RESUMO
Selective logging in Brazil allows for the removal of up to 90% of trees above 50 cm diameter of a given timber species, independent of a species' life history characteristics or how quickly it will recover. The genetic and demographic effects of selective logging on two Amazonian timber species (Dipteryx odorata Leguminosae, Jacaranda copaia Bignoniaceae) with contrasting ecological and reproductive characteristics were assessed in the same forest. Genetic diversity and gene flow were characterized by genotyping adults and seed sampled before and after logging, using hypervariable microsatellite markers. Overall, there were no short-term genetic impacts on the J. copaia population, with commercial application of current Brazilian forest management regulations. In contrast, for D. Odorata, selective logging showed a range of genetic impacts, with a 10% loss of alleles, and reductions in siring by pollen from trees within the 546-ha study area (23-11%) and in the number of pollen donors per progeny array (2.8-1.6), illustrating the importance of the surrounding landscape. Asynchrony in flowering between D. odorata trees led to trees with no breeding partners, which could limit the species reproduction and regeneration under current regulations. The results are summarized with other published studies from the same site and the implications for forest management discussed. The different types and levels of impacts associated with each species support the idea that ecological and genetic information by species, ecological guild or reproductive group is essential in helping to derive sustainable logging guidelines for tropical forests.
Assuntos
Bignoniaceae/genética , Dipteryx/genética , Agricultura Florestal/métodos , Fluxo Gênico , Endogamia , Árvores/genética , Brasil , Conservação dos Recursos Naturais , Variação Genética , Genótipo , Repetições de Microssatélites , Pólen/genética , Dinâmica PopulacionalRESUMO
The impact of logging and subsequent recovery after logging is predicted to vary depending on specific life history traits of the logged species. The Eco-gene simulation model was used to evaluate the long-term impacts of selective logging over 300 years on two contrasting Brazilian Amazon tree species, Dipteryx odorata and Jacaranda copaia. D. odorata (Leguminosae), a slow growing climax tree, occurs at very low densities, whereas J. copaia (Bignoniaceae) is a fast growing pioneer tree that occurs at high densities. Microsatellite multilocus genotypes of the pre-logging populations were used as data inputs for the Eco-gene model and post-logging genetic data was used to verify the output from the simulations. Overall, under current Brazilian forest management regulations, there were neither short nor long-term impacts on J. copaia. By contrast, D. odorata cannot be sustainably logged under current regulations, a sustainable scenario was achieved by increasing the minimum cutting diameter at breast height from 50 to 100 cm over 30-year logging cycles. Genetic parameters were only slightly affected by selective logging, with reductions in the numbers of alleles and single genotypes. In the short term, the loss of alleles seen in J. copaia simulations was the same as in real data, whereas fewer alleles were lost in D. odorata simulations than in the field. The different impacts and periods of recovery for each species support the idea that ecological and genetic information are essential at species, ecological guild or reproductive group levels to help derive sustainable management scenarios for tropical forests.
Assuntos
Bignoniaceae/genética , Conservação dos Recursos Naturais , Dipteryx/genética , Agricultura Florestal , Modelos Genéticos , Alelos , Brasil , Genética Populacional , Genótipo , Repetições de Microssatélites , Árvores/genéticaRESUMO
The Neotropical tree Hymenaea courbaril, locally known as Jatobá, is a valuable source of lumber and also produces comestible and medicinal fruit. We characterized Mendelian inheritance, linkage and genotypic disequilibrium at nine microsatellite loci isolated from H. courbaril, in order to determine if they would provide accurate estimates of population genetic parameters of this important Amazon species. The study was made on 250 open-pollinated offspring originated from 14 seed trees. Only one of nine loci presented significant deviation from the expected Mendelian segregation (1:1). Genotypic disequilibrium between pairwise loci was investigated based on samples from 55 adult and 56 juvenile trees. No genetic linkage between any paired loci was observed. After Bonferroni's corrections for multiple tests, we found no evidence of genotypic disequilibrium between pairs of loci. We conclude that this set of loci can be used for genetic diversity/ structure, mating system, gene flow, and parentage analyses in H. courbaril populations.
