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1.
J Med Imaging Radiat Sci ; 54(2S): S15-S16, 2023 06.
Artículo en Inglés | MEDLINE | ID: mdl-36922276

RESUMEN

Gerhardus George Visser Koch, also known as Erhard, is a qualified, independent practice, diagnostic radiographer from South Africa. Erhard's work experience ranges from having occupied various positions in both the public and private healthcare sectors. He has a passion for academia and research, currently occupying the role of a lecturer in diagnostic radiography. Erhard has a keen interest in radiation protection, health professions education, professional role extension and artificial intelligence. He loves animals, enjoys spending time in nature, likes to paint and travel. This free form poem is about my two cats, Jasper and Alice, and the significant role they play in my everyday life, more specifically so, my mental wellness. I simply cannot imagine my life without the two of them. Many have asked me where their names come from, and the answer is always: "No, it does not stem from the Twilight movies". Jasper and Alice were both rescued as kittens. They were abandoned and left to die. Shortly after, I adopted them from an animal rescue agency who shared their stories on social media. Jasper and Alice have always been by my side; through both personal and professional, downfalls and victories. Up to now, and from my 12 years of experience in the field, I have relocated several times. I have moved from one city to the next, all for the love of what I do and for the opportunities that came my way. I am happy to report that I have found my way back to academia, and this is where I'd like to stay.


Asunto(s)
Inteligencia Artificial , Masculino , Femenino , Animales , Gatos , Sudáfrica
2.
J Steroid Biochem Mol Biol ; 163: 129-35, 2016 10.
Artículo en Inglés | MEDLINE | ID: mdl-27142456

RESUMEN

SM6Met, a phytoestrogenic extract of Cyclopia subternata indigenous to the Western Cape province of South Africa, displays estrogenic attributes with potential for breast cancer chemoprevention. In this study, we report that SM6Met, in the presence of estradiol, induces a significant cell cycle G0/G1 phase arrest similar to the selective estrogen receptor modulator, tamoxifen. Furthermore, as a proof of concept, in the N-Methyl-N-nitrosourea induced rat mammary gland carcinogenesis model, SM6Met increases tumor latency by 7days and median tumor free survival by 42 days, while decreasing palpable tumor frequency by 32%, tumor mass by 40%, and tumor volume by 53%. Therefore, the current study provides proof of concept that SM6Met has definite potential as a chemopreventative agent against the development and progression of breast cancer.


Asunto(s)
Antineoplásicos Fitogénicos/farmacología , Cyclopia (Planta)/química , Glándulas Mamarias Animales/efectos de los fármacos , Neoplasias Mamarias Experimentales/tratamiento farmacológico , Fitoestrógenos/farmacología , Animales , Antineoplásicos Fitogénicos/aislamiento & purificación , Línea Celular Tumoral , Antagonistas de Estrógenos/farmacología , Femenino , Puntos de Control de la Fase G1 del Ciclo Celular/efectos de los fármacos , Puntos de Control de la Fase G1 del Ciclo Celular/genética , Humanos , Glándulas Mamarias Animales/metabolismo , Glándulas Mamarias Animales/patología , Neoplasias Mamarias Experimentales/inducido químicamente , Neoplasias Mamarias Experimentales/mortalidad , Neoplasias Mamarias Experimentales/patología , Metilnitrosourea , Fitoestrógenos/aislamiento & purificación , Ratas , Receptores de Estrógenos/antagonistas & inhibidores , Receptores de Estrógenos/genética , Receptores de Estrógenos/metabolismo , Análisis de Supervivencia , Tamoxifeno/farmacología , Carga Tumoral/efectos de los fármacos
3.
PLoS One ; 8(11): e79223, 2013.
Artículo en Inglés | MEDLINE | ID: mdl-24223909

