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1.
Biomed Phys Eng Express ; 10(4)2024 Jun 18.
Artigo em Inglês | MEDLINE | ID: mdl-38848695

RESUMO

Recent advancements in computational intelligence, deep learning, and computer-aided detection have had a significant impact on the field of medical imaging. The task of image segmentation, which involves accurately interpreting and identifying the content of an image, has garnered much attention. The main objective of this task is to separate objects from the background, thereby simplifying and enhancing the significance of the image. However, existing methods for image segmentation have their limitations when applied to certain types of images. This survey paper aims to highlight the importance of image segmentation techniques by providing a thorough examination of their advantages and disadvantages. The accurate detection of cancer regions in medical images is crucial for ensuring effective treatment. In this study, we have also extensive analysis of Computer-Aided Diagnosis (CAD) systems for cancer identification, with a focus on recent research advancements. The paper critically assesses various techniques for cancer detection and compares their effectiveness. Convolutional neural networks (CNNs) have attracted particular interest due to their ability to segment and classify medical images in large datasets, thanks to their capacity for self- learning and decision-making.


Assuntos
Algoritmos , Inteligência Artificial , Diagnóstico por Imagem , Processamento de Imagem Assistida por Computador , Neoplasias , Redes Neurais de Computação , Humanos , Neoplasias/diagnóstico por imagem , Neoplasias/diagnóstico , Processamento de Imagem Assistida por Computador/métodos , Diagnóstico por Imagem/métodos , Diagnóstico por Computador/métodos , Aprendizado Profundo
2.
Brain Res ; 1823: 148668, 2024 01 15.
Artigo em Inglês | MEDLINE | ID: mdl-37951563

RESUMO

Brain age in neuroimaging has emerged over the last decade and reflects the estimated age based on the brain MRI scan from a person. As a person ages, their brain structure will change, and these changes will be exclusive to males and females and will differ for each. White matter and grey matter density have a deeper relationship with brain aging. Hence, if the white matter and grey matter concentrations vary, the rate at which the brain ages will also vary. Neurodegenerative illnesses can be detected using the biomarker known as brain age. The development of deep learning has made it possible to analyze structural neuroimaging data in new ways, notably by predicting brain ages. We introduce the techniques and possible therapeutic uses of brain age prediction in this cutting-edge review. Creating a machine learning regression model to analyze age-related changes in brain structure among healthy individuals is a typical procedure in studies focused on brain aging. Subsequently, this model is employed to forecast the aging of brains in new individuals. The concept of the "brain-age gap" refers to the difference between an individual's predicted brain age and their actual chronological age. This score may serve as a gauge of the general state of the brain's health while also reflecting neuroanatomical disorders. It may help differential diagnosis, prognosis, and therapy decisions as well as early identification of brain-based illnesses. The following is a summary of the many forecasting techniques utilized over the past 11 years to estimate brain age. The study's conundrums and potential outcomes of the brain age predicted by current models will both be covered.


Assuntos
Encéfalo , Substância Branca , Masculino , Feminino , Humanos , Encéfalo/diagnóstico por imagem , Imageamento por Ressonância Magnética/métodos , Envelhecimento , Neuroimagem , Substância Branca/diagnóstico por imagem
3.
Vet World ; 8(12): 1396-9, 2015 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-27047050

RESUMO

AIM: Detection of aflatoxin B1 in Livestock compound Feed and feed ingredients by high-performance thin layer chromatography (HPTLC). MATERIALS AND METHODS: Chromatography was performed on HPTLC silica gel 60 F 254, aluminum sheets by CAMAG automatic TLC sampler 4, with mobile phase condition chloroform:acetone:water (28:4:0.06). Extraction of aflatoxin B1 from samples was done as per AOAC method and screening and quantification done by HPTLC Scanner 4 under wavelength 366 nm. RESULTS: A total of 97 livestock feed (48) and feed ingredients (49) samples received from different livestock farms and farmers were analyzed for aflatoxin B1of which 29 samples were contaminated, constituting 30%. Out of 48 livestock compound feed samples, aflatoxin B1 could be detected in 16 samples representing 33%, whereas in livestock feed ingredients out of 49 samples, 13 found positive for aflatoxin B1 representing 24.5%. CONCLUSION: HPTLC assures good recovery, precision, and linearity in the quantitative determination of aflatoxin B1 extracted from Livestock compound feed and feed ingredients. As more number of feed and feed ingredients are contaminated with aflatoxin B1 which causes deleterious effects in both animal and human beings, so there is a need for identifying the source of contamination, executing control measures, enabling better risk assessment techniques, and providing economic benefits.