Assuntos
Ligação Genética , Loci Gênicos/genética , Hymenaea/genética , Padrões de Herança/genética , Desequilíbrio de Ligação/genética , Repetições de Microssatélites/genética , Segregação de Cromossomos/genética , Cromossomos de Plantas/genética , Genótipo , Hymenaea/crescimento & desenvolvimento , Funções VerossimilhançaRESUMO
BACKGROUND: Intrinsic resistance of cancer cells is a major concern for the success of chemotherapy, and this undesirable feature stimulates further research into the design of new compounds and/or alternative multiple drug chemotherapy protocols. METHODS: In this study, we investigated the antitumoral potential of the coordination compounds [Cu(HPClNOL)Cl]Cl (1), [Fe(HPClNOL)Cl2]NO3(2) and [Mn(HPClNOL)Cl2] (3). Using the human, MCF-7 and A549, and the murine melanoma, B16-F10, cell lines, we determined the cytotoxicity, DCFH oxidation, disruption of mitochondrial membrane potential (ΔΨm), Sub-G1 and TUNEL positive cells, and caspase 8 and 9 activities. Fractional inhibitory concentration (FIC) and xenograft models were also assessed to evaluate the efficacy of antitumoral potential. RESULTS: We observed that only complex 1 was cytotoxic. The treatment of cancer cells with complex 1 triggered ROS generation and promoted the disruption of ΔΨm. Complex 1 increased the number of Sub-G1 and TUNEL positive cells, and the measurement of caspase 8 and 9 activity confirmed that apoptosis was triggered by the intrinsic pathway. FIC demonstrated that the combination of complex 1 with cisplatin was additive for the A549 cells whilst it was synergic for MCF-7 and B16-F10. Treatment with complex 1, either alone or combined with cisplatin, reduced tumor growth on xenograft models. CONCLUSIONS: The present study brings new clues regarding the mechanism of action of [Cu(HPClNOL)Cl]Cl, either alone or in combination with cisplatin. GENERAL SIGNIFICANCE: These results indicate that complex 1, administered either singly or in combination with current drugs, has real potential for use in cancer therapy.
Assuntos
Antineoplásicos/farmacologia , Cisplatino/farmacologia , Complexos de Coordenação/farmacologia , Cobre/farmacologia , Animais , Antineoplásicos/síntese química , Antineoplásicos/química , Proliferação de Células/efeitos dos fármacos , Sobrevivência Celular/efeitos dos fármacos , Cisplatino/química , Complexos de Coordenação/química , Cobre/química , Ensaios de Seleção de Medicamentos Antitumorais , Feminino , Humanos , Masculino , Camundongos , Camundongos Endogâmicos BALB C , Camundongos Endogâmicos C57BL , Camundongos Nus , Estrutura Molecular , Neoplasias Experimentais/tratamento farmacológico , Neoplasias Experimentais/metabolismo , Neoplasias Experimentais/patologia , Células Tumorais CultivadasRESUMO
BACKGROUND: Genetic and epigenetic variations of the serotonin transporter gene (SLC6A4) have been related to the etiology of depression. The 5-HTTLPR polymorphism at the SLC6A4 promoter region has two variants, a short allele (S) and a long allele (L), in which the S allele results in lower gene transcription and has been associated with depression. The short S-allele of 5-HTTLPR polymorphism of this gene has been associated with depression. In addition to molecular mechanisms, exposure to early life risk factors such as maternal depression seems to affect the development of depression in postnatal life. The present study investigated the association of 5-HTTLPR polymorphism and CpG DNA methylation (5mC) levels of an AluJb repeat element at the SLC6A4 promoter region in mother-child pairs exposed to maternal depression. METHODS: We analyzed DNA samples from 60 subjects (30 mother-child pairs) split into three groups, with and without major depression disorder (DSM-IV) among children and mothers. The genotyping of 5-HTTLPR polymorphism and quantification of 5mC levels was performed by qualitative PCR and methylation-sensitive restriction enzyme digestion, and real-time quantitative PCR (MSRED-qPCR), respectively. RESULTS: The sample analyzed presented a higher frequency of S allele of 5-HTTLPR (67.5%). Despite the high frequency of this allele, we did not find statistically significant differences between individuals carrying at least one S allele between the depression and healthy control subjects, or among the mother-child pair groups with different patterns of occurrence of depression. In the group where the mother and child were both diagnosed with depression, we found a statistically significant decrease of the 5mC level at the SLC6A4 promoter region. LIMITATIONS: The limitations are the relatively small sample size and lack of gene expression data available for comparison with methylation data. CONCLUSION: In this study, we demonstrated a repeat element specific 5mC level reduction in mother-child pairs, concordant for the diagnosis of depression.
