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1.
Clin Exp Dermatol ; 46(4): 694-703, 2021 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-33296524

RESUMO

BACKGROUND: Cepharanthine (CEP), a compound extracted from the vine Stephania cephalantha, is commonly prescribed to treat alopecia areata; however, the scientific evidence for its efficacy is limited. AIM: To investigate the effect of CEP and its structural analogues on human hair growth in vitro. METHODS: The effects of CEP and three of its structural analogues on the proliferation of human dermal papilla cells (hDPCs) and human outer root sheath cells (hORSCs) were investigated. Their effects on vascular endothelial growth factor (VEGF) expression were also assessed by real-time PCR. Activation of pathways leading to VEGF expression, such as intracellular Ca2+ mobilization and hypoxia-inducible factor (HIF) expression, was also characterized. RESULTS: CEP and two of its structural analogues significantly stimulated the growth of hDPCs but not hORSCs. Moreover, CEP and all three structural analogues significantly induced the expression of VEGF in hDPCs. CEP increased the intracellular Ca2+ concentration in hDPCs. CEP also increased the expression of HIF-1α and HIF-2α and induced the expression of HIF-responsive genes in hDPCs, even under normoxia. CONCLUSIONS: These results suggest that CEP and its structural analogues have the potential to restore hair growth by promoting the proliferation of hDPCs and increasing their expression of VEGF.


Assuntos
Anti-Inflamatórios não Esteroides/farmacologia , Benzilisoquinolinas/farmacologia , Proliferação de Células/efeitos dos fármacos , Pele/metabolismo , Fator A de Crescimento do Endotélio Vascular/metabolismo , Alopecia em Áreas/tratamento farmacológico , Anti-Inflamatórios não Esteroides/uso terapêutico , Benzilisoquinolinas/química , Benzilisoquinolinas/uso terapêutico , Cálcio/metabolismo , Linhagem Celular , Cabelo/efeitos dos fármacos , Cabelo/crescimento & desenvolvimento , Humanos , Estrutura Molecular , Reação em Cadeia da Polimerase em Tempo Real , Pele/efeitos dos fármacos
2.
Clin Exp Dermatol ; 41(3): 302-7, 2016 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-26453439

RESUMO

BACKGROUND: Androgenetic alopecia (AGA) is a hair loss disorder that commonly affects middle-aged men. To date, the properties of a number of natural or synthetic substances have been investigated for their ability to improve the condition. AIM: To evaluate the hair growth-promoting activities of an extract from the root of Sophora flavescens Aiton. METHODS: We used a human hair keratinocyte proliferation assay and ex vivo organ cultures of human hair follicle to examine the potential of the extract to stimulate hair growth via anagen elongation. We isolated the compounds promoting the growth of epithelial cells, and determined their chemical structures. A randomized, double-blinded, placebo-controlled clinical study for S. flavescens extract was carried out for 6 months with patients with AGA. RESULTS: The extract stimulated the proliferation of hair keratinocytes at a concentration of 0.1 ng/mL, while 100 ng/mL of the extract had a marked effect on hair shaft elongation in an organ culture of human hair follicle. Cell proliferation assay-directed fractionation led to the identification of two pterocarpan derivatives, L-maackiain and medicarpin, as active compounds that promote the proliferation of human hair keratinocytes. Studies in human subjects showed that improvement in the inspected alopecia scores in the lotion plus extract group were significant over a period of 6 months (P < 0.01). CONCLUSIONS: S. flavescens root extract is effective for the treatment of AGA. The isolated two pterocarpans might have important role in this effect.