RESUMEN

Hormone replacement therapy associated risks, and the concomitant reluctance of usage, has instigated the search for new generations of estrogen analogues that would maintain estrogen benefits without associated risks. Furthermore, if these analogues display chemo-preventative properties in breast and endometrial tissues it would be of great value. Both the selective estrogen receptor modulators as well as the selective estrogen receptor subtype modulators have been proposed as estrogen analogues with improved risk profiles. Phytoestrogen containing extracts of Cyclopia, an indigenous South African fynbos plant used to prepare Honeybush tea may serve as a source of new estrogen analogues. In this study three extracts, P104, SM6Met, and cup-of-tea, from two species of Cyclopia, C. genistoides and C. subternata, were evaluated for ER subtype specific agonism and antagonism both in transactivation and transrepression. For transactivation, the Cyclopia extracts displayed ERα antagonism and ERß agonism when ER subtypes were expressed separately, however, when co-expressed only agonism was uniformly observed. In contrast, for transrepression, this uniform behavior was lost, with some extracts (P104) displaying uniform agonism, while others (SM6Met) displayed antagonism when subtypes were expressed separately and agonism when co-expressed. In addition, breast cancer cell proliferation assays indicate that extracts antagonize cell proliferation in the presence of estrogen at lower concentrations than that required for proliferation. Furthermore, lack of uterine growth and delayed vaginal opening in an immature rat uterotrophic model validates the ERα antagonism of extracts observed in vitro and supports the potential of the Cyclopia extracts as a source of estrogen analogues with a reduced risk profile.


Asunto(s)
Receptor alfa de Estrógeno/antagonistas & inhibidores , Receptor beta de Estrógeno/agonistas , Fabaceae/química , Extractos Vegetales/farmacología , Animales , Western Blotting , Células COS , Proliferación Celular/efectos de los fármacos , Chlorocebus aethiops , Estradiol/análogos & derivados , Estradiol/farmacología , Receptor alfa de Estrógeno/genética , Receptor alfa de Estrógeno/metabolismo , Receptor beta de Estrógeno/genética , Receptor beta de Estrógeno/metabolismo , Fabaceae/clasificación , Femenino , Fulvestrant , Genisteína/farmacología , Humanos , Luciferasas/genética , Luciferasas/metabolismo , Células MCF-7 , FN-kappa B/genética , FN-kappa B/metabolismo , Fitoestrógenos/farmacología , Regiones Promotoras Genéticas/genética , Ratas , Ratas Wistar , Especificidad de la Especie , Útero/efectos de los fármacos , Útero/crecimiento & desarrollo , Vagina/efectos de los fármacos , Vagina/fisiología
4.
Planta Med ; 79(7): 580-90, 2013 May.
Artículo en Inglés | MEDLINE | ID: mdl-23609108

RESUMEN

Cyclopia Vent. species, commonly known as honeybush, are endemic to Southern Africa. The plant is traditionally used as an herbal tea but several health benefits have recently been recorded. This minireview presents an overview of polyphenols found in Cyclopia and focuses on the phytoestrogenic potential of selected polyphenols and of extracts prepared from the plant.


Asunto(s)
Cyclopia (Planta)/química , Fitoestrógenos/uso terapéutico , Fitoterapia , Extractos Vegetales/uso terapéutico , Polifenoles/uso terapéutico , Femenino , Humanos , Fitoestrógenos/farmacología , Extractos Vegetales/farmacología , Polifenoles/farmacología , Sudáfrica
5.
Endocrinology ; 151(11): 5279-93, 2010 Nov.
Artículo en Inglés | MEDLINE | ID: mdl-20881254

RESUMEN

The liver plays an important role in inflammation and stress by producing the acute phase proteins (APPs) required for resolution of inflammation as well as by delivering systemic glucose, through gluconeogenesis, required to fuel the stress response. Disruption of the interplay between interleukin 6 (IL-6) and glucocorticoids (GCs), the peripheral mediators of inflammation and stress, respectively, may lead to side-effects associated with the pharmacological use of GCs. The current study investigated the interplay between IL-6 and GCs in a hepatoma cell line (BWTG3) at protein (protein activity assays, Western blotting, and ELISA) and mRNA (qPCR) levels. Specifically, the action of dexamethasone (Dex), a known antiinflammatory drug and glucocorticoid receptor (GR) agonist, is compared to that of Compound A (CpdA), a selective glucocorticoid receptor agonist (SEGRA). CpdA, like IL-6, but unlike Dex, increases GR binding and decreases the metabolic enzymes, tyrosine aminotransferase, phosphoenolpyruvate carboxykinase, and gamma glutamyltransferase, at protein or mRNA level. Like Dex, both CpdA and IL-6 increase the positive APPs, serum amyloid A and C-reactive protein, and decrease the negative APP, corticosteroid binding globulin. The study shows that the GC, Dex, and IL-6 generally have divergent effects on the GR and metabolic enzymes, while their functions are convergent on the APPs. In contrast to Dex, CpdA has effects convergent to that of IL-6 on the GR, metabolic enzymes, and APPs. Thus these findings suggest that CpdA, like Dex, modulates APPs, leading to effective control of inflammation, while, in contrast to Dex, it is less likely to lead to GC-induced side-effects.


