RESUMO
Maltohexaose producing amylase (EC 3.2.1.-) is the fourth known exo-amylase, the three previously known being glucoamylase, beta-amylase and Pseudomonas stutzeri maltotetraose producing amylase. The enzyme after release from Aerobacter aerogenes cells by 0.1% sodium lauryl sulfate extraction was purified by ammonium sulfate precipitation, DEAE-Sephadex column chromatography and Sephadex G-100 gel filtration to 80-fold of the original sodium lauryl sulfate extract activity, It gave a single band on disc electrophoresis, and the molecular weight by gel filtration was 54 000. This amylase showed maximal activity at 50 degrees C and pH 6.80. The pH stability range was relatively wide, the enzyme retaining more than 90% of its initial activity in the range of 6.50-9.0. 80% of the activity was retained after 15 min at 50 degrees C. This enzyme produced maltohexaose from starch, amylose and amylopectin by exo-attack, but did not act on alpha- or beta-cyclodextrin, pullulan or maltohexaitol. Also the enzyme acted on beta-limit dextrins of amylopectin and glycogen to form branched oligosaccharides. The unusual reaction of this enzyme on beta-limit dextrin is discussed from the standpoint of the stereochemistry of 1,4-alpha- and 1,6-alpha-glucosidic bonds. This is the anomalous amylase for which it is recognized that 1,6-alpha-glucosidic linkages in the substrates can mimic the effect of 1,4-alpha-bonds, as previously observed in pseudo-priming reactions of E. coli phosphorylase.
Assuntos
Amilases/metabolismo , Enterobacter/enzimologia , Enterobacteriaceae/enzimologia , Amilases/isolamento & purificação , Amilopectina/metabolismo , Sítios de Ligação , Cálcio/farmacologia , Cátions Bivalentes , Cloromercurobenzoatos/farmacologia , Dextrinas/metabolismo , Glicogênio/metabolismo , Concentração de Íons de Hidrogênio , Iodoacetatos/farmacologia , Modelos Químicos , Oligossacarídeos/metabolismo , Relação Estrutura-Atividade , TemperaturaRESUMO
Intrathecal (i.t.) administration of spermine (0.1-10000 fmol), an endogenous polyamine, produced the behavioural response mainly consisting of biting and/or licking of the hindpaw along with a slight hindlimb scratching directed toward the flank in mice, which peaked at 5-15 min and almost disappeared at 30 min after an injection. The behaviour induced by spermine (10 pmol) was dose-dependently inhibited by intraperitoneal injection of morphine (0.125-0.5 mg/kg). The characteristic behaviour was also inhibited dose-dependently by i.t. co-administration of ifenprodil (62.5-4000 pmol), a competitive antagonist of the polyamine recognition site on N-methyl-D-aspartate (NMDA) receptor ion-channel complex, and D(-)-2-amino-5-phosphonovaleric acid (D-APV) (0.5-2 nmol) and 3-((+/-)-2-carboxypiperazin-4-yl)-propyl-1-phosphonic acid (CPP) (7. 8-500 pmol), the competitive NMDA receptor antagonists, and (5R, 10S)-(+)-5-methyl-10,11-dihydro-5H-dibenzo[a,b]cycloheptene-5, 10-imine hydrogen maleate (MK-801) (0.5-4 nmol), an NMDA ion-channel blocker, but not by 6-cyano-7-nitroquinoxaline-2,3-dione (CNQX), a non-NMDA receptor antagonist. Both (2S, 3S)-[cis-2-(diphenylmethyl)-N-[(2-methoxyphenyl)-methyl]-1-azabicy clo [2.2.2]octane-3-amine] (CP-96,345), a non-peptidic neurokinin-1 (NK-1) receptor antagonist, and CP-96,344, its inactive 2R,3R enantiomer, inhibited spermine-induced behavioural response in a dose-dependent manner. However, [Tyr(6), D-Phe(7), D-His(9)]-substance P(6-11) (sendide) and [D-Phe(7), D-His(9)]-substance P(6-11), the selective antagonists for NK-1 receptors, were without affecting spermine-induced behaviour. These results indicate that spermine-induced behaviour is mediated through the polyamine recognition site on NMDA receptor ion-channel complex without the involvement of substance P system in the mouse spinal cord.
