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1.
Neuropsychopharmacology ; 46(3): 579-602, 2021 02.
Artigo em Inglês | MEDLINE | ID: mdl-32781459

RESUMO

Maternal immune activation (MIA) and poor maternal nutritional habits are risk factors for the occurrence of neurodevelopmental disorders (NDD). Human studies show the deleterious impact of prenatal inflammation and low n-3 polyunsaturated fatty acid (PUFA) intake on neurodevelopment with long-lasting consequences on behavior. However, the mechanisms linking maternal nutritional status to MIA are still unclear, despite their relevance to the etiology of NDD. We demonstrate here that low maternal n-3 PUFA intake worsens MIA-induced early gut dysfunction, including modification of gut microbiota composition and higher local inflammatory reactivity. These deficits correlate with alterations of microglia-neuron crosstalk pathways and have long-lasting effects, both at transcriptional and behavioral levels. This work highlights the perinatal period as a critical time window, especially regarding the role of the gut-brain axis in neurodevelopment, elucidating the link between MIA, poor nutritional habits, and NDD.


Assuntos
Ácidos Graxos Ômega-3 , Efeitos Tardios da Exposição Pré-Natal , Animais , Comportamento Animal , Encéfalo , Feminino , Humanos , Inflamação , Microglia , Gravidez
2.
J Appl Microbiol ; 130(5): 1412-1424, 2021 May.
Artigo em Inglês | MEDLINE | ID: mdl-32955761

RESUMO

Lactic acid bacteria (LAB), widely used as starter cultures for the fermentation of a large variety of food, can improve the safety, shelf life, nutritional value and overall quality of the fermented products. In this regard, the selection of strains delivering health-promoting compounds is now the main objective of many researchers. Although most LAB are auxotrophic for several vitamins, it is known that certain strains have the capability to synthesize B-group vitamins. This is an important property since humans cannot synthesize most vitamins, and these could be obtained by consuming LAB fermented foods. This review discusses the use of LAB as an alternative to fortification by the chemical synthesis to increase riboflavin and folate concentrations in food. Moreover, it provides an overview of the recent applications of vitamin-producing LAB with anti-inflammatory/antioxidant activities against gastrointestinal tract inflammation. This review shows the potential uses of riboflavin and folates producing LAB for the biofortification of food, as therapeutics against intestinal pathologies and to complement anti-inflammatory/anti-neoplastic treatments.


Assuntos
Ácido Fólico/biossíntese , Alimentos Fortificados , Doenças Inflamatórias Intestinais/terapia , Lactobacillales/metabolismo , Mucosite/terapia , Riboflavina/biossíntese , Animais , Antioxidantes/análise , Fermentação , Alimentos Fermentados , Ácido Fólico/análise , Humanos , Lactobacillales/isolamento & purificação , Riboflavina/análise , Vitaminas/análise , Vitaminas/biossíntese
3.
J Appl Microbiol ; 130(6): 2063-2074, 2021 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-33128836

RESUMO

AIMS: To evaluate a mixture of selected lactic acid bacteria (LAB) (a riboflavin-producer, a folate-producer and an immunomodulatory strain) as co-adjuvant for 5-fluorouracil (5-FU) chemotherapy in cell culture and using a 4T1 cell animal model of breast cancer. METHODS AND RESULTS: The viability of Caco-2 cells exposed to 5-FU and/or LAB was analysed. Mice bearing breast tumour were treated with 5-FU and/or LAB. Tumour growth was measured. Intestinal mucositis (IM) was evaluated in small intestine; haematological parameters and plasma cytokines were determined. The bacterial mixture did not negatively affect the cytotoxic activity of 5-FU on Caco-2 cells. The LAB mixture attenuated the IM and prevented blood cell decreases associated with 5-FU treatment. Mice that received 5-FU and LAB mixture decreased tumour growth and showed modulation of systemic cytokines modified by both tumour growth and 5-FU treatment. The LAB mixture by itself delayed tumour growth. CONCLUSIONS: The mixture of selected LAB was able to reduce the side-effects associated with chemotherapy without affecting its primary anti-tumour activity. SIGNIFICANCE AND IMPACT OF THE STUDY: This bacterial mixture could prevent the interruption of conventional oncologic therapies by reducing undesirable side-effects. In addition, this blend would provide essential nutrients (vitamins) to oncology patients.