Assuntos
Alopecia/tratamento farmacológico , Cabelo/crescimento & desenvolvimento , Queratinócitos/efeitos dos fármacos , Extratos Vegetais/farmacologia , Raízes de Plantas/química , Sophora/química , Adulto , Proliferação de Células/efeitos dos fármacos , Fibroblastos/efeitos dos fármacos , Cabelo/efeitos dos fármacos , Folículo Piloso/efeitos dos fármacos , Humanos , Masculino , Pessoa de Meia-Idade , Extratos Vegetais/administração & dosagem , Pterocarpanos/química , Pterocarpanos/farmacologia
3.
Int J Cosmet Sci ; 37(6): 579-87, 2015 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-25925959

RESUMO

OBJECTIVE: Hair thickness is more important than hair density in the appearance of baldness in male with androgenetic alopecia (AGA). Adenosine improves hair loss by stimulating hair growth and by thickening hair shafts in women. The objective of this study was to evaluate the hair growth efficacy and safety of topical adenosine in men with AGA. METHODS: A lotion containing either adenosine or niacinamide was administered to the scalps of 102 Japanese men twice daily for 6 months in a double-blind, randomized study. Efficacy was evaluated by dermatologists who assessed the quality of the hair and by calculating the percentages of vellus-like and thick hairs among the vertex hairs, as well as hair density. RESULTS: Adenosine was significantly (P < 0.05) superior to niacinamide in terms of global improvement of AGA, increase in the percentage of thick hairs (at least 60 µm) and self-assessment of hair thickness by the study participants. No causal adverse event due to the adenosine lotion was observed. CONCLUSION: These data indicate that adenosine increases thick hair ratio in Japanese men with AGA, and this compound is useful for the improvement of AGA.


Assuntos
Adenosina/administração & dosagem , Alopecia/tratamento farmacológico , Cabelo/crescimento & desenvolvimento , Administração Tópica , Adulto , Humanos , Japão , Masculino , Pessoa de Meia-Idade
4.
Br J Dermatol ; 171(5): 1052-9, 2014 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-24981717

RESUMO

BACKGROUND: Androgenetic alopecia (AGA) is the most common type of baldness in men. The balding process is associated with the gradual miniaturization of hair follicles and successive hair loss. However, the relative contributions of hair density and diameter to AGA are still unclear. OBJECTIVES: Hair density and hair diameter were investigated in Japanese men with or without AGA to elucidate the importance of these factors in the balding process. METHODS: Male Japanese subjects with or without AGA (n = 369) were included in this study. Hair appearance at the vertex was evaluated by comparison with a series of standard photographs. Hair density was measured using a phototrichogram-based videomicroscopy technique, and hair diameter was assessed by comparison with a series of calibrated threads on the phototrichogram image. RESULTS: All subjects with AGA were ≥ 25 years of age. The mean percentage of thick hairs (> 80 µm) in all subjects with AGA was significantly lower than that in subjects without AGA aged ≥ 25 years (P < 0·01), but the mean percentage of vellus hairs (< 40 µm) in subjects with AGA was significantly higher (P < 0·001). By contrast, the mean density of the hair in all patients with AGA did not significantly differ from the density of those without AGA aged ≥ 25 years. However, the mean density of the hair in subjects without AGA aged < 25 years was significantly higher than that of both subjects without AGA aged ≥ 25 years (P < 0·001) and all subjects with AGA. CONCLUSIONS: Hair loss in men with AGA results mainly from the miniaturization of hair follicles rather than the loss of hair (shedding), at least for individuals who are ≥ 25 years of age and present with AGA.


Assuntos
Alopecia/patologia , Cabelo/patologia , Adolescente , Adulto , Distribuição por Idade , Alopecia/etnologia , Progressão da Doença , Humanos , Japão/etnologia , Masculino , Microscopia de Vídeo , Pessoa de Meia-Idade , Tamanho do Órgão/fisiologia , Fotografação , Adulto Jovem
5.
Dig Dis Sci ; 58(8): 2266-74, 2013 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-23649375

