Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 18 de 18
Filtrar
1.
Zhonghua Xue Ye Xue Za Zhi ; 45(8): 781-784, 2024 Aug 14.
Artigo em Chinês | MEDLINE | ID: mdl-39307727

RESUMO

Case 1: A 27-year-old female with ALK-positive anaplastic large cell lymphoma/leukemia; Case 2: A 27-year-old male with acute myeloid leukemia; Case 3: A 56-year-old male with myelodysplastic syndrome. These three patients underwent haploid hematopoietic stem cell transplantation and experienced severe oral mucosal inflammation, nausea, vomiting, diarrhea, and other symptoms over a long period, which significantly restricted eating. Neurological and psychiatric symptoms appeared at 50, 38, and 50 days following transplantation, respectively. The diagnosis of Wernicke encephalopathy was made by head magnetic resonance imaging, whereas the condition improved significantly after intravenous infusion of vitamin B(1).


Assuntos
Transplante de Células-Tronco Hematopoéticas , Encefalopatia de Wernicke , Humanos , Transplante de Células-Tronco Hematopoéticas/efeitos adversos , Masculino , Feminino , Adulto , Pessoa de Meia-Idade , Encefalopatia de Wernicke/etiologia , Encefalopatia de Wernicke/diagnóstico
2.
Zhonghua Xue Ye Xue Za Zhi ; 45(3): 249-256, 2024 Mar 14.
Artigo em Chinês | MEDLINE | ID: mdl-38716596

RESUMO

Objective: To analyze the efficacy of allo-HSCT with total body irradiation (TBI) and chemotherapy alone in the treatment of adult ALL and to explore the factors affecting prognosis. Methods: The clinical data of 95 adult patients with ALL who underwent allo-HSCT from January 2015 to August 2022 were included. According to the conditioning regimen, the patients were divided into two groups: the TBI plus cyclophosphamide (TBI/Cy) group (n=53) and the busulfan plus cyclophosphamide (Bu/Cy) group (n=42). Hematopoietic reconstitution after transplantation, GVHD, transplantation-related complications, relapse rate (RR), non-relapse mortality (NRM), OS, and LFS were compared, and the factors related to prognosis were analyzed. Results: The median time of neutrophil engraftment was 14 (10-25) days in the TBI/Cy group and 14 (10-24) days in the Bu/Cy group (P=0.106). The median time of megakaryocyte engraftment was 17 (10-42) days in the TBI/Cy group and 19 (11-42) days in the Bu/Cy group (P=0.488). The incidence of grade Ⅱ-Ⅳ acute GVHD (aGVHD) in the TBI/Cy and Bu/Cy groups was 41.5% and 35.7%, respectively (P=0.565). The incidence of grade Ⅲ-Ⅳ aGVHD in these two groups was 24.5% and 4.8%, respectively (P=0.009). The incidence of severe chronic GVHD in the two groups was 16.7% and 13.5%, respectively (P=0.689). The incidence of cytomegalovirus infection, Epstein-Barr virus infection, severe infection, and hemorrhagic cystitis in the two groups was 41.5% and 35.7% (P=0.565), 34.0% and 35.7% (P=0.859), 43.4% and 33.3% (P=0.318), and 20.8% and 50.0% (P=0.003), respectively. The median follow-up time was 37.1 months and 53.3 months in the TBI/Cy and Bu/Cy groups, respectively. The 2-year cumulative RR was 17.0% in the TBI/Cy group and 42.9% in the Bu/Cy group (P=0.017). The 2-year cumulative NRM was 24.5% and 7.1%, respectively (P=0.120). The 2-year LFS was 58.5% and 50.0%, respectively (P=0.466). The 2-year OS rate was 69.8% and 64.3%, respectively (P=0.697). In the multivariate analysis, the conditioning regimen containing TBI was a protective factor for relapse after transplantation (HR=0.304, 95% CI 0.135-0.688, P=0.004), whereas the effect on NRM was not significant (HR=1.393, 95% CI 0.355-5.462, P=0.634). Infection was an independent risk factor for OS after allo-HSCT in adult patients with ALL. Conclusion: allo-HSCT based on TBI conditioning regimen had lower relapse rate and lower incidence of hemorrhagic cystitis for adult ALL, compared with chemotherapy regimen. While the incidence o grade Ⅲ/Ⅳ aGVHD was hgher in TBI conditioning regimen than that in chemotherapy regimen.


