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1.
J Phys Chem C Nanomater Interfaces ; 125(11): 6387-6400, 2021 Mar 25.
Artigo em Inglês | MEDLINE | ID: mdl-33868543

RESUMO

Ternary lanthanide indium oxides LnInO3 (Ln = La, Pr, Nd, Sm) were synthesized by high-temperature solid-state reaction and characterized by X-ray powder diffraction. Rietveld refinement of the powder patterns showed the LnInO3 materials to be orthorhombic perovskites belonging to the space group Pnma, based on almost-regular InO6 octahedra and highly distorted LnO12 polyhedra. Experimental structural data were compared with results from density functional theory (DFT) calculations employing a hybrid Hamiltonian. Valence region X-ray photoelectron and K-shell X-ray emission and absorption spectra of the LnInO3 compounds were simulated with the aid of the DFT calculations. Photoionization of lanthanide 4f orbitals gives rise to a complex final-state multiplet structure in the valence region for the 4f n compounds PrInO3, NdInO3, and SmInO3, and the overall photoemission spectral profiles were shown to be a superposition of final-state 4f n-1 terms onto the cross-section weighted partial densities of states from the other orbitals. The occupied 4f states are stabilized in moving across the series Pr-Nd-Sm. Band gaps were measured using diffuse reflectance spectroscopy. These results demonstrated that the band gap of LaInO3 is 4.32 eV, in agreement with DFT calculations. This is significantly larger than a band gap of 2.2 eV first proposed in 1967 and based on the idea that In 4d states lie above the top of the O 2p valence band. However, both DFT and X-ray spectroscopy show that In 4d is a shallow core level located well below the bottom of the valence band. Band gaps greater than 4 eV were observed for NdInO3 and SmInO3, but a lower gap of 3.6 eV for PrInO3 was shown to arise from the occupied Pr 4f states lying above the main O 2p valence band.

2.
Nat Commun ; 10(1): 403, 2019 01 24.
Artigo em Inglês | MEDLINE | ID: mdl-30679422

RESUMO

Albuminuria affects millions of people, and is an independent risk factor for kidney failure, cardiovascular morbidity and death. The key cell that prevents albuminuria is the terminally differentiated glomerular podocyte. Here we report the evolutionary importance of the enzyme Glycogen Synthase Kinase 3 (GSK3) for maintaining podocyte function in mice and the equivalent nephrocyte cell in Drosophila. Developmental deletion of both GSK3 isoforms (α and ß) in murine podocytes causes late neonatal death associated with massive albuminuria and renal failure. Similarly, silencing GSK3 in nephrocytes is developmentally lethal for this cell. Mature genetic or pharmacological podocyte/nephrocyte GSK3 inhibition is also detrimental; producing albuminuric kidney disease in mice and nephrocyte depletion in Drosophila. Mechanistically, GSK3 loss causes differentiated podocytes to re-enter the cell cycle and undergo mitotic catastrophe, modulated via the Hippo pathway but independent of Wnt-ß-catenin. This work clearly identifies GSK3 as a critical regulator of podocyte and hence kidney function.


Assuntos
Albuminúria/metabolismo , Quinase 3 da Glicogênio Sintase/metabolismo , Nefropatias/metabolismo , Rim/fisiologia , Podócitos/metabolismo , Albuminúria/sangue , Albuminúria/patologia , Albuminúria/urina , Animais , Ciclo Celular , Linhagem Celular , Modelos Animais de Doenças , Drosophila , Deleção de Genes , Inativação Gênica , Quinase 3 da Glicogênio Sintase/genética , Glicogênio Sintase Quinase 3 beta/efeitos dos fármacos , Glicogênio Sintase Quinase 3 beta/genética , Glicogênio Sintase Quinase 3 beta/metabolismo , Via de Sinalização Hippo , Estimativa de Kaplan-Meier , Rim/patologia , Nefropatias/sangue , Nefropatias/patologia , Nefropatias/urina , Masculino , Camundongos , Podócitos/enzimologia , Podócitos/patologia , Isoformas de Proteínas/genética , Isoformas de Proteínas/metabolismo , Proteínas Serina-Treonina Quinases/genética , Proteínas Serina-Treonina Quinases/metabolismo , Proteômica , Ratos Wistar , Insuficiência Renal , Verteporfina/farmacologia , beta Catenina/metabolismo
3.
Sci Total Environ ; 631-632: 246-251, 2018 Aug 01.
Artigo em Inglês | MEDLINE | ID: mdl-29524900

RESUMO

Endocrine disruptors when introduced to waterways have many adverse health effects on wildlife and humans. These health effects vary from neurological, immune, carcinogenic and reproductive disorders. Currently, there are few wastewater treatment facilities that are purposefully treating endocrine disruptors as part of the normal wastewater treatment process. Current literature has shown that endocrine disruptors can be treated using conventional methods. These conventional methods are centered around the denitrification process, which is rarely adopted in Canada. This paper investigates the current wastewater effluent regulations and guidelines in Canada, Ontario and the European Union. The research identifies a policy strategy that would include denitrification in the wastewater treatment process to help eliminate endocrine disruptors and acutely toxic nitrogen based compounds. Our emphasis here is on action possible in the Province of Ontario Canada, give the context of the Great Lakes basin and the potential for early action to stimulate other jurisdictions to follow. Our recommendations while aimed at one jurisdiction, have broad application globally.