5.
Int J Radiat Oncol Biol Phys ; 79(5): 1523-31, 2011 Apr 01.
Artigo em Inglês | MEDLINE | ID: mdl-21310544

RESUMO

PURPOSE: Epithelial-to-mesenchymal transition (EMT) is a phenotype that alters cell morphology, disrupts morphogenesis, and increases motility. Our prior studies have shown that the progeny of human mammary epithelial cells (HMECs) irradiated with 2 Gy undergoes transforming growth factor ß (TGF-ß)-mediated EMT. In this study we determined whether radiation dose or quality affected TGF-ß-mediated EMT. METHODS AND MATERIALS: HMECs were cultured on tissue culture plastic or in Matrigel (BD Biosciences, San Jose, CA) and exposed to low or high linear energy transfer (LET) and TGF-ß (400 pg/mL). Image analysis was used to measure membrane-associated E-cadherin, a marker of functional epithelia, or fibronectin, a product of mesenchymal cells, as a function of radiation dose and quality. RESULTS: E-cadherin was reduced in TGF-ß-treated cells irradiated with low-LET radiation doses between 0.03 and 2 Gy compared with untreated, unirradiated cells or TGF-ß treatment alone. The radiation quality dependence of TGF-ß-mediated EMT was determined by use of 1 GeV/amu (gigaelectron volt/atomic mass unit) (56)Fe ion particles at the National Aeronautics and Space Administration's Space Radiation Laboratory. On the basis of the relative biological effectiveness of 2 for (56)Fe ion particles' clonogenic survival, TGF-ß-treated HMECs were irradiated with equitoxic 1-Gy (56)Fe ion or 2-Gy (137)Cs radiation in monolayer. Furthermore, TGF-ß-treated HMECs irradiated with either high- or low-LET radiation exhibited similar loss of E-cadherin and gain of fibronectin and resulted in similar large, poorly organized colonies when embedded in Matrigel. Moreover, the progeny of HMECs exposed to different fluences of (56)Fe ion underwent TGF-ß-mediated EMT even when only one-third of the cells were directly traversed by the particle. CONCLUSIONS: Thus TGF-ß-mediated EMT, like other non-targeted radiation effects, is neither radiation dose nor quality dependent at the doses examined.


Assuntos
Caderinas/análise , Células Epiteliais/efeitos da radiação , Transição Epitelial-Mesenquimal/efeitos da radiação , Fibronectinas/análise , Fator de Crescimento Transformador beta/farmacologia , Biomarcadores/análise , Mama/citologia , Técnicas de Cultura de Células/métodos , Radioisótopos de Césio/farmacologia , Colágeno , Ensaio de Unidades Formadoras de Colônias/métodos , Relação Dose-Resposta à Radiação , Combinação de Medicamentos , Células Epiteliais/química , Células Epiteliais/efeitos dos fármacos , Células Epiteliais/fisiologia , Transição Epitelial-Mesenquimal/efeitos dos fármacos , Transição Epitelial-Mesenquimal/fisiologia , Feminino , Humanos , Ferro/farmacologia , Laminina , Transferência Linear de Energia/fisiologia , Proteoglicanas , Eficiência Biológica Relativa
6.
Clin Cancer Res ; 14(19): 6193-7, 2008 Oct 01.
Artigo em Inglês | MEDLINE | ID: mdl-18829498

RESUMO

PURPOSE: Metastatic melanomas are generally resistant to chemotherapy and radiation, even when wild-type for p53. These tumors often grow in small nests where many of the cells have little contact with extracellular matrix (ECM). Previous work showed that M21 melanomas undergo apoptosis in response to chemotherapy when cells are adherent to ECM but not in suspension. Thus, reduced integrin-dependent adhesion to ECM could mediate therapy resistance. The goal of this study was to test whether stimulation of integrin signaling could increase chemotherapeutic efficacy. EXPERIMENTAL DESIGN: Colony forming assays and survival assays were used to test the responses of melanoma lines in vitro. Severe combined immunodeficient mice with subcutaneous human melanomas received chemotherapy with or without reagents that stimulate integrin signaling; tumor volume was then monitored over time. RESULTS: Clonal growth assays confirmed that M21 cells showed reduced sensitivity to the chemotherapeutic drug 1-beta-D-arabinofuranosylcytosine (araC). When five additional primary melanoma lines were screened, 80% showed higher sensitivity when adherent compared with suspended. Subcutaneous M21 tumors in vivo showed minimal ECM between tumor cells. To evaluate the importance of integrin signaling in chemoresistance in this model, mice were treated with araC, with or without the multivalent snake venom disintegrin contortrostatin or the activating anti-beta1 integrin antibody TS2/16. Although araC, TS2/16, or contortrostatin alone had little effect on M21 tumor growth, combining araC with either integrin signaling reagents strongly reduced growth (P = 0001). CONCLUSIONS: Loss of integrin-mediated adhesion is rate limiting for therapeutic response in this model. Combining chemotherapy with reagents that stimulate integrin signaling may therefore provide a new approach to therapy.