Assuntos
Transplante de Células-Tronco Hematopoéticas , Leucemia-Linfoma Linfoblástico de Células Precursoras , Condicionamento Pré-Transplante , Transplante Homólogo , Irradiação Corporal Total , Humanos , Transplante de Células-Tronco Hematopoéticas/métodos , Leucemia-Linfoma Linfoblástico de Células Precursoras/terapia , Condicionamento Pré-Transplante/métodos , Prognóstico , Adulto , Taxa de Sobrevida , Doença Enxerto-Hospedeiro/etiologia , Doença Enxerto-Hospedeiro/prevenção & controle , Ciclofosfamida/administração & dosagem , Masculino , Feminino , Pessoa de Meia-Idade
4.
Fa Yi Xue Za Zhi ; 36(5): 614-621, 2020 Oct.
Artigo em Chinês | MEDLINE | ID: mdl-33295160

RESUMO

ABSTRACT: Facial reconstruction is a way to recover facial morphology by restoring soft tissues based on unidentified skulls using the knowledge of anatomy, anthropology, aesthetics, and computer science. It is applied in forensic science, oral plastic surgery and archeology, and especially plays an important role in the identification of the origin of the unknown corpses in forensic science. Facial reconstruction is the supplementary means of identification when other approaches (such as DNA comparison, imaging matching, dental records comparison, etc.) cannot identify individual identity. Facial soft tissue thickness (FSTT) is the basis of facial reconstruction and with the development of imaging and computer science, the techniques for measuring FSTT are improving rapidly and many related researches have appeared. This paper summarizes the application of facial reconstruction in forensic science, the accuracy of different methods and the research progress of this field to provide reference to this field.


Assuntos
Face , Antropologia Forense , Face/anatomia & histologia , Face/cirurgia , Ciências Forenses , Pesquisa , Crânio/anatomia & histologia , Crânio/cirurgia
5.
Eur Rev Med Pharmacol Sci ; 23(10): 4458-4464, 2019 May.
Artigo em Inglês | MEDLINE | ID: mdl-31173321

RESUMO

OBJECTIVE: To study the effect of ulinastatin (UTI) on myocardial ischemia-reperfusion injury (MIRI) through the extracellular signal-regulated kinase (ERK) signaling pathway. MATERIALS AND METHODS: A total of 24 Sprague-Dawley rats were randomly divided into sham group (n=8), I/R group (n=8), and UTI group (n=8), and the rat model of MIRI was established. The changes in the content of serum biochemical indexes, including superoxide dismutase (SOD) and malondialdehyde (MDA), were detected using the kits, and the changes in the expressions of serum inflammatory factors, including interleukin-6 (IL-6) and tumor necrosis factor-α (TNF-α), were detected using the quantitative Reverse Transcription-Polymerase Chain Reaction (qRT-PCR) and enzyme-linked immunosorbent assay (ELISA) kits. Moreover, the ERK phosphorylation level in myocardial tissues was detected using the immunofluorescence method, and the ERK phosphorylation level and cleaved caspase-3 expression were detected via qRT-PCR and Western blotting. RESULTS: Compared with those in sham group, the serum SOD content significantly declined, while the MDA content was significantly increased in I/R group, and they were significantly improved in UTI group (p<0.01). The results of detection using qRT-PCR and ELISA kits revealed that the inflammatory factors (IL-6 and TNF-α) in UTI group were significantly improved (p<0.01). The immunofluorescence results showed that the ERK phosphorylation level in myocardial tissues was significantly increased in UTI group. The results of qRT-PCR and Western blotting manifested that both ERK phosphorylation level and cleaved caspase-3 expression were significantly improved in UTI group (p<0.01). CONCLUSIONS: UTI can play a protective role in MIRI through up-regulating the ERK signaling pathway.