Assuntos
Adjuvantes Imunológicos , Neoplasias da Mama/terapia , Fluoruracila/uso terapêutico , Lactobacillales/imunologia , Lactobacillales/metabolismo , Animais , Antineoplásicos/uso terapêutico , Células CACO-2 , Linhagem Celular , Sobrevivência Celular , Citocinas/sangue , Modelos Animais de Doenças , Feminino , Ácido Fólico/metabolismo , Humanos , Imunomodulação , Mucosa Intestinal/microbiologia , Mucosa Intestinal/patologia , Camundongos , Camundongos Endogâmicos BALB C , Mucosite/microbiologia , Mucosite/patologia , Riboflavina/metabolismo , Vitaminas
4.
Cancer Metab ; 8: 4, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32158544

RESUMO

BACKGROUND: Osteosarcoma (OS) is a malignant bone tumor that often develops during the period of rapid growth associated with adolescence. Despite successful primary tumor control accompanied by adjuvant chemotherapy, death from pulmonary metastases occurs in approximately 30% of patients within 5 years. As overall survival in patients remains unchanged over the last 30 years, urgent needs for novel therapeutic strategies exist. Cancer metastasis is characterized by complex molecular events which result from alterations in gene and protein expression/function. Recent studies suggest that metabolic adaptations, or "metabolic reprogramming," may similarly contribute to cancer metastasis. The goal of this study was to specifically interrogate the metabolic vulnerabilities of highly metastatic OS cell lines in a series of in vitro and in vivo experiments, in order to identify a tractable metabolically targeted therapeutic strategy for patients. METHODS: Nutrient deprivation and drug treatment experiments were performed in MG63.3, 143B, and K7M2 OS cell lines to identify the impact of glutaminase-1 (GLS1) inhibition and metformin treatment on cell proliferation. We functionally validated the impact of drug treatment with extracellular flux analysis, nuclear magnetic resonance (NMR) spectroscopy, and mass spectrometry. 13C-glucose and 13C-glutamine tracing was employed to identify specific contributions of these nutrients to the global metabolic profiles generated with GLS1 inhibition and metformin treatment in vivo. RESULTS: Highly metastatic OS cell lines require glutamine for proliferation, and exposure to CB-839, in combination with metformin, induces both primary tumor growth inhibition and a distinct reduction in metastatic outgrowth in vivo. Further, combination-treated OS cells showed a reduction in cellular mitochondrial respiration, while NMR confirmed the pharmacodynamic effects of glutaminase inhibition in tumor tissues. We observed global decreases in glycolysis and tricarboxylic acid (TCA) cycle functionality, alongside an increase in fatty acid oxidation and pyrimidine catabolism. CONCLUSIONS: This data suggests combination-treated cells cannot compensate for metformin-induced electron transport chain inhibition by upregulating glutaminolysis to generate TCA cycle intermediates required for cell proliferation, translating into significant reductions in tumor growth and metastatic progression. This therapeutic approach could be considered for future clinical development for OS patients presenting with or at high risk of developing metastasis.

5.
Br J Nutr ; 116(7): 1229-1235, 2016 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-27641762

RESUMO

It has been previously shown that Lactobacillus plantarum CRL 2130 is able to produce riboflavin in soyamilk. The aim of the present study was to evaluate the efficiency of this riboflavin-bio-enriched soyamilk to revert and/or prevent the nutritional deficiency of riboflavin using different animal models. When used to supplement the diets of previously depleted animals, it was shown that the growth, riboflavin status and morphology of the small intestines reverted to normal parameters and were similar to animals supplemented with commercial riboflavin. In the prevention model, the same tendency was observed, where animals that received soyamilk fermented with L. plantarum CRL 2130 did not show signs of riboflavin deficiency. This new bio-fortified soya-based product could be used as part of normal diets to provide a more natural alternative to mandatory fortification with riboflavin for the prevention of its deficiency.


