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1.
Transplant Proc ; 52(3): 977-981, 2020 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-32151388

RESUMO

BACKGROUND: Gastroesophageal reflux (GER) in recipients of lung transplant (LTX) is associated with chronic allograft rejection, presumably via microaspiration that damages airway epithelium. Most LTX programs perform a single post-LTX esophageal study to evaluate for GER; the efficacy of this test is unclear. METHODS: Patients with 1 year of post-LTX follow-up, including routine bronchoscopies with bronchoalveolar lavage fluid (BALF) samples as well as high-resolution esophageal manometry and pH probe monitoring (HREMpH), were evaluated. BALF samples were analyzed with competitive enzyme-linked immunosorbent assay to detect bile salts, which are indicative of aspiration. These results were compared to results of HREMpH studies post LTX. RESULTS: Ninety BALF samples were analyzed for bile salts and acted as disease positive for this evaluation. Of the 13 HREMpH cases, 8 were positive for GER, but only 3 were positive for bile salts via assay. Of the 5 HREMpH-negative cases, 2 experienced aspiration. A solitary HREMpH study had 60.0% sensitivity and 37.5% specificity with positive and negative likelihood ratios: 0.96 and 1.07, respectively. CONCLUSION: Microaspiration appears to be an intermittent phenomenon, and HREMpH screening poorly correlates with BALF evidence of aspiration; which may not be adequate. As aspiration detection is crucial in this population, further analysis is warranted.


Assuntos
Refluxo Gastroesofágico/diagnóstico , Transplante de Pulmão , Manometria/métodos , Aspiração Respiratória/diagnóstico , Adulto , Ácidos e Sais Biliares/análise , Líquido da Lavagem Broncoalveolar/química , Broncoscopia , Feminino , Humanos , Concentração de Íons de Hidrogênio , Masculino , Pessoa de Meia-Idade , Transplantados
2.
Artigo em Inglês | MEDLINE | ID: mdl-29205691

RESUMO

BACKGROUND: Gastroparesis is a complex clinical entity; many aspects of which remain unknown. Although most patients have idiopathic, diabetic, or postsurgical gastroparesis, many are thought to have measurable neuromuscular abnormalities. Immunotherapy has recently been utilized to treat suspected autoimmune gastrointestinal dysmotility. METHODS: Fourteen patients with symptoms of gastroparesis (Gp) who were refractory to drug/device were selected from 443 Gp patients from 2013 to 2015 who were treated at the University of Louisville motility center. All patients underwent a structural and psychiatric evaluation along with detailed psychological and behavioral examination to rule out eating disorders. We performed detailed neuromuscular evaluation and all 14 patients received at least 12 weeks of intravenous immunoglobulin (400 mg/kg infusion weekly). Response was defined subjectively (symptomatic improvement) using standardized IDIOM score system. KEY RESULTS: All 14 patients had serological evidence and/or tissue evidence of immunological abnormality. Post-IVIG therapy, there was a significant improvement in symptoms scores for nausea, vomiting, early satiety, and abdominal pain. CONCLUSIONS AND INFERENCES: Although limited by the absence of placebo group, the data illustrate the role of autoimmunity and neuromuscular evaluation in patients with gastroparesis and support the utility of a diagnostic trial of immunotherapy in an effort to improve therapeutic outcomes for such patients.


Assuntos
Gastroparesia/terapia , Imunoglobulinas Intravenosas/uso terapêutico , Imunoterapia/métodos , Adolescente , Adulto , Feminino , Gastroparesia/imunologia , Humanos , Masculino , Pessoa de Meia-Idade , Avaliação de Sintomas , Resultado do Tratamento , Adulto Jovem
3.
Chem Commun (Camb) ; 52(26): 4749-52, 2016 Apr 04.
Artigo em Inglês | MEDLINE | ID: mdl-26898721

RESUMO

DNA duplexes containing unnatural base-pair surrogates are attractive biomolecular nanomaterials with potentially beneficial photophysical or electronic properties. Herein we report the first X-ray structure of a duplex containing a phen-pair in the center of the double helix in a zipper like stacking arrangement.


