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1.
Br J Surg ; 107(12): 1625-1632, 2020 11.
Artigo em Inglês | MEDLINE | ID: mdl-32602959

RESUMO

BACKGROUND: A prognostic model was developed and validated using cancer registry data. This underpins an online decision support tool, informing primary treatment choice for women aged 70 years or older with hormone receptor-positive early breast cancer. METHODS: Data from women diagnosed between 2002 and 2010 in the English Northern and Yorkshire and West Midlands regions were used to develop the model. Primary treatment options of surgery with adjuvant endocrine therapy or primary endocrine therapy were compared. Models predicting the hazard of breast cancer-specific mortality and hazard of other-cause mortality were combined to derive survival probabilities. The model was validated externally using data from the Eastern Cancer Registration and Information Centre. RESULTS: The model was developed using data from 23 842 women, and validated externally on a data set from 14 526 patients. The overall model calibration was good. At 2 and 5 years, predicted mortality from breast cancer and other causes differed from the observed rate by less than 1 per cent. At 5 years, there were slight overpredictions in breast cancer mortality (2629 predicted versus 2556 observed deaths; P = 0·142) and mortality from all causes (6399 versus 6320 respectively; P = 0·583). The discrepancy varied between subgroups. Model discrimination was 0·75 or above for all mortality measures. CONCLUSION: A prognostic model for older women with oestrogen receptor-positive early breast cancer was developed and validated in the present study. This forms a basis for an online decision support tool (https://agegap.shef.ac.uk/).


ANTECEDENTES: Se ha desarrollado y validado un modelo pronóstico utilizando datos del registro de cáncer. Ello ha permitido ofrecer una herramienta online para facilitar la toma de decisiones respecto a la elección del tratamiento inicial en mujeres mayores de 70 años con cáncer de mama precoz y receptores de hormonas positivos. MÉTODOS: Se incluyeron un total de 23.842 mujeres, diagnosticadas entre 2002 y 2010 en las regiones del Norte, Yorkshire y West Midlands inglesas que cumplieron con los criterios de inclusión. Se compararon dos opciones de tratamiento: cirugía primaria asociada a tratamiento endocrino adyuvante o tratamiento primario endocrino. Para estimar la probabilidad de supervivencia se combinaron modelos predictivos para el riesgo de mortalidad específica por cáncer de mama y para el riesgo de mortalidad por otras causas. Se realizó una validación externa con datos del Eastern Cancer Registration and Information Center (n = 14.526). RESULTADOS: La calibración global del modelo fue buena. A los 2 y 5 años, la mortalidad anticipada por cáncer de mama y por otras causas difería de la observada en menos del 1%. A los 5 años, hubo una ligera sobrevaloración de la predicción de mortalidad por cáncer de mama (prevista versus real: 2.629 versus 2.556, P = 0,78) y de la mortalidad por todas las causas (6.399 versus 6.320, P = 0,14). Esta discrepancia varió entre subgrupos. La capacidad discriminativa del modelo fue del 0,75 o superior para todas las medidas de mortalidad. CONCLUSIÓN: En este estudio, se desarrolló y validó un modelo pronóstico para mujeres mayores con cáncer de mama precoz positivo para receptores de estrógenos. Esta herramienta que facilita la toma de decisiones está disponible online (https://agegap.shef.ac.uk/).


Assuntos
Neoplasias da Mama/diagnóstico , Regras de Decisão Clínica , Receptores de Estrogênio/metabolismo , Fatores Etários , Idoso , Neoplasias da Mama/mortalidade , Neoplasias da Mama/patologia , Neoplasias da Mama/cirurgia , Feminino , Humanos , Modelos Estatísticos , Prognóstico
2.
Clin Oncol (R Coll Radiol) ; 31(7): 444-452, 2019 07.
Artigo em Inglês | MEDLINE | ID: mdl-31122807