Asunto(s)
Inflamación/metabolismo , Interleucina-6/metabolismo , Hígado/metabolismo , Receptores de Glucocorticoides/metabolismo , Estrés Fisiológico/fisiología , Análisis de Varianza , Animales , Western Blotting , Línea Celular Tumoral , Células Cultivadas , Dexametasona/farmacología , Ensayo de Inmunoadsorción Enzimática , Glucocorticoides/farmacología , Interleucina-6/farmacología , Hígado/efectos de los fármacos , Ratones , Receptores de Glucocorticoides/agonistas , Reacción en Cadena de la Polimerasa de Transcriptasa Inversa
6.
J Biol Chem ; 285(11): 8061-75, 2010 Mar 12.
Artículo en Inglés | MEDLINE | ID: mdl-20037160

RESUMEN

Compound A (CpdA), a dissociated glucocorticoid receptor modulator, decreases corticosteroid-binding globulin (CBG), adrenocorticotropic hormone (ACTH), and luteneinizing hormone levels in rats. Whether this is due to transcriptional regulation by CpdA is not known. Using promoter reporter assays we show that CpdA, like dexamethasone (Dex), directly transrepresses these genes. Results using a rat Cbg proximal-promoter reporter construct in BWTG3 and HepG2 cell lines support a glucocorticoid receptor (GR)-dependent transrepression mechanism for CpdA. However, CpdA, unlike Dex, does not result in transactivation via glucocorticoid-responsive elements within a promoter reporter construct even when GR is co-transfected. The inability of CpdA to result in transactivation via glucocorticoid-responsive elements is confirmed on the endogenous tyrosine aminotransferase gene, whereas transrepression ability is confirmed on the endogenous CBG gene. Consistent with a role for CpdA in modulating GR activity, whole cell binding assays revealed that CpdA binds reversibly to the GR, but with lower affinity than Dex, and influences association of [(3)H]Dex, but has no effect on dissociation. In addition, like Dex, CpdA causes nuclear translocation of the GR, albeit to a lesser degree. Several lines of evidence, including fluorescence resonance energy transfer, co-immunoprecipitation, and nuclear immunofluorescence studies of nuclear localization-deficient GR show that CpdA, unlike Dex, does not elicit ligand-induced GR dimerization. Comparison of the behavior of CpdA in the presence of wild type GR to that of Dex with a dimerization-deficient GR mutant (GR(dim)) strongly supports the conclusion that loss of dimerization is responsible for the dissociated behavior of CpdA.


Asunto(s)
Adenina/farmacología , Citratos/farmacología , Dexametasona/farmacología , Glucocorticoides/farmacología , Glucosa/farmacología , Fosfatos/farmacología , Receptores de Glucocorticoides , Activación Transcripcional/efectos de los fármacos , Adenina/metabolismo , Animales , Células COS , Carcinoma Hepatocelular , Línea Celular Tumoral , Chlorocebus aethiops , Citratos/metabolismo , Dexametasona/metabolismo , Dimerización , Expresión Génica/efectos de los fármacos , Genes Reporteros/genética , Glucocorticoides/metabolismo , Glucosa/metabolismo , Humanos , Neoplasias Hepáticas , Ratones , Mutagénesis , Neuronas/citología , Fosfatos/metabolismo , Regiones Promotoras Genéticas/genética , Ratas , Ratas Wistar , Receptores de Glucocorticoides/química , Receptores de Glucocorticoides/genética , Receptores de Glucocorticoides/metabolismo , Relación Estructura-Actividad , Transcortina/genética , Activación Transcripcional/fisiología , Tritio , Tirosina Transaminasa/genética , Tirosina Transaminasa/metabolismo
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