. Results: Three main themes subsequently emerged from the study: ENs' positive experiences advancing in the Bachelor of Nursing Science (BNSc) programme; nurses' negative experiences advancing in the BNSc programme; and recommendations to ensure effective advancement in the BNSc programme Conclusion: The findings of this study revealed that ENs positively experience becoming a RN when it comes to self-development; however, they have negative experiences such as not receiving exemptions for prior learning and having to learn a new curriculum. Contribution: These findings may be used by the Faculty of Health Sciences, School of Nursing and Public Health management in order to develop targeted interventions and ongoing strategies during their curriculum review cycles to ensure positive student experiences and success within the programme.


Asunto(s)
Ciencias de la Salud
3.
BMC Med Imaging ; 20(1): 15, 2020 02 10.
Artículo en Inglés | MEDLINE | ID: mdl-32041550

RESUMEN

BACKGROUND: The Logan graphical analysis (LGA) algorithm is widely used to quantify receptor density for parametric imaging in positron emission tomography (PET). Estimating receptor density, in terms of the non-displaceable binding potential (BPND), from the LGA using the ordinary least-squares (OLS) method has been found to be negatively biased owing to noise in PET data. This is because OLS does not consider errors in the X-variable (predictor variable). Existing bias reduction methods can either only reduce the bias slightly or reduce the bias accompanied by increased variation in the estimates. In this study, we addressed the bias reduction problem by applying a different regression method. METHODS: We employed least-squares cubic (LSC) linear regression, which accounts for errors in both variables as well as the correlation of these errors. Noise-free PET data were simulated, for 11C-carfentanil kinetics, with known BPND values. Statistical noise was added to these data and the BPNDs were re-estimated from the noisy data by three methods, conventional LGA, multilinear reference tissue model 2 (MRTM2), and LSC-based LGA; the results were compared. The three methods were also compared in terms of beta amyloid (A ß) quantification of 11C-Pittsburgh compound B brain PET data for two patients with Alzheimer's disease and differing A ß depositions. RESULTS: Amongst the three methods, for both synthetic and actual data, LSC was the least biased, followed by MRTM2, and then the conventional LGA, which was the most biased. Variations in the LSC estimates were smaller than those in the MRTM2 estimates. LSC also required a shorter computational time than MRTM2. CONCLUSIONS: The results suggest that LSC provides a better trade-off between the bias and variability than the other two methods. In particular, LSC performed better than MRTM2 in all aspects; bias, variability, and computational time. This makes LSC a promising method for BPND parametric imaging in PET studies.


Asunto(s)
Enfermedad de Alzheimer/diagnóstico por imagen , Péptidos beta-Amiloides/química , Isótopos de Carbono/farmacocinética , Interpretación de Imagen Radiográfica Asistida por Computador/métodos , Algoritmos , Enfermedad de Alzheimer/metabolismo , Péptidos beta-Amiloides/metabolismo , Sesgo , Encéfalo/diagnóstico por imagen , Encéfalo/metabolismo , Isótopos de Carbono/química , Fentanilo/análogos & derivados , Fentanilo/química , Humanos , Análisis de los Mínimos Cuadrados , Tomografía de Emisión de Positrones , Relación Señal-Ruido
4.
J Neuroimmunol ; 310: 26-31, 2017 09 15.
Artículo en Inglés | MEDLINE | ID: mdl-28778441

RESUMEN

Environmental factors are implicated in the development of Parkinson's disease (PD). The aim of this study is to investigate the role of cell-mediated immunity upon a specific immune-stimulation with HSV-1 and human alpha-synuclein homologues peptides by using the intracellular cytokine method on Parkinson's patients and healthy controls. The study showed, for the first time, a specific response to TNF-α CD8, CD4 and NK cells after stimulation in PD patients. Our data show a possible role of the immune system in the pathogenesis of Parkinson's disease, and that HSV-1 infections may lead to a progression of the disease.