4.
J Frailty Aging ; 5(2): 121-5, 2016.
Artigo em Inglês | MEDLINE | ID: mdl-27224504

RESUMO

Extra physiotherapy has been associated with better outcomes in hospitalized patients, but this remains an under-researched area in geriatric medicine wards. We retrospectively studied the association between average physiotherapy frequency and outcomes in hospitalized geriatric patients. High frequency physiotherapy (HFP) was defined as ≥0.5 contacts/day. Of 358 eligible patients, 131 (36.6%) received low, and 227 (63.4%) HFP. Functional improvement (discharge versus admission) in the modified Rankin scale was greater in the HFP group (1.1 versus 0.7 points, P<0.001). The mean length of stay (LOS) of the HFP group was 6 days shorter (7 versus 13 days, P<0.001). After adjusting for age, gender, comorbidity (Charlson index), frailty (Clinical Frailty Scale), dementia and acute illness severity, HFP was an independent predictor of functional improvement, shorter LOS and likelihood of being discharged without a formal care package. Prospective research is needed to examine the effect of physiotherapy frequency and intensity in geriatric wards.


Assuntos
Demência/epidemiologia , Hospitalização/estatística & dados numéricos , Modalidades de Fisioterapia/estatística & dados numéricos , Recuperação de Função Fisiológica , Idoso , Idoso de 80 Anos ou mais , Comorbidade , Feminino , Idoso Fragilizado/estatística & dados numéricos , Avaliação Geriátrica/métodos , Humanos , Tempo de Internação , Masculino , Alta do Paciente , Avaliação de Resultados da Assistência ao Paciente , Estudos Retrospectivos , Medição de Risco , Fatores de Risco , Reino Unido/epidemiologia
5.
Nanoscale ; 6(10): 5172-80, 2014 May 21.
Artigo em Inglês | MEDLINE | ID: mdl-24700146

RESUMO

Hydrogels formed by ultrashort peptides are emerging as cost-effective materials for cell culture. However, L-peptides are labile to proteases, while their D-isomers are thought to not support cell growth as well. In contrast, the self-assembly behaviour and biological performance of heterochiral peptides (i.e., made of both d and l amino acids) are largely unknown. In this study, we evaluate the effects of amino acid chirality on tripeptide self-assembly and hydrogelation at physiological pH, and cytocompatibility in fibroblast cell culture. A series of uncapped hydrophobic tripeptides with all combinations of d, l amino acids was prepared, tested for self-assembly under physiological conditions, and analysed by circular dichroism, FT-IR, cryo-TEM, AFM, and Thioflavin T fluorescence imaging. Amino acid chirality has a profound effect on the peptides' supramolecular behaviour. Only selected isomers form hydrogels, and of amyloid structure, as confirmed by rheology and XRD. Importantly, they are able to maintain the viability and proliferation of fibroblasts in vitro. This study identifies two heterochiral gels that perform well in cell culture and will assist in the design of innovative and cost-effective peptide gel biomaterials.


Assuntos
Amiloide/química , Materiais Biocompatíveis/química , Hidrogéis/química , Peptídeos/química , Materiais Biocompatíveis/síntese química , Hidrogéis/síntese química , Concentração de Íons de Hidrogênio , Estereoisomerismo
6.
J Thromb Haemost ; 10(4): 662-9, 2012 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-22284746

RESUMO

BACKGROUND: Most physiologic processes exhibit diurnal fluctuations controlled by the circadian regulation of sleep-wake behavior and feeding cycles. In addition, many cell types express endogenous circadian rhythms that affect cell-specific processes. Independent reports support the hypothesis that thrombopoietin (TPO) is under circadian control. OBJECTIVES: The current study tested the hypothesis that CLOCK, a circadian transcription factor, may regulate Thpo, the gene encoding TPO. METHODS: Circadian gene expression patterns were analyzed in mice and in human cell lines, Small interfering RNA was used to knock down CLOCK expression in cell lines, and gene expression was also examined in Clock(Δ19/Δ19) mutant mice. RESULTS: It was found that there was a diurnal rhythm in the expression of Thpoin vivo in mice, and that this was associated with concomitant rhythms of protein abundance. Thpo was rhythmically expressed in human cell lines, consistent with the gene being directly or indirectly regulated by the circadian clock. Silencing of CLOCK in the Huh7 human hepatoma cell line led to a significant reduction in the rhythmicity of Thpo expression. The expression of Mpl in murine marrow also displayed diurnal rhythmicity in vivo. In Clock(Δ19/Δ19) mutant mice, Thpo and Mpl expression was disrupted and there was an increase in the number of mature megakaryocytes, but no change in the ploidy distribution within the megakaryocyte population. CONCLUSIONS: These findings establish that Clock regulates Thpo and Mpl expression in vivo, and demonstrate an important link between the body's circadian timing mechanisms and megakaryopoiesis.