RESUMO

AIMS: Adjuvant chemotherapy is recommended as a treatment for women with high recurrence risk early breast cancer. Older women are less likely to receive chemotherapy than younger women. This study investigated the impact of chemotherapy on breast cancer-specific survival in women aged 70 + years using English registry data. MATERIALS AND METHODS: Cancer registration data were obtained from two English regions from 2002 to 2012 (n = 29 728). The impact of patient-level characteristics on the probability of receiving adjuvant chemotherapy was explored using logistic regression. Survival modelling was undertaken to show the effect of chemotherapy and age/health status on breast cancer-specific survival. Missing data were handled using multiple imputation. RESULTS: In total, 11 735 surgically treated early breast cancer patients were identified. Use of adjuvant chemotherapy has increased over time. Younger age at diagnosis, increased nodal involvement, tumour size and grade, oestrogen receptor-negative or human epidermal growth factor receptor 2-positive disease were all associated with increased probability of receiving chemotherapy. Chemotherapy was associated with a significant reduction in the hazard of breast cancer-specific mortality in women with high risk cancer, after adjusting for patient-level characteristics (hazard ratio 0.74, 95% confidence interval 0.67-0.81). DISCUSSION: Chemotherapy is associated with an improved breast cancer-specific survival in older women with early breast cancer at high risk of recurrence . Lower rates of chemotherapy use in older women may, therefore, contribute to inferior cancer outcomes. Decisions on potential benefits for individual patients should be made on the basis of life expectancy, treatment tolerance and patient preference.


Assuntos
Neoplasias da Mama/tratamento farmacológico , Quimioterapia Adjuvante/métodos , Idoso , Neoplasias da Mama/mortalidade , Neoplasias da Mama/patologia , Feminino , Humanos , Sistema de Registros , Estudos Retrospectivos , Análise de Sobrevida
3.
Br J Surg ; 105(11): 1454-1463, 2018 10.
Artigo em Inglês | MEDLINE | ID: mdl-29790154

RESUMO

BACKGROUND: Primary endocrine therapy is used as an alternative to surgery in up to 40 per cent of women with early breast cancer aged over 70 years in the UK. This study investigated the impact of surgery versus primary endocrine therapy on breast cancer-specific survival (BCSS) in older women. METHODS: Cancer registration data for 2002-2010 were obtained from two English regions. A retrospective analysis was performed for women with oestrogen receptor (ER)-positive disease, using statistical modelling to show the effect of treatment (surgery or primary endocrine therapy) and age and health status on BCSS. Missing data were handled using multiple imputation. RESULTS: Cancer registration data on 23 961 women were retrieved. After data preprocessing, 18 730 of 23 849 women (78·5 per cent) were identified as having ER-positive disease; of these, 10 087 (53·9 per cent) had surgery and 8643 (46·1 per cent) had primary endocrine therapy. BCSS was worse in the primary endocrine therapy group than in the surgical group (5-year BCSS rate 69·4 and 89·9 per cent respectively). This was true for all strata considered, although the difference was less in the cohort with the greatest degree of co-morbidity. For older, frailer patients the hazard of breast cancer death had less relative impact on overall survival. CONCLUSION: BCSS in older women with ER-positive disease is worse if surgery is omitted. This treatment choice may contribute to inferior cancer outcomes. Selection for surgery on the basis of predicted life expectancy may permit choice of women for whom surgery confers little benefit.


Assuntos
Antineoplásicos Hormonais/uso terapêutico , Neoplasias da Mama/mortalidade , Sistema de Registros , Idoso , Idoso de 80 Anos ou mais , Neoplasias da Mama/tratamento farmacológico , Feminino , Humanos , Mastectomia , Seleção de Pacientes , Prognóstico , Estudos Retrospectivos , Fatores de Risco , Taxa de Sobrevida/tendências , Tempo para o Tratamento , Reino Unido/epidemiologia
4.
Clin Hemorheol Microcirc ; 58(4): 507-14, 2014.
Artigo em Inglês | MEDLINE | ID: mdl-24169096