Asunto(s)
Citocinas/metabolismo , Herpesvirus Humano 1/química , Enfermedad de Parkinson/patología , Péptidos/farmacología , Linfocitos T/efectos de los fármacos , alfa-Sinucleína/química , Anciano , Anciano de 80 o más Años , Femenino , Citometría de Flujo , Humanos , Células Asesinas Naturales/efectos de los fármacos , Masculino , Persona de Mediana Edad , Enfermedad de Parkinson/inmunología , alfa-Sinucleína/farmacología
5.
Clin Neurophysiol ; 126(10): 1871-8, 2015 Oct.
Artículo en Inglés | MEDLINE | ID: mdl-25622530

RESUMEN

OBJECTIVE: To study brainstem function in Parkinson's Disease (PD) at different stages, through a battery of vestibular-evoked myogenic potentials (VEMPs) and compare the results with scores on clinical scales assessing the presence of symptoms linked to brainstem involvement. METHODS: Cervical, masseter and ocular VEMPs were recorded in patients with early PD (n=14, disease duration 1.42±0.7years), advanced PD (n=19, disease duration 7.26±2.9years) and in 27 age-matched controls. In PD, the following clinical scales were administered: Mini-BESTest, REM sleep Behavior Disorder Screening Questionnaire (RBD-SQ), PD Sleep Scale, Epworth Sleepiness Scale and Geriatric Depression Scale. RESULTS: Rate of VEMPs alterations was higher (p<0.001) in PD than controls, but similar within PD groups. However, early and advanced PD showed a different pattern of abnormalities (p=0.02), being latency delay prevalent in the former and absence in the latter. VEMP impairment correlated directly with RBD-SQ scores in both PD cohorts and inversely with Mini-BESTest scores in advanced PD. CONCLUSIONS: VEMPs displayed progressive severity of alterations at different stages of PD, with remarkable correlations with presence of postural instability and RBD. SIGNIFICANCE: The combined use of VEMPs may provide interesting insights into the pathophysiological mechanisms of PD at the earliest and prodromal stage of the disease.


Asunto(s)
Tronco Encefálico/fisiopatología , Enfermedad de Parkinson/diagnóstico , Enfermedad de Parkinson/fisiopatología , Trastorno de la Conducta del Sueño REM/diagnóstico , Trastorno de la Conducta del Sueño REM/fisiopatología , Potenciales Vestibulares Miogénicos Evocados , Adulto , Anciano , Anciano de 80 o más Años , Estudios de Cohortes , Femenino , Humanos , Masculino , Persona de Mediana Edad , Potenciales Vestibulares Miogénicos Evocados/fisiología
6.
Neuropsychobiology ; 51(2): 100-6, 2005.
Artículo en Inglés | MEDLINE | ID: mdl-15741751

RESUMEN

Insulin and leptin are well known to be involved in the regulation of food intake and body weight. Recent studies have suggested that both hormones may also affect memory and learning processes. We explored whether the intrahippocampal administration of insulin or leptin improved spatial memory formation in rats following a radial maze task and whether the insulin and leptin receptor expression in different areas of the hippocampus was affected. Animals without a learning task were also investigated in order to differentiate between the influence of spatial learning and hormone application on receptor expression. Spatial memory formation was found unaltered following the different applications. The application of insulin increased the expression of the long form of the leptin receptor in the Ammon's horn and dentate gyrus region of the hippocampus in the learning group only. These data clearly show that learning is a prerequisite for the effect of insulin on leptin receptor expression.


Asunto(s)
Hipocampo/metabolismo , Hipoglucemiantes/farmacología , Insulina/farmacología , Leptina/metabolismo , Leptina/farmacología , Aprendizaje por Laberinto/fisiología , Receptor de Insulina/biosíntesis , Animales , Giro Dentado/efectos de los fármacos , Giro Dentado/metabolismo , Hipocampo/efectos de los fármacos , Procesamiento de Imagen Asistido por Computador , Hibridación in Situ , Inyecciones , Masculino , Aprendizaje por Laberinto/efectos de los fármacos , ARN Mensajero/biosíntesis , Ratas , Ratas Wistar , Receptor de Insulina/genética , Receptores de Superficie Celular/biosíntesis , Receptores de Superficie Celular/efectos de los fármacos , Receptores de Leptina
7.
Neurol Sci ; 25(4): 220-4, 2004 Oct.
Artículo en Inglés | MEDLINE | ID: mdl-15549508