Assuntos
Proteínas CLOCK/metabolismo , Ritmo Circadiano , Megacariócitos/metabolismo , Trombopoese , Trombopoetina/metabolismo , Animais , Proteínas CLOCK/genética , Ritmo Circadiano/genética , Regulação da Expressão Gênica , Células Hep G2 , Humanos , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Transgênicos , Mutação , Contagem de Plaquetas , Ploidias , Interferência de RNA , Receptores de Trombopoetina/genética , Receptores de Trombopoetina/metabolismo , Trombopoese/genética , Trombopoetina/sangue , Trombopoetina/genética , Fatores de Tempo , Transfecção
7.
Afr J Paediatr Surg ; 8(1): 49-56, 2011.
Artigo em Inglês | MEDLINE | ID: mdl-21478587

RESUMO

INTRODUCTION: The challenge of management with bilateral Wilms' tumours is the eradication of the neoplasm, while at the same time preserving renal function. Surgical management with a variety of nephron-sparing techniques, combined with chemotherapy and occasionally supplemented by transplantation has evolved over the last 30 years to achieve remarkable success. We document the experience of a single centre in a developing country. MATERIAL AND METHODS: Twenty-three bilateral Wilms' tumours were seen in our service between 1981 and 2007. Treatment was, in most cases, according to National Wilms' Tumour Study Group protocols, with initial bilateral biopsy, neoadjuvant chemotherapy, and tumourectomy. Technique of nephrectomy included full mobilization of the tumour-involved kidney, topical cooling with slush ice, vascular exclusion, tumour resection and reconstruction of the remnant kidney. RESULTS: Twelve patients are alive and free of disease one to 15 years after treatment, all with well-preserved renal function (lowest glomerular filtration rate was 65 ml/min per (1.73 m 2 ). None of the survivors have hypertension. Eleven have died (two of unrelated disease) including six of the seven with spread outside the kidney. All three with unfavourable histology are alive. Four of the five metachronous presentations are alive, as are eight of 12 patients with synchronous bilateral tumours who presented since 2000. CONCLUSIONS: Appropriate chemotherapy and nephron-sparing surgery can achieve good results with preservation of adequate renal function in nearly all cases. Unfavourable histology did not have a reduced survival in our series. Metastatic spread outside the kidney had a poor prognosis.


Assuntos
Protocolos de Quimioterapia Combinada Antineoplásica/uso terapêutico , Neoplasias Renais/cirurgia , Nefrectomia/métodos , Tumor de Wilms/cirurgia , Quimioterapia Adjuvante , Criança , Pré-Escolar , Intervalo Livre de Doença , Feminino , Humanos , Rim/fisiopatologia , Neoplasias Renais/classificação , Neoplasias Renais/tratamento farmacológico , Neoplasias Renais/mortalidade , Neoplasias Renais/patologia , Masculino , Terapia Neoadjuvante , Estadiamento de Neoplasias , Néfrons/patologia , Néfrons/cirurgia , Recuperação de Função Fisiológica , África do Sul , Resultado do Tratamento , Tumor de Wilms/classificação , Tumor de Wilms/tratamento farmacológico , Tumor de Wilms/mortalidade , Tumor de Wilms/patologia
8.
J Thromb Haemost ; 6(7): 1144-52, 2008 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-18419744

RESUMO

BACKGROUND: Circadian rhythms control a vast array of biological processes in a broad spectrum of organisms. The contribution of circadian rhythms to the development of megakaryocytes and the regulation of platelet biology has not been defined. OBJECTIVES: This study tested the hypothesis that murine megakaryocytes exhibit hallmarks of circadian control. METHODS: Mice expressing a PER2::LUCIFERASE circadian reporter protein and C57BI/6 mice were used to establish if megakaryocytes expressed circadian genes in vitro and in vivo. Mice were also subjected to 3 weeks on a restricted feeding regime to separate food-entrained from light-entrained circadian rhythms. Quantitative real time polymerase chain reaction (PCR), flow cytometry and imunohistochemistry were employed to analyse gene expression, DNA content and cell-cycle behavior in megakaryocytes collected from mice over a 24-h period. RESULTS: Megakaryocytes exhibited rhythmic expression of the clock genes mPer2 and mBmal1 and circadian rhythms in megakaryopoiesis. mPer2 and mBmal1 expression phase advanced 8 h to coincide with the availability of food; however, food availability had a more complex effect on megakaryopoiesis, leading to a significant overall increase in megakaryocyte ploidy levels and cell-cycle activity. CONCLUSIONS: Normal megakaryopoiesis requires synchrony between food- and light-entrained circadian oscillators.