Assuntos
DNA/química , Conformação de Ácido Nucleico , Fenantrenos/química , Cristalografia por Raios X
4.
Genetica ; 143(5): 597-612, 2015 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-26253053

RESUMO

Ecdysteroid titers, developmental landmarks and the presence of prominent amplifying regions (DNA puffs) have been compared during late larval to pupal development in four groups of Rhynchosciara americana larvae and in R. americana and Rhynchosciara milleri. Three prominent DNA puffs (B2, C3 and C8) expand and regress sequentially on the rising phase of the 20-hydroxyecdysone (20E) titer in R. americana as a firm, cellular cocoon is being constructed. A sharp rise in 20E coincides with the regression of these puffs. The shape of the 20E curve is similar in R. milleri, a species that does not construct a massive cocoon, but the behavior of certain DNA puffs and their temporal relationship to the curve differs. Regions corresponding to B2 and C3 can be identified in R. milleri by banding pattern similarity with R. americana chromosomes and, in the case of B2, by hybridization to an R. americana probe. A B2 puff appears in R. milleri as the 20E titer rises but remains small in all gland regions. A puff similar to the R. americana C3 puff occurs in posterior gland cells of R. milleri (C3(Rm)) after the B2 puff, but this site did not hybridize to R. americana C3 probes. C3(Rm) incorporated (3)H-thymidine above background, but showed less post-puff DNA accumulation than C3 of R. americana. R. americana C8 probes hybridized to a more distal region of the R. milleri C chromosome that did not appear to amplify or form a large puff. These differences can be related to developmental differences, in particular differences in cocoon construction between the two species.


Assuntos
Dípteros/genética , Proteínas e Peptídeos Salivares/genética , Animais , Cromossomos , Dípteros/metabolismo , Ecdisteroides/metabolismo , Feminino , Proteínas de Insetos/genética , Proteínas de Insetos/metabolismo , Larva/genética , Masculino , Proteínas e Peptídeos Salivares/metabolismo , Especificidade da Espécie
5.
J Vet Pharmacol Ther ; 32(6): 577-84, 2009 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-20444013

RESUMO

The present investigation evaluated arthritic pain in horses receiving daily placebo, undenatured type II collagen (UC-II) at 320, 480, or 640 mg (providing 80, 120, and 160 mg active UC-II, respectively), and glucosamine and chondroitin (5.4 and 1.8 g, respectively, bid for the first month, and thereafter once daily) for 150 days. Horses were evaluated for overall pain, pain upon limb manipulation, physical examination, and liver and kidney functions. Evaluation of overall pain was based upon a consistent observation of all subjects during a walk and a trot in the same pattern on the same surface. Pain upon limb manipulation was conducted after the walk and trot. It consisted of placing the affected joint in severe flexion for a period of 60 sec. The limb was then placed to the ground and the animal trotted off. The response to the flexion test was then noted with the first couple of strides the animal took. Flexion test was consistent with determining clinically the degree of osteoarthritis in a joint. Horses receiving placebo showed no change in arthritic condition, while those receiving 320 or 480 or 640 mg UC-II exhibited significant reduction in arthritic pain (P < 0.05). UC-II at 480 or 640 mg dose provided equal effects, and therefore, 480 mg dose was considered optimal. With this dose, reduction in overall pain was from 5.7 +/- 0.42 (100%) to 0.7 +/- 0.42 (12%); and in pain upon limb manipulation from 2.35 +/- 0.37 (100%) to 0.52 +/- 0.18 (22%). Although glucosamine and chondroitin treated group showed significant (P < 0.05) reduction in pain compared with pretreated values, the efficacy was less compared with that observed with UC-II. In fact, UC-II at 480 or 640 mg dose was found to be more effective than glucosamine and chondroitin in arthritic horses. Clinical condition (body weight, body temperature, respiration rate, and pulse rate), and liver (bilirubin, GGT, and ALP) and kidney (BUN and creatinine) functions remained unchanged, suggesting that these supplements were well tolerated.