RESUMEN

Cerebellar pathology commonly shows important motor signs and less evident cognitive dysfunction. The 'cerebellar cognitive affective syndrome' is characterised by impairment on executive function, spatial cognition, language and behaviour. We report the case of a man with acute onset of transitory motor features and severe mental disorders. Cranial CT and brain MRI revealed extended cerebellar lesions. Neuropsychological assessment disclosed deficits of attention, executive function and memory. Auditory event-related potentials showed abnormal P300. These data suggest a pure "cerebellar cognitive affective syndrome"and strengthen the hypothesis of cerebellar cognitive function modulation.


Asunto(s)
Enfermedades Cerebelosas/etiología , Cerebelo/fisiopatología , Trastornos del Conocimiento/etiología , Trastornos del Humor/etiología , Accidente Cerebrovascular/complicaciones , Anciano , Atención/fisiología , Enfermedades Cerebelosas/patología , Enfermedades Cerebelosas/psicología , Cerebelo/diagnóstico por imagen , Cerebelo/patología , Trastornos del Conocimiento/patología , Trastornos del Conocimiento/psicología , Potenciales Relacionados con Evento P300/fisiología , Humanos , Trastornos del Lenguaje/etiología , Trastornos del Lenguaje/patología , Trastornos del Lenguaje/psicología , Imagen por Resonancia Magnética , Masculino , Trastornos de la Memoria/complicaciones , Trastornos de la Memoria/patología , Trastornos de la Memoria/psicología , Trastornos del Humor/patología , Trastornos del Humor/psicología , Pruebas Neuropsicológicas , Accidente Cerebrovascular/patología , Accidente Cerebrovascular/psicología , Tomografía Computarizada por Rayos X
8.
Mol Ecol ; 13(6): 1481-94, 2004 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-15140092

RESUMEN

To unravel the postglacial colonization history and the current intercolony dispersal in the common eider, Somateria mollissima, we analysed genetic variation at a part of the mitochondrial control region and five unlinked autosomal microsatellite loci in 175 eiders from 11 breeding colonies, covering the entire European distribution range of this species. As a result of extreme female philopatry, mitochondrial DNA differentiation is substantial both among local colonies and among distant geographical regions. Our study further corroborates the previous hypothesis of a single Pleistocene refugium for European eiders. A nested clade analysis on mitochondrial haplotypes suggests that (i) the Baltic Sea eider population is genetically closest to a presumably ancestral population and that (ii) the postglacial recolonization progressed in a stepwise fashion via the North Sea region and the Faroe Islands to Iceland. Current long-distance dispersal is limited. Differentiation among colonies is much less pronounced at microsatellite loci. The geographical pattern of this nuclear genetic variation is to a large extent explained by isolation by distance. As female dispersal is very limited, the geographical pattern of nuclear variation is probably explained by male-mediated gene flow among breeding colonies. Our study provides genetic evidence for the assumed prominent postglacial colonization route shaping the present terrestrial fauna of the North Atlantic islands Iceland and the Faroes. It suggests that this colonization had been a stepwise process originating in continental Europe. It is the first molecular study on eider duck populations covering their entire European distribution range.


Asunto(s)
Patos/genética , Variación Genética , Genética de Población , Fenómenos de Retorno al Lugar Habitual , Reproducción/fisiología , Análisis de Varianza , Animales , Secuencia de Bases , Cartilla de ADN , ADN Mitocondrial/genética , Patos/fisiología , Europa (Continente) , Femenino , Frecuencia de los Genes , Geografía , Haplotipos/genética , Repeticiones de Microsatélite/genética , Datos de Secuencia Molecular , Dinámica Poblacional , Alineación de Secuencia , Análisis de Secuencia de ADN , Factores Sexuales
9.
J Neurol Neurosurg Psychiatry ; 74(7): 878-85, 2003 Jul.
Artículo en Inglés | MEDLINE | ID: mdl-12810771