Assuntos
Glicoproteínas/uso terapêutico , Inibidores de Hidroximetilglutaril-CoA Redutases/uso terapêutico , Sistema de Sinalização das MAP Quinases/efeitos dos fármacos , Traumatismo por Reperfusão Miocárdica/tratamento farmacológico , Animais , Caspase 3/biossíntese , Caspase 3/genética , Citocinas/sangue , Masculino , Malondialdeído/sangue , Fosforilação , Ratos , Ratos Sprague-Dawley , Superóxido Dismutase-1/metabolismo
6.
J Anim Sci ; 92(7): 3026-34, 2014 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-24879765

RESUMO

Heat stress adversely affects the productivity and immune status of dairy cows. The temperature-humidity index (THI) is commonly used to indicate the degree of heat stress on dairy cattle. We investigated the effects of different THI and Cr supplementation on the antioxidant capacity, the levels of heat shock protein 72 (Hsp72), and cytokine responses of lactating cows. The study used a total of 24 clinically healthy uniparous midlactation Holstein cows, which were randomly divided into 2 groups (n = 12 per group), and was conducted in 3 designated THI periods: low THI period (LTHI; THI = 56.4 ± 2.5), moderate THI period (MTHI; THI = 73.9 ± 1.7), and high THI period (HTHI; THI = 80.3 ± 1.0). The 2 groups of cows were fed corn and corn silage based basal diet supplemented chromium picolinate to provide 3.5 mg of Cr/cow daily (Cr+) or basal diet with no Cr (Cr-). The experiment was a 3 × 2 factorial design. The numbers of leukocytes (P < 0.05) and serum levels of glucose (P < 0.001) were lower; however, the serum levels of blood urea nitrogen (BUN; P < 0.001) and creatinine (P < 0.001) were greater in the MTHI and HTHI than in LTHI. The total antioxidant capacity in the serum was unaltered; an increase in superoxide dismutase activity (P < 0.001) and in serum malondialdehyde concentration (P < 0.001) was observed in the MTHI and HTHI compared with the LTHI. The high THI led to increases in serum concentrations of tumor necrosis factor-α (TNF-α; P < 0.001) and IL-10 (P < 0.05). Cows supplemented with Cr had lower (P = 0.009) serum concentrations of cholesterol but greater (P < 0.001, respectively) serum levels of Hsp72 and IL-10 compared with those without Cr supplementation in the HTHI. Western blot analysis revealed that cows supplemented with Cr had greater (P = 0.038) expression of the inhibitor of nuclear factor kappa B α (IκBα) in peripheral blood mononuclear cells (PBMC) compared with those without Cr supplementation in the HTHI, whereas the expression of Hsp72 in PBMC was unaltered. Data indicate that there is a decrease in glucose and increases in BUN and creatinine in the serum of midlactation cows under hot conditions during the summer and that these cows have a lowered oxidative capacity but an elevated antioxidant capacity. In addition, Cr may play an anti-inflammatory role in lactating cows by promoting the release of Hsp72, increasing the production of IL-10, and inhibiting the degradation of IκBα under hot conditions during the summer.


Assuntos
Bovinos/fisiologia , Citocinas/sangue , Proteínas de Choque Térmico HSP72/sangue , Resposta ao Choque Térmico/fisiologia , Umidade/efeitos adversos , Lactação/fisiologia , Oxirredução/efeitos dos fármacos , Ácidos Picolínicos/farmacologia , Animais , Bovinos/imunologia , Citocinas/fisiologia , Dieta/veterinária , Suplementos Nutricionais , Feminino , Proteínas de Choque Térmico HSP72/fisiologia , Resposta ao Choque Térmico/efeitos dos fármacos , Temperatura Alta/efeitos adversos , Interleucina-10/sangue , Lactação/efeitos dos fármacos , Malondialdeído/sangue , NF-kappa B/sangue , Superóxido Dismutase/sangue , Fator de Necrose Tumoral alfa/sangue
8.
Arch Biochem Biophys ; 392(1): 153-61, 2001 Aug 01.
Artigo em Inglês | MEDLINE | ID: mdl-11469806

RESUMO

ATP-binding cassette (ABC) transporters couple the binding and hydrolysis of ATP to the translocation of solutes across biological membranes. The so-called "Walker motifs" in each of the nucleotide binding domains (NBDs) of these proteins contribute directly to the binding and the catalytic site for the MgATP substrate. Hence mutagenesis of residues in these motifs may interfere with function. This is the case with the MRP1 multidrug transporter. However, interpretation of the effect of mutation in the Walker B motif of NBD1 (D792L/D793L) was confused by the fact that it prevented biosynthetic maturation of the protein. We have determined now that this latter effect is entirely due to the D792L substitution. This variant is unable to mature conformationally as evidenced by its remaining more sensitive to trypsin digestion in vitro than the mature wild-type protein. In vivo, the core-glycosylated form of that mutant is retained in the endoplasmic reticulum and degraded by the proteasome. A different substitution of the same residue (D792A) had a less severe effect enabling accumulation of approximately equal amounts of mature and immature MRP1 proteins in the membrane vesicles but still resulted in defective nucleotide interaction and organic anion transport, indicating that nucleotide hydrolysis at NBD1 is essential to MRP1 function.


