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1.
Clin Exp Dermatol ; 46(4): 694-703, 2021 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-33296524

RESUMEN

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.


Asunto(s)
Antiinflamatorios no Esteroideos/farmacología , Bencilisoquinolinas/farmacología , Proliferación Celular/efectos de los fármacos , Piel/metabolismo , Factor A de Crecimiento Endotelial Vascular/metabolismo , Alopecia Areata/tratamiento farmacológico , Antiinflamatorios no Esteroideos/uso terapéutico , Bencilisoquinolinas/química , Bencilisoquinolinas/uso terapéutico , Calcio/metabolismo , Línea Celular , Cabello/efectos de los fármacos , Cabello/crecimiento & desarrollo , Humanos , Estructura Molecular , Reacción en Cadena en Tiempo Real de la Polimerasa , Piel/efectos de los fármacos
2.
Clin Exp Dermatol ; 41(3): 302-7, 2016 Apr.
Artículo en Inglés | MEDLINE | ID: mdl-26453439

RESUMEN

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.


Asunto(s)
Alopecia/tratamiento farmacológico , Cabello/crecimiento & desarrollo , Queratinocitos/efectos de los fármacos , Extractos Vegetales/farmacología , Raíces de Plantas/química , Sophora/química , Adulto , Proliferación Celular/efectos de los fármacos , Fibroblastos/efectos de los fármacos , Cabello/efectos de los fármacos , Folículo Piloso/efectos de los fármacos , Humanos , Masculino , Persona de Mediana Edad , Extractos Vegetales/administración & dosificación , Pterocarpanos/química , Pterocarpanos/farmacología
3.
Int J Cosmet Sci ; 37(6): 579-87, 2015 Dec.
Artículo en Inglés | MEDLINE | ID: mdl-25925959

RESUMEN

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.


Asunto(s)
Adenosina/administración & dosificación , Alopecia/tratamiento farmacológico , Cabello/crecimiento & desarrollo , Administración Tópica , Adulto , Humanos , Japón , Masculino , Persona de Mediana Edad
4.
Br J Dermatol ; 171(5): 1052-9, 2014 Nov.
Artículo en Inglés | MEDLINE | ID: mdl-24981717

RESUMEN

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.


Asunto(s)
Alopecia/patología , Cabello/patología , Adolescente , Adulto , Distribución por Edad , Alopecia/etnología , Progresión de la Enfermedad , Humanos , Japón/etnología , Masculino , Microscopía por Video , Persona de Mediana Edad , Tamaño de los Órganos/fisiología , Fotograbar , Adulto Joven
5.
Dig Dis Sci ; 58(8): 2266-74, 2013 Aug.
Artículo en Inglés | MEDLINE | ID: mdl-23649375

RESUMEN

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.


Asunto(s)
Aspirina/toxicidad , Mucosa Gástrica/metabolismo , Moco/metabolismo , Gastropatías/inducido químicamente , Adulto , Relación Dosis-Respuesta a Droga , Fármacos Gastrointestinales/farmacología , Humanos , Masculino , Pentagastrina/farmacología , Estómago/efectos de los fármacos , Adulto Joven
6.
Am J Physiol Lung Cell Mol Physiol ; 303(10): L852-60, 2012 Nov 15.
Artículo en Inglés | MEDLINE | ID: mdl-22962014

RESUMEN

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.


Asunto(s)
Anexina A5/farmacología , Regulación de la Expresión Génica/efectos de los fármacos , Macrófagos Alveolares/enzimología , Elastasa Pancreática/efectos adversos , Enfisema Pulmonar/tratamiento farmacológico , Animales , Apoptosis/efectos de los fármacos , Lavado Broncoalveolar , Femenino , Regulación Enzimológica de la Expresión Génica/efectos de los fármacos , Humanos , Macrófagos Alveolares/patología , Metaloproteinasa 12 de la Matriz/biosíntesis , Metaloproteinasa 2 de la Matriz/biosíntesis , Ratones , Elastasa Pancreática/farmacología , Enfermedad Pulmonar Obstructiva Crónica/tratamiento farmacológico , Enfermedad Pulmonar Obstructiva Crónica/enzimología , Enfermedad Pulmonar Obstructiva Crónica/patología , Enfisema Pulmonar/inducido químicamente , Enfisema Pulmonar/enzimología , Enfisema Pulmonar/patología , ARN Mensajero/biosíntesis , Porcinos
7.
Transplant Proc ; 42(10): 3989-91, 2010 Dec.
Artículo en Inglés | MEDLINE | ID: mdl-21168607

RESUMEN

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.


Asunto(s)
Trasplante de Riñón , Riñón/fisiopatología , Donantes de Tejidos , Factores de Edad , Anciano , Femenino , Tasa de Filtración Glomerular , Humanos , Pruebas de Función Renal , Masculino
9.
Eur J Pediatr Surg ; 17(1): 2-5, 2007 Feb.
Artículo en Inglés | MEDLINE | ID: mdl-17407013

RESUMEN

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.


Asunto(s)
Enfermedades de los Conductos Biliares/congénito , Enfermedades de los Conductos Biliares/diagnóstico , Hemorragia/etiología , Dolor Abdominal/etiología , Adolescente , Antifibrinolíticos/uso terapéutico , Enfermedades de los Conductos Biliares/complicaciones , Conductos Biliares Extrahepáticos/patología , Niño , Preescolar , Dilatación Patológica , Femenino , Hemorragia/tratamiento farmacológico , Humanos , Lactante , Recién Nacido , Masculino , Vitamina K/uso terapéutico
10.
Appl Microbiol Biotechnol ; 64(1): 99-105, 2004 Mar.
Artículo en Inglés | MEDLINE | ID: mdl-14564491

RESUMEN

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.


