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1.
Sci Rep ; 14(1): 3530, 2024 02 12.
Artigo em Inglês | MEDLINE | ID: mdl-38347004

RESUMO

A series of novel azepine derivatives based on quinazolinone moiety was synthesized through the reaction of quinazolinone chalcones (2a-d) either with 2-amino aniline in acidic medium to give diazepines (3a-d) or with 2-aminophenol to offer oxazepine (4a-d). The structure of the synthesized compounds was confirmed via melting points, elemental analyses, and different spectroscopic techniques. Moreover, these newly compounds mode of action was investigated in-silico using molecular docking against the outer membrane protein A (OMPA), exo-1,3-beta-glucanase for their antimicrobial activity, and against Smoothened (SMO), transcription factor glioma-associated homology (SUFU/GLI-1), the main proteins of Hedgehog signaling pathway to inspect their anticancer potential. Our results showed that, diazepine (3a) and oxazepine (4a) offered the highest binding energy against the target OMPA/ exo-1,3-beta-glucanase proteins and exhibited the potent antimicrobial activities against E. coli, P. aeruginosa, S. aureus, B. subtilis, C. Albicans and A. flavus. As well, diazepine (3a) and oxazepine (4a) achieved the best results among the other compounds, in their binding energy against the target SMO, SUFU/GLI-1 proteins. The in-vitro cytotoxic study was done for them on panel of cancer cell lines HCT-116, HepG2, and MCF-7 and normal cell line WI-38. Conclusively, it was revealed that molecular docking in-silico simulations and the in-vitro experiments were agreed. As a result, our findings elucidated that diazepine (3a) and oxazepine (4a), have the potential to be used as antimicrobial agents and as possible cancer treatment medications.


Assuntos
Anti-Infecciosos , Antineoplásicos , Oxazepinas , Relação Estrutura-Atividade , Simulação de Acoplamento Molecular , Proteínas Hedgehog , Quinazolinonas/farmacologia , Proliferação de Células , Escherichia coli/metabolismo , Staphylococcus aureus/metabolismo , Glucana 1,3-beta-Glucosidase , Oxazepinas/farmacologia , Estudos Prospectivos , Anti-Infecciosos/farmacologia , Antineoplásicos/química , Estrutura Molecular , Ensaios de Seleção de Medicamentos Antitumorais
2.
Trop Anim Health Prod ; 55(3): 200, 2023 May 15.
Artigo em Inglês | MEDLINE | ID: mdl-37188905

RESUMO

Data on Egyptian buffalo first lactation records (n = 1167) available at Mehalet Mousa Farm (between 2002 and 2015) of the Animal Production Research Institute (APRI), Cairo, Egypt, were used to analyse the genetic parameters of total milk yield (TMY), lactation time (LP), and age at first calving (AFC). Additionally, four selection indices were created by using a single phenotypic standard derivation as relevant economic values. The data were evaluated using multiple-trait derivative-free restricted maximum likelihood (MTDFREML). The estimated heritabilities for TMY, LP, and AFC were 0.22, 0.17, and 0.08 respectively and the phenotypic and genetic correlations between TMY and LP were 0.76 and 0.56, respectively, and between AFC with TMY and LP were nеgаtivеs. Using a selection index that incorporates TMY, LP, and AFC (RIH = 0.68) looks to be optimum for increased genetic gain and a shorter generation interval; as a result, selection should thus be exercised near the end of the first lactation.


Assuntos
Búfalos , Feminino , Animais , Búfalos/genética , Egito
3.
Trop Anim Health Prod ; 51(8): 2405-2412, 2019 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-31183800

RESUMO

Carcass performance of 12 fattened male buffalo calves equally grouped by slaughter weights of 300, 350, 400, and 450 kg was evaluated. Six parameters of body measurements such as chest girth, height at withers, body length, body depth, width at pin bones, and diagonal body length were recorded for each calf immediately before slaughter to test their relationships with live body weight, carcass weight (hot and cold) and its components (head, legs, liver, heart, etc.), and eye muscle area at the 10th-13th ribs. Boneless meat and bones formed 36.6 to 39.0% and 9.3 to 11.0% of live weight, respectively. Chest girth had strong correlation with all carcass traits except bone weight and was the best predictor of boneless meat and carcass fat weights (R2 = 0.90, 0.78). The slaughter weight and height at withers and the 10th-13th rib fat weight were the best predictors of hot and cold carcass (R2 ≥ 97.0), carcass bones (R2 = 76%), and hot and cold carcass (R2 = 85.0, 86.5%) weights, respectively.


Assuntos
Composição Corporal , Peso Corporal , Búfalos/anatomia & histologia , Carne/estatística & dados numéricos , Tecido Adiposo , Animais , Osso e Ossos , Egito , Masculino , Músculos/anatomia & histologia , Fenótipo
4.
Artigo em Inglês | MEDLINE | ID: mdl-23743038

RESUMO

A combined experimental and theoretical study on molecular structure and vibrational frequencies of thioindigo was reported. The FT-IR spectrum of thioindigo is recorded in the solid phase. The equilibrium geometries, harmonic vibrational frequencies, thermo-chemical parameters, total dipole moment and HOMO-LUMO energies are calculated by density functional theory DFT/B3LYP utilizing 6-311G(d,p) basis set. Results showed that cis-isomer is highly recommended to be a promising structure for many applications in optoelectronic devices due to its high calculated dipole moment value (3.44 Debye) which indicates its high reactivity to interact with the surrounding molecules as compared to the trans-isomer which has no dipole moment. Both isomers have a similar HOMO-LUMO energy gap, of 3.02 eV (cis-isomer) and 2.78 eV (trans-isomer).


Assuntos
Corantes/química , Índigo Carmim/análogos & derivados , Índigo Carmim/química , Isomerismo , Modelos Moleculares , Espectroscopia de Infravermelho com Transformada de Fourier , Termodinâmica , Vibração
5.
Artigo em Inglês | MEDLINE | ID: mdl-23602957

RESUMO

In the present work both experimental and computational FT-IR spectroscopic studies on 3-Methyl-5-Pyrazolone (MP) were reported. Experimental FT-IR spectrum for MP compound is recorded in powder form. Important physical parameters were reported such as structural parameters, vibrational frequencies, entropy, total energy, total dipole moment and HOMO-LUMO energy gap using DFT/B3LYP/6-311G(d,p) basis set. MP molecule has a total dipole moment of 2.83 Debye and HOMO-LUMO energy gap of 5.80 eV. Results indicate also that exposure to UV changes the spin from singlet to doublet state; one can conclude that MP compound may undergo anomalous Zeeman like effect.


Assuntos
Pirazolonas/química , Eletricidade , Modelos Moleculares , Conformação Molecular , Pós , Espectroscopia de Infravermelho com Transformada de Fourier , Termodinâmica , Raios Ultravioleta , Vibração
6.
Artigo em Inglês | MEDLINE | ID: mdl-22154265

RESUMO

In this work, a combined experimental and theoretical study on molecular structure and vibrational frequencies of (E)-3-(dicyclopropyl methylene)-dihydro-4-[1-(2,5 dimethylfuran-3-yl) ethylidene] furan-2,5-dione [DCPF] were reported. The FT-IR spectra of DCPF isomers are recorded in the solid phase. The equilibrium geometries, harmonic vibrational frequencies, thermo-chemical parameters, total dipole moment and HOMO-LUMO energies are calculated by density functional theory DFT/B3LYP utilizing 6-311G(d,p) basis set. Results showed that scaled frequencies are in good agreement with experimental values. The HOMOs and the LUMOs energies of DCPF isomers were 3.8 and 2.7eV for E and C isomers,respectively.


Assuntos
Furanos/química , Espectroscopia de Infravermelho com Transformada de Fourier , Isomerismo , Modelos Moleculares , Teoria Quântica , Espectroscopia de Infravermelho com Transformada de Fourier/métodos
7.
Nucleosides Nucleotides Nucleic Acids ; 29(1): 55-71, 2010 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-20391193

RESUMO

Hydrazinolysis of 4-amino-6-[2-(4-methoxyphenyl)vinyl]-3-thioxo-3,4-dihydro-2H-[1,2,4] triazin-5-one (1) gave the corresponding hydrazino derivatives (2) Cyclocondensation of (2) with carbon disulfide furnished 8-amino-6-[2-(4-methoxyphenyl)vinyl]-3-thioxo-2,8-dihydro-3H-[1,2,4]triazolo[4,3-b][1,2,4]triazin-7-one (3) which was treated with 2,3,4,6- tetra-O-acetyl-alpha-D-glucopyranosyl bromide (4) in pyridine to give the corresponding N-glucosyl derivative 5, which deblocked to give 8. Compound 2 was reacted with isatin 9 and/or isatoic anhydride 10 to afford 11 and 12. Treatment of 11 and 12 with (4) in pyridine gave the corresponding mono glucosyl derivatives 13 and 14, which were deblocked by ammonia and afforded 15 and 16. Condensation of 2 with aldoses afforded the corresponding cyclic products 17a-f and with D-fructose furnished 18. Acetylation of 17b, d afforded the corresponding polyacetyl derivatives 19b,d. Compound 2 condensed with some aromatic aldehydes in boiling methanol and gave 20a-f. The newly synthesized compounds were tested as antimicrobial agents.


Assuntos
Anti-Infecciosos/farmacologia , Bactérias/efeitos dos fármacos , Carboidratos/farmacologia , Hidrazonas/farmacologia , Triazinas/farmacologia , Acetilação/efeitos dos fármacos , Anti-Infecciosos/química , Carboidratos/química , Glicosilação/efeitos dos fármacos , Hidrazonas/química , Testes de Sensibilidade Microbiana , Oxirredução/efeitos dos fármacos , Triazinas/química
8.
Phys Rev Lett ; 98(1): 015501, 2007 Jan 05.
Artigo em Inglês | MEDLINE | ID: mdl-17358484

RESUMO

Boron strongly modifies electronic and diffusion properties of graphite. We report the first ab initio study of boron interaction with the point defects in graphite, which includes structures, thermodynamics, and diffusion. A number of possible diffusion mechanisms of boron in graphite are suggested. We conclude that boron diffuses in graphite by a kick-out mechanism. This mechanism explains the common activation energy, but large magnitude difference, for the rate of boron diffusion parallel and perpendicular to the basal plane.

9.
Phys Rev Lett ; 91(2): 025505, 2003 Jul 11.
Artigo em Inglês | MEDLINE | ID: mdl-12906489

RESUMO

The atomic processes associated with energy storage and release in irradiated graphite have long been subject to untested speculation. We examine structures and recombination routes for interstitial-vacancy (I-V) pairs in graphite. Interaction results in the formation of a new metastable defect (an intimate I-V pair) or a Stone-Wales defect. The intimate I-V pair, although 2.9 eV more stable than its isolated constituents, still has a formation energy of 10.8 eV. The barrier to recombination to perfect graphite is calculated to be 1.3 eV, consistent with the experimental first Wigner energy release peak at 1.38 eV. We expect similar defects to form in carbon nanostructures such as nanotubes, nested fullerenes, and onions under irradiation.

10.
Biochem Pharmacol ; 60(5): 651-9, 2000 Sep 01.
Artigo em Inglês | MEDLINE | ID: mdl-10927023

RESUMO

Ketamine, etomidate, propofol, and pentobarbital were compared for effects on and interactions with the type 1 facilitative glucose transporter (GLUT-1). Fluxes of radiolabeled hexoses were used to determine the effects of anesthetics on GLUT-1 function. Hypotonic hemolysis of human erythrocytes was used to assess perturbations of membrane integrity. Quenching of intrinsic protein fluorescence was used to assess the direct interactions of anesthetics with purified GLUT-1. Pentobarbital, ketamine, etomidate, and propofol inhibited glucose transport in murine fibroblasts with IC(50) values of 0.8, 1. 6, 0.1, and 0.4 mM, respectively. Pentobarbital, ketamine, etomidate, and propofol also inhibited sugar transport in human erythrocytes. The IC(50) values for pentobarbital and ketamine exhibited substrate dependence for equilibrium exchange but not unidirectional effluxes. This was not observed for etomidate. Propofol did not inhibit equilibrium exchange but did inhibit unidirectional efflux with little substrate dependence. Pentobarbital protected against hemolysis, whereas etomidate and ketamine promoted hemolysis of erythrocytes. Propofol had no effect on membrane integrity. Pentobarbital, ketamine, and etomidate all interacted directly with GLUT-1, with apparent K(d) values of 2.2, 0.8, and 0.5 mM, respectively. Like barbiturates, ketamine, etomidate, and propofol inhibited GLUT-1 at concentrations near to those used pharmacologically. Inhibition of GLUT-1 by these intravenous general anesthetics was complex, exhibiting differential kinetic effects on equilibrium exchange versus unidirectional fluxes and contrasting substrate dependencies. Like barbiturates, ketamine and etomidate bound to GLUT-1 with affinities that paralleled inhibition of glucose transport. As a class, intravenous general anesthetics, in contrast to inhalation anesthetics, inhibit GLUT-1-mediated glucose transport.


Assuntos
Anestésicos/farmacologia , Etomidato/farmacologia , Glucose/metabolismo , Ketamina/farmacologia , Proteínas de Transporte de Monossacarídeos/metabolismo , Propofol/farmacologia , Células 3T3 , Animais , Transporte Biológico/efeitos dos fármacos , Membrana Celular/efeitos dos fármacos , Membrana Celular/metabolismo , Células Cultivadas , Eritrócitos/efeitos dos fármacos , Eritrócitos/metabolismo , Fibroblastos/efeitos dos fármacos , Fibroblastos/metabolismo , Fluorescência , Transportador de Glucose Tipo 1 , Hemólise , Humanos , Cinética , Camundongos , Proteínas de Transporte de Monossacarídeos/efeitos dos fármacos
11.
J Membr Biol ; 169(1): 45-53, 1999 May 01.
Artigo em Inglês | MEDLINE | ID: mdl-10227851

RESUMO

Barbiturates inhibit GLUT-1-mediated glucose transport across the blood-brain barrier, in cultured mammalian cells, and in human erythrocytes. Barbiturates also interact directly with GLUT-1. The hypotheses that this inhibition of glucose transport is (i) selective, preferring barbiturates over halogenated hydrocarbon inhalation anesthetics, and (ii) specific, favoring some GLUT-# isoforms over others were tested. Several oxy- and thio-barbiturates inhibited [3H]-2-deoxyglucose uptake by GLUT-1 expressing murine fibroblasts with IC50s of 0.2-2.9 mm. Inhibition of GLUT-1 by barbiturates correlates with their overall lipid solubility and pharmacology, and requires hydrophobic side chains on the core barbiturate structure. In contrast, several halogenated hydrocarbons and ethanol (all 10 mm). Thus, barbiturates selectively inhibit glucose transport by some, but not all, facilitative glucose transporter isoforms.


Assuntos
Barbitúricos/farmacologia , Proteínas de Transporte de Monossacarídeos/metabolismo , Células 3T3 , Anestésicos/farmacologia , Animais , Transporte Biológico , Glucose/metabolismo , Transportador de Glucose Tipo 1 , Halotano/metabolismo , Humanos , Hidrocarbonetos Halogenados/farmacologia , Isoflurano/metabolismo , Camundongos , Proteínas de Transporte de Monossacarídeos/efeitos dos fármacos , Ratos
12.
Biochemistry ; 35(48): 15222-7, 1996 Dec 03.
Artigo em Inglês | MEDLINE | ID: mdl-8952470

RESUMO

Barbiturates inhibit GLUT-1 mediated hexose transport both in vivo [Gjedde & Rasmussen (1980) J. Neurochem. 35, 1382-1387; Otsuka et al. (1991) Am. J. Physiol. 261, R265-R275] and in vitro [Honkanen et al. (1995) Biochemistry 34, 535-544]. In the present study, the mechanism by which barbiturates inhibit GLUT-1 mediated hexose transport was examined by measuring both unidirectional zero trans and equilibrium exchange fluxes of hexoses in the functionally well-characterized, GLUT-1 rich human erythrocyte system. Unidirectional influx were both inhibited (> 80%) by 10 mM pentobarbital (PB). This symmetrical inhibition of unidirectional flux by PB was virtually independent of cis sugar concentration (2-130 mM) and exhibited an IC50 of approximately 2 mM. In contrast to unidirectional sugar flux, PB inhibition of equilibrium exchange sugar flux is attenuated by increased substrate concentration (e.g., 88% inhibition at 1 mM Glc versus 40% inhibition at 130 mM Glc in the presence of 10 mM PB) and exhibits an IC50 of approximately 10 mM at 100 mM Glc. Other barbiturates were found to inhibit sugar flux in human erythrocytes in this differential manner. These findings, when viewed with kinetic models proposed for GLUT-1 mediated transport [Carruthers (1990) Physiol. Rev. 70, 1135-1176], are consistent with barbiturates being noncompetitive inhibitors of Glc translocation and preferentially inhibiting the unoccupied form of the carrier protein. We propose, therefore, that barbiturates may prevent or alter the conformational changes associated with the reorientation of the carrier protein within the membrane. Overall, these results imply that barbiturates may more strongly inhibit GLUT-1 mediated Glc flux in vivo when the trans Glc is near zero as a result of either metabolism or another transport process.


Assuntos
Barbitúricos/farmacologia , Eritrócitos/metabolismo , Hexoses/metabolismo , Proteínas de Transporte de Monossacarídeos/metabolismo , Configuração de Carboidratos , Eritrócitos/efeitos dos fármacos , Transportador de Glucose Tipo 1 , Humanos , Cinética , Pentobarbital/administração & dosagem , Pentobarbital/farmacologia , Fenobarbital/farmacologia , Secobarbital/farmacologia
13.
Arch Pharm (Weinheim) ; 327(10): 653-5, 1994 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-7826200

RESUMO

3'-Azidonucleosides 4 have been synthesized by condensation of silylated (Z)-5-ethylidenehydantoin and (Z)-5-benzylidenehydantoin with methyl 3-azido-5-O-tert-butyldiphenylsilyl-2,3-dideoxy-D-erythro-pento furanoside (3). The nucleosides 4 were deblocked on treatment with tetrabutylammonium fluoride. The ethylidene group isomerized from Z to E configuration during the nucleoside synthesis. The new nucleosides did not show any appreciable activities against HIV-1 or HSV-1.


Assuntos
Antivirais/síntese química , HIV-1/efeitos dos fármacos , Hidantoínas/farmacologia , Zidovudina/análogos & derivados , Zidovudina/farmacologia , Antivirais/farmacologia , Herpesvirus Humano 1/efeitos dos fármacos , Humanos , Hidantoínas/síntese química , Zidovudina/síntese química
14.
J Med Chem ; 37(1): 73-7, 1994 Jan 07.
Artigo em Inglês | MEDLINE | ID: mdl-8289203

RESUMO

S-Glycosylation took place on reaction of 5-alkylidene- and 5-arylidene-3-aryl-2-thiohydantoins with glycosyl halides under alkaline conditions. Bisglucosylation also took place when N-3 unsubstituted hydantoins were reacted. The bisglucosylated hydantoins produced N-3 glucosylated hydantoins on treatment with ammonia in methanol. In antiviral studies the most active compounds against both HSV-1 and HSV-2 were 5-(2-thienylmethylene)-3-phenyl-2-(2,3,4,6- tetra-O-acetyl-beta-D-glucopyranosyl)-2-thiohydantoin and 5-(2-thienylmethylene)-3-(4-chlorophenyl)-2-(2,3,4,6-tetra-O-acety l-beta-D- glucopyranosyl)-2-thiohydantoin.


Assuntos
Antivirais/síntese química , Herpesvirus Humano 1/efeitos dos fármacos , Herpesvirus Humano 2/efeitos dos fármacos , Feniltioidantoína/análogos & derivados , Animais , Antivirais/farmacologia , Glicosilação , Espectroscopia de Ressonância Magnética , Conformação Molecular , Estrutura Molecular , Feniltioidantoína/síntese química , Feniltioidantoína/farmacologia , Células Vero
15.
Hear Res ; 71(1-2): 80-90, 1993 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-8113147

RESUMO

Glutathione S-transferases (GSTs), a family of ubiquitous cytosolic isozymes, catalyze the detoxification of electrophilic substrates with reduced glutathione and participate in intracellular binding and transport of lipophilic substances. This study measured GST activity biochemically in the inner ear of the rat; determined the isozyme profile by Western blotting; and identified, immunohistochemically, the distribution of the mu and pi class GSTs in the organ of Corti. GST enzymatic activity in inner ear tissues ranged from 117 to 348 nmoles glutathione converted/min/mg protein, values somewhat higher than those found in brain (130) and much lower than in liver (1011). Of the GST isoforms, the pi class (identified by antibodies against the Yp subunit) was most prominent, the mu class (Yb1 subunit) clearly evident while the alpha class (Y(a) subunit) was barely detectable on Western blots. Immunocytochemical analysis showed differential distribution of the Yb1 and Yp subunits. The Yb1 subunit was present in the sensory cells, while supporting cells were not specifically stained. At the subcellular level, the isozyme was localized in the apical zones of inner (IHCs) and outer hair cells (OHCs) close to the cuticular plate. The extent of staining, however, varied between OHCs and IHCs. In the OHCs, staining appeared in discrete spots in the apical areas only, whereas in IHCs staining extended further towards the center of the cells. The Yp subunit was mainly localized to Deiters cell processes and pillar cells. Both Yb1 and Yp colocalized with tubulin-specific antibody. The functional significance of GST in the cochlear receptor cells is speculative. However, a role analogous to that in other tissues (detoxification, prostaglandin synthesis) can be assumed. In addition, an association of GST with the microtubule system is possible based on immunohistochemical colocalization with tubulin.


Assuntos
Glutationa Transferase/metabolismo , Células Ciliadas Auditivas Internas/enzimologia , Células Ciliadas Auditivas Externas/enzimologia , Órgão Espiral/enzimologia , Animais , Western Blotting , Encéfalo/enzimologia , Imunofluorescência , Glutationa Transferase/análise , Glutationa Transferase/química , Isoenzimas , Fígado/enzimologia , Masculino , Microscopia de Fluorescência , Inclusão em Plástico , Ratos , Ratos Wistar
16.
J Neurosci ; 13(5): 2013-23, 1993 May.
Artigo em Inglês | MEDLINE | ID: mdl-8478688

RESUMO

The glutathione S-transferases (GSTs) constitute a family of cytosolic isoenzymes and a structurally unrelated microsomal enzyme that is involved in the detoxication of electrophilic xenobiotics. These enzymes also participate in the intracellular binding and transport of a broad range of lipophilic compounds including bilirubin, and hormones such as the glucocorticoids and thyroid hormones. The present investigation demonstrates that GSTs are present in neurons of the brainstem, forebrain, and cerebellum. An isoenzyme-specific distribution of GSTs was found in cytoplasm, nuclei, and nucleoli. The regional and cellular distribution of cytosolic GSTs in the brain was studied by immunohistochemistry, spectrophotometric enzyme assay, and reverse-phase HPLC. Polyclonal antibody against microsomal GST was strongly reactive with Purkinje cells throughout the cerebellar cortex, and with neurons in the brainstem and hippocampus. Nuclei of Purkinje cells and of neurons in the brainstem, hippocampus, and cerebral cortex were immunopositive for alpha-class GST 1-1 (YaYa), whereas alpha-class GST 2-2 (YcYc) antibody was consistently immunoreactive with the nucleolus, but not with the nucleus or soma. All alpha-class GST antibodies studied were reactive, to various degrees, with astrocytes and choroid plexus; however, ependymal cells of the subventricular zones were immunonegative. alpha-class GST 8-8 (YkYk) immunoreactivity was specifically localized to endothelial cells and/or astrocytic end feet associated with blood vessels. Reverse-phase HPLC indicated that there were also substantial regional differences in the pattern of alpha-, mu-, and pi-class GST subunit expression. For example, the thalamus/hypothalamus had the highest GST activity and greatest concentration of total GST protein and mu-class GST subunit 6 (Yb3), whereas the brainstem had the greatest concentration of pi-class GST subunit (Yp). This regional variation in GST expression may be reflective of regional differences in cell populations. In cerebellar cortex, the concentration of mu-class GST subunit 4 (Yb2) was greatest in the flocculus and lowest in the vermis. This is of clinical interest because the pattern of expression of mu-class GST subunit 4 (Yb2) in the cerebellum coincides with the known regional susceptibility of this structure to degeneration after exposure to toxic or metabolic insults. The vermis is most susceptible to these insults, whereas the lateral lobes and flocculus are most resistant.(ABSTRACT TRUNCATED AT 400 WORDS)


Assuntos
Encéfalo/enzimologia , Glutationa Transferase/metabolismo , Isoenzimas/metabolismo , Neuroglia/enzimologia , Neurônios/enzimologia , Animais , Encéfalo/citologia , Cromatografia Líquida de Alta Pressão/métodos , Imuno-Histoquímica , Concentração Osmolar , Ratos , Distribuição Tecidual
17.
Hear Res ; 54(1): 75-90, 1991 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-1917719

RESUMO

Hyperbilirubinemia is a major problem in neonatal intensive care. Hearing impairment is one of its sequelae. Although lesions of the central auditory pathways are known to be associated with this disorder in both humans and homozygous Gunn rats, the presence of cochler pathology is still controversial. The purpose of this study was to examine the functional integrity of the peripheral auditory system in the Gunn rat. The Gunn rat is a mutant of the Wistar strain with congenital deficiency of the liver enzyme uridine diphosphoglucuronyl transferase which is essential for bilirubin conjugation. This deficiency is inherited as an autosomal recessive trait, with the homozygous animals (jj) showing evidence of bilirubin encephalopathy. The heterozygotes (Jj) have 50% enzyme deficiency and are not jaundiced. The Long-Evans rat served as a control. The approach was to study the discharge characteristics fo single auditory nerve fibers using standard procedures in a closed and calibrated sound system. Various response measurements which would reveal pathological processes in the cochlea were analyzed. In this study, spontaneous discharge rate distribution and interspike interval statistics derived from Gunn rat auditory nerve recordings were found to be within the normal range, and cochlear nerve histology showed no evidence of neuropathy.


Assuntos
Nervo Coclear/patologia , Icterícia/fisiopatologia , Nervo Vestibulococlear/fisiopatologia , Potenciais de Ação , Animais , Feminino , Hiperbilirrubinemia/patologia , Hiperbilirrubinemia/fisiopatologia , Icterícia/patologia , Masculino , Ratos , Ratos Gunn , Nervo Vestibulococlear/fisiologia
18.
Hear Res ; 54(1): 91-104, 1991 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-1917720

RESUMO

This study is the continuation of the functional probing of the auditory periphery in the normal and jaundiced rat. Threshold tuning curves from normal rat auditory nerve fibers were comparable to those reported in other mammals. Life-long unconjugated hyperbilirubinemia does not appear to have a widespread, demonstrable effect on cochlear frequency selectivity and sensitivity as measured by the shapes of FTCs of single auditory nerve fibers. Most fibers from the jj Gunn rats had threshold tuning curves as sharp as those from control animals (Jj Gunn and Long-Evans). Any difference seems to lie in a greater threshold variability, particularly for the high-SR fibers, for the Gunn rat strain. Two-tone rate suppression, particularly above CF, was detected in most fibers from the three groups of rats. The optimal suppression frequency (SF) as a function of CF displayed the same progression. Suppression thresholds at any given CF were generally higher for high-SR fibers than for low-SR fibers for all three groups of animals.


Assuntos
Icterícia/fisiopatologia , Nervo Vestibulococlear/fisiopatologia , Animais , Limiar Auditivo/fisiologia , Eletrofisiologia , Feminino , Heterozigoto , Homozigoto , Hiperbilirrubinemia/genética , Hiperbilirrubinemia/fisiopatologia , Icterícia/genética , Masculino , Ratos , Ratos Gunn , Nervo Vestibulococlear/fisiologia
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