RESUMO
Joubert syndrome (JS) is rare recessive disorders characterized by the combination of hypoplasia/aplasia of the cerebellar vermis, thickened and elongated superior cerebellar peduncles, and a deep interpeduncular fossa which is defined by neuroimaging and is termed the 'molar tooth sign'. JS is genetically highly heterogeneous, with at least 29 disease genes being involved. To further understand the genetic causes of JS, we performed whole-exome sequencing in 24 newly recruited JS families. Together with six previously reported families, we identified causative mutations in 25 out of 30 (24 + 6) families (83.3%). We identified eight mutated genes in 27 (21 + 6) Japanese families, TMEM67 (7/27, 25.9%) and CEP290 (6/27, 22.2%) were the most commonly mutated. Interestingly, 9 of 12 CEP290 disease alleles were c.6012-12T>A (75.0%), an allele that has not been reported in non-Japanese populations. Therefore c.6012-12T>A is a common allele in the Japanese population. Importantly, one Japanese and one Omani families carried compound biallelic mutations in two distinct genes (TMEM67/RPGRIP1L and TMEM138/BBS1, respectively). BBS1 is the causative gene in Bardet-Biedl syndrome. These concomitant mutations led to severe and/or complex clinical features in the patients, suggesting combined effects of different mutant genes.
Assuntos
Anormalidades Múltiplas/genética , Proteínas Adaptadoras de Transdução de Sinal/genética , Antígenos de Neoplasias/genética , Cerebelo/anormalidades , Anormalidades do Olho/genética , Doenças Renais Císticas/genética , Proteínas de Membrana/genética , Proteínas Associadas aos Microtúbulos/genética , Proteínas de Neoplasias/genética , Retina/anormalidades , Anormalidades Múltiplas/diagnóstico por imagem , Anormalidades Múltiplas/epidemiologia , Anormalidades Múltiplas/fisiopatologia , Alelos , Proteínas de Ciclo Celular , Cerebelo/diagnóstico por imagem , Cerebelo/fisiopatologia , Proteínas do Citoesqueleto , Anormalidades do Olho/diagnóstico por imagem , Anormalidades do Olho/epidemiologia , Anormalidades do Olho/fisiopatologia , Feminino , Heterogeneidade Genética , Predisposição Genética para Doença , Humanos , Japão/epidemiologia , Doenças Renais Císticas/diagnóstico por imagem , Doenças Renais Císticas/epidemiologia , Doenças Renais Císticas/fisiopatologia , Masculino , Mutação , Omã/epidemiologia , Linhagem , Retina/diagnóstico por imagem , Retina/fisiopatologiaRESUMO
Animals change their biological activities depending on their nutritional state. Reproductive functions, including sexual behavior, are suppressed under low-energy conditions; however, the underlying neuronal mechanism is poorly understood. Neuropeptide Y (NPY) is an orexigenic molecule released in response to low-energy conditions and has an inhibitory effect on sexual behavior. We examined how NPY is involved in energy state-dependent regulation of male sexual behavior. Mounting, intromission, and ejaculation were evaluated as parameters of sexual behavior. Almost all parameters indicated that fasting for 24h suppressed male sexual behavior. Intracerebroventricular injection of NPY inhibited sexual behavior in males that free-fed for 8h following 24-h fasting (fed males). We next examined whether the dorsal raphe nucleus (DRN), in which serotonergic (5-HT) neurons are distributed, is involved in NPY-mediated inhibition of male sexual behavior. NPY-positive processes immunoreactive for a presynaptic marker, synaptophysin, were distributed in the DRN of both fed and fasted males. Expression of the NPY Y1 receptor in 5-HT neurons was also observed. Direct injection of NPY or 8-OH-DPAT (a 5-HT1A receptor agonist that inhibits the activity of 5-HT neurons) into the DRN inhibited male sexual behavior in fed males. In contrast, injection of BIBP-3226, a NPY Y1 receptor antagonist, or (+)-DOI hydrochloride (DOI), a 5-HT2A/2C receptor agonist that activates 5-HT neurons, into the DRN partially recovered male sexual behavior in 24-h fasted males. These results suggest that NPY inhibits serotonergic neuronal activity via the Y1 receptor in the DRN, resulting in suppression of male sexual behavior in low-energy conditions.
Assuntos
Núcleo Dorsal da Rafe/metabolismo , Neuropeptídeo Y/metabolismo , Comportamento Sexual Animal/fisiologia , Transdução de Sinais/fisiologia , Animais , Jejum , Imuno-Histoquímica , Masculino , Camundongos , Neurônios Serotoninérgicos/metabolismoRESUMO
OBJECTIVES: Parkinson's disease (PD) is a multisystem neurodegenerative disease. We aimed to identify the relationship and factor structure among its different features. MATERIALS & METHODS: Motor, olfactory and cognitive function, and cardiac sympathetic denervation were evaluated in 125 patients with PD using the Unified Parkinson's Disease Rating Scale (UPDRS) part III score, odor stick identification test for the Japanese (OSIT-J), Mini-Mental State Examination (MMSE), and [(123) I] meta-iodobenzylguanidine (MIBG) cardiac scintigraphy (heart-to-mediastinum (H/M) ratio). Pearson's correlation and multiple regression analysis were used to evaluate the association among the four measures with age, gender, and disease duration as the covariates. Exploratory factor analysis was used to identify the underlying factor structure among the measures and covariates. RESULTS: Pearson's correlation and multiple regression analysis showed correlations between OSIT-J score and MIBG H/M ratio, OSIT-J and MMSE scores, UPDRS part III score and MIBG H/M ratio, UPDRS part III score and disease duration, and MMSE score and age. Factor analysis identified three factors: (i) age and MMSE score; (ii) MIBG H/M ratio and OSIT-J score; and (iii) UPDRS part III score and disease duration. CONCLUSIONS: Our results suggest that aging, PD-related pathogenesis, and disease duration underlie the multisystem neurodegeneration present in PD. Moreover, age and disease duration are the major risk factors for cognitive impairment and motor symptoms, respectively. Olfactory impairment and cardiac sympathetic denervation are strongly associated in PD.
Assuntos
Doença de Parkinson/complicações , Doença de Parkinson/fisiopatologia , Fatores Etários , Idade de Início , Idoso , Transtornos Cognitivos/diagnóstico , Análise Fatorial , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Análise de Regressão , Estudos Retrospectivos , Fatores de Risco , Índice de Gravidade de DoençaRESUMO
We examined the mucosal irritating and healing impairment effects of risedronate, a nitrogen-containing bisphosphonate (BPP), on rat stomachs, in comparison with those of alendronate and minodronate. Male SD rats were used in the following two studies; 1) the ulcerogenic effects of risedronate, alendronate and minodronate in the antral mucosa, and 2) the healing impairment effect of these drugs on gastric ulcers induced by thermocauterization. A single administration of BPPs to fasted rats produced ulcers in the antrum with severe edema and inflammation 3 days after refeeding, although the doses required for this action differed among these BPPs: alendronate >100 mg/kg, risedronate >300 mg/kg, minodronate >10 mg/kg. The generation of antral ulcers induced by these BPPs was accompanied by an increase in myeloperoxidase (MPO) activity and lipid peroxidation as well as a decrease in superoxide dismutase (SOD) activity and glutathione (GSH) content in the mucosa; the extent order of these changes was minodronate >alendronate >risedronate. On the other hand, the healing of gastric ulcers was significantly delayed by daily administration of alendronate (>30 mg/kg) and minodronate (>10 mg/kg), but not by risedronate, even at 60 mg/kg. Mucosal vascular endothelium-derived growth factor (VEGF) and basic fibroblast growth factor (bFGF) protein expressions were up-regulated after ulceration, in parallel with angiogenesis. Alendronate and minodronate decreased these expressions and angiogenesis, while risedronate had no effect. In conclusion, the gastric adverse effect of risedronate is less potent than alendronate and minodronate. It is assumed that risedronate may be used more safely than other BPPs as an antiresorptive drug in patients.
Assuntos
Alendronato/toxicidade , Difosfonatos/toxicidade , Ácido Etidrônico/análogos & derivados , Imidazóis/toxicidade , Úlcera Gástrica/induzido quimicamente , Cicatrização/efeitos dos fármacos , Animais , Relação Dose-Resposta a Droga , Ácido Etidrônico/química , Ácido Etidrônico/toxicidade , Masculino , Nitrogênio/toxicidade , Ratos , Ratos Sprague-Dawley , Ácido Risedrônico , Úlcera Gástrica/metabolismo , Úlcera Gástrica/patologia , Cicatrização/fisiologiaRESUMO
1. The study aimed to investigate the pharmacokinetics of thrombomodulin alpha (TM-alpha), human-soluble thrombomodulin in rats. 2. Intravenously administered TM-alpha was eliminated in two phases (T(1/2 alpha) = 0.2-0.3 h and T(1/2 beta) = 6-8 h), and the elimination curve was linear in a dose range of 10-250 microg kg(-1). Based on the results of tissue concentration studies after reaching the steady-state, the highest concentration of TM-alpha was seen in the plasma, suggesting the low levels of transfer to tissues (< or = 22% of plasma levels). 3. In vivo metabolism of TM-alpha was also analysed using high-performance liquid chromatography. The main peak observed in the plasma was TM-alpha, and even 72 h after the last dose of repeated administrations, 80% or more was unchanged form. Approximately half of the radioactivity excreted in the urine was recovered as a peak corresponding to TM-alpha. 4. The results reveal that although plasma clearance was lower in the renally impaired rats, the decrease was not large, with a difference of only about 20%. As a result, although the cause remains unclear, it is considered unlikely that the plasma concentrations of TM-alpha will vary considerably in patients with renal impairment.
Assuntos
Rim/metabolismo , Proteínas Recombinantes/farmacocinética , Trombomodulina/metabolismo , Animais , Cromatografia Líquida de Alta Pressão , Humanos , Injeções Intravenosas , Rim/patologia , Rim/fisiopatologia , Nefropatias/induzido quimicamente , Nefropatias/metabolismo , Masculino , Engenharia de Proteínas , Ratos , Ratos Sprague-Dawley , Proteínas Recombinantes/sangue , Proteínas Recombinantes/urina , Solubilidade , Trombomodulina/química , Trombomodulina/genéticaRESUMO
In order to obtain a greater uniformity of maturation, the growth of the fig fruit (Ficus carica L.) can be stimulated by the application of either olive oil, ethrel/ethephon or auxin. The three treatments induce ethylene production in figs. In this study, we investigated the regulatory mechanisms responsible for oil, auxin and ethylene induced ethylene production in figs. The ethylene production in response to olive oil, auxin, and propylene treatments and during ripening were all induced by 1-methylcyclopropene (1-MCP) and inhibited by propylene indicating a negative feedback regulation mechanism. Three 1-aminocyclopropane-1-carboxylic acid (ACC) synthase genes (Fc-ACS1, Fc-ACS2 and Fc-ACS3) and one ACC oxidase gene (Fc-ACO1) were isolated and their expression patterns in response to either oil, propylene or auxin treatment in figs determined. The expression patterns of Fc-ACS1 and Fc-ACO1 were clearly inhibited by 1-MCP and induced by propylene in oil treated and ripe fruits indicating positive regulation by ethylene, whereas Fc-ACS2 gene expression was induced by 1-MCP and inhibited by propylene indicating negative regulation by ethylene. The Fc-ACS3 mRNA showed high level accumulation in the auxin treated fruit. The inhibition of Fc-ACS3 gene by 1-MCP in oil treated and in ripe fruits suggests that auxin and ethylene modulate the expression of this gene by multi-responsive signal transduction pathway mechanisms. We further report that the olive oil-induced ethylene in figs involves the ACC-dependent pathway and that multiple ethylene regulatory pathways are involved during maturation and ripening in figs and each specific pathway depends on the inducer/stimulus.
Assuntos
Etilenos/biossíntese , Ficus/fisiologia , Frutas/fisiologia , Alcenos/farmacologia , Aminoácido Oxirredutases/metabolismo , Sequência de Bases , Ciclopropanos/farmacologia , Ficus/efeitos dos fármacos , Ficus/crescimento & desenvolvimento , Frutas/efeitos dos fármacos , Frutas/crescimento & desenvolvimento , Regulação da Expressão Gênica de Plantas , Ácidos Indolacéticos/farmacologia , Liases/metabolismo , Dados de Sequência Molecular , Azeite de Oliva , Reguladores de Crescimento de Plantas/farmacologia , Óleos de Plantas/farmacologia , Proteínas de Plantas/metabolismo , RNA Mensageiro/metabolismoRESUMO
X-ray and neutron diffraction have been used to investigate the formation of solid crystalline monolayers of all of the linear carboxylic acids from C(6) to C(14) at submonolayer coverage and from C(8) to C(14) at multilayer coverages, and to characterize their structures. X-rays and neutrons highlight different aspects of the monolayer structures, and their combination is therefore important in structural determination. For all of the acids with an odd number of carbon atoms, the unit cell is rectangular of plane group pgg containing four molecules. The members of the homologous series with an even number of carbon atoms have an oblique unit cell with two molecules per unit cell and plane group p2. This odd-even variation in crystal structure provides an explanation for the odd-even variation observed in monolayer melting points and mixing behavior. In all cases, the molecules are arranged in strongly hydrogen-bonded dimers with their extended axes parallel to the surface and the plane of the carbon skeleton essentially parallel to the graphite surface. The monolayer crystal structures have unit cell dimensions similar to certain close-packed planes of the bulk crystals, but the molecular arrangements are different. There is a 1-3% compression on increasing the coverage over a monolayer.
RESUMO
Acute axonal polyneuropathy and Wernicke-Korsakoff encephalopathy developed simultaneously in three patients. Nerve conduction studies (NCS) detected markedly decreased compound muscle action potentials (CMAPs) and sensory nerve action potentials (SNAPs) with minimal conduction slowing; sympathetic skin responses (SSRs) were also notably decreased. Sural nerve biopsies showed only mild axonal degeneration with scattered myelin ovoid formation. The symptoms of neuropathy lessened within two weeks after an intravenous thiamine infusion. CMAPs, SNAPs, and SSRs also increased considerably. We suggest that this is a new type of peripheral nerve impairment: physiological conduction failure with minimal conduction delay due to thiamine deficiency.
Assuntos
Axônios/fisiologia , Síndrome de Korsakoff/etiologia , Síndrome de Korsakoff/fisiopatologia , Condução Nervosa/fisiologia , Polineuropatias/etiologia , Polineuropatias/fisiopatologia , Deficiência de Tiamina/complicações , Deficiência de Tiamina/fisiopatologia , Doença Aguda , Adulto , Axônios/efeitos dos fármacos , Humanos , Síndrome de Korsakoff/tratamento farmacológico , Masculino , Pessoa de Meia-Idade , Condução Nervosa/efeitos dos fármacos , Polineuropatias/tratamento farmacológico , Tiamina/uso terapêutico , Deficiência de Tiamina/tratamento farmacológicoRESUMO
OBJECTIVES: It is often difficult to stimulate the proximal hypoglossal nerve by magnetic occipital stimulation, even in normal subjects. Therefore, we tested an improved method of stimulating the proximal hypoglossal nerve, using high voltage electrical stimulation. METHODS: The proximal hypoglossal nerve was activated by high voltage electrical stimulation using surface electrodes over the occipital skull. The compound muscle action potential (CMAP) was recorded from the lingual muscles using surface electrodes in 10 normal subjects. CMAP and F waves produced by distal hypoglossal nerve stimulation and motor evoked potentials produced by transcranial magnetic stimulation were also recorded. RESULTS: When the anode electrode was placed at the mastoid process and the cathode below the inion, the unilateral proximal hypoglossal nerve was readily stimulated supramaximally in all the subjects. The CMAP latency was the same as that obtained with magnetic occipital stimulation. The central motor conduction time (CMCT) calculated from the proximal CMAP was 4.1+/-0.4 ms in the contralateral corticobulbar tract and 4.4+/-0.4 ms in the ipsilateral. The CMCT calculated from the minimal F wave latency was 3.3+/-0.2 ms. CONCLUSIONS: The high voltage electrical stimulation is a useful method for stimulating the proximal hypoglossal nerve to estimate the CMCT of the corticobulbar tract.
Assuntos
Potencial Evocado Motor/fisiologia , Nervo Hipoglosso/fisiologia , Adulto , Estimulação Elétrica , Feminino , Humanos , Nervo Hipoglosso/citologia , Magnetismo , Masculino , Neurônios Motores/fisiologia , Tratos Piramidais/citologia , Tratos Piramidais/fisiologia , Língua/inervaçãoAssuntos
Hiperidrose/tratamento farmacológico , Mexiletina/uso terapêutico , Administração Oral , Adulto , Feminino , Hemangioma Cavernoso/complicações , Humanos , Hiperidrose/etiologia , Masculino , Pessoa de Meia-Idade , Neoplasias da Medula Espinal/complicações , Siringomielia/complicações , Resultado do TratamentoRESUMO
alpha-Tocopherol transfer protein (alpha-TTP) maintains the concentration of serum alpha-tocopherol (vitamin E), one of the most potent fat-soluble antioxidants, by facilitating alpha-tocopherol export from the liver. Mutations of the alpha-TTP gene are linked to ataxia with isolated vitamin E deficiency (AVED). We produced a model mouse of AVED by deleting the alpha-TTP gene, which showed ataxia and retinal degeneration after 1 year of age. Because the brain alpha-TTP functions in maintaining alpha-tocopherol levels in the brain, alpha-tocopherol was completely depleted in the alpha-TTP(-/-) mouse brain, and the neurological phenotype of alpha-TTP(-/-) mice is much more severe than that of wild-type mice when maintained on an alpha-tocopherol-deficient diet. Lipid peroxidation in alpha-TTP(-/-) mice brains showed a significant increase, especially in degenerating neurons. alpha-Tocopherol supplementation suppressed lipid peroxidation and almost completely prevented the development of neurological symptoms. This therapy almost completely corrects the abnormalities in a mouse model of human neurodegenerative disease. Moreover, alpha-TTP(-/-) mice may prove to be excellent animal models of delayed onset, slowly progressive neuronal degeneration caused by chronic oxidative stress.
Assuntos
Ataxia/genética , Proteínas de Transporte/fisiologia , Modelos Neurológicos , Neurônios/patologia , Estresse Oxidativo , Animais , Proteínas de Transporte/sangue , Proteínas de Transporte/genética , Feminino , Imuno-Histoquímica , Peroxidação de Lipídeos , Masculino , Camundongos , FenótipoRESUMO
We previously reported on the serum calcium-decreasing activity of recombinant protein factor referred to as caldecrin [Tomomura et al. (1995) J. Biol. Chem. 270, 30315-30321]. To address the mechanism of this serum calcium-decreasing activity, we investigated the effect of rat caldecrin on osteoclastic bone-resorbing activity. Wild-type caldecrin suppressed resorption pit formation by osteoclast on a dentine slice in a dose-dependent manner. The suppressive effect on the bone resorption was not affected by treatment of caldecrin with phenylmethyl sulfonyl fluoride or by use of protease-deficient mutant caldecrins. Recombinant procaldecrin (-13-239), and its fragments (-13-125), (1-111), (1-46), (47-111), and (126-239) were expressed as His-tagged thioredoxin fusion proteins and investigated for their ability to suppress bone resorption. The proform (-13-239) and fragment (-13-125) did not affect the suppressive activity, whereas fragments (1-111) and (126-239) did suppress the bone resorption. The bone-resorbing activity was also suppressed by fragment (47-111), not by fragment (1-46). Overlapping fragments (47-62), (47-79), (47-98), (56-111), (71-111), and (85-111) were compared for their suppressive activity. The fragments (47-62) and (85-111) did not affect the activity, but the other fragments suppressed the bone resorption. A synthetic peptide having the (71-79) sequence suppressed the bone resorption. These results suggest that amino acid sequence corresponding to rat caldecrin (aa 71-79) is responsible for the suppression of bone resorption by caldecrin.
Assuntos
Reabsorção Óssea , Osteoclastos/efeitos dos fármacos , Serina Endopeptidases/química , Serina Endopeptidases/farmacologia , Sequência de Aminoácidos , Animais , Cálcio/sangue , Quimotripsina/química , Precursores Enzimáticos/química , Precursores Enzimáticos/farmacologia , Mutação , Fragmentos de Peptídeos/química , Fragmentos de Peptídeos/farmacologia , Fluoreto de Fenilmetilsulfonil/farmacologia , Conformação Proteica , Coelhos , Ratos , Proteínas Recombinantes de Fusão/química , Proteínas Recombinantes de Fusão/farmacologia , Serina Endopeptidases/genética , Serina Endopeptidases/metabolismoRESUMO
OBJECTIVES: To evaluate conduction abnormalities in the proximal motor nerve in patients with acquired inflammatory demyelinating neuropathies by transcranial magnetic stimulation (TMS). METHODS: TMS intensity and background voluntary contraction (BVC) to evoke maximal size of motor evoked potential (MEP) in hand muscle were investigated in 24 normal subjects. Effect of experimentally induced conduction block by injecting local anesthetics in the peripheral nerve on MEP size was also studied in two normal subjects. In 22 patients with inflammatory demyelinating neuropathies, maximal MEPs were recorded in the deteriorating and recovery stages of the illness. RESULTS: In normal subjects, the MEP became maximal with 30-50% of maximal BVC and at more than 80% the maximal stimulator output of the 2.0 T circular coil. The change in MEP size well reflected the degree of conduction block induced by local anesthetics. Findings for patients suggested conduction abnormalities proximal to axilla in 9 patients, and that the abnormal reduction of Erb CMAP was the result of submaximal stimulation, not true conduction block, in 3 patients. The increase in MEP/wrist CMAP ratio was better correlated with improvement in muscle strength than with change in the axilla or Erb CMAP/wrist CMAP ratio. CONCLUSIONS: Problems such as conduction abnormalities in the motor tract of the central nervous system could not fully be excluded, but we consider that maximal MEP size can be used to predict proximal motor nerve conduction abnormalities.
Assuntos
Potenciais de Ação/fisiologia , Doenças Desmielinizantes/fisiopatologia , Potencial Evocado Motor/fisiologia , Nervo Mediano/fisiopatologia , Neurônios Motores/fisiologia , Músculo Esquelético/fisiopatologia , Condução Nervosa/fisiologia , Adulto , Idoso , Anestésicos Locais/farmacologia , Feminino , Síndrome de Guillain-Barré/fisiopatologia , Humanos , Inflamação/fisiopatologia , Masculino , Nervo Mediano/fisiologia , Pessoa de Meia-Idade , Músculo Esquelético/fisiologia , Tempo de Reação/fisiologia , Valores de Referência , Medula Espinal/fisiologia , Medula Espinal/fisiopatologia , Estimulação Magnética Transcraniana , Articulação do Punho/efeitos dos fármacos , Articulação do Punho/fisiologiaRESUMO
[reaction: see text] Synthesis of polyethynyl-substituted aromatic compounds was achieved efficiently by the use of the Negishi cross-coupling reaction, and this method, coupled with the Sonogashira reaction, was applied to the synthesis of differentially substituted hexaethynylbenzenes from chloroiodobenzenes.
RESUMO
The only reasonable way to reduce the potential for ball-related youth baseball injuries sustained by the defensive players (the majority of ball-related injuries) is to make the ball less injurious. The American Academy of Pediatrics' 1994 statement on youth baseball injuries in this regard reads, "Consideration should be given to utilizing low-impact NOCSAE-approved baseballs and softballs for children 5 to 14 years of age, if these balls demonstrate satisfactory playing characteristics and reduce injury risk. A variety of studies should be undertaken to determine the efficacy of low-impact balls in reducing serious impact injuries." The purpose of this study, in accordance with this AAP policy, is to investigate the following: A) injury reduction potential of softer baseballs, B) their bounce characteristics, and C) their acceptability by youth leagues. Six simple injury models were studied, baseball bounce characteristics were analyzed, and attitudes of safety baseballs among statewide Little League district presidents were surveyed. Injury models demonstrated less injury potential with safety baseballs compared to that with standard hard baseballs. Safety baseballs bounced higher after vertical drops and slow throws, but during fast throws (with the greatest injury potential), the bounce heights were similar for all ball types. Of 27 survey cards sent out, 13 were returned. While 9 respondents indicated that they were already using safety baseballs for the younger players, none of the 13 respondents indicated that they were planning to expand the use of safety baseballs in their leagues. In conclusion, safety baseballs are less injurious in these models. The bounce characteristics of safety baseballs are satisfactory. Youth baseball league officials are not very willing to expand the use of safety baseballs. We recommend using safety baseballs as a standard for all youth baseball leagues because these balls are safer.
Assuntos
Beisebol/lesões , Traumatismos em Atletas/prevenção & controle , Criança , Segurança de Equipamentos , HumanosRESUMO
Sepiapterin reductase (EC 1.1.1.153; SPR) is an enzyme involved in the biosynthesis of tetrahydrobiopterin; and SPR has been identified as a member of the NADP(H)-preferring short-chain dehydrogenase/reductase (SDR) family based on its catalytic properties for exogenous carbonyl compounds and molecular structure. To examine possible differences in the catalytic sites of SPR for exogenous carbonyl compounds and the native pteridine substrates, we investigated by site-directed mutagenesis the role of the highly conserved Ser-Tyr-Lys triad (Ser and YXXXK motif) in SPR, which was shown to be the catalytic site of SDR-family enzymes. From the analysis of catalytic constants for single- and double-point mutants against the triad, Ser and YXXXK motif, in the SPR molecule, participate in the reduction of the carbonyl group of both pteridine and exogenous carbonyl compounds. The Ser and the Tyr of the triad may co-act in proton transfer and stabilization for the carbonyl group of substrates, as was demonstrated for those in the SDR family. But either the Tyr or the Ser of SPR can function alone for proton transfer to a certain extent and show low activity for both substrates.
Assuntos
Oxirredutases do Álcool/química , Oxirredutases do Álcool/genética , Oxirredutases do Álcool/metabolismo , Motivos de Aminoácidos , Sequência de Aminoácidos , Animais , Sequência de Bases , Sequência Conservada , Primers do DNA/genética , Técnicas In Vitro , Cinética , Modelos Moleculares , Dados de Sequência Molecular , Mutagênese Sítio-Dirigida , Conformação Proteica , Ratos , Homologia de Sequência de Aminoácidos , Especificidade por SubstratoRESUMO
A new liquid chromatographic/mass spectrometric assay has been developed for the determination of DX-8951, a new anti-tumor drug, and its 4-hydroxymethyl metabolite (UM-1) in human plasma and urine. Solid-phase extractions were used for sample preparation. A gradient reverse-phase HPLC separation was developed with mobile phases consisting of trifluoroacetic acid and methanol. The detection was conducted using atmospheric pressure chemical ionization tandem mass spectrometry in the selected reaction monitoring mode. A structural analog, camptothecin (CPT), was used as the internal standard. The assay was validated for the determination of DX-8951 and UM-1 in human plasma and urine. The lower limits of quantitation of DX-8951 and UM-1 were 0.1 ng/mL in plasma and 1 ng/mL in urine. The method showed a satisfactory sensitivity, precision, accuracy, recovery and selectivity.
Assuntos
Antineoplásicos/farmacocinética , Camptotecina/farmacocinética , Cromatografia Líquida de Alta Pressão/métodos , Espectrometria de Massas/métodos , Antineoplásicos/sangue , Antineoplásicos/urina , Pressão Atmosférica , Calibragem , Camptotecina/análogos & derivados , Camptotecina/sangue , Camptotecina/urina , Humanos , Sensibilidade e EspecificidadeRESUMO
As a part of our studies on the metabolism of natural compounds, gallic acid was orally administered to rats. The urinary metabolites were analyzed by high-performance liquid chromatography, and their structures were determined to be pyrogallol (M1), pyrogallol-1-O-beta-D-glucuronide (M2), 4-O-methylgallic acid-3-O-sulfate (M3), 2-O-methylpyrogallol-1-O-beta-D-glucuronide (M4), 2-O-methylpyrogallol (M5), 4-O-methylgallic acid (M6), and unchanged gallic acid on the basis of chemical and spectral data. The radical scavenging effects of gallic acid and its urinary metabolites were evaluated using 1,1-diphenyl-2-picrylhydrazyl radical.
Assuntos
Bepridil/análogos & derivados , Bepridil/metabolismo , Ácido Gálico/urina , Picratos , Animais , Compostos de Bifenilo , Cromatografia Líquida de Alta Pressão , Sequestradores de Radicais Livres/metabolismo , Sequestradores de Radicais Livres/urina , Ácido Gálico/metabolismo , Masculino , Estrutura Molecular , RatosRESUMO
We investigated the characteristics of ethylene biosynthesis associated with ripening in banana (Musa sp. [AAA group, Cavendish subgroup] cv Grand Nain) fruit. MA-ACS1 encoding 1-aminocyclopropane-1-carboxylic acid (ACC) synthase in banana fruit was the gene related to the ripening process and was inducible by exogenous ethylene. At the onset of the climacteric period in naturally ripened fruit, ethylene production increased greatly, with a sharp peak concomitant with an increase in the accumulation of MA-ACS1 mRNA, and then decreased rapidly. At the onset of ripening, the in vivo ACC oxidase activity was enhanced greatly, followed by an immediate and rapid decrease. Expression of the MA-ACO1 gene encoding banana ACC oxidase was detectable at the preclimacteric stage, increased when ripening commenced, and then remained high throughout the later ripening stage despite of a rapid reduction in the ACC oxidase activity. This discrepancy between enzyme activity and gene expression of ACC oxidase could be, at least in part, due to reduced contents of ascorbate and iron, cofactors for the enzyme, during ripening. Addition of these cofactors to the incubation medium greatly stimulated the in vivo ACC oxidase activity during late ripening stages. The results suggest that ethylene production in banana fruit is regulated by transcription of MA-ACS1 until climacteric rise and by reduction of ACC oxidase activity possibly through limited in situ availability of its cofactors once ripening has commenced, which in turn characterizes the sharp peak of ethylene production.
Assuntos
Aminoácido Oxirredutases/genética , Etilenos/biossíntese , Regulação da Expressão Gênica de Plantas , Liases/genética , Reguladores de Crescimento de Plantas/biossíntese , Zingiberales/fisiologia , Aminoácido Oxirredutases/metabolismo , Sequência de Bases , Clonagem Molecular , Primers do DNA , Etilenos/farmacologia , Regulação Enzimológica da Expressão Gênica , Regulação da Expressão Gênica de Plantas/efeitos dos fármacos , Liases/metabolismo , Reguladores de Crescimento de Plantas/farmacologia , Proteínas Recombinantes/metabolismo , Reação em Cadeia da Polimerase Via Transcriptase Reversa , Zingiberales/genéticaRESUMO
BACKGROUND/AIMS: It has previously been reported that prostaglandin E2 (PGE2) promotes colon carcinogenesis. We therefore studied the effects of long-term administration of prostaglandin E2 (PGE2) on colon carcinogenesis in rats. METHODOLOGY: Rats received intrarectal n-methyl-n-nitrosourea (MNU) or n-methyl-n-nitrosoguanidine (MNNG) to induce the formation of colonic tumors. Rates then received indomethacin (IND) and/or PGE2, or nothing. After 44 weeks (MNU group) or 46 weeks (MNNG group), colon lesions were identified histologically and colonic mucosa PGE2 concentrations were measured by radioimmunoassay. RESULTS: The incidence of colon carcinoma in the control, MNU, MNU + IND, MNU + PGE2, and MNU + IND + PGE2 groups was 0/14, 5/15, 0/14, 4/10, and 2/9, respectively. In the MNNG group, no tumors were observed. Induction of colon carcinomas by MNU was completely inhibited by IND, while exogenous PGE2 blocked the inhibitory effect of IND. However, PGE2 administration did not accelerate colon carcinogenesis. Neither MNU nor MNNG alone resulted in increased colonic mucosal PGE2 concentrations, whereas exogenous PGE2 administration significantly increased mucosal PGE2 concentrations. IND significantly decreased the mucosal concentration of PEG2 with or without PGE2 administration. CONCLUSIONS: These results suggest that endogenous PGE2 in colon mucosa may be adequate to promote colon carcinoma. To block colon carcinogenesis, PGE2 levels in colonic mucosa must be decreased to less than endogenous levels.