Assuntos
Fermentação , Lactobacillus plantarum/metabolismo , Deficiência de Riboflavina/prevenção & controle , Riboflavina/biossíntese , Leite de Soja/química , Animais , Dieta , Feminino , Camundongos , Camundongos Endogâmicos BALB C , Riboflavina/administração & dosagem , Deficiência de Riboflavina/etiologia , Leite de Soja/metabolismo
6.
Osteoporos Int ; 24(7): 2105-14, 2013 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-23334732

RESUMO

UNLABELLED: We report the results of alendronate ingestion plus exercise in preventing the declines in bone mass and strength and elevated levels of urinary calcium and bone resorption in astronauts during 5.5 months of spaceflight. INTRODUCTION: This investigation was an international collaboration between NASA and the JAXA space agencies to investigate the potential value of antiresorptive agents to mitigate the well-established bone changes associated with long-duration spaceflight. METHODS: We report the results from seven International Space Station (ISS) astronauts who spent a mean of 5.5 months on the ISS and who took an oral dose of 70 mg of alendronate weekly starting 3 weeks before flight and continuing throughout the mission. All crewmembers had available for exercise a treadmill, cycle ergometer, and a resistance exercise device. Our assessment included densitometry of multiple bone regions using X-ray absorptiometry (DXA) and quantitative computed tomography (QCT) and assays of biomarkers of bone metabolism. RESULTS: In addition to pre- and post-flight measurements, we compared our results to 18 astronauts who flew ISS missions and who exercised using an early model resistance exercise device, called the interim resistance exercise device, and to 11 ISS astronauts who exercised using the newer advanced resistance exercise device (ARED). Our findings indicate that the ARED provided significant attenuation of bone loss compared with the older device although post-flight decreases in the femur neck and hip remained. The combination of the ARED and bisphosphonate attenuated the expected decline in essentially all indices of altered bone physiology during spaceflight including: DXA-determined losses in bone mineral density of the spine, hip, and pelvis, QCT-determined compartmental losses in trabecular and cortical bone mass in the hip, calculated measures of fall and stance computed bone strength of the hip, elevated levels of bone resorption markers, and urinary excretion of calcium. CONCLUSIONS: The combination of exercise plus an antiresoptive drug may be useful for protecting bone health during long-duration spaceflight.


Assuntos
Alendronato/uso terapêutico , Conservadores da Densidade Óssea/uso terapêutico , Terapia por Exercício/métodos , Osteoporose/prevenção & controle , Voo Espacial , Absorciometria de Fóton/métodos , Adulto , Alendronato/administração & dosagem , Biomarcadores/sangue , Biomarcadores/urina , Composição Corporal/fisiologia , Densidade Óssea/efeitos dos fármacos , Densidade Óssea/fisiologia , Conservadores da Densidade Óssea/administração & dosagem , Reabsorção Óssea/etiologia , Reabsorção Óssea/prevenção & controle , Terapia Combinada , Esquema de Medicação , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Osteoporose/etiologia , Osteoporose/fisiopatologia , Ausência de Peso/efeitos adversos
7.
Singapore Med J ; 51(11): 876-82, 2010 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-21140115

RESUMO

INTRODUCTION: Research in the developed countries has documented bone loss in adolescents who use depomedroxyprogesterone acetate (DMPA) as a contraceptive for less than two years. DMPA use often begins during adolescence in Bangladesh, a South Asian developing country, where more than 50% of women are undernourished. Poor nutrition is also associated with low bone mineral density (BMD) in South Asian women. We investigated the effects of long-term (two or more years) DMPA use on BMD in Bangladeshi women who started its use in their adolescence. METHODS: Lumbar spine and femur neck BMD were acquired using dual energy X-ray absorptiometry for 100 adolescents (50 DMPA users and 50 non-users) in a cross-sectional study in Dhaka, Bangladesh. Multivariate analysis was used to determine the associations between BMD and DMPA use. Stratified analysis of DMPA use investigated the determinants of BMD in both groups. RESULTS: The participants (mean age 18 +/- 2 years) were generally below their ideal body weight. No significant differences in BMD were found between the two groups. Weight (odds ratio [OR] 0.96, 95 percent confidence interval [CI], 0.92-1.00) and height (OR 0.68, 95 percent CI 0.49-0.94) were independent determinants (p-value is less than 0.05) of lumbar and femur neck BMD, respectively. CONCLUSION: Poor nutritional status, indicated by a less-than-ideal body weight, may be masking the effects of DMPA on bone loss among adolescent users. Our findings suggest that nutritional supplementation may be required with DMPA prescription to promote bone health in adolescent users who are approaching peak bone mass.