Assuntos
Condroitina/uso terapêutico , Colágeno Tipo II/uso terapêutico , Glucosamina/uso terapêutico , Doenças dos Cavalos/tratamento farmacológico , Osteoartrite/veterinária , Animais , Condroitina/administração & dosagem , Relação Dose-Resposta a Droga , Esquema de Medicação , Quimioterapia Combinada , Glucosamina/administração & dosagem , Cavalos , Osteoartrite/tratamento farmacológico , Dor/tratamento farmacológico , Dor/veterinária
6.
Genetica ; 128(1-3): 373-84, 2006.
Artigo em Inglês | MEDLINE | ID: mdl-17028965

RESUMO

In Drosophila melanogaster, inversion In(3R)Payne increases in frequency towards low latitudes and has been putatively associated with variation in size and thermal resistance, traits that also vary clinally. To assess the association between size and inversion, we obtained isofemale lines of inverted and standard karyotype of In(3R)Payne from the ends of the Australian D. melanogaster east coast cline. In the northern population, there was a significant association between In(3R)Payne and body size, with standard lines from this population being relatively larger than inverted lines. In contrast, the inversion had no influence on development time or cold resistance. We strengthened our findings further in a separate study with flies from populations from the middle of the cline as well as from the cline ends. These flies were scored for wing size and the presence of In(3R)Payne using a molecular marker. In females, the inversion accounted for around 30% of the size difference between cline ends, while in males the equivalent figure was 60%. Adaptive shifts in size but not in the other traits are therefore likely to have involved genes closely associated with In(3R)Payne. Because the size difference between karyotypes was similar in different populations, there was no evidence for coadaptation within populations.


Assuntos
Inversão Cromossômica , Drosophila melanogaster/genética , Aclimatação/genética , Animais , Austrália , Sequência de Bases , Tamanho Corporal/genética , Primers do DNA/genética , Drosophila melanogaster/anatomia & histologia , Drosophila melanogaster/fisiologia , Feminino , Genes de Insetos , Genética Populacional , Masculino , Característica Quantitativa Herdável , Asas de Animais/anatomia & histologia
7.
Rapid Commun Mass Spectrom ; 20(2): 181-4, 2006.
Artigo em Inglês | MEDLINE | ID: mdl-16345127

RESUMO

Stable isotope ratios ((13)C/(12)C and (15)N/(14)N) were measured in royal jelly (RJ) samples by isotope ratio mass spectrometry (IRMS) to evaluate authenticity and adulteration. Carbon and nitrogen isotope contents (given as delta values relative to a standard, delta(13)C, delta(15)N) of RJ samples from various European origins and samples from commercial sources were analyzed. Uniform delta(13)C values from -26.7 to -24.9 per thousand were observed for authentic RJ from European origins. Values of delta(15)N ranged from -1.1 to 5.8 per thousand depending on the plant sources of nectars and pollen. High delta(13)C values of several commercial RJ samples from -20.8 to -13.3 per thousand indicated adulteration with high fructose corn syrup (HFCS) as a sugar source. Use of biotechnologically produced yeast powder as protein source for the adulterated samples was assumed as delta(15)N values were lower, as described for C(4) or CAM plant sources. RJ samples from authentic and from adulterated production were distinguished. The rapid and reliable method is suitable for urgent actual requirements in food monitoring.