Assuntos
Fatores de Transcrição Hélice-Alça-Hélice Básicos/genética , Proteínas de Ciclo Celular/genética , Ingestão de Alimentos/fisiologia , Eritropoese , Megacariócitos/citologia , Proteínas Nucleares/genética , Periodicidade , Fatores de Transcrição/genética , Fatores de Transcrição ARNTL , Animais , Ciclo Celular , Ritmo Circadiano/genética , Ingestão de Alimentos/genética , Alimentos , Perfilação da Expressão Gênica , Regulação da Expressão Gênica , Camundongos , Camundongos Endogâmicos C57BL , Proteínas Circadianas Period
9.
J Phys Chem B ; 111(6): 1384-92, 2007 Feb 15.
Artigo em Inglês | MEDLINE | ID: mdl-17286353

RESUMO

In the quest to rationally design novel mesophase systems the challenge remains to deconvolute the relationship between structure, composition, and function. In the current study, novel glycerol-derived surfactants with high negative interfacial areas and a preference for inverse phase behavior have been targeted and synthesized. This has been achieved by application of the rule-of-thumb afforded by the critical packing parameter (CPP), namely, that inverse phase behavior is favored by wedge-shaped molecules with relatively small head group versus chain volume. Highly splayed hydrophobes with exaggerated cross section such as oleyl (cis-octadec-9-enyl) hexahydrofarnesyl (3,7,11-trimethyl-dodecyl) and phytanyl (3,7,11,15-tetramethyl-hexadecyl) were particularly successful for this purpose across many variations of head group. The phase behavior of the binary system in water of many of these surfactants is relatively simple. Typically, cubic or inverse hexagonal phases exist at the interface with water with the inverse micellar phases present at lower hydration. The inverse liquid crystalline phases were present for a broad range of temperatures and compositions.


Assuntos
Ácidos Glicéricos/síntese química , Cristais Líquidos/química , Tensoativos/síntese química , Água/química , Álcoois Graxos/química , Glicerol/análogos & derivados , Interações Hidrofóbicas e Hidrofílicas , Micelas , Microscopia , Modelos Moleculares , Ácido Oleico/química , Transição de Fase , Solubilidade , Temperatura
10.
Bioconjug Chem ; 18(1): 152-9, 2007.
Artigo em Inglês | MEDLINE | ID: mdl-17226968

RESUMO

Lyotropic mesophases of the inverse hexagonal or cubic type are nanostructured materials that result from the self-assembly of amphiphilic surfactant molecules in water. The extremely large area of the surfactant-water interface inherent within these structures makes them attractive media for sorbent or encapsulant systems. Here, we report on the development of a new class of polyvalent materials that are based on the incorporation of bioactive ligands within lyotropic mesophases. In particular, we have studied the potential for these materials to behave as polyvalent antitoxins by incorporating synthetic galactose amphiphiles, which mimic the natural cell surface ligand for the protein toxin ricin. The study demonstrates that cubic morphology lyotropic mesophases containing galactose amphiphiles exhibit high specificity ricin uptake, with favorably high dissociation constants and high capacities. We suggest that lyotropic mesophase polyvalent ligands are thus promising materials for the incorporation of a broad range of cell surface recognition moieties and hence may have wide applicability as materials capable of partaking in biological recognition processes.


Assuntos
Antitoxinas/química , Galactose/química , Ricina/química , Tensoativos/química , Estrutura Molecular , Soluções
11.
J Appl Toxicol ; 26(3): 247-52, 2006.
Artigo em Inglês | MEDLINE | ID: mdl-16489581

RESUMO

A selection of galactose and lactose analogues was evaluated for their potency in inhibiting the binding of ricin to immobilised asialofetuin, which is a model of the cell-surface receptor for ricin. The aim was to identify compounds that could be used as antagonists of ricin toxicity in vivo, and as more selective, and therefore safer, antitoxins. Although one of these analogues had been identified by molecular modelling in a previous study as a potentially potent inhibitor, it and the other carbohydrates studied were less effective than galactose and lactose themselves (I(50) = 1.39 and 0.74 mM, respectively). In an attempt to increase the potency of carbohydrate-based inhibitors, galactose was coupled to the surface of dendrimers. No synergistic interactions were observed from this multivalent approach. Encouraging results, however, were obtained with a self-assembled lyotropic mesophase gel containing novel synthetic galactose-based surfactants, which was able to sequester ricin from aqueous solution in a 2-phase system.