Assuntos
Densidade Óssea/efeitos dos fármacos , Anticoncepcionais Femininos/efeitos adversos , Desnutrição/complicações , Acetato de Medroxiprogesterona/efeitos adversos , Osteoporose/etiologia , Absorciometria de Fóton , Adolescente , Peso Corporal/efeitos dos fármacos , Intervalos de Confiança , Anticoncepcionais Femininos/farmacologia , Anticoncepcionais Femininos/uso terapêutico , Estudos Transversais , Feminino , Colo do Fêmur/patologia , Humanos , Modelos Logísticos , Vértebras Lombares/efeitos dos fármacos , Vértebras Lombares/patologia , Acetato de Medroxiprogesterona/farmacologia , Acetato de Medroxiprogesterona/uso terapêutico , Análise Multivariada , Estado Nutricional , Razão de Chances , Fatores de Risco , Fatores de Tempo , Adulto Jovem
8.
Artigo em Inglês | MEDLINE | ID: mdl-20635786

RESUMO

BACKGROUND: Screening for allergic diseases allows an early diagnosis to be made, thus reducing socioeconomic burden and enhancing quality of life. We determined the prevalence of elevated exhaled nitric oxide (eNO) levels and sensitization to common airborne allergens in schoolchildren from different socioeconomic backgrounds. MATERIAL AND METHODS: The study population comprised 271 children (136 boys) aged between 8 and 12 years in whom we applied skin prick tests and determined eNO levels. RESULTS: Thirty-five percent of the children were identified as atopic. There was a significantly higher prevalence of atopy in boys (43% vs. 27%). Among the children with a high socioeconomic status, 37% were atopic, compared with 30% of those with a low socioeconomic status. We observed a significantly lower prevalence of pollen sensitization in children of lower socioeconomic status (10% vs. 20%). In the atopic group, 51% had elevated eNO levels, while in the nonatopic group this value was 4%. The mean (SD) eNO level was 33.4 (26.6) ppb in the atopic group and 11.9 (6.4) ppb in the nonatopic group. No differences were found for eNO values in terms of gender or socioeconomic status. CONCLUSIONS: Our results emphasize the high prevalence of atopy in our population and suggest that determination of eNO levels could help to provide an early diagnosis. We also observed the following: (a) a significant difference in mean eNO values between atopic and nonatopic children; (b) a significantly lower prevalence of pollen sensitization in children of lower socioeconomic status; and (c) a higher prevalence of atopy in boys.


Assuntos
Alérgenos/imunologia , Óxido Nítrico/metabolismo , Pólen/imunologia , Rinite Alérgica Perene/imunologia , Testes Respiratórios/métodos , Criança , Feminino , Humanos , Masculino , Portugal/epidemiologia , Rinite Alérgica Perene/epidemiologia , Rinite Alérgica Perene/metabolismo , Testes Cutâneos/métodos , Fatores Socioeconômicos , Inquéritos e Questionários , População Urbana
9.
Bone ; 41(6): 973-8, 2007 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-17931994

RESUMO

The loss of bone mineral in NASA astronauts during spaceflight has been investigated throughout the more than 40 years of space travel. Consequently, it is a medical requirement at NASA Johnson Space Center (JSC) that changes in bone mass be monitored in crew members by measuring bone mineral density (BMD), with dual-energy X-ray absorptiometry (DXA) before and after flight, of astronauts who serve on long-duration missions (4-6 months). We evaluated this repository of medical data to track whether there is recovery of bone mineral that was lost during spaceflight. Our analysis was supplemented by BMD data from cosmonauts (by convention, a space traveler formally employed by the Russia Aviation and Space Agency or by the previous Soviet Union) who had also flown on long-duration missions. Data from a total of 45 individual crew members - a small number of whom flew on more than one mission - were used in this analysis. Changes in BMD (between 56 different sets of pre- and postflight measurements) were plotted as a function of time (days after landing). Plotted BMD changes were fitted to an exponential mathematical function that estimated: (i) BMD change on landing day (day 0) and (ii) the number of days after landing when 50% of the lost bone would be recovered ("50% recovery time") in the lumbar spine, trochanter, pelvis, femoral neck and calcaneus. In sum, averaged losses of bone mineral after long-duration spaceflight ranged between 2% and 9% across all sites with our recovery model predicting a 50% restoration of bone loss for all sites to be within 9 months.