Assuntos
Abelhas/química , Radioisótopos de Carbono , Ácidos Graxos/análise , Ácidos Graxos/química , Análise de Alimentos/métodos , Contaminação de Alimentos/análise , Espectrometria de Massas/métodos , Radioisótopos de Nitrogênio , Animais , Reprodutibilidade dos Testes , Sensibilidade e Especificidade
8.
J Gene Med ; 7(11): 1390-9, 2005 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-16025547

RESUMO

BACKGROUND: We have previously described a five-plasmid HIV-1 vector system that utilises a codon-optimised gagpol gene. While this system was shown to be safer than systems using proviral type helpers, the titre of virus produced was relatively low. Therefore, a process of optimising all aspects of virus production was initiated. METHODS: A systematic approach was taken to the optimisation of virus production by transient expression using a five-plasmid packaging system. Codon-manipulation was used to reduce homology between helper and vector constructs. Ultrafiltration and ultracentrifugation were used for large-scale virus production. RESULTS: We describe codon-optimised reading frames for Tat and Rev and the optimisation of virus production. The optimisation process resulted in an increase in virus titre of 7- to 8-fold. Several other approaches to increasing viral titre described by others proved ineffective in our system after it had been optimised. In addition, we show that by varying the ratio of the GagPol helper construct to vector, the infectivity of the virus could be controlled. The use of a novel codon-optimised HIV-1 GagPol expression construct with reduced homology to vector sequences significantly reduced transfer of gagpol sequences to transduced cells. Virus could be collected in serum-free medium without a significant loss of titre, which facilitated subsequent processing. Processing using a combination of ultrafiltration and ultracentrifugation allowed efficient and rapid processing of litre volumes of virus supernatant. CONCLUSIONS: By taking a systematic approach to optimising all aspects of our five-plasmid lentiviral vector system we improved titre, safety, large-scale production, and demonstrated that infectivity could be specifically controlled.


Assuntos
Vetores Genéticos , HIV-1/genética , Transdução Genética , Replicação Viral , Animais , Linhagem Celular , Códon , Meios de Cultura Livres de Soro , Proteínas de Fusão gag-pol/genética , Proteínas de Fusão gag-pol/metabolismo , Produtos do Gene gag/genética , Produtos do Gene gag/metabolismo , Genes rev , Genes tat , Infecções por HIV , HIV-1/isolamento & purificação , HIV-1/metabolismo , HIV-1/fisiologia , Humanos , Camundongos , Plasmídeos/genética , Plasmídeos/metabolismo
9.
Ann N Y Acad Sci ; 1031: 332-3, 2004 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-15753161

RESUMO

The role of specific amino acid residues in mediating the biochemical functions of tocopherol transfer protein (TTP) was investigated using site-directed mutagenesis and functional assays. These findings further current understanding of TTP mechanism of action and its role in human health.


Assuntos
Proteínas de Transporte/química , Proteínas de Transporte/fisiologia , Relação Estrutura-Atividade , Proteínas de Transporte/genética , Humanos , Fígado/química , Mutação , Vitamina E/metabolismo
10.
Chromosoma ; 112(3): 144-51, 2003 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-14579130

RESUMO

Drosophila melanogaster was transformed with an 18 kb fragment of the C3 DNA puff of Rhynchosciara americana, including the C3-22 gene and the origins of replication that direct amplification. Different tissues and developmental stages of five independent transgenic lines were analyzed by quantitative Southern blot hybridization. No indication was found that the transformed fragment was amplified, strongly suggesting that factors involved in DNA puff amplification have not been conserved in Drosophila. Transcription of the C3-22 gene in the transgenic lines was found to be at a low and constitutive level throughout development. These results indicate that, unlike other DNA puff genes, the factors that regulate the C3-22 gene are not conserved in Drosophila.


Assuntos
Cromossomos/genética , Dípteros/genética , Drosophila melanogaster/genética , Amplificação de Genes , Genes de Insetos , Transcrição Gênica/genética , Animais , Animais Geneticamente Modificados/genética , Southern Blotting , Vetores Genéticos , Hibridização In Situ , Hibridização in Situ Fluorescente , Ensaios de Proteção de Nucleases
11.
Acta Med Port ; 14(1): 65-70, 2001.
Artigo em Português | MEDLINE | ID: mdl-11321980