RESUMO

Fansidar® (sulfadoxine/pyrimethamine) and Coartem® (artemether/lumefantrine) are drugs that destroy malarial parasites and also produce free radicals which cause hemolysis of malaria-parasitized erythrocytes. This study investigated the effect of these drugs on the viscoelasticity of erythrocytes of ten healthy female subjects using the BioProfiler. The concentration for each of the two drugs were determined based on the therapeutic dose as normal, half the therapeutic dose as low and double the therapeutic dose as high. For Fansidar®, the concentrations were 0.15/0.01 mg/ml (low), 0.30/0.02 mg/ml (normal) and 0.60/0.04 mg/ml (high) based on the adult therapeutic dose of 1500/75 mg of sulfadoxine/pyrimethamine in the drug combination. For Coartem®, the concentrations were 0.03/0.19 mg/ml (low), 0.06/0.38 mg/ml (normal) and 0.12/0.76 mg/ml (high) based on the adult therapeutic dose of 320/1920 mg of artermether/lumefantrine in the drug combination. There was a statistically significant (p < 0.05) decrease in viscosity, elasticity and relaxation time with Coartem® at normal and high doses. Fansidar® also showed significant (p < 0.05) reductions in these parameters only in the high dose. This suggests that Coartem® generated significant free radicals at normal and high doses, with Fansidar® only in the high dose, resulting in increased hemolysis and ultimately reduced viscoelasticity.


Assuntos
Antimaláricos/farmacologia , Artemisininas/farmacologia , Membrana Eritrocítica/efeitos dos fármacos , Etanolaminas/farmacologia , Fluorenos/farmacologia , Pirimetamina/farmacologia , Sulfadoxina/farmacologia , Adulto , Combinação Arteméter e Lumefantrina , Viscosidade Sanguínea/efeitos dos fármacos , Combinação de Medicamentos , Feminino , Humanos , Técnicas In Vitro , Adulto Jovem
5.
J S Afr Vet Assoc ; 73(1): 13-22, 2002 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-12088066

RESUMO

The organic component of the avian eggshell can be divided into 3 portions, the shell membranes, the matrix and the cuticle. These have been well characterised in the chicken but little has been published with regard to the ostrich (Struthio camelus). A number of recent studies have indicated that the cause of intra-shell embryonic deaths in the ostrich is similar to intra-shell embryonic deaths that occur in the chicken. These deaths in the chicken are associated with the loss of or damage to the waxy cuticle and other organic components of the eggshell, which is reported to be absent in the ostrich eggshell. In this study, preliminary morphological and histochemical analyses, at the level of the light and electron microscope, have characterised the various organic components of the ostrich eggshell. The results of the histochemical and electron microscopical analyses suggest that there may only be 1 shell membrane in this species, which could play a major role in the limitation of bacterial penetration to the embryonic chamber The shell membrane has a distinct elemental profile as determined by EDS analysis. The matrix is shown to decrease in mesh size from the mammillary layer to the vertical crystal layer. The closer packing of the mesh may indicate the presence of a morphologically discernible termination signal to calcification or the remnants of an evolutionary calcified cuticle. The matrix of the pores may also form a defensive barrier against bacterial invasion, which could be damaged as a result of dipping the eggs before incubation.


Assuntos
Casca de Ovo/anatomia & histologia , Struthioniformes , Animais , Cálcio/análise , Carbono/análise , Casca de Ovo/química , Microanálise por Sonda Eletrônica/veterinária , Histocitoquímica/veterinária , Lectinas , Magnésio/análise , Membranas/ultraestrutura , Microscopia Eletrônica/veterinária , Microscopia Eletrônica de Varredura/veterinária , Potássio/análise , Struthioniformes/embriologia , Enxofre/análise
6.
Br Poult Sci ; 42(3): 338-43, 2001 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-11469553

RESUMO

1. The histochemistry and ultrastructure of pheasant eggs were compared on the basis of blue or brown shell colour. 2. Differences in lectin histochemistry of the outer shell membrane calcification surface indicate a biochemical disruption of the calcification sites in blue eggs. 3. Significant differences were observed in all aspects of eggshell ultrastructure with blue eggs having thinner shells with structural defects. 4. Poor hatchability of blue eggs may reflect high rates of weight loss associated with a defective eggshell.