Assuntos
Agressão/efeitos dos fármacos , Comportamento Animal/efeitos dos fármacos , Prurido/induzido quimicamente , Espermina/farmacologia , Analgésicos Opioides/farmacologia , Animais , Relação Dose-Resposta a Droga , Antagonistas de Aminoácidos Excitatórios/farmacologia , Membro Posterior/fisiologia , Injeções Espinhais , Masculino , Camundongos , Morfina/farmacologia , Antagonistas dos Receptores de Neurocinina-1 , Prurido/psicologia , Espermina/administração & dosagem , Espermina/antagonistas & inibidores , Fatores de TempoRESUMO
Intrathecal (i.t.) administration of morphine in the spinal subarachnoid space of mice produced a severe hindlimb scratching followed by biting and licking. The onset of the scratching behaviour was observed 60-70 s after i.t. injection of morphine (60 and 90 nmol), and had a duration of 3-4 min. The morphine-induced behaviour was increased additively by i.t. co-administration of substance P (SP). This characteristic behavioural response was inhibited dose-dependently by i.t. co-administration of the tachykinin NK-1 receptor antagonists, sendide and CP-96,345. Significant antagonistic effects of SP (1-7), a putative antagonist for NK-1 receptors and [D-Phe7, D-His9]SP (6-11), a selective antagonist for SP receptors, were observed against the morphine-induced behaviour. Pretreatment with i.t. SP antiserum and i.t. capsaicin resulted in reduction of the response to morphine. I.t. administration of somatostatin (SOM) antiserum, cysteamine, a relatively selective depletor of SOM and cyclo-SOM, a SOM receptor antagonist, produced no inhibitory effect on the morphine-induced behaviour. These results demonstrate that a spinal system of neurones containing SP may be involved in elicitation of the behavioural episode following i.t. injection of morphine in mice.
Assuntos
Comportamento Animal/efeitos dos fármacos , Morfina/farmacologia , Entorpecentes/farmacologia , Medula Espinal/fisiologia , Substância P/fisiologia , Animais , Capsaicina/administração & dosagem , Capsaicina/farmacologia , Cistamina/administração & dosagem , Cistamina/farmacologia , Relação Dose-Resposta a Droga , Inibidores Enzimáticos/administração & dosagem , Inibidores Enzimáticos/farmacologia , Antagonistas de Hormônios/administração & dosagem , Antagonistas de Hormônios/farmacologia , Injeções Espinhais , Masculino , Camundongos , Camundongos Endogâmicos , Morfina/administração & dosagem , Morfina/antagonistas & inibidores , Antagonistas de Entorpecentes/administração & dosagem , Antagonistas de Entorpecentes/farmacologia , Entorpecentes/administração & dosagem , Somatostatina/administração & dosagem , Somatostatina/antagonistas & inibidores , Somatostatina/farmacologia , Substância P/análogos & derivados , Substância P/farmacologia , Taquicininas/administração & dosagem , Taquicininas/antagonistas & inibidoresRESUMO
To determine the role of mu-opioid receptor subtypes, mu1 and mu2, in antinociception induced by intrathecal (i.t.) or intracerebroventricular (i.c.v.) injection of morphine, we assessed the effect of naloxonazine, a selective antagonist at mu1-opioid receptors. The antinociceptive effects of morphine were measured using four different nociceptive tests. The selective mu1 antagonist, naloxonazine (35 mg/kg, s.c.), 24 h before testing antagonized the antinociceptive effect of morphine on responses to chemical and thermal stimuli to a greater extent than that on responses to mechanical stimuli, as judged from ED50 values. The present results suggest that the antinociceptive activity of both i.t. and i.c.v. morphine on responses to chemical and thermal stimuli may be mediated through the mu1-opioid receptor subtype (naloxonazine-sensitive sites). These findings may be interpreted as indicative of the existence of mu1-receptor subtypes capable of mediating antinociception not only in supraspinal sites but also in spinal sites.
Assuntos
Analgésicos Opioides/farmacologia , Analgésicos/farmacologia , Morfina/farmacologia , Naloxona/análogos & derivados , Receptores Opioides mu/fisiologia , Medula Espinal/fisiologia , Animais , Interações Medicamentosas , Injeções Intraventriculares , Injeções Espinhais , Masculino , Camundongos , Naloxona/farmacologia , Medição da Dor , Receptores Opioides mu/antagonistas & inibidores , Receptores Opioides mu/classificaçãoRESUMO
Recent studies have shown that free D-serine, an agonist for the N-methyl-D-aspartate receptor, is present in the forebrain of rats. In present study, we raised antibodies against D-serine and examined the distribution of both endogenous and intracerebroventricularly administered D-serine in the rat forebrain by an immunocytochemical method. D-Serine-like immunoreactive cells were found in glial cells in the brains of the rats injected with D-serine into the lateral ventricle. No immunoreactive cells were seen in the brains of untreated rats. The results suggest that glial cells may accumulate and catabolize D-serine to regulate the concentration of this neuroactive amino acid in the forebrain.