RESUMO

In the literature, there are few reports of posterior cerebral artery aneurysms resulting from isolated dissections. In these cases the treatment is still a matter of discussion and includes anticoagulation, surgical intervention, endovascular techniques and conservative management. We present five cases of Posterior Cerebral Artery (PCA) aneurysms, with angiographic criteria of dissection (double lumen, proximal narrowing), all being situated at the P2 segment, three being close to the P1/P2 junction. In one case, a large aneurysm ruptured during the attempted catheterization with subsequent death of the patient. In three patients occlusion of the parent vessel was performed with Guglielmi detachable coils located proximal to the aneurysm, with no new neurological deficits. In the other case there was spontaneous thrombosis of the aneurysm. Occlusion of the parent vessel by endovascular techniques in dissecting PCA aneurysms has a low probability of neurological deficits and seems to be an appropriate approach for these aneurysms.


Assuntos
Angioscopia , Dissecção Aórtica/terapia , Aneurisma Intracraniano/terapia , Adulto , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Estudos Retrospectivos
12.
Acta Med Port ; 14(1): 71-5, 2001.
Artigo em Português | MEDLINE | ID: mdl-11321982

RESUMO

Dural arterio-venous shunts (DAVS) of the anterior cranial fossa are quite rare. There are only a few cases reported in the literature. The authors present 5 cases of dural arterio-venous shunts (DAVS) of the anterior cranial fossa, allowing more data for later reviews of this rare and aggressive localisation of DAVS. The clinical set, imaging findings (with emphasis in diagnostic angiography), treatment and outcome in these 5 patients are described. Haemorrhage was the presenting form in 4 patients; the other case presented was investigated for headache. There were bilateral symmetric feeders in two patients, unilateral feeders in another two and unilateral predominant feeders in one; contribution of the external carotid artery, when present, was always minimal. Venous drainage included one or combinations of these: superior sagittal sinus, sylvian veins and cavernous sinus. Three patients had venous aneurysms in anterior cranial fossa; of these, two presented with haemorrhage, but the third one of them has been asymptomatic for 7 years. Three patients were treated by surgical exclusion of the shunt and became clinical and angiographicaly normal. According to the literature, our cases confirm the highly aggressive behaviour of these DAVS. Surgical treatment is an efficacious method of therapy and should be done as soon as possible. Embolization can be attempted but is technically difficult and eventually too expensive.


Assuntos
Fístula Arteriovenosa/diagnóstico , Dura-Máter/irrigação sanguínea , Adulto , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Base do Crânio
13.
J Nutr ; 131(2): 378S-81S, 2001 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-11160565

RESUMO

Most tocopherols and tocotrienols, with the exception of alpha-tocopherol, are not retained by humans. This suggests that alpha-tocopherol is recognized uniquely; therefore, it may exert an exclusive function. alpha-Tocopherol possesses distinct properties that are independent of its prooxidant, antioxidant or radical-scavenging ability. alpha-Tocopherol specifically inhibits protein kinase C, the growth of certain cells and the transcription of the CD36 and collagenase genes. Activation events have also been seen on the protein phosphatase 2A (PP(2)A) and on the expression of other genes (alpha-tropomyosin and connective tissue growth factor). Neither ss-tocopherol nor probucol possessed the same specialty functions as alpha-tocopherol. Recently, we isolated a new ubiquitous cytosolic alpha-tocopherol binding protein (TAP). Its motifs suggest that it is a member of the hydrophobic ligand-binding protein family (CRAL-TRIO). TAP may also be involved in the regulation of cellular alpha-tocopherol concentration and alpha-tocopherol-mediated signaling.