RESUMO

BACKGROUND: Gastric mucus is considered to play an essential role in gastric mucosal defense mechanisms, especially when irritants are present in the stomach. AIM: To investigate the relationship between low-dose aspirin-induced gastropathy and gastric secretory function, especially gastric mucus secretion, in healthy volunteers. METHODS: Thirty male, asymptomatic, Helicobacter pylori pylori-negative healthy volunteers were asked to take 100 mg of enteric-coated aspirin (Bayaspirin) once a day for 10 days. Endoscopic examination was performed before and 3 and 10 days after drug administration. The extent of endoscopically assessed gastric mucosal injury was semi-quantitatively evaluated according to the modified Lanza score. The pentagastrin-stimulated gastric juice was collected for 10 min during the endoscopic examination and subjected to analysis for gastric acid (mEq/10 min) or mucus (mg hexose/10 min) output. RESULTS: Overall, the 10-day aspirin treatment significantly increased gastric mucus secretion from 0.8 (interquartile range 1.7) to 1.6 (1.6) mg hexose/10 min (P < 0.05), with a concomitant and significant decrease in the gastric acid/mucus ratio from 4.3 (5.2) to 2.9 (4.7) (P < 0.01). Subsequent analysis of two subgroups of volunteers categorized according to their endoscopic status ("severe gastropathy" vs. "modest gastropathy") revealed that changes in gastric secretory parameters occurred exclusively in those subjects without severe gastric injury; there was no alteration in these parameters in subjects with severe gastric injury. CONCLUSIONS: The results of this study suggest that the reactive increase in gastric mucus secretion is an adaptive defense mechanism against low-dose aspirin-induced gastropathy. In some individuals, such a response may be insufficient to prevent the development of severe mucosal injury and even ulcers and their complications.


Assuntos
Aspirina/toxicidade , Mucosa Gástrica/metabolismo , Muco/metabolismo , Gastropatias/induzido quimicamente , Adulto , Relação Dose-Resposta a Droga , Fármacos Gastrointestinais/farmacologia , Humanos , Masculino , Pentagastrina/farmacologia , Estômago/efeitos dos fármacos , Adulto Jovem
6.
Am J Physiol Lung Cell Mol Physiol ; 303(10): L852-60, 2012 Nov 15.
Artigo em Inglês | MEDLINE | ID: mdl-22962014

RESUMO

Efferocytosis is believed to be a key regulator for lung inflammation in chronic obstructive pulmonary disease. In this study we pharmacologically inhibited efferocytosis with annexin V and attempted to determine its impact on the progression of pulmonary emphysema in mouse. We first demonstrated in vitro and in vivo efferocytosis experiments using annexin V, an inhibitor for phosphatidylserine-mediated efferocytosis. We then inhibited efferocytosis in porcine pancreatic elastase (PPE)-treated mice. PPE-treated mice were instilled annexin V intranasally starting from day 8 until day 20. Mean linear intercept (Lm) was measured, and cell apoptosis was assessed in lung specimen obtained on day 21. Cell profile, apoptosis, and mRNA expression of matrix metalloproteinases (MMPs) and growth factors were evaluated in bronchoalveolar lavage (BAL) cells on day 15. Annexin V attenuated macrophage efferocytosis both in vitro and in vivo. PPE-treated mice had a significant higher Lm, and annexin V further increased that by 32%. More number of macrophages was found in BAL fluid in this group. Interestingly, cell apoptosis was not increased by annexin V treatment both in lung specimens and BAL fluid, but macrophages from mice treated with both PPE and annexin V expressed higher MMP-2 mRNA levels and had a trend for higher MMP-12 mRNA expression. mRNA expression of keratinocyte growth factor tended to be downregulated. We showed that inhibited efferocytosis with annexin V worsened elastase-induced pulmonary emphysema in mice, which was, at least partly, attributed to a lack of phenotypic change in macrophages toward anti-inflammatory one.