Assuntos
Dendrímeros/farmacologia , Galactose/farmacologia , Lactose/farmacologia , Receptores de Superfície Celular/metabolismo , Ricina/antagonistas & inibidores , Assialoglicoproteínas/metabolismo , Linhagem Celular Tumoral , Sobrevivência Celular/efeitos dos fármacos , Dendrímeros/química , Fetuínas , Galactose/química , Humanos , Lactose/química , Modelos Biológicos , Estrutura Molecular , Ligação Proteica , Ricina/toxicidade , Relação Estrutura-Atividade , alfa-Fetoproteínas/metabolismo
12.
J Pediatr Surg ; 39(9): 1321-7, 2004 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-15359384

RESUMO

BACKGROUND/PURPOSE: The aim of this study was to retrospectively evaluate and compare the clinical features, treatment strategy, pathology, and outcome of all patients with hepatoblastoma treated at an African hospital over a 31-year period (1970 to 2001). METHODS: Forty patients with hepatoblastoma were divided into 3 groups according to the treatment given. Group I (1970 to 1983, 14 patients) had no protocol therapy; group II (1984 to 1988, 6 patients) received protocol treatment according to Children's Study Group (CCSG) guidelines; group III (1989 to 2001, 20 patients) received SIOPEL protocol therapy. All available clinical, surgical, radiologic, and pathologic data were reviewed and analyzed. RESULTS: Overall patient survival was as follows: group I, 14%; group II, 50%, and group III, 80%. Deaths in group II were caused by chemotherapy-induced immunosuppression only. Prognostic data for group III showed that all tumor-related deaths could be predicted by identifying multifocal disseminated growth patterns (P =.001) or vascular invasion (P =.001) in resected tumors. Of the 40 diagnostic tumor biopsies performed, 2 significant complications (1 death, 1 intraperitoneal tumor seeding) occurred. Histologic criteria evaluating these biopsies were not predictive of overall survival. CONCLUSIONS: The introduction of protocol therapy has resulted in a marked improvement in survival. Immunosuppression-related sepsis in our setting resulted in unacceptable mortality in patients treated according to CCSG guidelines. A diagnostic biopsy in hepatoblastoma is of value but not without complications. Preoperative chemotherapy followed by complete surgical excision according to International Society of Paediatric Oncology guidelines yields excellent results with a current survival rate of 80%.


Assuntos
Protocolos de Quimioterapia Combinada Antineoplásica/uso terapêutico , Hepatoblastoma/cirurgia , Neoplasias Hepáticas/cirurgia , Terapia Neoadjuvante , Protocolos de Quimioterapia Combinada Antineoplásica/administração & dosagem , Protocolos de Quimioterapia Combinada Antineoplásica/efeitos adversos , Administração de Caso/tendências , Pré-Escolar , Cisplatino/administração & dosagem , Terapia Combinada , Doxorrubicina/administração & dosagem , Feminino , Hepatectomia , Hepatoblastoma/diagnóstico por imagem , Hepatoblastoma/tratamento farmacológico , Hepatoblastoma/mortalidade , Hepatoblastoma/secundário , Humanos , Hospedeiro Imunocomprometido , Lactente , Recém-Nascido , Neoplasias Hepáticas/diagnóstico por imagem , Neoplasias Hepáticas/tratamento farmacológico , Neoplasias Hepáticas/mortalidade , Neoplasias Hepáticas/patologia , Neoplasias Pulmonares/secundário , Masculino , Estadiamento de Neoplasias , Prognóstico , Radiografia , Estudos Retrospectivos , Sepse/etiologia , Sepse/mortalidade , África do Sul/epidemiologia , Análise de Sobrevida , Resultado do Tratamento , Carga Tumoral
13.
S Afr Med J ; 94(7): 533-6, 2004 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-15285454