Assuntos
Transportadores de Cassetes de Ligação de ATP/química , Transportadores de Cassetes de Ligação de ATP/genética , Mutação , Transportadores de Cassetes de Ligação de ATP/metabolismo , Motivos de Aminoácidos , Sequência de Aminoácidos , Substituição de Aminoácidos , Animais , Sítios de Ligação , Cricetinae , Cisteína Endopeptidases/metabolismo , Humanos , Dados de Sequência Molecular , Proteínas Associadas à Resistência a Múltiplos Medicamentos , Complexos Multienzimáticos/antagonistas & inibidores , Complexos Multienzimáticos/metabolismo , Mutagênese Sítio-Dirigida , Mutação de Sentido Incorreto , Nucleotídeos/metabolismo , Complexo de Endopeptidases do Proteassoma , Conformação Proteica , Processamento de Proteína Pós-Traducional , Estrutura Terciária de Proteína , Proteínas Recombinantes/química , Proteínas Recombinantes/genética , Proteínas Recombinantes/metabolismo , Tripsina
9.
Mol Cell ; 4(1): 137-42, 1999 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-10445036

RESUMO

Many cystic fibrosis transmembrane conductance regulator (CFTR) mutants are recognized as aberrant by the quality control apparatus at the endoplasmic reticulum (ER) and are targeted for degradation. The mechanism whereby nascent chains are distinguished as either competent or incompetent for ER export has not been elucidated. Here we show that export-incompetent chains display multiple arginine-framed tripeptide sequences like the one recently identified in ATP-sensitive K+ channels. Replacement of arginine residues at positions R29, R516, R555, and R766 with lysine residues to inactivate four of these motifs simultaneously causes delta F508 CFTR, present in approximately 90% of CF patients, to escape ER quality control and function at the cell surface. Interference with recognition of these signals may be helpful in the management of CF.


Assuntos
Arginina/genética , Regulador de Condutância Transmembrana em Fibrose Cística/genética , Células Cultivadas , Canais de Cloreto/genética , Cloretos/metabolismo , Retículo Endoplasmático/metabolismo , Imunofluorescência , Humanos , Lisina/genética , Mutagênese Sítio-Dirigida , Mutação , Transdução de Sinais/genética
10.
Dev Biol ; 207(2): 257-70, 1999 Mar 15.
Artigo em Inglês | MEDLINE | ID: mdl-10068462

RESUMO

The severe neurological deficit in embryos carrying null mutations for the retinoblastoma (Rb) gene suggests that Rb plays a crucial role in neurogenesis. While developing neurons undergo apoptosis in vivo neural precursor cells cultured from Rb-deficient embryos appear to differentiate and survive. To determine whether Rb is an essential regulator of the intrinsic pathway modulating terminal mitosis we examined the terminal differentiation of primary cortical progenitor cells and bFGF-dependent neural stem cells derived from Rb-deficient mice. Although Rb -/- neural precursor cells are able to differentiate in vitro we show that these cells exhibit a significant delay in terminal mitosis relative to wild-type cells. Furthermore, Rb -/- cells surviving in vitro exhibit an upregulation of p107 that is found in complexes with E2F3. This suggests that p107 may partially compensate for the loss of Rb in neural precursor cells. Functional ablation of Rb family proteins by adenovirus-mediated delivery of an E1A N-terminal mutant results in apoptosis in Rb-deficient cells, consistent with the interpretation that other Rb family proteins may facilitate differentiation and survival. While p107 is upregulated and interacts with the putative Rb target E2F3 in neural precursor cells, our results indicate that it clearly cannot restore normal E2F regulation. Rb-deficient cells exhibit a significant enhancement of E2F 1 and 3 activity throughout differentiation concomitant with the aberrant expression of E2F-inducible genes. In these studies we show that Rb is essential for the regulation of E2F 1 and 3 activity as well as the onset of terminal mitosis in neural precursor cells.