Assuntos
Anexina A5/farmacologia , Regulação da Expressão Gênica/efeitos dos fármacos , Macrófagos Alveolares/enzimologia , Elastase Pancreática/efeitos adversos , Enfisema Pulmonar/tratamento farmacológico , Animais , Apoptose/efeitos dos fármacos , Lavagem Broncoalveolar , Feminino , Regulação Enzimológica da Expressão Gênica/efeitos dos fármacos , Humanos , Macrófagos Alveolares/patologia , Metaloproteinase 12 da Matriz/biossíntese , Metaloproteinase 2 da Matriz/biossíntese , Camundongos , Elastase Pancreática/farmacologia , Doença Pulmonar Obstrutiva Crônica/tratamento farmacológico , Doença Pulmonar Obstrutiva Crônica/enzimologia , Doença Pulmonar Obstrutiva Crônica/patologia , Enfisema Pulmonar/induzido quimicamente , Enfisema Pulmonar/enzimologia , Enfisema Pulmonar/patologia , RNA Mensageiro/biossíntese , Suínos
7.
Transplant Proc ; 42(10): 3989-91, 2010 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-21168607

RESUMO

Recent studies suggest that the overall survival and risk of end-stage renal disease among renal transplant donors are similar to those of the general population, but few studies focused on elderly donors. Among 88 donors who underwent retroperitoneoscopic live donor nephrectomies; 20 (22.7%) were elderly, namely, older than 65 years. Perioperative characteristics, such as sex, donor kidney side (left or right), body mass index, operative time, blood loss, and complication rate were not significantly different among groups classified by age: young (<50), middle (50-65), or elderly (>65). One month after kidney donation, the serum, creatinine values in the young, middle, and elderly groups increased to 1.05 ± 0.25, 0.96 ± 0.24, and 1.06 ± 0.15 mg/dL (P = .103) and the estimated glomerular filtration rate (eGFR) decrease to 63 ± 10, 63 ± 14, 56 ± 8 mL/min/1.73 m(2), respectively (P = .037). At three months and at three years after donation these parameters showed the same degree of improvement in all groups. Percentage of eGFR (% eGFR) of its pre-donation value in the young and middle groups improved up to 21% and up to 9%, respectively, until four years after donation, whereas that of the elderly group remained unchanged below 1%. In conclusion residual renal function after retroperitoneoscopic kidney donation in elderly donors was stable and acceptable during mid-term observation. Our retroperitoneoscopic approach was safe.


Assuntos
Transplante de Rim , Rim/fisiopatologia , Doadores de Tecidos , Fatores Etários , Idoso , Feminino , Taxa de Filtração Glomerular , Humanos , Testes de Função Renal , Masculino
9.
Eur J Pediatr Surg ; 17(1): 2-5, 2007 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-17407013

RESUMO

AIM OF THE STUDY: Although a bleeding tendency as a first symptom is a critical condition in congenital biliary dilatation (CBD), the clinical details of this symptom remain unclear. We assessed this condition in children with CBD in this paper. MATERIALS AND METHODS: Sixty-five children with CBD were treated at our institute between 1983 and 2004. The children, initially presenting with bleeding manifestations such as intracranial hemorrhage and bloody stools, were defined as the bleeding group, and the remaining children with digestive symptoms such as abdominal pain and vomiting were defined as the digestive group. The clinical features were compared between these two groups. RESULTS: In 6 of the 65 cases, bleeding manifestations were noted (9.2 %). All six had cystic-type choledochal dilatation. The mean age of the bleeding group was significantly younger than that of the digestive group, and bleeding was more frequent, especially in infants less than 12 months of age. In a laboratory study, the bleeding group showed a more prolonged blood coagulation time than the digestive group did. Serum amylase and lipase levels in the bleeding group were almost normal, while those in the digestive group were significantly higher. The direct bilirubin level in the bleeding group was significantly higher than that in the digestive group. CONCLUSIONS: Disturbed blood coagulation due to vitamin K deficiency related to cholestasis results in a bleeding tendency in children with CBD. Therefore, pediatric surgeons should be aware of this rare but critical condition which can be prevented by rapid and precise treatment with vitamin K supplementation.


Assuntos
Doenças dos Ductos Biliares/congênito , Doenças dos Ductos Biliares/diagnóstico , Hemorragia/etiologia , Dor Abdominal/etiologia , Adolescente , Antifibrinolíticos/uso terapêutico , Doenças dos Ductos Biliares/complicações , Ductos Biliares Extra-Hepáticos/patologia , Criança , Pré-Escolar , Dilatação Patológica , Feminino , Hemorragia/tratamento farmacológico , Humanos , Lactente , Recém-Nascido , Masculino , Vitamina K/uso terapêutico
10.
Appl Microbiol Biotechnol ; 64(1): 99-105, 2004 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-14564491

RESUMO

Improper protein-folding often results in inclusion-body formation in a protein expression system using Escherichia coli. To express such proteins in the soluble fraction of E. coli cytoplasm, we developed an expression system by fusing the target protein with an archaeal FK506 binding protein (FKBP). It has been reported that an archaeal FKBP from a hyperthermophilic archaeon, Thermococcus sp. KS-1 (TcFKBP18), possesses not only peptidyl-prolyl cis-trans isomerase activity, but also chaperone-like activity to enhance the refolding yield of an unfolded protein by suppressing irreversible protein aggregation. To study the effect of this fusion strategy with FKBP on the expression of foreign protein in E. coli, a putative rhodanese (thiosulfate sulfurtransferase) from a hyperthermophilic archaeon and two mouse antibody fragments were used as model target proteins. When they were expressed alone in E. coli, they formed insoluble aggregates. Their genes were designed to be expressed as a fusion protein by connecting them to the C-terminal end of TcFKBP18 with an oligopeptide containing a thrombin cleavage site. By fusing TcFKBP18, the expression of the target protein in the soluble fraction was significantly increased. The percentage of the soluble form in the expressed protein reached 10-28% of the host soluble proteins. After purification and protease digestion of the expressed antibody fragment-TcFKBP18 fusion protein, the cleaved antibody fragment (single-chain Fv) showed specific binding to the antigen in ELISA. This indicated that the expressed antibody fragment properly folded to the active form.


Assuntos
Escherichia coli/genética , Escherichia coli/metabolismo , Expressão Gênica , Proteínas Recombinantes de Fusão/metabolismo , Proteínas de Ligação a Tacrolimo/genética , Proteínas Arqueais/genética , Proteínas de Bactérias/biossíntese , Clonagem Molecular , Eletroforese em Gel de Poliacrilamida , Ensaio de Imunoadsorção Enzimática , Fragmentos de Imunoglobulinas/genética , Fragmentos de Imunoglobulinas/metabolismo , Corpos de Inclusão/metabolismo , Chaperonas Moleculares/genética , Chaperonas Moleculares/metabolismo , Muramidase/análise , Muramidase/imunologia , Peptidilprolil Isomerase/genética , Peptidilprolil Isomerase/metabolismo , Proteínas Recombinantes de Fusão/análise , Solubilidade , Tiossulfato Sulfurtransferase/genética , Tiossulfato Sulfurtransferase/metabolismo
11.
Eur J Pediatr Surg ; 12(5): 345-7, 2002 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-12469265

RESUMO

Recently a few articles have been published concerning the long-term follow-up of vaginoplasty of cloaca. However, no postoperative evaluation has been fully described and, in particular, the late complications are still unknown. We report a case of tuboovarian abscess after colonic vaginoplasty for high cloacal anomaly in a 13-year-old girl. She required a left salpingo-oophorectomy and postoperatively showed regular menstruation. Therefore we stress that tubo-ovarian abscess is one of the important late complications after colonic vaginoplasty for high cloacal anomaly.


Assuntos
Abscesso/etiologia , Cloaca/anormalidades , Cloaca/cirurgia , Ooforite/etiologia , Complicações Pós-Operatórias , Salpingite/etiologia , Abscesso/cirurgia , Adolescente , Anus Imperfurado/cirurgia , Feminino , Procedimentos Cirúrgicos em Ginecologia , Humanos , Ooforite/cirurgia , Procedimentos de Cirurgia Plástica , Salpingite/cirurgia , Vagina/anormalidades , Vagina/cirurgia
14.
Gene ; 256(1-2): 319-26, 2000 Oct 03.
Artigo em Inglês | MEDLINE | ID: mdl-11054562

RESUMO

The halophilic archaeum, Halobacterium cutirubrum, has been shown to have a cyclophilin-type peptidyl-prolyl cis-trans isomerase (PPIase). Because most archaeal genomes studied only have genes for FK506-binding proteins (FKBPs) as a PPIase, it has been unclear whether H. cutirubrum has an FKBP-type PPIase or not. In the present study, a gene encoding an FKBP-type PPIase was cloned from genomic DNA of H. cutirubrum and then sequenced. This FKBP was deduced to be composed of 303 amino acid residues with a molecular mass of 33.3kDa. Alignment of its amino acid sequence with those of other reported FKBPs showed that it contained two insertion sequences in the regions corresponding to the bulge and flap of human FKBP12, which are common to archaeal FKBPs. Its C-terminal amino acid sequence was approximately 130 amino acids longer than the FKBPs of Methanococcus thermolithotrophicus and Thermococcus sp. KS-1. Among the 14 conserved amino acid residues that form the FK506 binding pocket, only three were found in this FKBP. This gene was expressed as a fusion protein with glutathione S-transferase (GST) in Escherichia coli, and the N-terminal GST portion was removed by protease digestion. The purified recombinant FKBP showed a weak PPIase activity with a low sensitivity to FK506. This FKBP suppressed aggregation of the unfolded protein.


Assuntos
Halobacterium/genética , Peptidilprolil Isomerase/genética , Proteínas de Ligação a Tacrolimo/genética , Sequência de Aminoácidos , Sequência de Bases , DNA Arqueal/química , DNA Arqueal/genética , Expressão Gênica , Glutationa Transferase/genética , Glutationa Transferase/metabolismo , Halobacterium/enzimologia , Cinética , Dados de Sequência Molecular , Peptidilprolil Isomerase/metabolismo , Proteínas Recombinantes de Fusão/genética , Proteínas Recombinantes de Fusão/metabolismo , Alinhamento de Sequência , Análise de Sequência de DNA , Homologia de Sequência de Aminoácidos , Especificidade por Substrato , Proteínas de Ligação a Tacrolimo/metabolismo
15.
J Bacteriol ; 182(8): 2134-41, 2000 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-10735855

RESUMO

Nocardioides sp. strain KP7 grows on phenanthrene but not on naphthalene. This organism degrades phenanthrene via 1-hydroxy-2-naphthoate, o-phthalate, and protocatechuate. The genes responsible for the degradation of phenanthrene to o-phthalate (phd) were found by Southern hybridization to reside on the chromosome. A 10.6-kb DNA fragment containing eight phd genes was cloned and sequenced. The phdA, phdB, phdC, and phdD genes, which encode the alpha and beta subunits of the oxygenase component, a ferredoxin, and a ferredoxin reductase, respectively, of phenanthrene dioxygenase were identified. The gene cluster, phdAB, was located 8. 3 kb downstream of the previously characterized phdK gene, which encodes 2-carboxybenzaldehyde dehydrogenase. The phdCD gene cluster was located 2.9 kb downstream of the phdB gene. PhdA and PhdB exhibited moderate (less than 60%) sequence identity to the alpha and beta subunits of other ring-hydroxylating dioxygenases. The PhdC sequence showed features of a [3Fe-4S] or [4Fe-4S] type of ferredoxin, not of the [2Fe-2S] type of ferredoxin that has been found in most of the reported ring-hydroxylating dioxygenases. PhdD also showed moderate (less than 40%) sequence identity to known reductases. The phdABCD genes were expressed poorly in Escherichia coli, even when placed under the control of strong promoters. The introduction of a Shine-Dalgarno sequence upstream of each initiation codon of the phdABCD genes improved their expression in E. coli. E. coli cells carrying phdBCD or phdACD exhibited no phenanthrene-degrading activity, and those carrying phdABD or phdABC exhibited phenanthrene-degrading activity which was significantly less than that in cells carrying the phdABCD genes. It was thus concluded that all of the phdABCD genes are necessary for the efficient expression of phenanthrene-degrading activity. The genetic organization of the phd genes, the phylogenetically diverged positions of these genes, and an unusual type of ferredoxin component suggest phenanthrene dioxygenase in Nocardioides sp. strain KP7 to be a new class of aromatic ring-hydroxylating dioxygenases.


Assuntos
Actinomycetales/genética , Oxigenases/genética , Fenantrenos/metabolismo , Actinomycetales/enzimologia , Motivos de Aminoácidos , Sequência de Aminoácidos , Clonagem Molecular , Sequência Consenso , Sequência Conservada , Escherichia coli/genética , Ferredoxinas/genética , Genes Bacterianos , Dados de Sequência Molecular , Família Multigênica , Oxigenases/biossíntese , Oxigenases/classificação , Ácidos Ftálicos/metabolismo , Filogenia , Proteínas Recombinantes/biossíntese , Mapeamento por Restrição , Análise de Sequência de DNA , Homologia de Sequência de Aminoácidos
16.
Biophys J ; 77(4): 2175-83, 1999 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-10512836

RESUMO

The effect of nucleotide binding on the structure of the F(1)-ATPase beta subunit from thermophilic bacillus PS-3 (TF(1)beta) was investigated by monitoring the NMR signals of the 12 tyrosine residues. The 3,5-proton resonances of 12 tyrosine residues could be observed for the specifically deuterated beta subunit. The assignment of 3,5-proton resonances of all of the tyrosine residues was accomplished using 14 mutant proteins, in each of which one or two tyrosine residues were replaced by phenylalanine. Binding of Mg. ATP induced an upfield shift of Tyr(341) resonance, suggesting that their aromatic rings are stacked to each other. Besides Tyr(341), the signal shift observed on Mg.ATP binding was restricted to the resonances of Tyr(148), Tyr(199), Tyr(238), and Tyr(307), suggesting that Mg.ATP induces a conformational change in the hinge region. This can be correlated to the change from the open to closed conformations as implicated in the crystal structure. Mg.ADP induced a similar but distinctly different conformational change. Therefore, the intrinsic conformational change in the beta subunit induced by the nucleotide binding is proposed to be one of the essential driving forces for the F(1) rotation. Reconstitution experiments showed that Tyr(277), one of the four conserved tyrosines, is essential to the formation of the alpha(3)beta(3)gamma complex.


Assuntos
Bacillus/enzimologia , ATPases Translocadoras de Prótons/química , ATPases Translocadoras de Prótons/metabolismo , Tirosina/metabolismo , Difosfato de Adenosina/metabolismo , Trifosfato de Adenosina/metabolismo , Adenilil Imidodifosfato/metabolismo , Substituição de Aminoácidos , Sequência Conservada , Deutério/química , Deutério/metabolismo , Concentração de Íons de Hidrogênio , Ligantes , Modelos Moleculares , Mutação , Ressonância Magnética Nuclear Biomolecular , Conformação Proteica , ATPases Translocadoras de Prótons/genética , Prótons , Temperatura , Titulometria , Tirosina/química , Tirosina/genética
17.
Neurol Res ; 21(6): 599-610, 1999 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-10491823

RESUMO

The short- and long-term effects of static compression of the cochlear nerve were studied in dogs. The nerve was exposed in the cerebellopontine angle and a modified aneurysm clip was applied to reduce the diameter of the nerve trunk to 50%, 40%, 30% or 20% of normal (designated respectively as 50%, 60%, 70%, and 80% compression). Brainstem auditory evoked potentials (BAEPs) were monitored intraoperatively and post-operatively. The animals were sacrificed between 5 and 119 days after nerve compression and temporal bones were examined histologically. In the 50% compression group, all peaks except peak I disappeared immediately after nerve compression. After release of the clip, however, peak II and subsequent components recovered and prolonged interpeak latency (IPL) between peaks I and IV normalized within 7 days. In the 60% compression group, recovery was incomplete for as long as 49 days after compression. Significant histological changes were not always reflected in the electrophysiological recordings, as shown by the finding of multiple cavitations at the compressed portion of the cochlear nerve in cases in which conduction block of cochlear nerve impulses was reversible. In the 70% compression group, peak IV did not reappear for more than 1 week, and histological examination revealed severe damage to all cochlear nerve fibers except those from the apical turn, which lie in the center of the cochlear nerve trunk. Severe injury occurred to the cochlear nerve fibers that are situated more superficially in the nerve, which are tonotopically responsible for the perception of high-frequency sound and the generation of BAEPs. This means that the BAEP changes due to cochlear nerve compression would be detectable by BAEP monitoring, although changes in the apical region of the cochlea are not fully detectable by BAEP monitoring. In the 80% compression group, all peaks except peak I were lost permanently and the amplitude of peak I, which had been preserved in the acute phase, gradually decreased. Reversibility of impaired cochlear nerve impulse conduction was related to the severity of compression, and at some level of compression between 70% and 80% the nerve fibers generating BAEPs permanently lost the ability to conduct electrical impulses proximal to the site of compression. In the 70% and 80% compression groups, the amplitude of peak I gradually decreased over the first 30 days after compression and did not change significantly thereafter. Histologically, the branches of the internal auditory artery were resilient to compression, although they are easily avulsed due to stretch force. Furthermore, retrograde degeneration of cochlear neurons triggered by compression at the cisternal portion of the cochlear nerve was apparent. Such slowly progressive degeneration of nerve fibers may play a part in development of the delayed postoperative hearing disturbance.


Assuntos
Nervo Coclear/patologia , Nervo Coclear/fisiopatologia , Síndromes de Compressão Nervosa/patologia , Síndromes de Compressão Nervosa/fisiopatologia , Neuroma Acústico/complicações , Animais , Nervo Coclear/cirurgia , Cães , Potenciais Evocados Auditivos do Tronco Encefálico/fisiologia , Síndromes de Compressão Nervosa/cirurgia , Fibras Nervosas/patologia , Gânglio Espiral da Cóclea/citologia , Gânglio Espiral da Cóclea/patologia , Instrumentos Cirúrgicos , Fatores de Tempo
20.
Chemosphere ; 38(6): 1331-7, 1999 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-10070721

RESUMO

The nucleotide sequence of the gene cluster, phdEFABGHCD, encoding enzymes responsible for the transformation of phenanthrene to 1-hydroxy-2-naphthoate in Nocardioides sp. strain KP7 was determined. This gene cluster, which may constitute a single operon, resided at 6.1-kb downstream of the phdIJK gene cluster encoding the enzymes for the transformation of 1-hydroxy-2-naphthoate to o-phthalate. In general, the phd products exhibited moderate degrees of homology with isofunctional enzymes found in pathways for the degradation of other aromatic compounds. Remarkably, the phdC gene product had features of the [3Fe-4S] type ferredoxin, which has not been found so far as a component of the ring-hydroxylating dioxygenase. Escherichia coli carrying the genes for phenanthrene dioxygenase, phdABCD, was capable to oxidize phenanthrene.


Assuntos
Genes Bacterianos , Fenantrenos/metabolismo , Propionibacteriaceae/enzimologia , Propionibacteriaceae/genética , Biodegradação Ambiental , Escherichia coli/enzimologia , Escherichia coli/genética , Dados de Sequência Molecular , Família Multigênica , Oxigenases/genética , Plasmídeos/genética
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