Assuntos
Densidade Óssea/fisiologia , Doenças Ósseas Metabólicas/metabolismo , Doenças Ósseas Metabólicas/patologia , Voo Espacial , Adulto , Feminino , Humanos , Masculino , Fatores de Tempo
10.
Artigo em Inglês | MEDLINE | ID: mdl-17396004

RESUMO

The potential for loss of bone mineral mass due to space flight was recognized by space scientists even before man's first venture into micro-gravity. Early life science studies in both the U.S. and Russian space programs attempted to measure the effects of reduced gravity on skeletal homeostasis, and these measurements have become more sophisticated with time. Bone-related measurements have typically included: bone mineral density measured by X-ray absorptiometry and more recently CT scanning; bonerelated hormones and other biochemical markers of bone turnover; and calcium excretion and balance. These measurements, conducted over the last 4 decades, have shed light on the nature of disuse bone loss and have provided preliminary information regarding bone recovery. Ground-based analog (bed rest) studies have provided information complementary to the space flight data and have allowed the testing of various countermeasures to bone loss. In spite of the wealth of knowledge obtained thus far, many questions remain regarding bone loss, bone recovery, and the factors affecting these skeletal processes. This paper will summarize the skeletal data obtained to date by the U.S. and Russian space programs and in ground-based disuse studies. In addition, related body composition data will be briefly discussed, as will possible countermeasures to space flight-induced bone loss.


Assuntos
Repouso em Cama/efeitos adversos , Osso e Ossos/fisiologia , Voo Espacial , Ausência de Peso/efeitos adversos , Animais , Composição Corporal/fisiologia , Conservadores da Densidade Óssea/uso terapêutico , Reabsorção Óssea/tratamento farmacológico , Reabsorção Óssea/etiologia , Difosfonatos/uso terapêutico , Humanos , Modelos Biológicos , Contramedidas de Ausência de Peso
11.
J Dairy Sci ; 90(4): 1920-8, 2007 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-17369232

RESUMO

Administration of kefir and a kefir cell-free fraction (KF) to mice injected with breast tumor cells produced, locally in the mammary gland, different profiles of cells secreting cytokines. Here, the immune cell populations in mammary glands affected by the cyclic consumption of kefir or KF for 2 or 7 d were evaluated using a breast tumor model. Apoptosis was also assayed as another mechanism involved in tumor growth delay. The rate development of tumor cells, IgA(+) cells, and CD4+ and CD8+ T lymphocytes was monitored in mammary gland tissues. The number of Bcl-2(+) cells in the mammary gland was compared with the apoptosis observed in the tumor. Two-day cyclical administration of both products delayed tumor growth and increased the number of IgA(+) cells in the mammary gland. Changes in the balance between CD4+ and CD8+ cells in the mammary gland were observed in mice from the group fed KF cyclically for 2 d, such that the number of CD4+ cells increased when the number of CD8+ cells remained constant. Mice that received 2-d cyclic administration of KF showed significant increases in the number of apoptotic cells and decreases in Bcl-2(+) cells in the mammary gland, compared with the tumor control group. The present study allows a better understanding of the mechanisms (immune and nonimmune) involved in the antitumor effect observed in mice administered kefir or KF. The importance of nonmicrobial components released during milk fermentation to obtain the beneficial antitumor effects is also reported.


Assuntos
Neoplasias da Mama/prevenção & controle , Linfócitos T CD4-Positivos/imunologia , Linfócitos T CD8-Positivos/imunologia , Produtos Fermentados do Leite/imunologia , Neoplasias Mamárias Experimentais/prevenção & controle , Animais , Antineoplásicos/imunologia , Antineoplásicos/uso terapêutico , Apoptose , Neoplasias da Mama/imunologia , Linhagem Celular Tumoral , Suplementos Nutricionais , Modelos Animais de Doenças , Feminino , Imunoglobulina A/imunologia , Glândulas Mamárias Animais/citologia , Glândulas Mamárias Animais/imunologia , Neoplasias Mamárias Experimentais/imunologia , Camundongos , Camundongos Endogâmicos BALB C , Proteínas Proto-Oncogênicas c-bcl-2/imunologia
12.
Cytokine ; 34(1-2): 1-8, 2006 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-16697655

RESUMO

Previous studies have shown that compounds released during milk fermentation by Lactobacillus helveticus are implicated in the antitumour effect of this product. Here the effects of the consumption, during 2 or 7 days, of kefir or kefir cell-free fraction (KF) on the systemic and local immune responses in mammary glands and tumours using a murine hormone-dependent breast cancer model were studied. In the tumour control group, mice did not receive these products. At the end of the feeding period, mice were injected subcutaneously with tumour cells in the mammary gland. Four days post-injection, they received kefir or KF on a cyclical basis. Rate of tumour development, cytokines in serum; mammary gland tissue, and tumour isolated cells were monitored. Two-day cyclical administration of both products delayed tumour growth. Both kefir and KF increased IL-10 in serum and decreased IL-6(+) cells (cytokine involved in oestrogen synthesis) in mammary glands. Two-day cyclical administration of KF increased IL-10(+) cells in mammary glands and in tumours and decreased IL-6(+) cells in tumour. This study demonstrated the modulatory capacity of KF on the immune response in mammary glands and tumours and the importance of the administration period to obtain this effect.