Assuntos
Antineoplásicos/farmacologia , Genes p53 , Integrinas/agonistas , Melanoma/tratamento farmacológico , Adjuvantes Farmacêuticos/farmacologia , Animais , Apoptose , Linhagem Celular Tumoral , Citarabina/farmacologia , Matriz Extracelular/metabolismo , Humanos , Integrinas/metabolismo , Oncologia/métodos , Camundongos , Camundongos SCID , Transdução de Sinais
7.
Mar Environ Res ; 65(5): 445-55, 2008 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-18358526

RESUMO

Studies on the Arabian Sea coastal anoxia have been of immense interest, but despite its ecological significance there is sparse understanding of the microbes involved. Hence, observations were carried out off Goa (15 degrees 30'N, 72 degrees 40'E to 15 degrees 30'N, 72 degrees 59'E) to understand the processes that mediate the changes in various inorganic nitrogen species in the water column during anoxia. Water column chemistry showed a clear distinct oxic environment in the month of April and anoxic condition in October. Our study based on microbial signatures indicated that oxygen deficit appeared as a well-defined nucleus almost 40 km away from the coast during the oxic period (April) and spreads there after to the entire water column synchronizing with the water chemistry. Striking results of net changes in inorganic nitrogen species in nitrification blocked and unblocked experimental systems show that denitrification is the predominant process in the water column consuming available nitrate ( approximately 0.5 microM) to near zero levels within approximately 72 h of incubation. These observations have been supported by concomitant increase in nitrite concentration ( approximately 4 microM). Similar studies on denitrification-blocked incubations, demonstrate the potential of nitrification to feed denitrification. Nitrification could contribute almost 4.5 microM to the total nitrate pool. It was found that the relation between ammonium and total dissolved inorganic nitrogen (DIN) pool (r=0.98, p<0.001, n=122) was significant compared to the latter with nitrite and nitrate. The occurrence of high ammonium under low phosphate conditions corroborates our observations that ammonium does not appear to be locked under low oxygen regimes. It is suggested that ammonium actively produced by detrital breakdown (ammonification) is efficiently consumed through nitrification process. The three processes in concert viz. ammonification, nitrification and denitrification appear to operate in more temporal and spatial proximity than hitherto appreciated in these systems and this gives additional cues on the absence of measurable nitrate at surface waters, which was earlier attributed only to efficient algal uptake. Hence we hypothesize that the alarming nitrous oxide input into the atmosphere could be due to high productivity driven tighter nitrification-denitrification coupling, rather than denitrification driven by extraneous nitrate.


Assuntos
Bactérias/metabolismo , Nitrogênio/metabolismo , Oxigênio/análise , Água do Mar/química , Microbiologia da Água , Bactérias/classificação , Índia , Nitratos/metabolismo , Nitritos/metabolismo , Fosfatos/análise , Densidade Demográfica , Compostos de Amônio Quaternário/análise , Temperatura , Fatores de Tempo
8.
Int J Radiat Biol ; 83(11-12): 803-11, 2007.
Artigo em Inglês | MEDLINE | ID: mdl-18058368

RESUMO

PURPOSE: The first reports that ionizing radiation (IR) induces rapid and persistent activation of transforming growth factor beta1 (TGFbeta) were nearly two decades ago. Subsequent studies have shown that TGFbeta is a major mediator of cellular and tissue responses to IR and have revealed novel facets of its complex biology. RESULTS: We and others have recently shown that inhibition of production or signaling of TGFbeta in epithelial cells modulates radiosensitivity and impedes activation of the DNA damage response program. The primary transducer of cellular response to DNA damage caused by ionizing radiation is the nuclear protein kinase ataxia telangiectasia mutated, whose activity is severely compromised when TGFbeta is inhibited. Thus, in conjunction, with its well-recognized contribution to normal tissue fibrosis, the role of TGFbeta in the genotoxic stress program provides a previously unsuspected avenue to modulate radiotherapy. CONCLUSIONS: We hypothesize that identification of the circumstances and tumors in which TGFbeta manipulation enhances tumor cell radiosensitivity, while protecting normal tissues, could significantly increase therapeutic index.


Assuntos
Neoplasias/radioterapia , Fator de Crescimento Transformador beta/antagonistas & inibidores , Animais , Proteínas Mutadas de Ataxia Telangiectasia , Proteínas de Ciclo Celular/metabolismo , Dano ao DNA , Proteínas de Ligação a DNA/metabolismo , Expressão Gênica , Humanos , Modelos Biológicos , Neoplasias/tratamento farmacológico , Neoplasias/genética , Neoplasias/metabolismo , Proteínas Serina-Treonina Quinases/metabolismo , Tolerância a Radiação/efeitos dos fármacos , Tolerância a Radiação/fisiologia , Radiobiologia , Transdução de Sinais/efeitos dos fármacos , Transdução de Sinais/fisiologia , Transdução de Sinais/efeitos da radiação , Fator de Crescimento Transformador beta/metabolismo , Proteínas Supressoras de Tumor/antagonistas & inibidores , Proteínas Supressoras de Tumor/metabolismo
9.
Cancer Res ; 67(18): 8662-70, 2007 Sep 15.
Artigo em Inglês | MEDLINE | ID: mdl-17875706