RESUMO

UNLABELLED: Objectives. To record the age-specific incidence rate (ASIR) for diagnosed acute lymphoblastic leukaemia (ALL) in coloured and white children aged 0 - 12 years in the Western Cape (WC). DESIGN: A retrospective population-based study using the 1991 population census to calculate the mean annual childhood population and the ASIR for ALL in the 0 - 4, 5 - 9 and 10 - 12-year age groups in rural and Cape Town metropolitan areas for the period 1983 - 1999. Odds ratios were calculated using EpiInfo 2000. SETTING: Registry records of the paediatric cancer units at Tygerberg and Red Cross War Memorial Children's hospitals where all children with ALL in the WC were initially treated. SUBJECTS: All white and coloured children aged 0 - 12 years diagnosed as having ALL from 1983 - 1999. OUTCOME MEASURES: The ASIR by age and ethnic group in rural and metropolitan patients in the WC. RESULTS: The estimated annual childhood population in 1991 was 709 151 with 80.4% coloured and 19.6% white children, of whom 60% were resident in the Cape Town metropolitan area and 40% in the rural area of the WC. Of 246 children with ALL diagnosed in the period 1983 - 1999, 144 were male and 102 female. The ASIR in coloured children aged 0 - 4 years was 17.1/10(6) in the rural and 30.5/10(6) in the metropolitan area, compared with 55.7/10(6) and 56.2/10(6) respectively in white children. In the 5 - 9-year age group the ASIR in coloured children was 10.0/10(6) in the rural and 16.6/10(6) in the metropolitan area compared with 27.6/10(6) and 26.7/10(6) respectively in white children. The 10 - 12-year age group had comparable incidence rates in both populations and geographical areas. Only one case occurred within a 20 km radius of the Koeberg nuclear reactor. CONCLUSIONS: White children have an ASIR for ALL comparable to rates of diagnosis in the USA, while only half as many coloured children aged 0 - 9 years were diagnosed in both the rural and metropolitan areas. This contrast may indicate significant underdiagnosis of ALL in coloured children over the period in question. The change in health policy since 1994, which has improved access to primary health care, may improve the rate of diagnosis among coloured and black children.


Assuntos
População Negra , Leucemia-Linfoma Linfoblástico de Células Precursoras/etnologia , População Branca , Adolescente , Distribuição por Idade , Criança , Pré-Escolar , Feminino , Humanos , Incidência , Lactente , Recém-Nascido , Masculino , Saúde da População Rural , África do Sul/epidemiologia , Saúde da População Urbana
14.
Dev Biol ; 266(2): 334-45, 2004 Feb 15.
Artigo em Inglês | MEDLINE | ID: mdl-14738881

RESUMO

The formation of the essential functional unit of the ovary, the primordial follicle, occurs during fetal life in humans. Factors regulating oogonial proliferation and interaction with somatic cells before primordial follicle formation are largely unknown. We have investigated the expression, localisation and functional effects of activin and its receptors in the human fetal ovary at 14-21 weeks gestation. Expression of mRNA for the activin betaA and betaB subunits and the activin receptors ActRIIA and ActRIIB was demonstrated by RT-PCR. Expression of betaA mRNA increased 2-fold across the gestational range examined. Activin subunits and receptors were localised by immunohistochemistry. The betaA subunit was expressed by oogonia, and the betaB subunit and activin receptors were expressed by both oogonia and somatic cells. BetaA expression was increased in larger oogonia at later gestations, but was low in oocytes within newly formed primordial follicles. Treatment of ovary fragments with activin A in vitro increased both the number of oogonia present and oogonial proliferation, as detected by bromodeoxyuridine (BrdU) incorporation. These data indicate that activin may be involved in the autocrine and paracrine regulation of germ cell proliferation in the human ovary during the crucial period of development leading up to primordial follicle formation.


Assuntos
Receptores de Activinas Tipo II/metabolismo , Ativinas/metabolismo , Células Germinativas/fisiologia , Subunidades beta de Inibinas/metabolismo , Ovário/fisiologia , Subunidades Proteicas/metabolismo , Receptores de Activinas Tipo II/genética , Ativinas/genética , Divisão Celular/fisiologia , Sobrevivência Celular/fisiologia , Células Cultivadas , Feminino , Idade Gestacional , Humanos , Subunidades beta de Inibinas/genética , Folículo Ovariano/citologia , Folículo Ovariano/embriologia , Folículo Ovariano/metabolismo , Ovário/citologia , Ovário/embriologia , Subunidades Proteicas/genética
15.
S Afr Med J ; 93(10): 793-6, 2003 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-14652975

RESUMO

OBJECTIVES: To record the number of haemophilicas aged 0-18 years in the Western Cape (WC), what event led to the diagnosis, the level of clotting factor, treatment, functional status of their joints and impact of the disease on the family. DESIGN: A prospective study of patients registered with the South African National Haemophilia Registry and new patients, utilising the patients' paediatricians, hospital records, patient and guardian interviews, physical examination and provincial nurse haemophilia co-ordinators. SETTING: Haemophilia care centres at the three WC academic hospitals, regional hospitals and homes of patients. Two elective medical students, MHH and JJH, collected the information. SUBJECTS: All boys with confirmed haemophilia A or B in the WC. OUTCOME MEASURES: Events that led to diagnosis, degree of haemophilia, use of clotting factor, functional status, and effect on family. RESULTS: Of 78 patients (59 haemophilia A, 19 haemophilia B) identified, 49 could be studied. Forty-three per cent had severe, 29% moderate and 22% mild disease (6% unknown). Family history was present in 49%, but led to diagnosis in only 12%. The most common first symptoms were subcutaneous and mucosal bleeding. Delay in diagnosis varied from 0 to 9 months. Twenty-nine per cent of guardians were suspected of child abuse. RSA produced clotting factor was used 'on demand' in 73% of patients, for periodic prophylaxis in 20% and as continuous prophylaxis in 7%. Joints were functionally restricted in 43% of patients. The majority of guardians (59%) said the disease had a major impact on the family. CONCLUSIONS: The diagnosis of haemophilia in children with a positive family history was often delayed. Haemophilia causes significant morbidity in our patients and their families.