Assuntos
Músculo Liso/efeitos dos fármacos , Vitamina E/farmacologia , Vitamina E/fisiologia , Células Cultivadas , Regulação da Expressão Gênica/efeitos dos fármacos , Humanos , Músculo Liso/fisiologia , Fosfoproteínas Fosfatases , Proteína Quinase C/antagonistas & inibidores , Proteína Fosfatase 2 , Processamento de Proteína Pós-Traducional , Transcrição Gênica/efeitos dos fármacos
15.
Genome ; 43(5): 786-95, 2000 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-11081968

RESUMO

Polytene chromosome analysis is presented for Rhynchosciara baschanti, a species belonging to the americana-like group of Rhynchosciara. R. baschanti chromosomes show morphological differences in centromeric and telomeric regions compared to two other members within the group, R. americana and R. hollaenderi. In addition, fixed band and autosomal inversion differences were noted. Physical mapping data showed synteny among the taxa under study for DNA puffs and single-copy or histone gene probes, whereas rDNA and poly-(r)A probes showed different diagnostic patterns. The activity of developmentally active genes and the pattern of thymidine incorporation into DNA puff sites of R. baschanti are consistent with those found in the two previously studied species, except for lower levels of expression at some of these sites. These results suggest that differential duplication of specific DNA sequences, in particular repetitive and homopolymeric DNA, has played a role in the chromosomal evolution of these Rhynchosciara species. Inversions and band dimorphisms have also occurred, but the processes leading to their maintenance and fixation appear to have been slow, since these three species are in general chromosomally monomorphic.


Assuntos
Cromossomos , Citogenética/métodos , Dípteros/genética , Animais , DNA Ribossômico , Dípteros/classificação , Evolução Molecular , Feminino , Regulação da Expressão Gênica no Desenvolvimento , Masculino , Meiose , Mitose , Mapeamento Físico do Cromossomo
16.
J Biol Chem ; 275(33): 25672-80, 2000 Aug 18.
Artigo em Inglês | MEDLINE | ID: mdl-10829015

RESUMO

Vitamin E (alpha-tocopherol) is an essential dietary nutrient for humans and animals. The mechanisms involved in cellular regulation as well as in the preferential cellular and tissue accumulation of alpha-tocopherol are not yet well established. We previously reported (Stocker, A., Zimmer, S., Spycher, S. E., and Azzi, A. (1999) IUBMB Life 48, 49-55) the identification of a novel 46-kDa tocopherol-associated protein (TAP) in the cytosol of bovine liver. Here, we describe the identification, the molecular cloning into Escherichia coli, and the in vitro expression of the human homologue of bovine TAP, hTAP. This protein appears to belong to a family of hydrophobic ligand binding proteins, which have the CRAL (cis-retinal binding motif) sequence in common. By using a biotinylated alpha-tocopherol derivative and the IASys resonant mirror biosensor, the purified recombinant protein was shown to bind tocopherol at a specific binding site with K(d) 4.6 x 10(-7) m. Northern analyses showed that hTAP mRNA has a size of approximately 2800 base pairs and is ubiquitously expressed. The highest amounts of hTAP message are found in liver, brain, and prostate. In conclusion, hTAP has sequence homology to proteins containing the CRAL_TRIO structural motif. TAP binds to alpha-tocopherol and biotinylated tocopherol, suggesting the existence of a hydrophobic pocket, possibly analogous to that of SEC14.


Assuntos
Proteínas de Transporte/química , Lipoproteínas , Transativadores , Vitamina E/química , Motivos de Aminoácidos , Sequência de Aminoácidos , Animais , Sítios de Ligação , Biotinilação , Northern Blotting , Proteínas de Transporte/metabolismo , Bovinos , Cromatografia de Afinidade , Cromatografia em Gel , Cromatografia Líquida de Alta Pressão , Cromatografia por Troca Iônica , Clonagem Molecular , Reagentes de Ligações Cruzadas , Brometo de Cianogênio/metabolismo , Citosol/metabolismo , Escherichia coli/metabolismo , Humanos , Focalização Isoelétrica , Cinética , Metabolismo dos Lipídeos , Fígado/metabolismo , Dados de Sequência Molecular , RNA Mensageiro/metabolismo , Proteínas Recombinantes/metabolismo , Homologia de Sequência de Aminoácidos , Fatores de Tempo , Distribuição Tecidual , Vitamina E/análogos & derivados , Vitamina E/biossíntese , Vitamina E/genética
17.
J Nutr ; 130(7): 1649-52, 2000 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-10867030