Assuntos
Produtos Fermentados do Leite/metabolismo , Citocinas/biossíntese , Neoplasias Mamárias Experimentais/prevenção & controle , Neoplasias Experimentais/prevenção & controle , Extratos Vegetais/farmacologia , Animais , Antineoplásicos/farmacologia , Linhagem Celular Tumoral , Sistema Imunitário , Lactobacillus helveticus/metabolismo , Leucócitos Mononucleares/metabolismo , Camundongos , Camundongos Endogâmicos BALB C , Leite
13.
Aging Ment Health ; 8(5): 410-21, 2004 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-15511739

RESUMO

We present a stress process framework as a model for understanding how religiosity may influence the expansion of stress. Survey data from informal caregivers to a spouse with Alzheimer's disease or a related dementia (n = 200) were analyzed to observe the relationships among three variables: (1) care-related stress, (2) religiosity, and (3) depression. This sample, which has a mean age of 73 years, demonstrates high rates of self-described religiosity, church attendance and frequency of prayer. Using these criteria, women and racial/ethnic minority caregivers are the most religious. In a series of multivariate analyses, we found strong evidence to suggest that there is an expansion of care-related stressors leading to depression in this sample. Religiosity, as measured here, appears to be largely unrelated to stress and stress expansion. We found no evidence to suggest that it moderates stress expansion. However, these data do suggest that one stressor--feelings of role overload--is correlated with greater levels of self-perceived religiosity, which among caregivers who have health problems of their own is associated with greater depressive symptomatology. Thus, for a sub-sample of these caregivers, we find weak evidence of a mediation effect wherein one subjective, non-organizational dimension of religiosity is a conduit of the harmful effects of stress (rather than a suppressor). Results and data limitations are discussed in relation to better assessing the role of religiosity and spirituality in the experience of the stress process.


Assuntos
Cuidadores/psicologia , Depressão/psicologia , Religião e Psicologia , Estresse Psicológico/psicologia , Atividades Cotidianas , Idoso , Doença de Alzheimer , Depressão/diagnóstico , Depressão/epidemiologia , Feminino , Humanos , Masculino , Espiritualidade , Estresse Psicológico/diagnóstico , Estresse Psicológico/epidemiologia , Inquéritos e Questionários
14.
Protein Expr Purif ; 17(1): 89-95, 1999 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-10497073

RESUMO

Tissue transglutaminase purified from guinea pig livers has a very broad substrate specificity in comparison with other members of the transglutaminase family and therefore is useful for substrate analogue kinetic studies. Modifications made in our laboratory to the standard purification protocol (J. E. Folk and S. I. Chung, 1985, Methods Enzymol. 113, 358-364) have yielded a 28% increase in specific activity and 55% increase in overall yield, while reducing the number of steps to the purification. Herein we report some of the highest yields and specific activities for guinea pig liver transglutaminase found in the literature, as well as the use of lyophilization as a solution to the long-standing problem of enzyme stability during storage.


Assuntos
Fígado/enzimologia , Transglutaminases/isolamento & purificação , Animais , Cromatografia em Gel , Cromatografia por Troca Iônica , Eletroforese em Gel de Poliacrilamida , Estabilidade Enzimática , Liofilização , Cobaias , Cinética , Peso Molecular , Especificidade por Substrato , Transglutaminases/metabolismo
15.
Cancer Invest ; 16(1): 6-11, 1998.
Artigo em Inglês | MEDLINE | ID: mdl-9474245

RESUMO

The objective of this cross-sectional study was to determine lumbar spine bone mineral density (BMD) in breast cancer patients previously treated with adjuvant chemotherapy. Sixteen of 27 patients who received adjuvant chemotherapy became permanently amenorrheic as a result of chemotherapy. BMD was measured at the lumbar spine using dual energy X-ray absorptiometry (DEXA). Chemotherapy drugs and dosages along with a history of risk factors for reduced bone density including activity level, tobacco and/or alcohol use, metabolic bone disease, family history, and hormone exposure were identified. Results showed that women who became permanently amenorrheic as a result of chemotherapy had BMD 14% lower than women who maintained menses after chemotherapy. Chemotherapy-treated women who maintained ovarian function had normal BMD. This study suggests that women who have premature menopause as a result of chemotherapy for breast cancer are at increased risk of bone loss and may be at risk for early development of osteoporosis. Women who maintain menses do not appear to be at risk for accelerated trabecular bone loss.