RESUMO

Transforming growth factor beta1 (TGFbeta) is a tumor suppressor during the initial stage of tumorigenesis, but it can switch to a tumor promoter during neoplastic progression. Ionizing radiation (IR), both a carcinogen and a therapeutic agent, induces TGFbeta activation in vivo. We now show that IR sensitizes human mammary epithelial cells (HMEC) to undergo TGFbeta-mediated epithelial to mesenchymal transition (EMT). Nonmalignant HMEC (MCF10A, HMT3522 S1, and 184v) were irradiated with 2 Gy shortly after attachment in monolayer culture or treated with a low concentration of TGFbeta (0.4 ng/mL) or double treated. All double-treated (IR + TGFbeta) HMEC underwent a morphologic shift from cuboidal to spindle shaped. This phenotype was accompanied by a decreased expression of epithelial markers E-cadherin, beta-catenin, and ZO-1, remodeling of the actin cytoskeleton, and increased expression of mesenchymal markers N-cadherin, fibronectin, and vimentin. Furthermore, double treatment increased cell motility, promoted invasion, and disrupted acinar morphogenesis of cells subsequently plated in Matrigel. Neither radiation nor TGFbeta alone elicited EMT, although IR increased chronic TGFbeta signaling and activity. Gene expression profiling revealed that double-treated cells exhibit a specific 10-gene signature associated with Erk/mitogen-activated protein kinase (MAPK) signaling. We hypothesized that IR-induced MAPK activation primes nonmalignant HMEC to undergo TGFbeta-mediated EMT. Consistent with this, Erk phosphorylation was transiently induced by irradiation and persisted in irradiated cells treated with TGFbeta, and treatment with U0126, a MAP/Erk kinase (MEK) inhibitor, blocked the EMT phenotype. Together, these data show that the interactions between radiation-induced signaling pathways elicit heritable phenotypes that could contribute to neoplastic progression.


Assuntos
Mama/efeitos dos fármacos , Mama/efeitos da radiação , Transformação Celular Neoplásica/efeitos dos fármacos , Transformação Celular Neoplásica/efeitos da radiação , Fator de Crescimento Transformador beta/farmacologia , Mama/metabolismo , Mama/patologia , Transformação Celular Neoplásica/metabolismo , Transformação Celular Neoplásica/patologia , Ativação Enzimática , Células Epiteliais/efeitos dos fármacos , Células Epiteliais/patologia , Células Epiteliais/efeitos da radiação , Humanos , Sistema de Sinalização das MAP Quinases/efeitos dos fármacos , Sistema de Sinalização das MAP Quinases/efeitos da radiação , Mesoderma/efeitos dos fármacos , Mesoderma/patologia , Mesoderma/efeitos da radiação , Quinases de Proteína Quinase Ativadas por Mitógeno/metabolismo
10.
Ultrasound Med Biol ; 33(7): 1057-63, 2007 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-17448590

RESUMO

To examine whether the magnitude-squared coherence between uterine and umbilical blood flow velocity waveforms can, in conjunction with estimated fetal weight, uterine and umbilical pulsatility indices, fetal and maternal heart rates, diastolic notching and the amniotic fluid index, create a sensitive and specific model for the prediction of placental dysfunction. Binary logistic prediction models are created for preeclampsia, pregnancy induced hypertension and intrauterine growth restriction in a study group of 284 unselected midtrimester pregnancies. In each study group, the median value of derived parameters were compared with the uncomplicated pregnancy control group. The magnitude-squared coherence function between the uterine and umbilical flow velocity waveforms was found to be a statistically significant predictor of preeclampsia during the midtrimester of pregnancy. The magnitude-squared coherence did not improve the prediction of intrauterine growth restriction or pregnancy induced hypertension. The inclusion of magnitude-squared coherence as one of the prediction parameters may improve the early identification of pregnancies subsequently complicated by preeclampsia.


Assuntos
Sangue Fetal/diagnóstico por imagem , Placenta/fisiopatologia , Complicações na Gravidez/diagnóstico por imagem , Útero/diagnóstico por imagem , Adulto , Peso ao Nascer/fisiologia , Velocidade do Fluxo Sanguíneo/fisiologia , Índice de Massa Corporal , Feminino , Sangue Fetal/fisiologia , Retardo do Crescimento Fetal/diagnóstico por imagem , Retardo do Crescimento Fetal/fisiopatologia , Idade Gestacional , Frequência Cardíaca/fisiologia , Frequência Cardíaca Fetal/fisiologia , Humanos , Hipertensão Induzida pela Gravidez/diagnóstico por imagem , Hipertensão Induzida pela Gravidez/fisiopatologia , Recém-Nascido , Pré-Eclâmpsia/diagnóstico por imagem , Pré-Eclâmpsia/fisiopatologia , Gravidez , Complicações na Gravidez/fisiopatologia , Fatores de Risco , Ultrassonografia Doppler/métodos , Artérias Umbilicais/diagnóstico por imagem , Útero/irrigação sanguínea
11.
J Steroid Biochem Mol Biol ; 103(3-5): 811-4, 2007 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-17270431