Asunto(s)
Escherichia coli/genética , Escherichia coli/metabolismo , Expresión Génica , Proteínas Recombinantes de Fusión/metabolismo , Proteínas de Unión a Tacrolimus/genética , Proteínas Arqueales/genética , Proteínas Bacterianas/biosíntesis , Clonación Molecular , Electroforesis en Gel de Poliacrilamida , Ensayo de Inmunoadsorción Enzimática , Fragmentos de Inmunoglobulinas/genética , Fragmentos de Inmunoglobulinas/metabolismo , Cuerpos de Inclusión/metabolismo , Chaperonas Moleculares/genética , Chaperonas Moleculares/metabolismo , Muramidasa/análisis , Muramidasa/inmunología , Isomerasa de Peptidilprolil/genética , Isomerasa de Peptidilprolil/metabolismo , Proteínas Recombinantes de Fusión/análisis , Solubilidad , Tiosulfato Azufretransferasa/genética , Tiosulfato Azufretransferasa/metabolismo
11.
Eur J Pediatr Surg ; 12(5): 345-7, 2002 Oct.
Artículo en Inglés | MEDLINE | ID: mdl-12469265

RESUMEN

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.


Asunto(s)
Absceso/etiología , Cloaca/anomalías , Cloaca/cirugía , Ooforitis/etiología , Complicaciones Posoperatorias , Salpingitis/etiología , Absceso/cirugía , Adolescente , Ano Imperforado/cirugía , Femenino , Procedimientos Quirúrgicos Ginecológicos , Humanos , Ooforitis/cirugía , Procedimientos de Cirugía Plástica , Salpingitis/cirugía , Vagina/anomalías , Vagina/cirugía
14.
Gene ; 256(1-2): 319-26, 2000 Oct 03.
Artículo en Inglés | MEDLINE | ID: mdl-11054562

RESUMEN

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.


Asunto(s)
Halobacterium/genética , Isomerasa de Peptidilprolil/genética , Proteínas de Unión a Tacrolimus/genética , Secuencia de Aminoácidos , Secuencia de Bases , ADN de Archaea/química , ADN de Archaea/genética , Expresión Génica , Glutatión Transferasa/genética , Glutatión Transferasa/metabolismo , Halobacterium/enzimología , Cinética , Datos de Secuencia Molecular , Isomerasa de Peptidilprolil/metabolismo , Proteínas Recombinantes de Fusión/genética , Proteínas Recombinantes de Fusión/metabolismo , Alineación de Secuencia , Análisis de Secuencia de ADN , Homología de Secuencia de Aminoácido , Especificidad por Sustrato , Proteínas de Unión a Tacrolimus/metabolismo
15.
J Bacteriol ; 182(8): 2134-41, 2000 Apr.
Artículo en Inglés | MEDLINE | ID: mdl-10735855

RESUMEN

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.


Asunto(s)
Actinomycetales/genética , Oxigenasas/genética , Fenantrenos/metabolismo , Actinomycetales/enzimología , Secuencias de Aminoácidos , Secuencia de Aminoácidos , Clonación Molecular , Secuencia de Consenso , Secuencia Conservada , Escherichia coli/genética , Ferredoxinas/genética , Genes Bacterianos , Datos de Secuencia Molecular , Familia de Multigenes , Oxigenasas/biosíntesis , Oxigenasas/clasificación , Ácidos Ftálicos/metabolismo , Filogenia , Proteínas Recombinantes/biosíntesis , Mapeo Restrictivo , Análisis de Secuencia de ADN , Homología de Secuencia de Aminoácido
16.
Biophys J ; 77(4): 2175-83, 1999 Oct.
Artículo en Inglés | MEDLINE | ID: mdl-10512836

RESUMEN

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.


Asunto(s)
Bacillus/enzimología , ATPasas de Translocación de Protón/química , ATPasas de Translocación de Protón/metabolismo , Tirosina/metabolismo , Adenosina Difosfato/metabolismo , Adenosina Trifosfato/metabolismo , Adenilil Imidodifosfato/metabolismo , Sustitución de Aminoácidos , Secuencia Conservada , Deuterio/química , Deuterio/metabolismo , Concentración de Iones de Hidrógeno , Ligandos , Modelos Moleculares , Mutación , Resonancia Magnética Nuclear Biomolecular , Conformación Proteica , ATPasas de Translocación de Protón/genética , Protones , Temperatura , Volumetría , Tirosina/química , Tirosina/genética
17.
Neurol Res ; 21(6): 599-610, 1999 Sep.
Artículo en Inglés | MEDLINE | ID: mdl-10491823

RESUMEN

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.


Asunto(s)
Nervio Coclear/patología , Nervio Coclear/fisiopatología , Síndromes de Compresión Nerviosa/patología , Síndromes de Compresión Nerviosa/fisiopatología , Neuroma Acústico/complicaciones , Animales , Nervio Coclear/cirugía , Perros , Potenciales Evocados Auditivos del Tronco Encefálico/fisiología , Síndromes de Compresión Nerviosa/cirugía , Fibras Nerviosas/patología , Ganglio Espiral de la Cóclea/citología , Ganglio Espiral de la Cóclea/patología , Instrumentos Quirúrgicos , Factores de Tiempo
20.
Chemosphere ; 38(6): 1331-7, 1999 Mar.
Artículo en Inglés | MEDLINE | ID: mdl-10070721

RESUMEN

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.


Asunto(s)
Genes Bacterianos , Fenantrenos/metabolismo , Propionibacteriaceae/enzimología , Propionibacteriaceae/genética , Biodegradación Ambiental , Escherichia coli/enzimología , Escherichia coli/genética , Datos de Secuencia Molecular , Familia de Multigenes , Oxigenasas/genética , Plásmidos/genética
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