RESUMO

In the last 10 years precise cellular functions of alpha-tocopherol, some of which are independent of its antioxidant/radical-scavenging ability, have been revealed. Absorption of alpha-tocopherol from the gut is a selective process. Other tocopherols are not absorbed or are absorbed to a lesser extent. At the post-translational level, alpha-tocopherol inhibits protein kinase C and 5-lipoxygenase and activates protein phosphatase 2A and diacylglycerol kinase. Some genes [platelet glycoprotein IV/thrombospondin receptor/class B scavenger receptor (CD36), alpha-tocopherol transfer protein (alpha-TTP), alpha-tropomyosin, connective tissue growth factor and collagenase] are affected by alpha-tocopherol at the transcriptional level. alpha-Tocopherol also inhibits cell proliferation, platelet aggregation, monocyte adhesion and the oxygen burst in neutrophils. Other antioxidants, such as beta-tocopherol and probucol, do not mimic these effects, suggesting a nonantioxidant, alpha-tocopherol-specific molecular mechanism.


Assuntos
Vitamina E/farmacologia , Animais , Adesão Celular/efeitos dos fármacos , Divisão Celular/efeitos dos fármacos , Diacilglicerol Quinase/metabolismo , Ativação Enzimática , Humanos , Inibidores de Lipoxigenase , Fosfoproteínas Fosfatases/metabolismo , Agregação Plaquetária/efeitos dos fármacos , Proteína Quinase C/antagonistas & inibidores , Proteína Fosfatase 2 , Processamento de Proteína Pós-Traducional/efeitos dos fármacos , Espécies Reativas de Oxigênio/metabolismo , Transcrição Gênica/efeitos dos fármacos
18.
Prog Lipid Res ; 39(3): 231-55, 2000 May.
Artigo em Inglês | MEDLINE | ID: mdl-10799717

RESUMO

Vitamin E was originally considered a dietary factor of animal nutrition especially important for normal reproduction. The significance of vitamin E has been subsequently proven as a radical chain breaking antioxidant that can protect the integrity of tissues and play an important role in life processes. More recently alpha-tocopherol has been found to possess functions that are independent of its antioxidant/radical scavenging ability. Absorption in the body is alpha-tocopherol selective and other tocopherols are not absorbed or are absorbed to a lesser extent. Furthermore, pro-oxidant effects have been attributed to tocopherols as well as an anti-nitrating action. Non-antioxidant and non-pro-oxidant molecular mechanisms of tocopherols have been also described that are produced by alpha-tocopherol and not by beta-tocopherol. alpha-Tocopherol specific inhibitory effects have been seen on protein kinase C, on the growth of certain cells and on the transcription of some genes (CD36, and collagenase). Activation events have been seen on the protein phosphatase PP2A and on the expression of other genes (alpha-tropomyosin and Connective Tissue Growth Factor). Non-antioxidant molecular mechanisms have been also described for gamma-tocopherol, delta-tocopherol and tocotrienols.


Assuntos
Vitamina E/fisiologia , Antioxidantes , Humanos , Proteína Quinase C/antagonistas & inibidores , Relação Estrutura-Atividade , Vitamina E/química , Vitamina E/farmacocinética , Deficiência de Vitamina E/complicações
19.
Int Arch Allergy Immunol ; 121(3): 183-93, 2000 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-10729776