RESUMO

The hormonal form of vitamin D, 1,25-dyhydroxyvitamin D3 (1,25(OH)2D3), is implicated in a wide range of functions other than its classical role in calcium and phosphorous homeostasis. When Toxoplasma gondii-infected BALB/c mice were treated with 1,25(OH)2D3, they succumb to death sooner than their counterparts. But they showed less parasite burden in tissues which was further supported by mild pathological lesions. As an effort to understand the physiological mechanism for the above observation an in vitro study was performed. Fewer parasites were observed when 1,25(OH)2D3 pre-treated murine intestinal epithelial cells were challenged with parasites. Moreover, the observed inhibition was dose-dependent and had a maximum effect with 10(-7)M of 1,25(OH)2D3. However, no observable difference was observed, when pre-incubated parasites were added to cells suggesting that the observed inhibition was a result of an effect from 1,25(OH)2D3 on Toxoplasma intracellular growth. Our data support the notion that 1,25(OH)2D3 may inhibit intra cellular T. gondii parasite proliferation in vivo and in vitro.


Assuntos
Calcitriol/farmacologia , Calcitriol/uso terapêutico , Toxoplasma/efeitos dos fármacos , Toxoplasma/crescimento & desenvolvimento , Toxoplasmose/tratamento farmacológico , Toxoplasmose/parasitologia , Animais , Feminino , Camundongos , Camundongos Endogâmicos BALB C , Toxoplasmose/patologia
12.
Environ Int ; 32(2): 229-34, 2006 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-16216326

RESUMO

Monthly collections of the clam Paphia malabarica were made for period of 1 year from May 2002 to April 2003 from Verem, Mandovi estuary, Goa. Clams were categorised into two groups, 25-35 mm (small size) and 35-40 mm (big size). Significant difference was not observed in the accumulation of metals in the whole soft tissue between the two size groups. Irrespective of size, annual mean, metal content recorded as microg/g dry weight in the whole soft tissue was 3.8, 30.3, 13.5, 36.6 and 105.7, respectively, for Cd, Pb, Cu, Zn and Fe. Of the two toxic elements Cd and Pb, Cd content was almost uniform throughout the year except for a rise in September for the small size and October for the big size. Pb, on the other hand, was low from the beginning of the monsoon and exhibited distinct accumulation from December onwards up to April, May and, to some extent, June. The pattern was similar in both the size groups, the values being higher for the bigger size group. The three essential elements Cu, Fe and Zn exhibit trends similar to one another with peaks in September and December-January in both the size groups. Cadmium accumulation was highest in the mantle and adductor muscle, Lead, in foot, Copper, in digestive gland and gonad, and Zn and Fe, in gills. Correlation coefficient between different metal couplings as tested statistically revealed significant coupling for Zn-Fe (r 0.92) in the bigger size group, the same was observed between Cu-Fe (r 0.62) and Cd-Zn (r 0.94). Seasonal difference in Pb accumulation was highly significant.


Assuntos
Bivalves/metabolismo , Metais Pesados/análise , Poluentes Químicos da Água/análise , Animais , Sistema Digestório/química , Monitoramento Ambiental , Contaminação de Alimentos , Brânquias/química , Gônadas/química , Humanos , Índia , Metais Pesados/metabolismo , Músculos/química , Medição de Risco , Água do Mar , Frutos do Mar , Poluentes Químicos da Água/metabolismo
13.
Cancer Res ; 65(23): 10862-71, 2005 Dec 01.
Artigo em Inglês | MEDLINE | ID: mdl-16322233

RESUMO

The initial invasive processes during cancer development remain largely unknown. Stromelysin-3/matrix metalloproteinase 11 (ST3/MMP11) is associated with tumor invasion and poor prognosis. We present novel evidence that adipocytes present at human breast tumor invasive front are induced by cancer cells to express ST3. Using mouse syngeneic model, light and electron microscopy showed that in ST3-deficient mice but not in wild-type mice, forced cancer cell-adipocyte interaction/crosstalk results in adipocyte membrane alteration, allowing cancer cell fat infiltration and death. Thus, adipocytes are involved in initial cancer cell survival into connective tissue, and this effect is ST3 mediated. This suggested that ST3 might play a role in adipocyte metabolism. Accordingly, ST3-deficient mice exhibited fat excess and increased mRNA levels of peroxisome proliferator-activated receptor gamma (PPARgamma) and adipocyte protein 2 (aP2) adipogenic markers, indicating that, in vivo, ST3 negatively regulates fat homeostasis. Moreover, ST3-deficient mouse embryonic fibroblasts exhibited a dramatic enhanced potential to differentiate into adipocytes associated with increased PPARgamma and aP2 expression, and recombinant ST3 treatment reverted their differentiation. Thus, in vitro, ST3 reduces adipocyte differentiation in an autocrine manner. High fibroblasts/adipocytes ratio is a stroma feature, and peritumoral fibroblast origin remains debated. Our results support the concept that invading cancer cells aberrantly restore the negative ST3 function on adipogenesis into proximal adipocytes/preadipocytes, leading to the accumulation/maintenance of a particular peritumoral fibroblast subpopulation. Accordingly, in human breast tumors, we observed that ST3-expressing peritumoral fibroblasts are distinct from alpha-smooth muscle actin-expressing myofibroblasts. This constitutes the first report of implication of a MMP in cancer cell-adipocyte interaction/crosstalk during early steps of connective tissue invasion.