Assuntos
Transtorno Depressivo Maior/genética , Epigênese Genética , Mães , Regiões Promotoras Genéticas , Proteínas da Membrana Plasmática de Transporte de Serotonina/genética , Adolescente , Adulto , Alelos , Estudos de Casos e Controles , Criança , Metilação de DNA , Feminino , Predisposição Genética para Doença/genética , Genótipo , Humanos , Masculino , Pessoa de Meia-Idade , Polimorfismo Genético , Adulto JovemRESUMO
The relationships among CBF, cerebral energy metabolism, Na+ pump activity, and electrocorticograms (ECoG) following graded hypotension were studied in 48 gerbils. Energy metabolism and Na+ pump activity were estimated by in vivo 31P and 23Na nuclear magnetic resonance (NMR) spectroscopy, and CBF was determined by [14C]iodoantipyrine methods at the end of the experiments. The CBF measured in normotensive animals was 0.51 +/- 0.07 ml/g brain/min. Following graded hypotension, no 31P spectral change was observed until CBF fell to 0.21-0.27 ml/g brain/min, at which level the intracellular pH began to decrease in association with ECoG voltage reduction. At a CBF level of 0.18-0.23 ml/g brain/min, phosphocreatine (PCr) began to decrease in association with inorganic phosphate (Pi) elevation. At this level, ECoG became isoelectric, although no adenosine triphosphate (ATP) change yet resulted. At a flow level of 0.12-0.14 ml/g brain/min, ATP began to decrease gradually. At 0.04-0.05 ml/g brain/min, PCr and ATP virtually disappeared, and the 23Na signal intensity suddenly changed. The present study demonstrated flow thresholds for the development of tissue acidosis, PCr-Pi changes, and ATP reduction. It appears that functional suppression occurs prior to ATP changes, whereas Na+ pump failure results after ATP depletion.
Assuntos
Encéfalo/fisiopatologia , Circulação Cerebrovascular , Metabolismo Energético , Hipotensão/fisiopatologia , Canais Iônicos/fisiologia , Sódio/metabolismo , Animais , Sangue , Pressão Sanguínea , Dióxido de Carbono/sangue , Eletroencefalografia , Gerbillinae , Concentração de Íons de Hidrogênio , Espectroscopia de Ressonância Magnética , Masculino , Oxigênio/sangueRESUMO
In this study, 15-deoxyspergualin (DSG) or cyclosporine (CsA) was administered to heterotopically heart-grafted rats for 15 days, commencing on the day of transplantation. In addition, a 31P nuclear magnetic resonance (NMR) technique was applied to investigate the in vivo energy metabolism of the graft. A significant prolongation of graft survival was observed in groups treated with 2.5 mg/kg and 5 mg/kg of DSG, when compared with the control group not treated with an immunosuppressant. One graft in the DSG 2.5 mg/kg-treated group and one in the 5 mg/kg-treated group survived for more than 100 days after grafting. The 31P NMR study demonstrated that, although rejection occurred in the rats treated with 2.5 mg/kg of DSG during the early period after transplantation, 5 mg/kg of DSG inhibited rejection completely. As for CsA, while 2 mg/kg of the drug did not affect graft survival, 5 mg/kg and 14 mg/kg significantly prolonged survival. It was revealed by 31P NMR, however, that CsA 5 mg/kg did not quite inhibit rejection by itself, and 14 mg/kg of CsA, which was the tolerogenic dose, exerted a cardiotoxic effect. In consequence, DSG seems to be a powerful immunosuppressant with a low toxic effect.