Assuntos
Neoplasias da Mama/tratamento farmacológico , Adulto , Fatores Etários , Densidade Óssea , Neoplasias da Mama/patologia , Cálcio/metabolismo , Ciclofosfamida/administração & dosagem , Dieta , Feminino , Humanos , Menopausa , Pessoa de Meia-Idade , Osteoporose/genética , Aptidão Física , Projetos Piloto
16.
Acta Astronaut ; 36(8-12): 463-6, 1995.
Artigo em Inglês | MEDLINE | ID: mdl-11540977

RESUMO

Body mass, calcium and skeletal changes occur in humans who have worked in microgravity. Physiologic changes are seen as early as one week and are still occurring 312 days into space flight. The physiologic changes in bone and mineral metabolism may be among those which limits long duration space flight if an adequate countermeasure is not developed. The purpose of this paper is to summarize what is known about calcium dynamics and bone mineral changes as well as associated changes of body mass induced by space flight. The data reported is from a variety of studies conducted in both actual and simulated space flight.


Assuntos
Índice de Massa Corporal , Densidade Óssea/fisiologia , Osso e Ossos/metabolismo , Cálcio/metabolismo , Voo Espacial , Ausência de Peso/efeitos adversos , Medicina Aeroespacial , Repouso em Cama , Desmineralização Patológica Óssea/etiologia , Desmineralização Patológica Óssea/metabolismo , Desmineralização Patológica Óssea/urina , Osso e Ossos/fisiopatologia , Calcâneo/metabolismo , Cálcio/urina , Humanos , Fósforo/metabolismo , Fósforo/urina
17.
Bone ; 16(4 Suppl): 301S-304S, 1995 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-7626318

RESUMO

Negative calcium balance is a known consequence of bed rest, and is manifested in elevated urine and fecal calcium (Ca). Elevated fecal Ca can result from either decreased absorption, increased endogenous fecal excretion, or both. We measured the Ca absorption and endogenous fecal excretion in eight healthy male volunteers before and during 4 months of bed rest. Dual isotope (n = 6) or single isotope (n = 2) methods in conjunction with Ca balance were used to calculate true and net Ca absorption and endogenous fecal excretion. Stool Ca increased from 797 mg/day (mean intake 991 mg/day) to 911 mg/day during bed rest, whereas urine Ca excretion increased from 174 to 241 mg/day. True Ca absorption decreased from 31 +/- 7% of Ca intake pre-bed rest to 24 +/- 2% during bed rest, (p < 0.05) and returned toward pre-bed rest values within 5-6 weeks following reambulation. Endogenous fecal excretion did not change significantly, and therefore, most of the increased fecal Ca resulted from changes in absorption. However, in one individual, endogenous fecal Ca excretion was the major contributor to Ca loss. Ionized Ca and pyridinium crosslinks increased and 1,25(OH)2 vitamin D decreased during bed rest, similar to the decrease in Ca absorption; parathyroid hormone (PTH), calcitonin, serum albumin, phosphorus, and total serum Ca were unchanged. Although alkaline phosphatase, osteocalcin, and PTH were unchanged during bed rest, they were elevated during reambulation. These changes accompanied by increased Ca absorption and balance and decreased ionized and total serum Ca suggest a rebound in bone formation following immobilization.


Assuntos
Repouso em Cama/efeitos adversos , Cálcio da Dieta/farmacocinética , Cálcio/metabolismo , Fezes/química , Absorção , Adulto , Fosfatase Alcalina/sangue , Calcitonina/sangue , Cálcio/sangue , Cálcio/urina , Di-Hidroxicolecalciferóis/sangue , Humanos , Marcação por Isótopo , Masculino , Pessoa de Meia-Idade , Hormônio Paratireóideo/sangue , Fósforo/sangue , Albumina Sérica/metabolismo
18.
J Magn Reson Imaging ; 4(6): 823-7, 1994.
Artigo em Inglês | MEDLINE | ID: mdl-7865943