Assuntos
Adipócitos/citologia , Adipogenia/fisiologia , Neoplasias da Mama/patologia , Comunicação Celular/fisiologia , Metaloendopeptidases/fisiologia , Adipócitos/metabolismo , Animais , Neoplasias da Mama/metabolismo , Diferenciação Celular/fisiologia , Neoplasias do Colo/metabolismo , Neoplasias do Colo/patologia , Embrião de Mamíferos , Feminino , Fibroblastos/citologia , Fibroblastos/metabolismo , Humanos , Masculino , Metaloproteinase 11 da Matriz , Metaloendopeptidases/biossíntese , Metaloendopeptidases/deficiência , Camundongos , Camundongos Endogâmicos BALB C , Invasividade Neoplásica
14.
Int J Cancer ; 113(5): 775-81, 2005 Feb 20.
Artigo em Inglês | MEDLINE | ID: mdl-15499617

RESUMO

The in vivo disposition and antitumor efficacy of a newly developed phosphinic matrix metalloproteinase inhibitor (RXP03) were examined. RXP03 potently inhibits MMP-11, MMP-8 and MMP-13, but not MMP-1 and MMP-7. Twenty-four hours after i.p. injection into mice, most of the RXP03 was recovered intact in plasma, feces (biliary excretion) and tumor tissue. Pharmacokinetic parameters indicated that, after an i.p. dose of 100 microg/day, the plasma concentration of RXP03 over 24 hr remained higher than the Ki values determined for MMP-11, MMP-8 and MMP-13. Efficacy of RXP03 on the growth of primary tumors induced by s.c. injection of C(26) colon carcinoma cells in mice was observed to depend both on RXP03 doses and treatment schedules. Tumor volumes in mice treated for 18 days with 50, 100 and 150 microg/day of RXP03 were decreased compared with control tumor volumes, 100 microg/day being the most effective dose. Treatment at higher dose (600 microg/day) did not significantly reduce the tumor size as compared to control. Short treatments with RXP03 100 microg/day, 3 to 7 days after C(26) inoculation, were more effective on tumor growth than continuous treatment over 18 days. Strikingly, RXP03 treatment started 6 days after the C(26) injection and continued until day 18 led to stimulation of tumor growth, as compared to control. These paradoxical effects, depending on the RXP03 treatment schedule, underline the need to define carefully the spatiotemporal function of each MMP at various stages of tumor growth to achieve optimal therapeutic effects by MMP inhibitor treatment.


Assuntos
Neoplasias do Colo/tratamento farmacológico , Inibidores Enzimáticos/farmacologia , Inibidores de Metaloproteinases de Matriz , Oligopeptídeos/farmacologia , Fragmentos de Peptídeos/farmacologia , Alquilantes/toxicidade , Animais , Apoptose/efeitos dos fármacos , Proliferação de Células/efeitos dos fármacos , Neoplasias do Colo/induzido quimicamente , Neoplasias do Colo/enzimologia , Progressão da Doença , Relação Dose-Resposta a Droga , Esquema de Medicação , Cinética , Linfócitos do Interstício Tumoral , Metaloproteinases da Matriz/metabolismo , Camundongos , Camundongos Endogâmicos BALB C , Nitrosometiluretano/toxicidade
15.
IEEE Trans Biomed Eng ; 51(11): 2085-8, 2004 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-15536910

RESUMO

The application of ultrasound in assessing the fetal cardiovascular system often requires the accurate estimation of maximum blood flow velocity waveforms using Doppler measurements. The modified geometric method estimates the maximum Doppler frequency as the frequency at which the vertical distance between the integrated spectrum and the reference line that connects the origin to the maximum value of the integrated spectrum is the largest. This paper presents a mathematical formulation for a class of maximum blood flow velocity estimation algorithms that includes the modified geometric method. The analysis provides a rationale for the continued use of the modified geometric method for estimating the maximum frequency envelopes of Doppler signals. This paper also contains experimental results demonstrating the superiority of the modified geometric method over a commonly used threshold crossing method.