Assuntos
Aves/embriologia , Casca de Ovo/ultraestrutura , Ovos , Embrião não Mamífero/fisiologia , Pigmentação , Animais , Aves/fisiologia , Casca de Ovo/fisiologia , Ovos/normas , Microscopia Eletrônica de Varredura/veterinária , Porosidade , Redução de Peso
7.
J Audiov Media Med ; 23(3): 113-8, 2000 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-11070580

RESUMO

Change in medical curricula is a worldwide trend. Concomitant with this is a change in the role of the microscope and its contribution to a student's career. In this questionnaire-based study the perceptions of medical, dental and veterinary students to microscopy and alternative forms of histology tuition, as well as the role of microscopy in their future careers, was assessed. Veterinary students indicate a strong preference for the microscope and microscopy training due to the importance of the microscope in their chosen career, whilst medical and dental students are somewhat ambivalent. However, the students would not choose to eliminate the microscope entirely from their studies.


Assuntos
Educação em Veterinária , Microscopia/tendências , Estudantes de Odontologia , Estudantes de Medicina , Atitude do Pessoal de Saúde , Histologia , Humanos , Estudantes/psicologia
8.
J S Afr Vet Assoc ; 71(2): 97-102, 2000 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-11030359

RESUMO

The ultrastructure of the eggshell of the domestic hen has been well researched and structural studies of other avian species, such as the ostrich, often base their interpretation of egg shell structure on that of the chicken. In the ostrich, lowered hatchability and hatching trauma may be due to shell ultrastructural abnormalities. In the present study the ultrastructure of the calcified portion, and the outer shell membrane (OSM), of domesticated ostrich eggshells was investigated using standard electron microscopic techniques. Transmission and scanning electron microscopy studies demonstrated intimate contact between cup-shaped structures present on the OSM and the mammillary layer of the calcified portion of the shell. The initial calcium carbonate growth of the calcified shell was of a dendritic nature with nucleation sites on the surface of the cup's contents. The dendritic growth gave way to a more randomly-orientated, smaller crystallite growth structure, which changed in form as it neared the vertical crystal layer (VCL). The VCL is described as being both amorphous and 'crumbly' depending on the plane of fracture. These observations suggest that firstly, initial calcification is contained within the cups and is then directed outwards to form the shell and that secondly, the VCL may contain an evolutionary, calcified cuticular layer. These observations serve as a baseline for studies investigating the effect of shell structure and strength on hatchling trauma and the influence of maternal diet.


Assuntos
Casca de Ovo/ultraestrutura , Struthioniformes , Animais , Carbonato de Cálcio/análise , Cristalização , Dieta/veterinária , Casca de Ovo/química , Membranas/ultraestrutura , Microscopia Eletrônica , Microscopia Eletrônica de Varredura , Resistência à Tração
9.
Microsc Res Tech ; 40(6): 434-9, 1998 Mar 15.
Artigo em Inglês | MEDLINE | ID: mdl-9551623

RESUMO

The histochemistry technique for localizing adenylate cyclase has been developed over the past two decades. Early efforts were directed at overcoming the criticism of the lead capture technique, the inhibition of the enzyme by fixation, and problems associated with the substrate. The introduction of alternative metal ions, strontium and cerium, offered solutions to the criticism of the lead capture technique. The inhibition of the enzyme by the various fixation methods used has been rarely overcome satisfactorily and the use of non-fixed material during incubation is one of the alternatives that has been suggested. The introduction of adenylate (beta-gamma-methylene) diphosphate as an alternative substrate offers a solution to the problems associated with commercially available adenylyl imidodiphosphate. Although no standard medium or method has been accepted by all researchers, the histochemical technique still has a place in the arsenal of the modern cell biologist. The technique localizes the active enzyme, as opposed to the protein, active and nonactive, by immunocytochemistry and the precursors of the protein by in situ hybridization methods.