Assuntos
Proteínas de Transporte , Proteínas de Ciclo Celular , Neurônios/metabolismo , Proteína do Retinoblastoma/genética , Células-Tronco/metabolismo , Fatores de Transcrição/metabolismo , Adenoviridae/genética , Animais , Apoptose , Diferenciação Celular/genética , Células Cultivadas , Proteínas de Ligação a DNA/genética , Fatores de Transcrição E2F , Fator de Transcrição E2F1 , Fator de Transcrição E2F3 , Fator 2 de Crescimento de Fibroblastos/metabolismo , Regulação da Expressão Gênica no Desenvolvimento , Imuno-Histoquímica , Camundongos , Camundongos Knockout , Mitose , Proteínas Nucleares/genética , Ligação Proteica , Proteína 1 de Ligação ao Retinoblastoma , Proteína p107 Retinoblastoma-Like , Fator de Transcrição DP1
11.
J Biol Chem ; 273(37): 23844-8, 1998 Sep 11.
Artigo em Inglês | MEDLINE | ID: mdl-9726996

RESUMO

Membrane vesicles prepared from cells expressing the multidrug resistance-associated protein (MRP) transport glutathione S-conjugates of hydrophobic substrates in an ATP dependent manner. Purified MRP possesses ATPase activity which can be further stimulated by anticancer drugs or leukotriene C4. However, the detailed relationship between ATP hydrolysis and drug transport has not been established. How the ATPase activity of MRP is regulated in the cell is also not known. In this report, we have examined the effects of different nucleotides on the ATPase activity of purified MRP. We have found that pyrimidine nucleoside triphosphates have little effect on enzymatic activity. In contrast, purine nucleotides dATP, dGTP, and adenosine 5'-(beta,gamma-imido)triphosphate function as competitive inhibitors. Somewhat unexpectedly, low concentrations of all the nucleoside diphosphates (NDPs) tested, except UDP, stimulate the ATPase activity severalfold. ADP or GDP at higher concentrations was inhibitory, reflecting NDP binding to the substrate site. On the other hand, the enhancement of hydrolysis at low NDP concentrations must reflect interactions with a separate site. Therefore, we postulate the presence of at least two types of nucleotide binding sites on the MRP, a catalytic site(s) to which ATP preferentially binds and is hydrolyzed and a regulatory site to which NDPs preferentially bind and stimulate hydrolysis. Interestingly, the stimulatory effects of drugs transported by MRP and NDPs are not additive, i.e. drugs are not able to further stimulate the NDP-activated enzyme. Hence, the two activation pathways intersect at some point. Since both nucleotide binding domains of MRP are likely to be required for drug stimulation of ATPase activity, the two sites that we postulate may also involve both domains.


Assuntos
Transportadores de Cassetes de Ligação de ATP/metabolismo , Difosfato de Adenosina/farmacologia , Adenosina Trifosfatases/metabolismo , Desoxirribonucleotídeos/farmacologia , Resistência a Múltiplos Medicamentos , Ribonucleotídeos/farmacologia , Transportadores de Cassetes de Ligação de ATP/isolamento & purificação , Animais , Linhagem Celular , Cricetinae , Ativação Enzimática , GTP Fosfo-Hidrolases/metabolismo , Humanos , Cinética , Proteínas Associadas à Resistência a Múltiplos Medicamentos , Proteínas Recombinantes/isolamento & purificação , Proteínas Recombinantes/metabolismo , Especificidade por Substrato , Transfecção
12.
J Gen Physiol ; 110(4): 355-64, 1997 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-9379168

RESUMO

Permeability of the cystic fibrosis transmembrane conductance regulator (CFTR) chloride channel to polyatomic anions of known dimensions was studied in stably transfected Chinese hamster ovary cells by using the patch clamp technique. Biionic reversal potentials measured with external polyatomic anions gave the permeability ratio (P/P) sequence NO > Cl > HCO > formate > acetate. The same selectivity sequence but somewhat higher permeability ratios were obtained when anions were tested from the cytoplasmic side. Pyruvate, propanoate, methane sulfonate, ethane sulfonate, and gluconate were not measurably permeant (P/P < 0.06) from either side of the membrane. The relationship between permeability ratios from the outside and ionic diameters suggests a minimum functional pore diameter of approximately 5.3 A. Permeability ratios also followed a lyotropic sequence, suggesting that permeability is dependent on ionic hydration energies. Site-directed mutagenesis of two adjacent threonines in TM6 to smaller, less polar alanines led to a significant (24%) increase in single channel conductance and elevated permeability to several large anions, suggesting that these residues do not strongly bind permeating anions, but may contribute to the narrowest part of the pore.