Assuntos
Algoritmos , Velocidade do Fluxo Sanguíneo , Monitorização Fetal/métodos , Interpretação de Imagem Assistida por Computador/métodos , Síndromes da Apneia do Sono/diagnóstico , Síndromes da Apneia do Sono/embriologia , Artérias Umbilicais/diagnóstico por imagem , Feminino , Humanos , Gravidez , Síndromes da Apneia do Sono/fisiopatologia , Ultrassonografia Doppler/métodos
16.
Cancer Res ; 63(18): 5844-9, 2003 Sep 15.
Artigo em Inglês | MEDLINE | ID: mdl-14522908

RESUMO

In human carcinomas, stromelysin-3/matrix metalloproteinase 11 (ST3, MMP11) expression by nonmalignant fibroblastic cells located in the immediate vicinity of cancer cells is a bad prognostic factor. Using mouse models of primary tumors, it has been demonstrated that ST3 is a key player during local invasion, favoring cancer cell survival in connective tissue through an antiapoptotic function. To investigate the ST3 impact on additional phases of cancer cell invasion, we developed mammary gland cancer prone MMTV-ras transgenic mice in wild-type (ras+/+;ST3+/+) or ST3-deficient (ras+/+;ST3-/-) genotype and studied their whole natural cancer history. The tumor-free survival and delay between the first ras oncogenic hit and primary tumor appearance increased in ras+/+;ST3-/- mice (P < 0.000001 and <0.0000007, respectively). A systematic search for occult primary tumors and metastases revealed, in addition to a lower total number and size of primary tumors (P < 0.02), an unexpected higher number of metastases (P < 0.01) in ras+/+;ST3-/- mice. Moreover, for a similar number and size of primary invasive tumors, ras+/+;ST3-/- mice developed more metastases, indicating that the cancer cells evolving in ST3-deficient stroma have an increased potential to hematogenous dissemination. We conclude that the ST3 microenvironment is a consistently active partner of invading cancer cells but that its function differs throughout cancer progression, being tumor enhancer or repressor in processes leading to local or distal invasion. Such a dual effect for an MMP might shed light, at least partially, for the absence of survival benefit for patients included in anti-MMP clinical trials.


Assuntos
Transformação Celular Viral/fisiologia , Genes ras/fisiologia , Neoplasias Mamárias Experimentais/enzimologia , Neoplasias Mamárias Experimentais/patologia , Vírus do Tumor Mamário do Camundongo/fisiologia , Metaloendopeptidases/fisiologia , Animais , Feminino , Neoplasias Hepáticas Experimentais/enzimologia , Neoplasias Hepáticas Experimentais/secundário , Neoplasias Pulmonares/enzimologia , Neoplasias Pulmonares/secundário , Masculino , Neoplasias Mamárias Experimentais/virologia , Metaloproteinase 11 da Matriz , Metaloendopeptidases/deficiência , Camundongos , Camundongos Transgênicos
17.
IEEE Trans Biomed Eng ; 50(8): 950-7, 2003 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-12892322

RESUMO

This paper presents a new measure of heart rate variability (HRV) that can be estimated using Doppler ultrasound techniques and is robust to variations in the angle of incidence of the ultrasound beam and the measurement noise. This measure employs the multiple signal characterization (MUSIC) algorithm which is a high-resolution method for estimating the frequencies of sinusoidal signals embedded in white noise from short-duration measurements. We show that the product of the square-root of the estimated signal-to-noise ratio (SNR) and the mean-square error of the frequency estimates is independent of the noise level in the signal. Since varying angles of incidence effectively changes the input SNR, this measure of HRV is robust to the input noise as well as the angle of incidence. This paper includes the results of analyzing synthetic and real Doppler ultrasound data that demonstrates the usefulness of the new measure in HRV analysis.


Assuntos
Algoritmos , Frequência Cardíaca Fetal/fisiologia , Ultrassonografia Pré-Natal/métodos , Artérias Umbilicais/diagnóstico por imagem , Artérias Umbilicais/fisiologia , Envelhecimento/fisiologia , Velocidade do Fluxo Sanguíneo , Cardiotocografia/métodos , Ecocardiografia Doppler/métodos , Eletrocardiografia/métodos , Feminino , Idade Gestacional , Coração/fisiologia , Humanos , Gravidez , Controle de Qualidade , Processos Estocásticos
18.
Oncogene ; 22(24): 3770-80, 2003 Jun 12.
Artigo em Inglês | MEDLINE | ID: mdl-12802284

RESUMO

MLN64, is invariably coamplified and coexpressed with erbB-2 in breast cancers. The human MLN64 and ERBB2 genes are positioned at less than 50 kb from each other, on chromosome 17q12. To understand the molecular basis of MLN64 overexpression in cancer, the genomic region containing the MLN64 and ERBB2 genes was isolated and mapped. The two genes, DARPP32 and Telethonin, flanking MLN64 respectively on its centromeric and telomeric sides, although coamplified, are not overexpressed in breast cancer cells, indicating that gene amplification is not sufficient to allow overexpression. The MLN64 minimal promoter was isolated and found to be a housekeeping gene promoter containing four potential Sp1 binding elements. Using Sp1-deficient Drosophila SL2 cells, MLN64 promoter activity was induced in a dose-dependent manner by exogenous Sp1 addition. Furthermore, mutation of each individual Sp1 element resulted in a significant decrease in reporter gene activity, indicating that all the Sp1 binding elements are functional and act together to promote gene expression. Since the ERBB2 promoter is also positively regulated by Sp1, this study indicates that MLN64 and ERBB2 genes share common transcriptional controls together with a physical link on chromosome 17q. We speculate that, in addition to the oncogenic potential of erbB-2 overexpression, the unbalanced action of MLN64 contributes to the poor clinical outcome of breast tumors bearing this amplified region.