Assuntos
Hemofilia A/epidemiologia , Hemofilia B/epidemiologia , Adolescente , Criança , Maus-Tratos Infantis/diagnóstico , Maus-Tratos Infantis/estatística & dados numéricos , Pré-Escolar , Família/psicologia , Hematoma/etiologia , Hemofilia A/diagnóstico , Hemofilia B/diagnóstico , Hemorragia/etiologia , Humanos , Lactente , Recém-Nascido , Artropatias/etiologia , Masculino , Estudos Prospectivos , Sistema de Registros , Dermatopatias/etiologia , África do Sul/epidemiologia
16.
Ultramicroscopy ; 94(3-4): 283-91, 2003 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-12524198

RESUMO

A combined scanning near field optical/atomic force microscope (AFM) is used to obtain surface force measurements between a near field sensing tip and a tapered optical fibre surface, whilst simultaneously detecting the intensity of the evanescent field emanating from the fibre. The tapered optical fibre acts as a compliant sample to demonstrate the possible use of the near field intensity measurement system in determining 'real' surface separations from normal AFM surface force measurements at sub-nanometer resolution between deformable surfaces.


Assuntos
Microscopia de Força Atômica/métodos , Óptica e Fotônica/instrumentação , Algoritmos , Radiação , Propriedades de Superfície
17.
J Clin Endocrinol Metab ; 87(7): 3417-27, 2002 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-12107261

RESUMO

The regulation of germ cell number in the developing ovary is central to female reproduction. Members of the Bcl-2 family of proapoptotic and antiapoptotic proteins have been implicated in this process in rodents. We investigated the expression of Mcl-1, Bcl-2, Bax, and BAD at 13-21 gestational wk in the human fetal ovary and of Mcl-1 in the adult ovary. mRNA expression of Mcl-1 and its short form Mcl-1s, Bcl-2, Bax, and BAD was demonstrated in fetal ovary by RT-PCR. Hybridization array analysis suggested a selective increase in Mcl-1 expression between 14 and 18 wk gestation, which was confirmed by quantitative PCR. There was a corresponding change in the expression of Mcl-1 protein, detected by immunohistochemistry, from germ cells at the periphery of the ovary at 14-16 wk to the largest germ cells, including oocytes within newly formed primordial follicles, at 21 wk. Mcl-1 was also expressed by oocytes of primordial and preantral follicles in the adult. Bax and BAD immunostaining was detected in both somatic and germ cells in the fetal ovary, whereas Bcl-2 was restricted to somatic cells: no changes in expression were observed. Apoptotic cells, detected by terminal deoxynucleotidyl transferase-mediated dUTP nick end labeling, were observed in all fetal ovaries but were infrequent. These results confirm that Bcl-2 family members are differentially expressed in several cell types within the developing human ovary. Increased mRNA expression and the changing distribution of Mcl-1 in germ cells as they develop into primordial follicles as well as persistence in the growing oocyte in the adult may indicate an important role for this survival/antiapoptotic factor throughout germ cell development and maturation.


Assuntos
Feto/metabolismo , Proteínas de Neoplasias/metabolismo , Oócitos/fisiologia , Folículo Ovariano/embriologia , Proteínas de Transporte/genética , Proteínas de Transporte/metabolismo , DNA Complementar/genética , Desenvolvimento Embrionário e Fetal , Feminino , Feto/citologia , Humanos , Immunoblotting , Imuno-Histoquímica , Marcação In Situ das Extremidades Cortadas , Proteína de Sequência 1 de Leucemia de Células Mieloides , Análise de Sequência com Séries de Oligonucleotídeos , Ovário/embriologia , Reação em Cadeia da Polimerase , Proteínas Proto-Oncogênicas/genética , Proteínas Proto-Oncogênicas/metabolismo , Proteínas Proto-Oncogênicas c-bcl-2/genética , Proteínas Proto-Oncogênicas c-bcl-2/metabolismo , RNA Mensageiro/metabolismo , Reação em Cadeia da Polimerase Via Transcriptase Reversa , Distribuição Tecidual , Proteína X Associada a bcl-2 , Proteína de Morte Celular Associada a bcl
18.
Reproduction ; 123(6): 779-88, 2002 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-12052232