Assuntos
Ânions/metabolismo , Regulador de Condutância Transmembrana em Fibrose Cística/metabolismo , Sequência de Aminoácidos , Animais , Células CHO , Cricetinae , Regulador de Condutância Transmembrana em Fibrose Cística/genética , Regulação da Expressão Gênica , Ativação do Canal Iônico/genética , Ativação do Canal Iônico/fisiologia , Potenciais da Membrana/fisiologia , Dados de Sequência Molecular , Mutagênese , Técnicas de Patch-Clamp , Permeabilidade
13.
J Biol Chem ; 272(49): 30962-8, 1997 Dec 05.
Artigo em Inglês | MEDLINE | ID: mdl-9388243

RESUMO

Human multidrug resistance protein (MRP) was expressed at high levels in stably transfected baby hamster kidney (BHK-21) cells. These cells exhibited a pattern of cross-resistance to several different drugs typical of an MRP-mediated phenotype despite the addition of 10 histidine residues at the C terminus to facilitate purification. Consistent with this functional evidence of the presence of MRP at the surface of these transfectants, strong signals were detected by immunoblotting and immunofluorescence using a specific monoclonal antibody to MRP. There was intense uniform staining of the cell surface as well as weaker staining of intracellular membranes. MRP-containing membranes were solubilized in 1% N-dodecyl-beta-D-maltoside in the presence of 0.4% sheep brain phospholipids. Two sequential affinity purification steps on Ni-NTA agarose and wheat germ agglutinin agarose provided substantial enrichment, and contaminating bands were not detected. ATPase activity of the purified protein was assayed in the presence of the phospholipids, which had been maintained throughout all purification steps. ATP was hydrolyzed in proportion to the amount of purified protein assayed, and typical Michaelis-Menten behavior was exhibited, yielding estimations of Km of approximately 3.0 mM and Vmax of 0.46 micromol mg-1 min-1. This activity was moderately stimulated by the drugs that others have shown to be transported by MRP-containing membrane vesicles. This stimulation was enhanced by reduced glutathione as is its drug transport, and oxidized glutathione, itself a substrate for transport, caused a strong stimulation. These data describe the first purification of MRP and provide the first direct evidence that the molecule possesses drug-stimulated ATPase activity.


Assuntos
Transportadores de Cassetes de Ligação de ATP/metabolismo , Adenosina Trifosfatases/metabolismo , Resistência a Múltiplos Medicamentos , Proteínas de Neoplasias/metabolismo , Transportadores de Cassetes de Ligação de ATP/genética , Transportadores de Cassetes de Ligação de ATP/isolamento & purificação , Animais , Clonagem Molecular , Cricetinae , DNA Complementar/química , Células HeLa , Humanos , Cinética , Proteínas Associadas à Resistência a Múltiplos Medicamentos , Transfecção
14.
J Comp Neurol ; 358(3): 343-52, 1995 Jul 31.
Artigo em Inglês | MEDLINE | ID: mdl-7560291

RESUMO

The seemingly contradictory observations in previous publications that gamma-aminobutyric acid (GABA) is detected in all cell bodies of the suprachiasmatic nucleus (SCN) and that terminals originating from the SCN are only 20-30% GABA positive prompted us to investigate whether this might be explained by a preference of colocalization in terminals of certain peptidergic neurons in the SCN or by a day/night rhythm in GABA synthesis. At three different circadian times, animals were perfusion fixed, and their SCNs were stained for vasopressin (VP), somatostatin (SOM), or vasoactive intestinal polypeptide (VIP). Subsequently, the number of GABA peptide-positive terminals was determined using GABA postembedding staining in ultrathin sections. It appeared that the highest percentage of colocalization with GABA was detected in VIP terminals (38%) and the lowest in VP terminals (15%). No differences in colocalization percentages could be observed in any parameter at any circadian time. In the dorsomedial hypothalamus, one of the target areas of the VP and VIP fibers from the SCN, a colocalization of GABA within VP and VIP terminals was found similar to that in the SCN. In the region of the somatostatin-containing neurons in the SCN, a number of axoaxonal contacts could be observed that sometimes exhibited synaptic specializations. In nearly all cases, the axoaxonic terminals contained GABA and/or SOM. The conclusion is that the high level of intrinsic GABAergic connections in the SCN represents a putatively powerful mechanism to synchronize or shut down the activity of the SCN. We discuss the possibility that, depending on the firing frequency of the neurons, the colocalization of GABA with all peptides under investigation allows for the selection of which transmitter is released, the peptidergic one or the amino acid.