Assuntos
Neoplasias da Mama/genética , Proteínas de Transporte , Regulação Neoplásica da Expressão Gênica , Proteínas de Membrana/genética , Fator de Transcrição Sp1/fisiologia , Sequência de Aminoácidos , Sequência de Bases , Sítios de Ligação , Proteína beta Intensificadora de Ligação a CCAAT/fisiologia , Linhagem Celular , Sequência Conservada , Feminino , Amplificação de Genes , Genes erbB-2 , Humanos , Proteínas de Membrana/química , Dados de Sequência Molecular , Regiões Promotoras Genéticas
19.
Mol Cell Biochem ; 130(1): 29-40, 1994 Jan 12.
Artigo em Inglês | MEDLINE | ID: mdl-7514715

RESUMO

Cellular morphology, macromolecular composition, (DNA, RNA and Protein content) marker enzyme activities for neurons [neuron specific enolase (NSE)] and astrocytes [glutamine synthetase (GS)] and plasma membrane protein profiles in the bulk isolated neurons and astrocytes from control and ethanol treated rats were studied. One month aged Wistar rats were given ethanol as sole drinking fluid for 10 weeks. Scanning electron microscopy revealed a characteristic cell surface smoothening in astrocytes due to ethanol treatment. DNA levels were unaltered, while RNA and Protein contents were decreased in astrocytes and neurons. Further, 3H-leucine incorporation into proteins was decreased in neurons and astrocytes derived from ethanol treated rats indicating reduced protein synthesis in neurons and astrocytes. GS activity was affected severely suggesting impairment in astrocytic functions. Plasma membrane protein composition was analyzed by 2-D electrophoresis. The analysis indicated several protein defects in the plasma membranes of neurons and astrocytes, which might be involved in 'membrane disorder' during ethanol challenge. 125I-Wheat Germ agglutinin binding studies showed three prominent proteins (160, 116 and 97 kDa) in astrocyte membrane fraction suggesting the possible involvement of N-terminal glycoproteins in altered astrocyte morphology during ethanol ingestion. Impairment in the astrocyte cell functions, protein changes in plasma membrane and cellular morphology studies suggest that astrocytes may be more vulnerable than neurons for ethanol effects.


Assuntos
Alcoolismo/patologia , Astrócitos/efeitos dos fármacos , Etanol/farmacologia , Proteínas de Membrana/análise , Neurônios/efeitos dos fármacos , Alcoolismo/metabolismo , Animais , Astrócitos/química , Astrócitos/ultraestrutura , Comportamento Animal/efeitos dos fármacos , Peso Corporal/efeitos dos fármacos , Encéfalo/patologia , DNA/análise , Etanol/sangue , Feminino , Glutamato-Amônia Ligase/metabolismo , Masculino , Neurônios/química , Neurônios/ultraestrutura , Fosfopiruvato Hidratase/metabolismo , Proteínas/análise , RNA/análise , Ratos , Ratos Wistar
20.
Mol Cell Biochem ; 130(1): 41-8, 1994 Jan 12.
Artigo em Inglês | MEDLINE | ID: mdl-8190119

RESUMO

The endogenous protein phosphorylation patterns in plasma membranes of bulk isolated neurons and astroglia from control and chronic ethanol treated rats have been investigated. Chronic ethanol treatment resulted in increased phosphorylation of specific proteins with molecular weights 116, 63 and 60 kDa in both neurons and astrocytes. These proteins were further resolved by 2-DE and the analysis suggested an increased phosphorylation of congruent to 10-15 proteins, of which 116 kDa protein is phosphorylated to a higher extent by ethanol. Further, decreased phosphorylation was noticed in D-95 and D-63 proteins in neurons and D-78 and D-54 proteins in astrocytes. Alkali stability experiments for identifying the phosphoamino acid involved in phosphorylation of 116, 63 and 60 kDa proteins suggested that tyrosine and threonine are not involved and probably serine is the likely site for phosphorylation during chronic ethanol treatment. The phosphorylation of specific membrane proteins during chronic ethanol treatment might contribute to ethanol evoked cellular dysfunction.


Assuntos
Alcoolismo/metabolismo , Astrócitos/efeitos dos fármacos , Etanol/farmacologia , Proteínas de Membrana/metabolismo , Neurônios/efeitos dos fármacos , Animais , Astrócitos/metabolismo , Encéfalo/metabolismo , Encéfalo/patologia , Membrana Celular/metabolismo , Feminino , Masculino , Neurônios/metabolismo , Fosfoproteínas/análise , Fosforilação , Ratos , Ratos Wistar , Serina/análise , Hidróxido de Sódio
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