Assuntos
Adenilil Ciclases/análise , Histocitoquímica/métodos , Trifosfato de Adenosina/análogos & derivados , Trifosfato de Adenosina/análise , Adenilil Imidodifosfato/análise , Animais , Histocitoquímica/história , História do Século XX , Fixação de Tecidos
10.
Microsc Res Tech ; 40(6): 488-91, 1998 Mar 15.
Artigo em Inglês | MEDLINE | ID: mdl-9551630

RESUMO

The enzyme adenylyl cyclase (AC) plays a pivotal role in smooth muscle relaxation. Biochemical evidence suggests that AC is predominantly located in the outer layers of the myometrium; however, neither immunocytochemical nor histochemical studies have been undertaken to demonstrate the specific cellular distribution of the enzyme in this tissue. As part of an ongoing study of the human myometrium, a polyclonal antibody against types V and VI AC was used to detect the presence of these isoforms in sections of formalin-fixed, wax-embedded myometrial tissue. A positive reaction was seen in the cytoplasm of the smooth muscle cells with the midmyometrial area having the greatest number of positive cells, when compared to the subserosal and subendometrial areas. It is hypothesized that AC isoform type VI is the predominant isoform present in the myometrium and that the percentage distribution of positive cells reflects the area of highest myometrial activity during parturition.


Assuntos
Adenilil Ciclases/análise , Miométrio/enzimologia , Adulto , Feminino , Humanos , Imuno-Histoquímica , Pessoa de Meia-Idade
11.
Hum Reprod Update ; 4(5): 520-5, 1998.
Artigo em Inglês | MEDLINE | ID: mdl-10027604

RESUMO

The aim of this study was to determine whether the ultrastructure of the non-neoplastic myometrial portion (host myometrium) of fibromyomatous uteri is normal or abnormal when compared to that of fibromyomata and normal myometria. Myometrial samples from 23 normal and 54 fibromyomatous uteri were examined at the ultrastructural level using standard electron microscopy techniques. Ultrastructural abnormalities of certain cellular organelles were noted in myocytes of fibromyomata but not in those of normal or host myometria. The sarcolemmal dense bands of host myometrial myocytes were of significantly greater length than those of normal myometria, but not significantly different to those of fibromyomata. Consequently, the numbers of caveolae in host myometria and fibromyomata are conceivably decreased in comparison to normal myometria. Host myometria can be, therefore, considered to be structurally abnormal. The specific structural abnormality noted may affect calcium metabolism in these tissues by causing a decrease in the cellular calcium extrusion mechanism and thus raising intracellular calcium concentrations. Such an abnormality may provide an answer, in terms of contraction abnormalities, for the unexplained infertility that occurs in a small percentage of symptomatic myomatous patients.


Assuntos
Infertilidade Feminina/patologia , Leiomioma/fisiopatologia , Leiomioma/ultraestrutura , Miométrio/patologia , Neoplasias Uterinas/fisiopatologia , Neoplasias Uterinas/ultraestrutura , Feminino , Humanos , Infertilidade Feminina/complicações , Infertilidade Feminina/fisiopatologia , Leiomioma/complicações , Miométrio/ultraestrutura , Neoplasias Uterinas/complicações
12.
Cent Afr J Med ; 44(12): 305-7, 1998 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-10921201

RESUMO

OBJECTIVE: To determine the incidence of Rotavirus infection in children under five years of age presenting with diarrhoea. DESIGN: Cross sectional study. SETTING: Mapulaneng Hospital, Bushbuckridge, Republic of South Africa. SUBJECTS: 50 children under five years of age presenting with diarrhoea. MAIN OUTCOME MEASURES: Rotavirus seroprevalence. RESULTS: Out of 50, 24 (48%) had detectable Rotavirus particles in their stools. The highest incidence of infection was observed among the seven to 12 months age group. Out of the 245 positive subjects 22 (91.7%) were breast fed. CONCLUSION: This study shows that diarrhoea in children under five years of age is probably caused by Rotavirus in Bushbuckridge. We therefore recommend that all children presenting with diarrhoea should be screened for Rotavirus.