RESUMO

The quality of volume-localized magnetic resonance spectroscopy is affected by eddy currents caused by gradient switching. Eddy currents can be reduced with improved gradient systems; however, it has been suggested that the distortion due to eddy currents can be compensated for during postprocessing with a single-frequency reference signal. The authors propose modifying current techniques for acquiring the single-frequency reference signal by using relaxation weighting to reduce interference from components that cannot be eliminated by digital filtering alone. Additional sequences with T1 or T2 weighting for reference signal acquisition are shown to have the same eddy current characteristics as the original signal without relaxation weighting. The authors also studied a new eddy current correction method that does not require a single-frequency reference signal. This method uses two free induction decays (FIDs) collected from the same volume with two sequences with opposite gradients. Phase errors caused by eddy currents are opposite in these two FIDs and can be canceled completely by combining the FIDs. These methods were tested in a phantom. Eddy current distortions were corrected, allowing quantitative measurement of structures such as the -CH = CH- component, which is otherwise undetectable.


Assuntos
Processamento de Imagem Assistida por Computador , Espectroscopia de Ressonância Magnética , Algoritmos , Artefatos , Cloretos/química , Óleo de Milho/química , Análise de Fourier , Ligação de Hidrogênio , Magnetismo , Compostos de Manganês/química , Modelos Estruturais , Processamento de Sinais Assistido por Computador , Água/química
19.
J Bone Miner Res ; 5(2): 153-8, 1990 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-2316403

RESUMO

A group of 68 premenopausal women participated in a controlled 12 month exercise program. Two groups were matched according to age, body size (body mass index), and typical activity level. Data collection included bone mineral density (BMD) of the lumbar spine with dual-photon absorptiometry and of the os calcis with single-photon absorptiometry, lean body mass, urinary calcium/creatinine, and urinary gamma-carboxyglutamic acid (Gla). Subjects were given a daily 500 mg supplement of elemental calcium. There was no significant difference between groups in terms of diet, in urinary calcium/creatinine or Gla, or in lean body mass. The weight lifting group had a nonsignificant increase in mean lumbar BMD of 0.81% and the control group exhibited a nonsignificant decrease of 0.5%. However, a paired t-test revealed a significant change in the means in either group or as matched pairs. The relatively small change seen as a result of this modified Nautilus exercise program may prevent moderate weight lifting from being a practical answer for osteoporosis, even in a highly motivated population.


Assuntos
Densidade Óssea/fisiologia , Levantamento de Peso , Adulto , Cálcio/urina , Creatinina/urina , Feminino , Humanos , Pessoa de Meia-Idade , Osteocalcina/urina
20.
J Bone Miner Res ; 4(2): 143-8, 1989 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-2499164

RESUMO

We have designed a cyclic regimen for the treatment of osteoporosis based on the activate, depress, free, and repeat (ADFR) concept. Osteoclastic bone resorption is activated by 7 days of oral neutral phosphate and inhibited with a brief pulse (5 days) of etidronate disodium at a high dose (20 mg/kg body weight). Patients next take calcium supplements for 48 days before resuming phosphate to enter the next cycle. Osteoporotic women increased the bone mineral density of the lumbar spine at 6 months by 7.2 +/- 5.2% (mean +/- SD, N = 14) and at 12 months by 8.2 +/- 4.0% (N = 8). Control observations in regularly exercising postmenopausal women (N = 30) showed no significant change in spine mineral density after 20 months (0.5 +/- 3.2%), confirming the stability of the measurement technique. The two patients who responded poorly to the cyclic regimen each showed a blunted rise in serum PTH during oral phosphate administration, suggesting that the rise in PTH induced by oral phosphate may be an important component of this cyclic regimen. This preliminary study does not identify which component or components of the regimen are responsible for the increase in bone mass but provides positive encouragement for randomized studies designed to determine the optimum dosage, duration, and timing of each component of the regimen.


Assuntos
Ácido Etidrônico/uso terapêutico , Osteoporose/tratamento farmacológico , Fosfatos/uso terapêutico , Adulto , Idoso , Idoso de 80 Anos ou mais , Reabsorção Óssea/efeitos dos fármacos , Cálcio/sangue , Esquema de Medicação , Quimioterapia Combinada , Ácido Etidrônico/administração & dosagem , Feminino , Humanos , Pessoa de Meia-Idade , Osteoporose/metabolismo , Hormônio Paratireóideo/sangue , Fosfatos/administração & dosagem , Coluna Vertebral/efeitos dos fármacos , Coluna Vertebral/metabolismo
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