Assuntos
Somatostatina/análise , Núcleo Supraquiasmático/química , Peptídeo Intestinal Vasoativo/análise , Vasopressinas/análise , Ácido gama-Aminobutírico/análise , Animais , Transporte Axonal/fisiologia , Ritmo Circadiano/fisiologia , Imuno-Histoquímica , Masculino , Perfusão , Ratos , Ratos Sprague-Dawley , Ratos Wistar
15.
J Biol Chem ; 269(28): 18572-5, 1994 Jul 15.
Artigo em Inglês | MEDLINE | ID: mdl-7518437

RESUMO

Technical difficulties in obtaining three-dimensional structures of intrinsic membrane proteins continues to limit understanding of their function. However, considerable insight can be gained from their two-dimensional topological arrangement in the lipid bilayer. Efficient molecular genetic approaches are available to discern the topology of prokaryotic but not of eukaryotic membrane proteins. The absolute asymmetry of the sidedness of their N-glycosylation was employed here to develop such a method using the cystic fibrosis transmembrane conductance regulator (CFTR). Insertion by in vitro mutagenesis of N-glycosylation consensus sequences (NXS/T) in predicted cytoplasmic and extracytoplasmic loops between hydrophobic sequences capable of traversing the membrane established the membrane topology of CFTR. This provides the first experimental evaluation of the original topological model of CFTR based solely on hydropathy algorithms and a method which may be generally applicable for the in vivo evaluation of the topology of other mammalian membrane proteins.


Assuntos
Proteínas de Membrana/química , Proteínas de Membrana/fisiologia , Estrutura Secundária de Proteína , 1-Metil-3-Isobutilxantina/farmacologia , Algoritmos , Sequência de Aminoácidos , Animais , Sequência de Bases , Bucladesina/farmacologia , Células CHO , Membrana Celular/metabolismo , Membrana Celular/ultraestrutura , Canais de Cloreto/biossíntese , Canais de Cloreto/química , Colforsina/farmacologia , Sequência Consenso , Cricetinae , Regulador de Condutância Transmembrana em Fibrose Cística , Glicosilação , Humanos , Bicamadas Lipídicas , Mamíferos , Proteínas de Membrana/biossíntese , Dados de Sequência Molecular , Mutagênese Sítio-Dirigida , Proteínas Recombinantes/biossíntese , Proteínas Recombinantes/química , Proteínas Recombinantes/efeitos dos fármacos , Transfecção
16.
Nature ; 366(6450): 79-82, 1993 Nov 04.
Artigo em Inglês | MEDLINE | ID: mdl-7694154

RESUMO

Cystic fibrosis transmembrane conductance regulator (CFTR) is a non-rectifying, low-conductance channel regulated by ATP and phosphorylation, which mediates apical chloride conductance in secretory epithelia and malfunctions in cystic fibrosis (CF). Mutations at Lys 335 and Arg 347 in the sixth predicted transmembrane helix of CFTR alter its halide selectivity in whole-cell studies and its single channel conductance, but the physical basis of these alterations is unknown and permeation in CFTR is poorly understood. Here we present evidence that wild-type CFTR can contain more than one anion simultaneously. The conductance of CFTR passes through a minimum when channels are bathed in mixtures of two permeant anions. This anomalous mole fraction effect can be abolished by replacing Arg 347 with an aspartate and can be toggled on or off by varying the pH after the same residue is replaced with a histidine. Thus the CFTR channel should provide a convenient model in which to study multi-ion pore behaviour and conduction. The loss of multiple occupancy may explain how naturally occurring CF mutations at this site cause disease.