RESUMEN

OBJECTIVE: (1) To assess cognitive function and cerebral magnetic resonance imaging (MRI) involvement in relapsing-remitting multiple sclerosis; (2) to monitor disease evolution, cognitive dysfunction, and cerebral lesion burden over time (mean 8.5 year follow up period); (3) to study the relation between clinical, neuropsychological, and MRI data. On follow up assessment, visual and auditory oddball event related potentials (ERPs) were recorded as psychophysiological evaluation of cognitive status. Correlations between neuropsychological, MRI, and ERP data were also analysed. METHODS: Neuropsychological study assessed verbal and non-verbal IQ, deterioration index (DI) from WAIS subtests, conceptual reasoning, attention, verbal and visuospatial short-term and long term memory. MRI assessment detected presence of demyelinating lesions by using a semiquantitative method as well as cortical and subcortical atrophy over time. RESULTS: Attention, short-term and long term visuospatial memory were mildly impaired at baseline and remained unaltered longitudinally. At retesting a significant worsening of verbal long term memory (p=0.023), DI presence (p=0.041) and the increase of supratentorial and subtentorial MRI lesions load (p=0.001) emerged. Expanded disability status scale score correlated significantly with total lesion burden at both evaluations (p=0.043 and p=0.024 respectively). Temporal, occipital, and frontal horn lesions as well as cortical atrophy correlated significantly with attention and memory tests at baseline. Follow up assessment revealed significant correlation between cortical atrophy and attention as well as visuospatial short-term memory; spatial long term memory correlated significantly with lesions in body of lateral ventricle and frontal lobe. ERP study showed P300 latency abnormalities in 75% of patients, involving specifically more visual P300 (58.4 % of cases) than auditory wave (41.6 %). Visual P300 latency and amplitude correlated significantly with DI and auditory P300 latency with frontal horn and brain stem lesions. CONCLUSIONS: These findings revealed mild cognitive impairment in MS patients particularly consistent with slowing information processing over time. Increased MRI lesions do not correlate with the clinical course of the disease and cognitive deficit evolution. Thus, cognitive dysfunction could be related to disease peculiarity and not to the time course. Correlations between P300, neuropsychological, and MRI findings provide further information about ERP application to examine cognitive impairment in MS and probably to investigate their neural origin.


Asunto(s)
Corteza Cerebral/patología , Trastornos del Conocimiento/etiología , Trastornos del Conocimiento/patología , Personas con Discapacidad/psicología , Esclerosis Múltiple/complicaciones , Esclerosis Múltiple/psicología , Adulto , Atrofia , Atención , Progresión de la Enfermedad , Femenino , Humanos , Pruebas de Inteligencia , Estudios Longitudinales , Imagen por Resonancia Magnética , Masculino , Trastornos de la Memoria/etiología , Esclerosis Múltiple/patología , Periodicidad
10.
Phytomedicine ; 9(7): 654-8, 2002 Oct.
Artículo en Inglés | MEDLINE | ID: mdl-12487331

RESUMEN

The orcinol derivatives tenuiorin (1) and methyl orsellinate (2) were identified as active components of an extract from the lichen Peltigera leucophlebia (Nyl.) Gyeln. showing in vitro inhibitory activity against 15-lipoxygenase from soybeans. The compounds were subsequently tested for in vitro activity against 5-lipoxygenase from porcine leucocytes and proved to be moderately active, with IC50 values of 41.6 microM and 59.6 microM respectively. Tenuiorin is a known constituent of several Peltigera species but has not previously been isolated from P. leucophlebia. As correlation between 5-lipoxygenase inhibition and antiproliferative effects has earlier been witnessed for related lichen metabolites, tenuiorin and methyl orsellinate were further tested for antiproliferative activity on cultured human breast (T-47D)-, pancreatic (PANC-1)- and colon (WIDR) cancer cell lines. The monomeric methyl orsellinate exhibited no detectable antiproliferative activity whereas the trimeric tenuiorin caused moderate/weak reduction in [3H]-thymidine uptake of the pancreatic- and colon cancer cells, with ED50 values of 87.9 and 98.3 microM respectively.


Asunto(s)
Extractos Celulares/farmacología , Líquenes , Inhibidores de la Lipooxigenasa , Resorcinoles/farmacología , Neoplasias de la Mama/tratamiento farmacológico , División Celular/efectos de los fármacos , Humanos , Concentración 50 Inhibidora , Espectroscopía de Resonancia Magnética , Resorcinoles/química , Resorcinoles/aislamiento & purificación , Timidina/metabolismo , Tritio , Células Tumorales Cultivadas/efectos de los fármacos
11.
Clin Neurophysiol ; 113(6): 853-61, 2002 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-12048044

RESUMEN

OBJECTIVES: To investigate the relationship between amyotrophic lateral sclerosis (ALS) and cognitive function by means of oddball event-related potentials (ERPs) and to determine the usefulness of this methodology in the cognitive status assessment of physically disabled patients. METHODS: Visual and auditory oddball ERPs were recorded in 16 consecutive sporadic ALS patients. A comprehensive battery of neuropsychological (NP) tests assessed intelligence, executive functions, attention, memory, word fluency, visuo-motor and visual-constructive skills. RESULTS: All patients performed visual and auditory ERPs and 75% of cases showed abnormal N200 and/or P300 waves. Ten patients (62.5%) carried out the entire psychometric evaluation with significant impairment on tests of executive function and attention. A significant correlation between delayed visual (P<0.04) and auditory (P<0.04) P300 latency and impaired NP tests was found. CONCLUSIONS: In agreement with literature data, our findings confirm the hypothesis of cognitive impairment in ALS patients especially on attention and executive functions suggesting a more extensive degeneration beyond the motor areas. ALS causes severe physical disabilities and such a condition may interfere with NP testing. Thus, the P300 seems to be a useful tool for the assessment of cognition and attention when severe physical deficits are present.


Asunto(s)
Esclerosis Amiotrófica Lateral/fisiopatología , Potenciales Evocados Auditivos , Potenciales Evocados Visuales , Adulto , Anciano , Encéfalo/fisiopatología , Cognición/fisiología , Potenciales Relacionados con Evento P300 , Femenino , Humanos , Masculino , Persona de Mediana Edad
12.
Neurol Sci ; 22(6): 459-62, 2002 Mar.
Artículo en Inglés | MEDLINE | ID: mdl-11976978

RESUMEN

To evaluate possible cause-effect relationships between hyperostosis frontalis interna and cognitive dysfunction, we performed a neurophysiological (event-related potentials, ERPs) and neuropsychological study in a case of Morgagni-Stewart-Morel (MSM) syndrome associated with frontal lobe compression. Neuropsychological evaluation evidenced selective impairment of executive function. Visual and auditory oddball ERPs revealed delayed P300 latency and reduced auditory P300 amplitude with multi-peaked morphology. ERP abnormalities and cognitive dysfunction could be due to the frontal bone-cortex conflict documented by neuroradiological investigations.


Asunto(s)
Trastornos del Conocimiento/fisiopatología , Potenciales Relacionados con Evento P300 , Hiperostosis Frontal Interna/fisiopatología , Trastornos del Conocimiento/diagnóstico , Potenciales Relacionados con Evento P300/fisiología , Femenino , Hueso Frontal/patología , Lóbulo Frontal/patología , Humanos , Hiperostosis Frontal Interna/diagnóstico , Hiperostosis Frontal Interna/psicología , Persona de Mediana Edad
13.
Artículo en Inglés | MEDLINE | ID: mdl-11041543

RESUMEN

1. Conflicting reports are available regarding the sensitivity of patients with Dementia with Lewy bodies (DLB) to risperidone. 2. The authors studied a rare familial case of probable DLB, who developed a documented episode of neuroleptic malignant syndrome (NMS) following the exposure to risperidone. Previously, the patient had had an episode of NMS on trifluoperazine. 3. The discontinuance of risperidone, in combination with a mild increase of dopaminergic therapy, led to a complete recovery in few days. 4. In patients with DLB, a continued vigilance for extrapyramidal side effects, including NMS, would be advisable during the use of risperidone.


Asunto(s)
Antipsicóticos/efectos adversos , Enfermedad por Cuerpos de Lewy/tratamiento farmacológico , Síndrome Neuroléptico Maligno/fisiopatología , Risperidona/efectos adversos , Antipsicóticos/uso terapéutico , Femenino , Humanos , Enfermedad por Cuerpos de Lewy/genética , Persona de Mediana Edad , Síndrome Neuroléptico Maligno/etiología , Risperidona/uso terapéutico
14.
Phytochemistry ; 54(6): 591-5, 2000 Jul.
Artículo en Inglés | MEDLINE | ID: mdl-10963452

RESUMEN

A novel diastereomer of ocobullenone. designated as sibyllenone, was isolated from the stem bark of mature Ocotea bullata in the course of a search for anti-inflammatory compounds from this plant. The stereostructure was established by X-ray crystallography and corroborated by NOESY analysis. Ocobullenone, obtained previously, was re-isolated and crystallised successfully for X-ray analysis, thus making possible an accurate spatial comparison of ocobullenone, iso-ocobullenone and the new stereoisomer. Tested pharmacologically for cyclooxygenase-1 and 2, and 5-lipoxygenase inhibition, sibyllenone was the only compound from O. bullata which showed good inhibitory activity towards 5-lipoxygenase.


Asunto(s)
Antiinflamatorios/aislamiento & purificación , Dioxanos/aislamiento & purificación , Lauraceae/química , Inhibidores de la Lipooxigenasa/aislamiento & purificación , Plantas Medicinales/química , Antiinflamatorios/química , Araquidonato 5-Lipooxigenasa/química , Cristalografía por Rayos X , Ciclooxigenasa 1 , Ciclooxigenasa 2 , Inhibidores de la Ciclooxigenasa 2 , Inhibidores de la Ciclooxigenasa/química , Inhibidores de la Ciclooxigenasa/aislamiento & purificación , Dioxanos/química , Isoenzimas/antagonistas & inhibidores , Inhibidores de la Lipooxigenasa/química , Espectroscopía de Resonancia Magnética , Prostaglandina-Endoperóxido Sintasas , Estereoisomerismo
15.
J Ethnopharmacol ; 71(1-2): 219-30, 2000 Jul.
Artículo en Inglés | MEDLINE | ID: mdl-10904166

RESUMEN

Ocotea bullata (Lauraceae), one of the top-ten traditional medicinal plants used in KwaZulu-Natal, is close to extinction through high demand and destructive harvesting methods. The stem bark is traditionally used to cure headaches, urinary disorders and stomach problems. Substitution of leaves for bark provides a possible resource management solution for this threatened medicinal plant. One aim of this study was to compare the chemical composition of O. bullata leaves and bark using TLC, HPLC and GC-MS analysis. The characteristic analytical fingerprints of leaf and bark extracts showed great similarities. A second aim was to investigate the pharmacological properties of O. bullata as a remedy against headaches. Leaf and bark extracts were tested in terms of cyclooxygenase-1 and 5-lipoxygenase inhibition. Extracts from the bark exhibited moderate inhibitory activity in both test systems. Extracts from fresh leaves were superior to bark extracts in terms of their in vitro inhibitory activity against cyclooxygenase-1 and 5-lipoxygenase. Volatiles obtained from n-hexane extracts of leaves and bark showed better inhibitory activity towards cyclooxygenase-1 and especially towards 5-lipoxygenase than the original n-hexane extracts. Volatiles were therefore recognized as one of the main active principles in O. bullata with regards to the anti-inflammatory properties of this medicinal plant. This lends support to the traditional usage of O. bullata bark as an inhalant or snuff.


Asunto(s)
Lauraceae/química , Plantas Medicinales/química , Animales , Clorofila/química , Cromatografía Líquida de Alta Presión , Cromatografía en Capa Delgada , Ciclooxigenasa 1 , Inhibidores de la Ciclooxigenasa/aislamiento & purificación , Inhibidores de la Ciclooxigenasa/farmacología , Cromatografía de Gases y Espectrometría de Masas , Técnicas In Vitro , Isoenzimas/metabolismo , Inhibidores de la Lipooxigenasa/farmacología , Epidermis de la Planta/química , Extractos Vegetales/farmacología , Hojas de la Planta/química , Prostaglandina-Endoperóxido Sintasas/metabolismo , Ovinos , Sudáfrica , Porcinos
17.
Science ; 272(5258): 16b, 1996 Apr 05.
Artículo en Inglés | MEDLINE | ID: mdl-17789959
19.
Genes Chromosomes Cancer ; 10(1): 1-6, 1994 May.
Artículo en Inglés | MEDLINE | ID: mdl-7519868

RESUMEN

Colorectal carcinogenesis is associated with the accumulation of genetic changes involving both dominant oncogenes and tumor suppressor genes. Although at least four different genes have been implicated in the process, the detection of allele loss from other regions of the genome suggests the involvement of additional genes. The short arm of chromosome 8 is one of these regions; loss of heterozygosity occurs at rates ranging from 30 to 50%. To define the region of common deletion containing the putative tumor suppressor gene, we analyzed a series of 87 carcinomas for allele loss in different regions of the short arm of chromosome 8 by using Southern blot analysis and a panel of polymorphic probes. We found allele loss in 33% of our cases, which involves two separate regions, one in the p-terminal region of the chromosome, 8p23.1-pter, where 45% of informative cases demonstrated loss, and the other in the mid-p region, at 8p21, where 31% of cases showed allele loss. No tumors showed loss of heterozygosity for both regions. These findings suggest the presence of two discrete genes related to colorectal carcinogenesis on the short arm of chromosome 8.


Asunto(s)
Alelos , Deleción Cromosómica , Cromosomas Humanos Par 8 , Neoplasias Colorrectales/genética , Heterocigoto , Humanos
20.
Toxicol Appl Pharmacol ; 121(2): 264-74, 1993 Aug.
Artículo en Inglés | MEDLINE | ID: mdl-8346543

RESUMEN

A method based on image analysis and applicable in pharmacology and toxicology is described that has been designed to meet the statistical requirements for the determination of liver hypertrophy or hyperplasia. An algorithm has been developed to detect and count fluorescent nuclei in Feulgen-stained liver sections (12,500 to 25,000 nuclei or 170 to 350 fields of observation per section within 2-4 hr) by means of fully automatic image analysis with the Leitz Texture Analysis System (TAS) (up to 23 sections in series on the microscope stage). The applicability of this method to conventionally derived, formaldehyde-fixed, tissue sections has been tested on 3-microns sections cut from archived paraplast blocks of already diagnosed materials. Alterations in the liver induced by eight different compounds administered perorally for 28 days to rats have been studied. The morphometric results were found to be specific for a given compound and revealed reproducible and statistically significant dose dependencies of hypertrophy or hyperplasia, or both. Increased frequencies of mitotic figures observed by eye correlated reasonably well with the morphometrically determined hyperplasia, but many hyperplastic livers revealed no mitotic figures. By contrast, the histological diagnoses of an increased degree of hypertrophy were only poorly correlated with the morphometric determinations and, in many instances, were made in livers showing no decrease in the frequency of nuclei. On the other hand, the results from electron microscopy agreed well with the corresponding morphometric analyses: in cases with predominant hypertrophy the proliferation of the smooth endoplasmic reticulum was distinct or striking, or the peroxisomes were altered and increased in number, whereas no obvious ultrastructural changes were seen in cases of morphometrically exclusive hyperplasia.


Asunto(s)
Núcleo Celular/patología , Procesamiento de Imagen Asistido por Computador/métodos , Hígado/patología , Animales , Recuento de Células , Diagnóstico Diferencial , Hiperplasia/diagnóstico , Hiperplasia/patología , Hipertrofia/diagnóstico , Hipertrofia/patología , Hígado/ultraestructura , Masculino , Tamaño de los Órganos , Ratas , Ratas Sprague-Dawley
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