RESUMO

BACKGROUND: Restimulation of T lymphocytes via the TCR/CD3 complex can result in CD95/CD95L-dependent activation-induced cell death (AICD). Although the correlation of AICD sensitivity to the T helper 1 phenotype was confirmed in different studies, the underlying mechanism is still debated. Thus, it has been suggested that in Th2 cells, AICD resistance is controlled by a TCR-induced upregulation of the CD95-associated inhibitory phosphatase, FAP-1. We and others demonstrated that AICD resistance is associated with a reduced surface expression of CD95L upon restimulation. METHODS: Utilizing RT-PCR, Western blotting and flow cytometry, we analyzed time-dependent changes in levels of CD95L mRNA, cytosolic protein and surface expression in five long-term human T cell clones and polarized helper populations. RESULTS: We confirm that the inducible CD95L surface expression is lower or absent in all tested AICD-resistant clones as compared to sensitive cells. It is of interest that striking differences with respect to the activation-dependent inducibility of CD95L mRNA expression in individual resistant clones were observed. In addition, alterations in the expression of the inhibitory phosphatase FAP-1 or TCR-dependent changes in CD95 sensitivity in AICD-resistant clones could be ruled out as a mechanism for AICD resistance of human T cell clones. CONCLUSIONS: (1) The data presented strongly support the previous notion that AICD resistance of human T cell clones is mainly regulated by a differential expression of CD95L. (2) Differential expression of CD95L on individual resistant clones results from a lack of mRNA induction in one set and from a markedly decreased surface expression of translated protein in another set of clones.


Assuntos
Apoptose/imunologia , Ativação Linfocitária/imunologia , Subpopulações de Linfócitos T/imunologia , Anticorpos Monoclonais/toxicidade , Proteínas de Transporte/imunologia , Polaridade Celular/imunologia , Células Clonais/imunologia , Técnicas de Cocultura , Citotoxicidade Imunológica , Proteína Ligante Fas , Humanos , Imunidade Inata , Células Jurkat , Ligantes , Glicoproteínas de Membrana/biossíntese , Glicoproteínas de Membrana/genética , Proteína Tirosina Fosfatase não Receptora Tipo 13 , Proteínas Tirosina Fosfatases/imunologia , RNA Mensageiro/biossíntese , Complexo Receptor-CD3 de Antígeno de Linfócitos T/imunologia , Complexo Receptor-CD3 de Antígeno de Linfócitos T/fisiologia , Subpopulações de Linfócitos T/enzimologia , Linfócitos T Auxiliares-Indutores/enzimologia , Linfócitos T Auxiliares-Indutores/imunologia , Linfócitos T Auxiliares-Indutores/metabolismo , Células Tumorais Cultivadas , Receptor fas/imunologia , Receptor fas/toxicidade
20.
Antioxid Redox Signal ; 2(3): 397-404, 2000.
Artigo em Inglês | MEDLINE | ID: mdl-11229353

RESUMO

The present review is a continuation of earlier essays on the uptake mechanisms and the biological function of vitamin E. There are eight naturally occurring homologues of vitamin E, which differ in their structure and in biological activity in vivo and in vitro. Various studies have suggested that after normal gastrointestinal absorption of dietary vitamin E specific mechanisms favor the preferential accumulation of one of its homologues, alpha-tocopherol, in the human body. This process is thought to be mediated in part by the alpha-tocopherol transfer protein (alpha-TTP) in the liver cytoplasm. The mechanism and pathway by which alpha-TTP specifically incorporates alpha-tocopherol into plasma lipoproteins is not yet fully understood. Because alpha-tocopherol is widely distributed in tissues in various concentrations but alpha-TTP resides only in liver, its role as intracellular carrier of alpha-tocopherol seems unlikely. However, recent data indicate that a system of alpha-tocopherol-binding proteins is involved in these processes that favor the localization of alpha-tocopherol at the sites where it is required. The current status of the evidence for the regulation of alpha-tocopherol levels and their impact on cellular signaling is discussed.


Assuntos
Proteínas de Membrana , Vitamina E/química , Vitamina E/fisiologia , Absorção , Proteínas de Transporte/química , Proteínas de Transporte/fisiologia , Citoplasma/metabolismo , Humanos , Fígado/metabolismo , Modelos Biológicos , Modelos Moleculares , Proteínas de Transferência de Fosfolipídeos , Transporte Proteico , Transdução de Sinais , Vitamina E/metabolismo
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