Assuntos
Imuno-Histoquímica/métodos , Neuroglia/fisiologia , Serina/metabolismo , Animais , Corpo Caloso , Injeções Espinhais , Masculino , Prosencéfalo/fisiologia , Ratos , Ratos WistarRESUMO
Intraplantar injection of capsaicin into the mouse hindpaw produced an acute nociceptive response. The involvement of N-methyl-D-aspartate (NMDA) receptors was examined by intrathecal administration of various excitatory amino acid (EAA) receptor antagonists. The selective and competitive NMDA receptor antagonists, D(-)-2-amino-5-phosphono-valeric acid (APV) and (+/-)-3-(2-carboxypiperazin-4-yl) propyl-1-phosphoric acid (CPP), were most potent in inhibiting the nociceptive response induced by capsaicin (ED50, 0.23 nmol and 0.12 nmol). The noncompetitive NMDA receptor antagonist dizocilpine (MK-801) and the non-NMDA antagonist, 6-cyano-7-nitroquinoxaline-2,3-dione (CNQX) had similar effects on the capsaicin-induced nociception (ED50, 2.90 and 7.98 nmol), while ketamine and 7-chlorokynurenic acid were without effect. Ifenprodil, an antagonist at the receptor-coupled polyamine site, showed a significant reduction of the nociceptive response (ED50, 13.8 nmol). The inhibitory effects of APV, CPP, MK-801, and ifenprodil were reversed by co-administration of NMDA. Coadministration of alpha-amino-3-hydroxy-5-methyl-4-isoxazole-propionic acid (AMPA) or kainate resulted in a marked reduction of CNQX-induced antinociception. The present results suggest that the NMDA receptor plays a key role in spinal nociceptive processing as measured by the capsaicin test in mice. This nociceptive test may be useful for evaluating competitive NMDA antagonists.
Assuntos
Capsaicina/farmacologia , Nociceptores/efeitos dos fármacos , Receptores de N-Metil-D-Aspartato/efeitos dos fármacos , Medula Espinal/efeitos dos fármacos , Animais , Capsaicina/antagonistas & inibidores , Antagonistas de Aminoácidos Excitatórios/farmacologia , Injeções Espinhais , Masculino , Camundongos , Camundongos Endogâmicos , Medição da Dor/efeitos dos fármacos , Receptores de N-Metil-D-Aspartato/antagonistas & inibidoresRESUMO
To validate use of the common cotton-eared marmoset (Callithrix jacchus) in inhalation toxicity studies, its nasal morphology was examined. The nasal turbinates each consisted of one maxilloturbinate and one ethmoturbinate: these were more planar in structure than the comparable structures of rodents or dogs. The nasal cavity epithelia comprised squamous epithelium (SE), nasal transitional epithelium (NTE), respiratory epithelium (RE) and olfactory epithelium (OE), listed in order of occurrence from anterior to posterior positions. NTE was distributed as a narrow band lying between SE and RE. OE was limited to the dorsal part of the cavity, which was structurally similar to that of the macaque or man. Overall, this study revealed structural the similarity of the whole nasal cavity in the marmoset to that of macaques or humans. Prediction of nasal cavity changes in man based on extrapolation from experimentally induced changes in the common marmoset therefore seems likely to be feasible, making it a useful animal model for inhalation studies.
Assuntos
Cavidade Nasal/anatomia & histologia , Mucosa Nasal/anatomia & histologia , Conchas Nasais/anatomia & histologia , Animais , Callithrix , Cães , Humanos , Macaca , Cavidade Nasal/citologia , Mucosa Nasal/citologia , Especificidade da EspécieRESUMO
We report a 57-year-old man who developed Wallenberg syndrome and vertebral artery dissection, probably as a complication of neck rotation during golf exercise. He noticed pain in the neck during golf exercise. About 16 hours later, he developed numbness in the right hand, cold sweat, vertigo, hiccup, double vision and ataxia in gait. Neurological examination on the 22nd day revealed a right Wallenberg syndrome. The right vertebral angiogram showed a marked stenosis of the vertebral artery at the portion across the dura, and a dissecting aneurysm in the portion from its entrance into the posterior fossa through the exit of the right posterior inferior cerebellar artery. Quick rotation and/or extension of the neck and head during golf exercise probably caused the vertebral artery dissection, resulting in Wallenberg syndrome. More attention should be paid to relatively trivial trauma as the cause of stroke, especially in the victims of younger ages.
Assuntos
Dissecção Aórtica/etiologia , Traumatismos em Atletas/complicações , Golfe , Síndrome Medular Lateral/etiologia , Insuficiência Vertebrobasilar/etiologia , Humanos , Masculino , Pessoa de Meia-IdadeRESUMO
We report a case of pseudoxanthoma elasticum (PXE) associated with asymptomatic multiple cerebral infarction on magnetic resonance imaging (MRI), endocrinological abnormalities and multiple congenital physical anomalies. A 40-year-old woman suddenly developed paresthesia in the right half of the body. Physical examination demonstrated loosening of the skin and yellowish papules in the neck and axilla, retinal angioid streaks, cardiac mitral regurgitation, congenital aplasia of the uterus and vagina, and congenital abduction palsy of the right eye. The biopsy of the papules in the neck showed typical features of PXE. Laboratory tests revealed positive antibodies to thyroglobulin and microsome, high TSH level with normal free T3 and T4, and impaired glucose tolerance. The laboratory data and the findings of ultrasonic examination on the thyroid suggested presence of Hashimoto's disease. MRI of the brain demonstrated multiple cerebral infarcts through they were asymptomatic. MRI failed to clarify the lesion responsible for the hemiparesthesia. Carotid arteriography showed slight stenosis with ulceration near the origin of the right internal carotid artery, and severe stenosis of the horizontal portion of the right middle cerebral artery. MRI study of the brain is recommended in PXE patients since the complication of brain pathology worsens the prognosis of the disease.
Assuntos
Anormalidades Múltiplas , Infarto Cerebral/etiologia , Intolerância à Glucose/complicações , Hipotireoidismo/complicações , Pseudoxantoma Elástico/complicações , Adulto , Infarto Cerebral/diagnóstico , Feminino , Humanos , Imageamento por Ressonância MagnéticaRESUMO
The ultrasonic sound velocities of cross-linked orthorhombic hen egg-white lysozyme (HEWL) crystals, including a large amount of water in the crystal, were measured using an ultrasonic pulse-echo method. As a result, seven elastic constants of orthorhombic crystals were observed to be C11 = 5.24 GPa, C22 = 4.87 GPa, C12 = 4.02 GPa, C33 = 5.23 GPa, C44 = 0.30 GPa, C55 = 0.40 GPa, and C66 = 0.43 GPa, respectively. However, C13 and C23 could not be observed because the suitable crystal planes could not be cut from bulk crystals. We conclude that the observed elastic constants of the cross-linked crystals are coincident with those of the intrinsic crystals without cross-linking. Moreover, the characteristics of the elastic constants in orthorhombic HEWL crystals are due to the fact that the shear elastic constants, C44, C55, and C66, are softer than in tetragonal crystals. That is, the shear components, C44, C55, and C66, are one half of those of the tetragonal crystals.
Assuntos
Cristalização , Modelos Químicos , Modelos Moleculares , Muramidase/química , Muramidase/ultraestrutura , Simulação por Computador , Módulo de Elasticidade , Técnicas de Imagem por Elasticidade , Dureza , Conformação Proteica , Resistência ao Cisalhamento , Estresse MecânicoRESUMO
This review addresses the field of nanoscience as viewed through the lens of the scientific career of Peter Eklund, thus with a special focus on nanocarbons and nanowires. Peter brought to his research an intense focus, imagination, tenacity, breadth and ingenuity rarely seen in modern science. His goal was to capture the essential physics of natural phenomena. This attitude also guides our writing: we focus on basic principles, without sacrificing accuracy, while hoping to convey an enthusiasm for the science commensurate with Peter's. The term 'colloquial review' is intended to capture this style of presentation. The diverse phenomena of condensed matter physics involve electrons, phonons and the structures within which excitations reside. The 'nano' regime presents particularly interesting and challenging science. Finite size effects play a key role, exemplified by the discrete electronic and phonon spectra of C(60) and other fullerenes. The beauty of such molecules (as well as nanotubes and graphene) is reflected by the theoretical principles that govern their behavior. As to the challenge, 'nano' requires special care in materials preparation and treatment, since the surface-to-volume ratio is so high; they also often present difficulties of acquiring an experimental signal, since the samples can be quite small. All of the atoms participate in the various phenomena, without any genuinely 'bulk' properties. Peter was a master of overcoming such challenges. The primary activity of Eklund's research was to measure and understand the vibrations of atoms in carbon materials. Raman spectroscopy was very dear to Peter. He published several papers on the theory of phonons (Eklund et al 1995a Carbon 33 959-72, Eklund et al 1995b Thin Solid Films 257 211-32, Eklund et al 1992 J. Phys. Chem. Solids 53 1391-413, Dresselhaus and Eklund 2000 Adv. Phys. 49 705-814) and many more papers on measuring phonons (Pimenta et al 1998b Phys. Rev. B 58 16016-9, Rao et al 1997a Nature 338 257-9, Rao et al 1997b Phys. Rev. B 55 4766-73, Rao et al 1997c Science 275 187-91, Rao et al 1998 Thin Solid Films 331 141-7). His careful sample treatment and detailed Raman analysis contributed greatly to the elucidation of photochemical polymerization of solid C(60) (Rao et al 1993b Science 259 955-7). He developed Raman spectroscopy as a standard tool for gauging the diameter of a single-walled carbon nanotube (Bandow et al 1998 Phys. Rev. Lett. 80 3779-82), distinguishing metallic versus semiconducting single-walled carbon nanotubes, (Pimenta et al 1998a J. Mater. Res. 13 2396-404) and measuring the number of graphene layers in a peeled flake of graphite (Gupta et al 2006 Nano Lett. 6 2667-73). For these and other ground breaking contributions to carbon science he received the Graffin Lecture award from the American Carbon Society in 2005, and the Japan Carbon Prize in 2008. As a material, graphite has come full circle. The 1970s renaissance in the science of graphite intercalation compounds paved the way for a later explosion in nanocarbon research by illuminating many beautiful fundamental phenomena, subsequently rediscovered in other forms of nanocarbon. In 1985, Smalley, Kroto, Curl, Heath and O'Brien discovered carbon cage molecules called fullerenes in the soot ablated from a rotating graphite target (Kroto et al 1985 Nature 318 162-3). At that time, Peter's research was focused mainly on the oxide-based high-temperature superconductors. He switched to fullerene research soon after the discovery that an electric arc can prepare fullerenes in bulk quantities (Haufler et al 1990 J. Phys. Chem. 94 8634-6). Later fullerene research spawned nanotubes, and nanotubes spawned a newly exploding research effort on single-layer graphene. Graphene has hence evolved from an oversimplified model of graphite (Wallace 1947 Phys. Rev. 71 622-34) to a new member of the nanocarbon family exhibiting extraordinary electronic properties. Eklund's career spans this 35-year odyssey.
Assuntos
Carbono/química , Nanotubos/química , Nanotubos/ultraestrutura , Condutividade Elétrica , Substâncias Macromoleculares/química , Conformação Molecular , Tamanho da Partícula , Refratometria , Propriedades de Superfície , VibraçãoRESUMO
AIMS: The association between the expression of androgen receptor (AR) or androgen-converting enzymes and malignant potential in prostate cancer (PCa) was examined. METHODS: PCa specimens from 44 cases of stage II, 10 cases of stage III, four cases of stage IV and two recurrent cases were semi-quantitatively studied with immunohistochemistry for AR and androgen-converting enzymes. RESULTS: The expression scores for AR, 5alpha-reductase type 1 (SRD5A1), 5alpha-reductase type 2 (SRD5A2), and aldo-keto reductase family 1 member C3 (AKR1C3) in the metastatic lesion of stage IV or recurrent cancer (n = 6) were 284.2 (30.1), 300 (0.0), 279.2 (51) and 254.2 (74.9), respectively; these scores were significantly higher than the respective scores of 121.8 (82.1), 135.1 (59.7), 167.0 (66.4) and 150.5 (62.8) for stage II and III cancer (n = 54) (p<0.001, p<0.001, p = 0.002 and p = 0.018, respectively). The expression scores for AR and SRD5A1 in stage II and III cancer with Gleason score 7 (n = 19) were 128.7 (72.3) and 150.5 (52.9); these were significantly higher than the scores of 78.8 (67.2) and 100.0 (39.6), respectively, for cancers with a Gleason score of < or =6 (n = 20) (p = 0.032 and p = 0.002, respectively). The expression scores for AR, SRD5A1 and AKR1C3 in stage II and III cancer with primary Gleason pattern > or =4 (n = 21) were 158.1 (84.3), 158.3 (61.1) and 173.8 (64.8); these were significantly higher than the scores of 98.6 (72.8), 120.3 (54.7) and 135.6 (57.6), respectively, for cancers with primary Gleason pattern < or =3 (n = 33) (p = 0.011, p = 0.026 and p = 0.034, respectively). Within Gleason score 9 cancer, the expression scores for AR and SRD5A1 in the primary lesion of stage IV (n = 3) were 276.7 (5.8) and 283.3 (28.9); these scores were significantly higher than the scores of 182.1 (86.0) and 140.0 (56.6), respectively, for stage II and III cancer (n = 7) (p = 0.027 and p = 0.001, respectively). CONCLUSIONS: Both AR and androgen-converting enzymes were upregulated in high-grade or advanced PCa.