Assuntos
Diarreia/virologia , Infecções por Rotavirus/epidemiologia , Estudos Transversais , Diarreia/epidemiologia , Fezes/virologia , Feminino , Humanos , Incidência , Lactente , Recém-Nascido , Masculino , Rotavirus/isolamento & purificação , África do Sul/epidemiologia
13.
Cancer Genet Cytogenet ; 98(1): 1-3, 1997 Oct 01.
Artigo em Inglês | MEDLINE | ID: mdl-9309110

RESUMO

Cosmid probes specific for the major BCR/ABL rearrangement (commercially available probes) were employed by us to evaluate 134 patients with the clinical diagnosis of chronic myelocytic leukemia (CML). The following represent our main observations: 1) No significant statistical difference regarding a false positive fusion signal was seen in the distribution pattern between the Ph negative (-) cases (110) and the normal controls (3.23 +/- 1.97 vs 2.8 +/- 1.92, respectively). 2) The mean percentage of cells with a positive fusion signal in the Ph positive (+) CML cases at presentation was 70 +/- 12.3 in bone marrow samples (12 cases) and 45 +/- 12.4 in blood samples (3 cases). 3) A significant discrepancy was seen between the interphase FISH and cytogenetics data in the monitoring of four out of eight patients post-therapy. The clinical significance of this observation needs to be clarified. 4) Three Ph(-) patients with significant leukocytosis had closely adjacent but not fused signals (20%, 16%, and 20% of cells, respectively, vs. the control: 4%). This may indicate a temporal and spatial association between chromosomes 9 and 22 prior to the BCR/ABL rearrangement (Ph chromosome formation).


Assuntos
Proteínas de Fusão bcr-abl/genética , Rearranjo Gênico , Leucemia Mielogênica Crônica BCR-ABL Positiva/genética , Idoso , Sondas de DNA , Feminino , Humanos , Hibridização in Situ Fluorescente , Masculino
14.
Acta Histochem ; 96(3): 265-79, 1994 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-7531930

RESUMO

The ventral epidermis of the frog Rana fuscigula is a typical tight epithelium which acts as a functional syncytium in the active transepithelial transport of sodium ions. Transport across this epithelium is regulated by cyclic adenosine monophosphate (cAMP). This study was undertaken to formulate an optimal protocol for the localization, within this epithelium, of adenylate cyclase; the enzyme involved in cAMP synthesis. The ventral epithelium of R. fuscigula was collagenase treated and processed using five different fixation/incubation protocols. The components of a basal incubating medium were modified by changing the localizing agent, adding adenylate cyclase stimulators and inhibitors of other enzymes. Control incubations undertaken included a) leaving the substrate out, b) prior heat inactivation of the enzyme, c) specific blockers and d) incubation for alkaline phosphatase as an alternative enzyme. The samples were then processed for electron microscopy. Localization of adenylate cyclase was best obtained, when fixing the tissue after incubation for 30 min at 37 degrees C. The medium that gave the best and most consistent localization contained magnesium chloride; as a required ion, theophylline, dithiothreitol, ouabain, levamisole; as enzyme inhibitors, forskolin; as a stimulator of adenylate cyclase, lead nitrate; as the capture agent and column purified adenylyl imidodiphosphate; as the substrate.


Assuntos
Adenilil Ciclases/análise , Inibidores de Adenilil Ciclases , Adenilil Ciclases/isolamento & purificação , Animais , Epitélio/enzimologia , Epitélio/ultraestrutura , Esterases/antagonistas & inibidores , Histocitoquímica , Chumbo , Microscopia Eletrônica , Tetróxido de Ósmio , Ranidae , Coloração e Rotulagem , Fixação de Tecidos
15.
Histochem J ; 26(6): 495-503, 1994 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-7928403

RESUMO

A modified cytochemical technique with 5'-adenylylimidodiphosphate as substrate, was used to examine the distribution of adenylate cyclase in cells comprising the transepithelial Na+ transport pathway in isolated frog skin epithelium. Particular attention was paid to the effects of fixation on the activity and localization of adenylate cyclase. Fixation in glutaraldehyde alone or in combination with paraformaldehyde reduced the amount of reaction product, while better results were obtained using unfixed tissues. Optimum results were obtained following stimulation of adenylate cyclase with forskolin and in the presence of specific metabolic inhibitors. Adenylate cyclase was localized in the basolateral membranes of the principal cells which constitute a functional syncytium for Na+ transport and was absent from the apical membranes of the outermost granulosum cells. This distribution is consistent with the transepithelial Na+ transport model and defines the functional morphology of the cells involved in Na+ transport across frog skin. The results are compatible with the process of Na+ re-absorption across other epithelial cells, verifying that frog skin is a convenient model-tissue to study Na+ transport mechanisms. Adenylate cyclase was also found in membranes of the mitochondria-rich cells, a minor and parallel Na+ transporting pathway.


Assuntos
Adenilil Ciclases/análise , Ranidae/metabolismo , Pele/enzimologia , Sódio/metabolismo , Adenilil Ciclases/metabolismo , Adenilil Ciclases/fisiologia , Animais , Transporte Biológico/fisiologia , Colforsina/farmacologia , Epitélio/efeitos dos fármacos , Epitélio/enzimologia , Epitélio/fisiologia , Fixadores , Histocitoquímica/métodos , Pele/citologia , Fenômenos Fisiológicos da Pele
16.
Pigment Cell Res ; 6(4 Pt 1): 209-14, 1993 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-8248018

RESUMO

We have examined hair bulb and skin melanocytes of rufous albinos from Southern Africa to further characterize this form of albinism. In the skin melanocytes we find both eumelanosomes and pheomelanosomes at various stages of melanization and, in addition, there appeared to be many aberrant incompletely melanized melanosomes. On average, rufous melanosomes are 30% smaller than normal black skin melanosomes. In the keratinocytes, the melanosomes are packaged into distinct aggregations, whereas in normal black skin, they occur singly. We suggest that the reddish skin color of these albinos is a consequence of an increase in the pheomelanin synthesis resulting in a raised pheomelanin/eumelanin ratio and that the aggregation of melanosomes results in a skin color slightly lighter than normal. In hair bulb melanocytes, only eumelanosomes were seen and these were mostly incompletely melanized. These findings correlate with our visual observations that the hair color of Southern African albinos is very pale (light brown or ginger). Based on our observations, we speculate on the possible cause of rufous albinism.


Assuntos
Albinismo Oculocutâneo/patologia , Cabelo/ultraestrutura , Melanócitos/ultraestrutura , Pele/ultraestrutura , Albinismo Oculocutâneo/epidemiologia , Albinismo Oculocutâneo/metabolismo , Agregação Celular , Cabelo/metabolismo , Cabelo/fisiologia , Humanos , Queratinócitos/metabolismo , Queratinócitos/fisiologia , Queratinócitos/ultraestrutura , Melaninas/metabolismo , Melanócitos/metabolismo , Melanócitos/fisiologia , Microscopia Eletrônica , Pele/metabolismo , Fenômenos Fisiológicos da Pele , África do Sul/epidemiologia
17.
Antonie Van Leeuwenhoek ; 55(4): 297-302, 1989 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-2729957

RESUMO

Four strains of an undescribed, soil-borne species of the genus Myxozyma were recovered. A description of the new species, Myxozyma kluyveri, and a key to the species accepted in the genus are given.


Assuntos
Fungos Mitospóricos/classificação , Composição de Bases , Carbono/metabolismo , DNA Fúngico/análise , Fungos Mitospóricos/genética , Fungos Mitospóricos/metabolismo , Nitrogênio/metabolismo , Microbiologia do Solo , África do Sul
18.
Antonie Van Leeuwenhoek ; 55(2): 189-95, 1989.
Artigo em Inglês | MEDLINE | ID: mdl-2742374

RESUMO

Six strains of an undescribed, leaf-borne species of the genus Sporobolomyces were recovered. A description of the new species, Sporobolomyces phylladus, is given.


Assuntos
Fungos Mitospóricos/classificação , Meios de Cultura , Fungos Mitospóricos/crescimento & desenvolvimento , Fungos Mitospóricos/fisiologia , África do Sul , Esporos Fúngicos , Temperatura
19.
Antonie Van Leeuwenhoek ; 54(3): 201-6, 1988.
Artigo em Inglês | MEDLINE | ID: mdl-3421666

RESUMO

Three strains of an undescribed, leaf-borne species of the genus Sporobolomyces were recovered. A description of the new species, Sporobolomyces phyllomatis, is given.


Assuntos
Basidiomycota/isolamento & purificação , África Austral , Basidiomycota/classificação , Basidiomycota/metabolismo , Meios de Cultura , Plantas/microbiologia , Esporos Fúngicos , Temperatura
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