RESUMO

Inhibins and activins have roles in the regulation of cell proliferation and differentiation in a variety of tissues. This study investigated the distribution of the three inhibin/activin subunits (alpha, betaA and betaB) and their receptors in the human testis between week 13 and week 19 of gestation using RT-PCR and immunohistochemistry. mRNA for all three subunits and for the activin type II receptors ActRIIA and ActRIIB was detected at all stages of gestation examined. Sertoli cells showed intense immunostaining for the alpha subunit and some staining for the betaB subunit, whereas only the betaB subunit was detected in gonocytes. No betaA subunit staining was detected within the tubules. All three subunits were localized to interstitial Leydig cells. Cells of the rete testis and the epididymal epithelium also showed immunostaining for betaB; however, staining for the other subunits was weak or absent. Peritubular cells showed intense immunostaining for the beta-glycan inhibin receptor, which was also localized to interstitial cells, but was not detected within the tubular compartment, rete testis or epididymal epithelium. ActRIIA was detected in gonocytes and in interstitial cells; ActRIIB was distributed widely. These data indicate that fetal Leydig and Sertoli cells have the potential to produce both activins and inhibins, whereas gonocytes may produce only activin B. The distribution of activin and inhibin receptors implies that the intratubular compartment and developing duct system are sites of action of activin B but not inhibin at this stage of development, whereas both activins and inhibins may be involved in the development and function of the peritubular and interstitial cells.


Assuntos
Actinas/metabolismo , Receptores de Ativinas/metabolismo , Subunidades beta de Inibinas/metabolismo , Testículo/embriologia , Actinas/análise , Actinas/genética , Receptores de Ativinas/análise , Receptores de Ativinas/genética , Humanos , Imuno-Histoquímica/métodos , Subunidades beta de Inibinas/análise , Subunidades beta de Inibinas/genética , Masculino , Proteoglicanas/metabolismo , Receptores de Fatores de Crescimento Transformadores beta/metabolismo , Reação em Cadeia da Polimerase Via Transcriptase Reversa , Testículo/metabolismo
19.
J Exp Psychol Appl ; 7(1): 3-12, 2001 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-11577618

RESUMO

People often have knowledge about the chances of events but are unable to express their knowledge in the form of coherent probabilities. This study proposed to correct incoherent judgment via an optimization procedure that seeks the (coherent) probability distribution nearest to a judge's estimates of chance. This method was applied to the chances of simple and complex meteorological events, as estimated by college undergraduates. No judge responded coherently, but the optimization method found close (coherent) approximations to their estimates. Moreover, the approximations were reliably more accurate than the original estimates, as measured by the quadratic scoring rule. Methods for correcting incoherence facilitate the analysis of expected utility and allow human judgment to be more easily exploited in the construction of expert systems.


Assuntos
Julgamento , Aprendizagem por Probabilidade , Adulto , Sistemas Inteligentes , Feminino , Humanos , Masculino , Estudantes/psicologia , Tempo (Meteorologia)
20.
Pediatr Surg Int ; 17(5-6): 378-81, 2001 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-11527170

RESUMO

Liver transplantation (LT) for malignancy has had disappointing long-term results due to tumour recurrence. Ex-vivo dissection and auto-transplantation have had poor results when the tumor was obstructing bile ducts. Advances in liver surgery have made extensive liver resection safer, but cases of "unresectable" tumours due to site and size still present. A 10-year-old boy was referred with jaundice due to a 6 x 8-cm central (segment 4) tumour shown on biopsy to be a fibrolamellar hepatocellular carcinoma. Ultrasound (US) and Computed Tomography also showed dilatation of intrahepatic bile ducts in both lobes. Angiography showed a large tumour mass supplied by the left branch of the hepatic artery, a low take-off of a right branch of the hepatic artery, and a very displaced but patent portal vein. The initial surgical consensus was that the tumour was unresectable. The patient was listed for LT with the plan of first attempting resection with a liver graft-in-waiting. An extended left hepatectomy was performed under total vascular exclusion with resection of the tumour, which had extended from segment 4 into surrounding segments 1, 3, 5, and 8. Intraoperative US assisted in planning the resection. The right hepatic vein, artery, and the right branch of the portal vein could be preserved and a Roux loop was anastomosed to a markedly dilated segment 6 and 7 intrahepatic duct for bile drainage. Vascular exclusion time was 30 min. The patient made a good recovery without major complications. Jaundice and bile-duct dilatation resolved. On follow up at 5 years there was no recurrence. The liver graft-in-waiting gave the surgical team confidence to proceed with an extensive resection beyond a "point of no return" and allowed good clearance of the disease and avoidance of LT with all the long-term consequences of immunosuppression. This mandates that extensive hepatic surgery in children should be carried out in centres that have a facility for LT should the need arise.


Assuntos
Carcinoma Hepatocelular/cirurgia , Hepatectomia/métodos , Neoplasias Hepáticas/cirurgia , Carcinoma Hepatocelular/patologia , Criança , Tomada de Decisões , Humanos , Neoplasias Hepáticas/patologia , Transplante de Fígado , Masculino
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