Assuntos
Ânions/metabolismo , Canais de Cloreto/fisiologia , Canais Iônicos/fisiologia , Proteínas de Membrana/fisiologia , Sequência de Aminoácidos , Animais , Arginina , Células CHO , Canais de Cloreto/genética , Cloretos/metabolismo , Cricetinae , Fibrose Cística/metabolismo , Regulador de Condutância Transmembrana em Fibrose Cística , Canais Iônicos/genética , Potenciais da Membrana/fisiologia , Proteínas de Membrana/genética , Dados de Sequência Molecular , Mutagênese Sítio-Dirigida , Tiocianatos/metabolismo
17.
J Comp Neurol ; 335(1): 42-54, 1993 Sep 01.
Artigo em Inglês | MEDLINE | ID: mdl-7691904

RESUMO

The purpose of the present study was to investigate the sites in the hypothalamus where the suprachiasmatic nucleus (SCN) may influence corticosteroid secretion. In spite of the well established, SCN-mediated, daily rhythms in adrenocorticotrophic hormone (ACTH) and corticosteroid secretion, previous studies determining the projections of the suprachiasmatic nucleus failed to illustrate direct connections with corticotrophin-releasing hormone neurons (CRH). In order to identify where in the central nervous system the SCN may influence corticosteroid secretion, areas were selected that contained SCN efferents contacting neurons involved in the stress response. To achieve this in the present study, SCN efferents were visualized by Pha-L tract-tracing, together with the neurons involved in the stress response by immunocytochemical staining for c-fos protein. The sites where these efferents contacted c-fos-positive neurons were established by light microscopic double staining and electron microscopic immunocytochemical studies. It appeared that apart from the medial parvocellular area of the paraventricular nucleus (PVN) of the hypothalamus, many more regions showed fos-positive neurons. Sites where SCN efferents contacted such neurons are limited only to areas immediately adjacent to these putative CRH neurons but are not concentrated on these neurons themselves. These areas consist of the periventricular and rostral PVN together with the dorsomedial hypothalamus: all three regions are known to project into the PVN. Therefore, it is concluded that the SCN transmits its information related to corticosteroid secretion via interneurons in and around the PVN to the CRH-containing neurons, rather than by a direct interaction with these neurons themselves.


Assuntos
Corticosteroides/metabolismo , Hormônio Adrenocorticotrópico/metabolismo , Estresse Fisiológico/patologia , Núcleo Supraquiasmático/ultraestrutura , Animais , Vias Eferentes/ultraestrutura , Imuno-Histoquímica , Masculino , Microscopia , Microscopia Eletrônica , Neurônios/ultraestrutura , Fito-Hemaglutininas , Proteínas Proto-Oncogênicas c-fos/análise , Ratos , Ratos Wistar , Coloração e Rotulagem , Núcleo Supraquiasmático/metabolismo , Peptídeo Intestinal Vasoativo/análise , Vasopressinas/análise
18.
J Biol Chem ; 268(15): 11304-11, 1993 May 25.
Artigo em Inglês | MEDLINE | ID: mdl-7684377

RESUMO

The cystic fibrosis transmembrane conductance regulator (CFTR) plays a central role in transepithelial ion transport by acting as a tightly regulated apical chloride channel. Regulation is achieved by the concerted action of ATP at conserved nucleotide binding folds and serine phosphorylation at multiple sites by protein kinases A (PKA) and C (PKC). A previous investigation concluded that activation by PKA is critically dependent on phosphorylation at four of the nine predicted PKA sites in the R domain (S660A, S737A, S795A, S813A), because a "Quad" mutant lacking these sites could not be activated. We show in the present work that not only can this mutant be phosphorylated and activated, but a mutant in which all 10 predicted PKA sites have been altered still retains significant PKA-activated function. Potentiation of the PKA response by PKC is also preserved in this mutant. Thus CFTR may be regulated by cryptic PKA sites which also mediate interactions between different kinases. Such hierarchical phosphorylation of CFTR by obvious and cryptic PKA sites could provide a metered response to secretagogues.


Assuntos
Canais Iônicos/fisiologia , Proteínas de Membrana/genética , Proteínas de Membrana/metabolismo , Mutagênese Sítio-Dirigida , Proteínas Quinases/metabolismo , Sequência de Aminoácidos , Animais , Sequência de Bases , Células CHO , Canais de Cloreto , Códon/genética , Cricetinae , Fibrose Cística/genética , Fibrose Cística/metabolismo , Regulador de Condutância Transmembrana em Fibrose Cística , Humanos , Iodetos/metabolismo , Cinética , Potenciais da Membrana , Fosfatos/metabolismo , Fosforilação , Reação em Cadeia da Polimerase/métodos , Estrutura Secundária de Proteína , Proteínas Recombinantes/metabolismo , Mapeamento por Restrição , Transfecção
SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA