Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 51
Filtrar
1.
Heredity (Edinb) ; 115(3): 188-94, 2015 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-25853517

RESUMO

Phosphine (PH3) fumigation is the primary method worldwide for controlling insect pests of stored commodities. Over-reliance on phosphine, however, has led to the emergence of strong resistance. Detailed genetic studies previously identified two loci, rph1 and rph2, that interact synergistically to create a strong resistance phenotype. We compared the genetics of phosphine resistance in strains of Rhyzopertha dominica and Tribolium castaneum from India and Australia, countries having similar pest species but widely differing in pest management practices. Sequencing analysis of the rph2 locus, dihydrolipoamide dehydrogenase (dld), identified two structurally equivalent variants, Proline49>Serine (P49S) in one R. dominica strain and P45S in three strains of T. castaneum from India. These variants of the DLD protein likely affect FAD cofactor interaction with the enzyme. A survey of insects from storage facilities across southern India revealed that the P45/49S variant is distributed throughout the region at very high frequencies, in up to 94% of R. dominica and 97% of T. castaneum in the state of Tamil Nadu. The abundance of the P45/49S variant in insect populations contrasted sharply with the evolutionary record in which the variant was absent from eukaryotic DLD sequences. This suggests that the variant is unlikely to provide a strong selective advantage in the absence of phosphine fumigation.


Assuntos
Besouros/genética , Di-Hidrolipoamida Desidrogenase/genética , Proteínas de Insetos/genética , Resistência a Inseticidas/genética , Fosfinas , Animais , Austrália , Besouros/enzimologia , Evolução Molecular , Armazenamento de Alimentos , Fumigação , Frequência do Gene , Índia , Inseticidas , Polimorfismo de Nucleotídeo Único , Análise de Sequência de DNA , Tribolium/enzimologia , Tribolium/genética
2.
PLoS One ; 17(3): e0264785, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-35298502

RESUMO

The variability of clinical course and prognosis of COVID-19 highlights the necessity of patient sub-group risk stratification based on clinical data. In this study, clinical data from a cohort of Indian COVID-19 hospitalized patients is used to develop risk stratification and mortality prediction models. We analyzed a set of 70 clinical parameters including physiological and hematological for developing machine learning models to identify biomarkers. We also compared the Indian and Wuhan cohort, and analyzed the role of steroids. A bootstrap averaged ensemble of Bayesian networks was also learned to construct an explainable model for discovering actionable influences on mortality and days to outcome. We discovered blood parameters, diabetes, co-morbidity and SpO2 levels as important risk stratification features, whereas mortality prediction is dependent only on blood parameters. XGboost and logistic regression model yielded the best performance on risk stratification and mortality prediction, respectively (AUC score 0.83, AUC score 0.92). Blood coagulation parameters (ferritin, D-Dimer and INR), immune and inflammation parameters IL6, LDH and Neutrophil (%) are common features for both risk and mortality prediction. Compared with Wuhan patients, Indian patients with extreme blood parameters indicated higher survival rate. Analyses of medications suggest that a higher proportion of survivors and mild patients who were administered steroids had extreme neutrophil and lymphocyte percentages. The ensemble averaged Bayesian network structure revealed serum ferritin to be the most important predictor for mortality and Vitamin D to influence severity independent of days to outcome. The findings are important for effective triage during strains on healthcare infrastructure.


Assuntos
COVID-19/mortalidade , Hospitalização/estatística & dados numéricos , Adolescente , Adulto , Idoso , Idoso de 80 Anos ou mais , Teorema de Bayes , COVID-19/epidemiologia , COVID-19/etiologia , Criança , China/epidemiologia , Feminino , Humanos , Índia/epidemiologia , Aprendizado de Máquina , Masculino , Pessoa de Meia-Idade , Modelos Estatísticos , Medição de Risco/métodos , Fatores de Risco , Adulto Jovem
3.
Nat Med ; 7(3): 350-5, 2001 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-11231635

RESUMO

Epstein-Barr virus (EBV) is an oncogenic virus associated with a number of human malignancies including Burkitt lymphoma, nasopharyngeal carcinoma, lymphoproliferative disease and, though still debated, breast carcinoma. A subset of latent EBV antigens is required for mediating immortalization of primary B-lymphocytes. Here we demonstrate that the carboxy-terminal region of the essential latent antigen, EBNA-3C, interacts specifically with the human metastatic suppressor protein Nm23-H1. Moreover, EBNA-3C reverses the ability of Nm23-H1 to suppress the migration of Burkitt lymphoma cells and breast carcinoma cells. We propose that EBNA-3C contributes to EBV-associated human cancers by targeting and altering the role of the metastasis suppressor Nm23-H1.


Assuntos
Antígenos Virais/metabolismo , Herpesvirus Humano 4/imunologia , Proteínas Monoméricas de Ligação ao GTP/metabolismo , Metástase Neoplásica , Núcleosídeo-Difosfato Quinase , Fatores de Transcrição/metabolismo , Sequência de Bases , Núcleo Celular/metabolismo , Primers do DNA , Humanos , Nucleosídeo NM23 Difosfato Quinases , Ligação Proteica , Células Tumorais Cultivadas
4.
Int J Obstet Anesth ; 45: 67-73, 2021 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-33298343

RESUMO

INTRODUCTION: Shock index and continuous non-invasive haemoglobin monitoring (SpHb) have both been proposed for the timely recognition of postpartum haemorrhage (PPH). We sought to determine, in parallel, the association of each of shock index and SpHb with blood loss after vaginal delivery. METHODS: Sixty-six women were recruited to this prospective observational study. Shock index and SpHb were recorded postpartum for 120 min. The association between each of shock index and SpHb with quantitative blood loss (QBL) at 30, 60 and 120 min postpartum was determined using linear mixed models. Area-under-the-receiver-operator-characteristic (AUROC) curves were constructed to evaluate the diagnostic ability of shock index and SpHb to detect PPH (defined as QBL ≥1000 mL). RESULTS: Shock index trend was associated with QBL over the first 30 min (r=0.37, P=0.002), but not over 60 or 120 min. There was an association of SpHb trend with QBL over the first 30 min (P=0.06), but not over 60 min (r=-0.32, P=0.009) or 120 min (r=-0.26, P=0.03). Maximum shock index within 60 min correlated with QBL (r=0.54, P <0.001) and was a predictor of PPH (P=0.0012, AUROC 0.796). Maximum change in SpHb within 60 min negatively correlated with QBL (r=-0.4, P <0.001) and was a predictor of PPH (P=0.048, AUROC 0.761). CONCLUSIONS: The trend of shock index and its peak values are associated with blood loss after vaginal delivery and are early indicators of PPH. Negative trend of SpHb is a late sign of PPH and has a weaker association with blood loss than shock index.


Assuntos
Hemorragia Pós-Parto , Parto Obstétrico , Feminino , Hemoglobinas/análise , Humanos , Projetos Piloto , Hemorragia Pós-Parto/diagnóstico , Gravidez , Estudos Prospectivos
5.
J Thromb Haemost ; 16(7): 1296-1306, 2018 07.
Artigo em Inglês | MEDLINE | ID: mdl-29723935

RESUMO

Essentials Risk of intracranial hemorrhage (ICH) may differ between direct oral anticoagulants (DOACs). We compared the risk of ICH between DOACs using network meta-analysis. Dabigatran 110 mg and 150 mg were safer than rivaroxaban on Bayesian analysis. Dabigatran 110 mg ranked as the safest DOAC while rivaroxaban ranked last. SUMMARY: Background The comparative risk of intracranial hemorrhage (ICH) among direct oral anticoagulants (DOACs) (dabigatran, rivaroxaban, apixaban and edoxaban) remains unclear. Objective To determine the difference in risk of ICH between DOACs Methods Seventeen randomized controlled trials (RCTs) were selected using PubMed/MEDLINE, EMBASE and CENTRAL (Inception, 31 December 2017). Estimates were reported as odds ratio (OR) with 95% credible interval (CR.I) in Bayesian network meta-analysis (NMA), and OR with 95% confidence interval (CI) in traditional meta-analyses. Relative ranking probability of each group was generated based on surface under the cumulative ranking curve (SUCRA). Results In NMA of 116 618 patients from 17 RCTs (apixaban = 19 495 patients, rivaroxaban = 14 157 patients, dabigatran = 16 074 patients, edoxaban = 11 652 patients, and comparator = 55 315 patients), all DOACs were safer than warfarin for risk of ICH. Dabigatran 110 mg ranked as the safest drug (SUCRA, 0.85) and reduced the risk of ICH by 56% compared to rivaroxaban (OR, 0.44; 95% Cr.I, 0.22-0.82). Pairwise meta-analysis validated these findings, showing that DOACs were safer than warfarin (OR, 0.46; 95% CI, 0.35-0.59). Subgroup analysis showed that the benefit was present when DOACs were used in non-valvular atrial fibrillation (NVAF) (OR, 0.51; 95% CI, 0.38-0.68) or venous thromboembolism (VTE) (OR, 0.32; 95% CI, 0.18-0.58). Conclusion Dabigatran 110 mg may be the safest choice among any anticoagulant regarding risk of ICH. Both dabigatran 110 mg and 150 mg were safer than rivaroxaban.


Assuntos
Antitrombinas/administração & dosagem , Antitrombinas/efeitos adversos , Inibidores do Fator Xa/administração & dosagem , Inibidores do Fator Xa/efeitos adversos , Hemorragias Intracranianas/induzido quimicamente , Administração Oral , Teorema de Bayes , Dabigatrana/administração & dosagem , Dabigatrana/efeitos adversos , Humanos , Hemorragias Intracranianas/diagnóstico , Pirazóis/administração & dosagem , Pirazóis/efeitos adversos , Piridinas/administração & dosagem , Piridinas/efeitos adversos , Piridonas/administração & dosagem , Piridonas/efeitos adversos , Medição de Risco , Fatores de Risco , Rivaroxabana/administração & dosagem , Rivaroxabana/efeitos adversos , Tiazóis/administração & dosagem , Tiazóis/efeitos adversos , Resultado do Tratamento
6.
Neoplasia ; 19(12): 1003-1011, 2017 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-29121598

RESUMO

Advanced head and neck squamous cell carcinoma (HNSCC) remains a therapeutic challenge due to the development of therapy resistance. Several studies have implicated the development of cancer stem cells as a possible mechanism for therapy resistance in HNSCC. Heat shock protein 90's (Hsp90's) molecular chaperone function is implicated in pathways of resistance in HNSCC. Therefore, in the present study, we investigated the efficacy of novel C-terminal Hsp90 inhibitors (KU711 and KU757) in targeting HNSCC cancer stem cells (CSCs). Treatment of HNSCC human cell lines MDA1986, UMSCC 22B, and UMSCC 22B cisplatin-resistant cells with the KU compounds indicated complete blockage of self-renewal for the resistant and parent cell lines starting from 20 µM KU711 and 1 µM KU757. Dose-dependent decrease in the cancer stem cell markers CD44, ALDH, and CD44/ALDH double-positive cells was observed for all cell lines after treatment with KU711 and KU757. When cells were treated with either drug, migration and invasion were downregulated greater than 90% even at the lowest concentrations of 20 µM KU711 and 1 µM KU757. Western blot showed >90% reduction in client protein "stemness" marker BMI-1 and mesenchymal marker vimentin, as well as increase in epithelial marker E-cadherin for both cell lines, indicating epithelial to mesenchymal transition quiescence. Several CSC-mediated miRNAs that play a critical role in HNSCC therapy resistance were also downregulated with KU treatment. In vivo, KU compounds were effective in decreasing tumor growth with no observed toxicity. Taken together, these results indicate that KU compounds are effective therapeutics for targeting HNSCC CSCs.


Assuntos
Antineoplásicos/farmacologia , Carcinoma de Células Escamosas/metabolismo , Proteínas de Choque Térmico HSP90/antagonistas & inibidores , Neoplasias de Cabeça e Pescoço/metabolismo , Células-Tronco Neoplásicas/efeitos dos fármacos , Células-Tronco Neoplásicas/metabolismo , Domínios e Motivos de Interação entre Proteínas/efeitos dos fármacos , Animais , Biomarcadores , Carcinoma de Células Escamosas/tratamento farmacológico , Carcinoma de Células Escamosas/patologia , Linhagem Celular Tumoral , Autorrenovação Celular/efeitos dos fármacos , Sobrevivência Celular/efeitos dos fármacos , Modelos Animais de Doenças , Resistencia a Medicamentos Antineoplásicos , Regulação Neoplásica da Expressão Gênica , Proteínas de Choque Térmico HSP90/química , Neoplasias de Cabeça e Pescoço/tratamento farmacológico , Neoplasias de Cabeça e Pescoço/patologia , Humanos , Camundongos , MicroRNAs/genética , Transdução de Sinais , Carcinoma de Células Escamosas de Cabeça e Pescoço , Células Tumorais Cultivadas , Ensaios Antitumorais Modelo de Xenoenxerto
7.
Surg Endosc ; 20(1): 61-3, 2006 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-16333531

RESUMO

BACKGROUND: The aim of this study is to highlight the role of minimally invasive surgery in the form of laparoscopy-assisted truncal vagotomy (TV) with ante-colic posterior gastrojejunostomy (PGJ) for benign gastric outlet obstruction (GOO). GOO is relatively common in southern India due to various factors. From 1994 to 2004, 762 patients with GOO were operated on (open TV with PGJ) in our center. METHODS: From November 2003 to November 2004, 18 patients with GOO underwent the laparoscopic procedure in our unit. The procedure involves laparoscopic TV followed by the ante-colic PGJ performed extracorporeally through a 3.5-cm transverse incision in the upper abdomen. RESULTS: The advantages of this procedure are that pain, hospital stay, size of wound, incidence of incisional hernia, and postoperative complications are reduced and the patient returns to work earlier. The results are comparable to those of a totally laparoscopic TV with PGJ. CONCLUSION: This procedure is relatively easy to perform because the anastomosis is done extracorporeally, and it is less expensive than the use of endostaplers. Thus, more surgeons should be encouraged to perform laparoscopic TV with PGJ.


Assuntos
Obstrução da Saída Gástrica/patologia , Obstrução da Saída Gástrica/cirurgia , Gastroenterostomia , Laparoscopia , Procedimentos Cirúrgicos Minimamente Invasivos , Vagotomia Troncular/métodos , Idoso , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Estudos Retrospectivos , Resultado do Tratamento
8.
Indian J Gastroenterol ; 25(1): 37-8, 2006.
Artigo em Inglês | MEDLINE | ID: mdl-16567894

RESUMO

A 47-year-old man presented with epigastric pain relieved by bilious vomiting since one month. He had undergone truncal vagotomy with posterior gastrojejunostomy for benign gastric outlet obstruction 2 years ago. Endoscopy showed distension and stasis in the afferent loop, bile gastritis and esophagitis. Laparoscopic Braun jejunojejunostomy relieved his symptoms.


Assuntos
Síndromes Pós-Gastrectomia/diagnóstico , Síndromes Pós-Gastrectomia/cirurgia , Gastrectomia/efeitos adversos , Obstrução da Saída Gástrica/cirurgia , Humanos , Jejunostomia/efeitos adversos , Jejunostomia/métodos , Masculino , Pessoa de Meia-Idade , Estenose Pilórica/cirurgia , Vagotomia Troncular
9.
Cancer Res ; 38(7): 1996-2002, 1978 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-657137

RESUMO

Spleen cells from tumor-bearing mice when cultured for 3 to 5 days released a soluble factor into the media that suppressed the stimulation of lymph node and spleen cells by tumor antigen or mitogens. Spleens from mice bearing MC43 tumors for 14 days were capable of producing suppressor factor in vitro, while those from mice bearing the tumor for 10 days or less failed to do so. Lymph node cells from the same animals did not produce suppressor factor in vitro. The suppressor factor was produced by a nonadherent cell population, was heat stable, was lost on dialysis, and did not appear to be tumor antigen or thymidine.


Assuntos
Imunidade , Terapia de Imunossupressão , Sarcoma Experimental/imunologia , Baço/imunologia , Animais , Adesão Celular , Feminino , Fibrossarcoma/imunologia , Imunidade/efeitos dos fármacos , Técnicas In Vitro , Linfonodos/imunologia , Ativação Linfocitária , Linfócitos/imunologia , Camundongos , Camundongos Endogâmicos C3H , Mitógenos/farmacologia , Mitomicinas/farmacologia , Timidina/farmacologia
10.
Indian J Surg ; 77(Suppl 1): 72-4, 2015 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-25972650

RESUMO

Vascular malformations are rare congenital vascular anomalies composed of inappropriately connected vasculature. They are usually present at birth, are progressive, infiltrative and require intervention. Vascular malformations need to be differentiated from haemangiomas which are congenital vascular neoplasms. We present a case of vascular malformation in a 6-year old child who presented with a progressive swelling in the neck and was treated by surgical excision. This case is being presented because of its peculiar clinical presentation.

11.
Biochem Pharmacol ; 33(5): 793-8, 1984 Mar 01.
Artigo em Inglês | MEDLINE | ID: mdl-6712709

RESUMO

We measured several biochemical effects of 10 days of intragastric administration of phosphatidylcholine (10 mmoles/kg) to rats because of the expanding clinical use of chronic phosphatidylcholine treatment for disorders involving impaired cholinergic neurotransmission. The plasma and erythrocyte choline concentrations were increased 3.5-fold, which was the same percent increase as found after an acute treatment with phosphatidylcholine. The lipid and fatty acid compositions of the plasma were also altered; free and total cholesterol levels increased, triglycerides increased, the monoene fatty acids generally decreased, and the diene and tetraene fatty acids generally increased. We found no effect of this treatment on the hepatic microsomal cytochrome P-450 activity or on the N-demethylation of benzphetamine or methamphetamine. Ten days of phosphatidylcholine treatment increased the concentration of choline in the brain but had no effect on the concentration of acetylcholine, the activity of choline acetyltransferase, cholinesterase activity, the apparent KD or Bmax of muscarinic receptors, or the fatty acid composition of rat brain lipids. These findings indicate that the largest effect caused by this treatment was an increase in the choline levels. No indication of altered cholinergic metabolism was observed. Further studies of the effects of chronic phosphatidylcholine treatment are required to clarify its therapeutic mechanism of action.


Assuntos
Fosfatidilcolinas/farmacologia , Acetilcolinesterase/metabolismo , Administração Oral , Animais , Encéfalo/metabolismo , Colina/sangue , Colina O-Acetiltransferase/metabolismo , Eritrócitos/metabolismo , Ácidos Graxos/metabolismo , Masculino , Microssomos Hepáticos/enzimologia , Fosfatidilcolinas/administração & dosagem , Ratos , Ratos Endogâmicos , Receptores Muscarínicos/metabolismo
12.
Lipids ; 21(9): 603-7, 1986 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-3762333

RESUMO

To test whether vitamin E deficiency might influence the course of essential fatty acid (EFA) deficiency, Long Evans rats were fed diets containing a marginal amount (1.5% of calories) of 18:2 omega 6 or 18:3 omega 3 fatty acid with complete absence of the other and with or without vitamin E. Vitamin E contents decreased continuously in serum and liver in all rats fed the E-free diets but in the brains of only the rats fed the marginal 18:3 omega 3, E-free diet. It is considered that the vitamin E is cooxidized in the liver with 22:6 omega 3, since this fatty acid is very low in livers of the rats fed the marginal 18:2 omega 6 diet but much higher in livers of the rats fed the marginal 18:3 omega 3 diet. Brain 22:6 omega 3 values are comparable for both groups. The source of 22:6 omega 3 is evidently in the mother's milk, since following weaning there is a precipitous drop in 22:6 omega 3 in serum, liver and carcass of rats on the 18:2 omega 6--containing diet. No significant signs of EFA deficiency were seen in the E-deficient rats.


Assuntos
Ácidos Graxos Essenciais/deficiência , Deficiência de Vitamina E/metabolismo , Animais , Encéfalo/efeitos dos fármacos , Encéfalo/metabolismo , Gorduras na Dieta/metabolismo , Ingestão de Energia , Ácidos Graxos/análise , Técnicas In Vitro , Ácidos Linoleicos/metabolismo , Fígado/efeitos dos fármacos , Fígado/metabolismo , Ratos , Vitamina E/farmacologia , Deficiência de Vitamina E/complicações
13.
Lipids ; 14(1): 47-51, 1979 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-423709

RESUMO

Incorporation of radioactivity from intracranially injected radioactive leucine, isoleucine (ketogenic amino acids), octanoic acid and beta-hydroxybutyric acid into the brain lipids of 15 to 16 day-old rats was examined. The results showed that radioactivity from all the above precursors was incorporated into brain lipids. Radioactivity from injected isoleucine was incorporated into odd numbered fatty acids indicating an alternate pathway to alpha-oxidation for the biosynthesis of these fatty acids in the brain. For some as yet unclear reasons, a substantial portion of the radioactivity from injected octanoic acid was incorporated into free fatty acids. Utilization of these compounds for providing carbon for lipogenesis during development under unstressed normal conditions is discussed.


Assuntos
Encéfalo/metabolismo , Caprilatos/metabolismo , Hidroxibutiratos/metabolismo , Isoleucina/metabolismo , Leucina/metabolismo , Lipídeos/biossíntese , Animais , Radioisótopos de Carbono , Ácidos Graxos/biossíntese , Marcação por Isótopo , Ratos
14.
Lipids ; 10(4): 238-41, 1975 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-27521071

RESUMO

Twelve-thirteen day old rats were given 1-(14)C linolenic acid by intraperitoneal injection. Fatty acids were isolated from the brains of animals sacrificed at the end of 8 and 48 hr and 15 and 45 days. Eight hr after the tracer, radioactivity was found neither in 18∶3 nor its endproduct, 22∶6, and palmitate was the most highly radioactive component. At longer intervals, 22∶6 seemed to retain much of the radioactivity, whereas palmitate showed a precipitous decline in radioactivity. Initial oxidation of linolenate and sparing of the linolenate complexed with polar lipids are discussed.

15.
Lipids ; 10(4): 242-7, 1975 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-27521072

RESUMO

Metabolism of 1-(14)C linolenic acid was studied in growing animals by injecting the tracer intraperitoneally into 12-13 day old suckling rats and following up the results by sacrificing groups of animals at 8 hr, 48 hr, 15 day, and 45 day intervals. In the first 15 days, there was a greater decrease in radioactivity of brain total lipids compared to the later period, although the earlier age period is characterized by lipid deposition rather than breakdown. Since the 18∶3 ω3 family of fatty acids occurs largely in the brain total phosphatidyl ethanolamine fraction, we expected that, in the initial period, total phosphatidyl ethanolamine would be the most highly radioactive component. However, results showed that 8 hr after the tracer phosphatidyl choline had the highest specific radioactivity. When the total phosphatidyl ethanolamine fraction was resolved into diacyl and alk-1-enyl species, it was found that radioactivity was not distributed evenly between the two species. There was a progressive increase in radioactivity of the alkenyl and a decrease in the diacyl species. Forty-eight hr after the tracer, however, the radioactivity of phosphatidyl ethanolamine increased and at 45 days remained slightly higher than phosphatidyl choline. Radioactivity of cholesterol, a result of synthesis from acetate undoubtedly derived from the breakdown of tracer linolenate, was also high 48 hr after tracer and remained high until 45 days.

16.
Lipids ; 11(9): 689-92, 1976 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-994760

RESUMO

[3-(14)C] Eicosatrienoic acid (delta11,14,17) chemically synthesized from [-(14)C] linolenic acid was injected intracranially into 14-day old rats and sacrificed 8 hr later. The analysis of brain fatty acids by radio-gas liquid chromatography before and after ozonolysis showed that the tetraene fraction consisted of a desaturated product, delta5,11,17-20:4, and its elongated product, delta7,13,16,19-22:4. Both of these products, with a combined total of 61% of the total radioactivity recovered in the tetraene fraction, contain a nonmethylene interrupted double bond system and, therefore, are unsuitable for further desaturation. The other two components, delta6,9,12,15-18:4 and delta8,11,14,14-20:4, must have been formed from delta9,12,15-18:3, formed by retroconversion of the starting material 20:3, followed by desaturation and elongation. These results suggest a lack of delta8 desaturase in the developing brain, leading to formation of delta5,11,14,17-20:4 rather than delta8,11,14,17-20:4. However, the nonmethylene interrupted doulbe bond isomer does not restrict chain elongation.


Assuntos
Encéfalo/metabolismo , Ácidos Graxos Dessaturases/deficiência , Ácidos Graxos Insaturados/metabolismo , Animais , Colesterol/biossíntese , Cromatografia Gasosa , Ácidos Graxos não Esterificados/metabolismo , Feminino , Lipídeos/biossíntese , Masculino , Ratos , Triglicerídeos/biossíntese
17.
Lipids ; 16(5): 389-92, 1981 May.
Artigo em Inglês | MEDLINE | ID: mdl-7253847

RESUMO

Since direct intracranial injections of precursors indicate that cholesterol is synthesized in the brain at all ages, there must be a mode of disposal also. The sterol nucleus itself is not degraded by mammalian systems but the side chain can be metabolized. [26-14C] cholesterol was therefore injected directly into the brain of 8- to 19-day-old rats which were sacrificed at the end of 24 hr, 1 week and 2 weeks after injection. The results indicate that, irrespective of the interval between injection and sacrifice, all of the radioactivity was found in the free cholesterol or the cholesterol component of the sterol esters. No radioactivity was found in the fatty acids of the phospholipids. We therefore conclude that the side chain of the cholesterol does not get metabolized to propionyl CoA, which in turn, could lead to fatty acid synthesis. Radioactivity in the serum, even after 2 weeks, indicates that there must be a slow but steady exchange between the brain and the blood that would explain the route of exit for brain cholesterol.


Assuntos
Encéfalo/metabolismo , Colesterol/metabolismo , Animais , Ésteres do Colesterol/sangue , Ésteres do Colesterol/metabolismo , Metabolismo dos Lipídeos , Lipídeos/sangue , Fígado/metabolismo , Ratos
18.
Lipids ; 11(1): 67-71, 1976 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-1250069

RESUMO

Thirteen-day old rats were given intracranial injections of 1-14C linolenic acid (all cis 9, 12, 15 octadecatrienoic acid) and were sacrificed after 8 hr. Analysis of brain fatty acids showed that 16:0, 18:0, 18:1, 18:3, 20:3, 20:4, 20:5, 22:5, and 22:6 were labeled. The total fatty acid methyl esters were separated into classes according to degree of unsaturation on a AgNO3:SiO2 impregnated plate. The bands were scraped off and the eluted fatty acids were first analyzed by radio-gas liquid chromatography and then subjected to reductive ozonolysis to determine double bond position. The saturated acids, 16:0 and 18:0, as well as the monosaturated 18:1, must have been formed from radioactive acetate produced by beta oxidation of the injected linolenate. Among the polyunsaturated fatty acids, the triene fraction was characterized and identified as 18:3 omega3 (delta9, 12, 15), the starting material, and 20:3 omega3 (delta11, 14, 17); the tetraene fraction was identified as 20:4 omega3 (delta2, 11, 14, 17); the pentaene fraction was identified as 20:5 omega3 (delta5, 8, 11, 14, 17) and 22:5 omega3 (delta7, 10, 13, 16, 19); and, finally, the hexaene fraction was shown to be 22:6 omega3 (delta4, 7, 10, 13, 16, 19). The biosynthesis of these omega3 family fatty acids in the brain in situ is discussed.


Assuntos
Encéfalo/metabolismo , Ácidos Graxos Insaturados/biossíntese , Ácidos Linolênicos/metabolismo , Envelhecimento , Animais , Encéfalo/crescimento & desenvolvimento , Colesterol/biossíntese , Feminino , Glicerídeos/biossíntese , Masculino , Fosfolipídeos/biossíntese , Ratos
19.
Lipids ; 16(5): 328-35, 1981 May.
Artigo em Inglês | MEDLINE | ID: mdl-7253841

RESUMO

The lipids of liver mitochondria prepared from normal rats and from rats made hypothyroid by thyroidectomy and injection with 131 INa contained similar amounts, per mg protein, of total lipids, phospholipids, neutral lipids and lipid phosphorus. Hypothyroidism caused a doubling of the relative amounts of mitochondrial cardiolipins (CL; to 20.5% of the phospholipid P) and an accompanying trend (although statistically not significant) toward decreased amounts of both phosphatidylcholines (PC) and phosphatidylserines (PS), with phosphatidylethanolamines (PE) remaining unchanged. The pattern of elevated 18:2 fatty acyl content and depleted 20:4 acyl groups of the mitochondrial phospholipids of hypothyroid preparations was reflected to varying degrees in the resolved phospholipids, with PC showing greater degrees of abnormality than PE, and CL showing none. Hypothyroidism produced the same abnormal pattern of fatty acyl distributions in liver microsomal total lipids as was found in the mitochondria. Hypothyroid rats, when killed 6 hr after injection of [1-14C] labeled linoleate, showed the following abnormalities: the liver incorporated less label into lipids, and converted 18:2 not exclusively to 20:4 (as normals do) but instead incorporated the label mainly into saturated fatty acids. These data, together with the known decrease in beta-oxidation, suggest that hypothyroidism involves possible defective step(s) in the conversion of 18:2 to 20:4.


Assuntos
Metabolismo dos Lipídeos , Microssomos Hepáticos/metabolismo , Mitocôndrias Hepáticas/metabolismo , Tireoidectomia , Animais , Cardiolipinas/metabolismo , Ácidos Graxos/metabolismo , Masculino , Fosfatidilcolinas/metabolismo , Fosfatidilserinas/metabolismo , Ratos
20.
Proc Inst Mech Eng H ; 212(4): 303-15, 1998.
Artigo em Inglês | MEDLINE | ID: mdl-9769698

RESUMO

In the area of orthopaedic implants, particularly total hip joint replacements, a metal-plastic combination is still the most popular choice consisting of a femoral head fabricated from 316L stainless steel, Ti alloy or Co-Cr alloy in contact with an ultra-high molecular weight polyethylene (UHMWPD) acetabular cup. It is recently considered that wear of the UHMWPE cup is of major concern. Generation of the wear debris can have adverse effects on the body, both localized and systemic. It is envisaged that wear of the prosthetic components, particularly those fabricated from UHMWPE can be reduced through the use of surface coatings. The aim of this investigation was to deposit a selection of refractory element nitride-based coatings (TiN, TiA1N, ZrN) onto 316L stainless steel substrates, using physical vapour deposition (PVD) technology and to study their sliding wear behaviour in contact with both UHMWPE and 316L stainless steel pins, using a pin-on-plate testing rig. Tests were conducted in Ringers solution and Ringers solution plus bone cement particles. The volume of material removed from the pins served as an indication of their wear behaviour. Wear mechanisms were identified using scanning electron microscopy. The results of these findings and the potential for these coatings to be used in orthopaedic applications are discussed.


Assuntos
Ligas/normas , Prótese de Quadril/normas , Polietilenos/normas , Aço Inoxidável/normas , Titânio/normas , Zircônio/normas , Fenômenos Biomecânicos , Humanos , Teste de Materiais , Microscopia Eletrônica de Varredura , Espectrometria por Raios X
SELEÇÃO DE REFERÊNCIAS
Detalhe da pesquisa