Assuntos
Ciclosporinas/uso terapêutico , Transplante de Coração , Imunossupressores/uso terapêutico , Animais , Metabolismo Energético , Sobrevivência de Enxerto/efeitos dos fármacos , Guanidinas/uso terapêutico , Espectroscopia de Ressonância Magnética , Masculino , Miocárdio/metabolismo , Ratos , Ratos Endogâmicos ACIRESUMO
We investigated the effect of 15-deoxyspergualin (DSG) on graft rejection, starting administration at the onset of rejection and on the induction of immunologic unresponsiveness. Hearts from WKAH rats were transplanted into the neck of ACI rats. The energy metabolism of the grafted hearts was followed by 31P nuclear magnetic resonance spectroscopy. The day that energy metabolism started to fall was defined as the onset of rejection, and intraperitoneal administration of DSG was initiated at 5 mg/kg/day for 15 days from this day. The grafted heart arrested in 2 of 10 rats 9 and 11 days after transplantation, respectively, but the remaining 8 recovered from rejection and 5 of them showed evidence of immunologic unresponsiveness. Of 10 rats treated with DSG from the day of transplantation, only 1 rat showed evidence of unresponsiveness. The initiation of DSG treatment from the onset of rejection resulted in a higher percentage of induction of unresponsiveness. Therefore, DSG was considered to specifically inhibit lymphocyte clone expansion at the onset of rejection. Spleen cells obtained from recipients 7-10 days after the end of DSG treatment were administered to syngeneic ACI rats grafted with WKAH hearts. Graft survival was significantly prolonged, but long-term unresponsiveness could not be transferred. However, immunologic unresponsiveness could be adoptively transferred in 3 of 5 rats receiving spleen cells from syngeneic rats that had recovered from rejection after DSG treatment and had acquired long-term unresponsiveness. These results suggest that suppressor cells are resistant to DSG and are spared and participate in the maintenance of immunologic unresponsiveness.
Assuntos
Rejeição de Enxerto/efeitos dos fármacos , Transplante de Coração , Imunossupressores/uso terapêutico , Animais , Metabolismo Energético , Guanidinas/farmacologia , Guanidinas/uso terapêutico , Imunização Passiva , Imunossupressores/farmacologia , Espectroscopia de Ressonância Magnética , Masculino , Miocárdio/metabolismo , Miocárdio/patologia , Fósforo , Ratos , Ratos Endogâmicos ACI , Ratos Endogâmicos , Linfócitos T Reguladores/transplanteRESUMO
In our previous paper (Horio et al., Biochim Biophys Acta 858: 153-160, 1986), we reported that the addition of gentamicin in vitro to rabbit renal brush-border membrane vesicles decreases the apparent Vmax of Na+-dependent D-glucose transport without affecting the apparent Km. In the present study, we investigated the effects of gentamicin on the physical state of spin-labeled rabbit renal brush-border membranes, using electron spin resonance spectrometry. Brush-border membrane vesicles were prepared from outer cortex (mainly contains early proximal tubule) and outer medulla (containing primarily late proximal tubule), and the gentamicin toxicities in both preparations were compared. Significant decreases were observed in the membrane fluidity of 5 mM gentamicin-treated brush-border membranes. The fluidity of outer cortical brush-border membranes was affected at both 25 degrees and 35 degrees, whereas that of outer medullary membranes was affected only at 35 degrees. Two different stearic acid spin labels revealed that gentamicin affected the fluidity only in the superficial region of the membranes. We also demonstrated that the gentamicin-induced decreases in Na+-dependent D-glucose transport and in the membrane fluidity were recovered by washing gentamicin-treated brush-border membranes. We suggest that gentamicin binds to the superficial region of brush-border membranes and inhibits Na+-dependent D-glucose transport across brush-border membranes through the decrease in the membrane fluidity.
Assuntos
Gentamicinas/toxicidade , Córtex Renal/efeitos dos fármacos , Medula Renal/efeitos dos fármacos , Fluidez de Membrana/efeitos dos fármacos , Microvilosidades/efeitos dos fármacos , Animais , Óxidos N-Cíclicos/metabolismo , Espectroscopia de Ressonância de Spin Eletrônica , Glucose/metabolismo , Córtex Renal/metabolismo , Medula Renal/metabolismo , Cinética , Masculino , Coelhos , Sódio/farmacologia , Marcadores de SpinRESUMO
Human plasma high density lipoproteins (HDL) have been labeled with N-(1-oxyl-2,2,6,6-tetramethyl-4-piperidinyl)maleimide (NEM-TEMPO). The spin-labeled HDL exhibited an ESR spectrum containing signals of both strongly immobilized and weakly immobilized components by the reaction with a high concentration of NEM-TEMPO, while an ESR spectrum containing only signals of a strongly immobilized component range between 4 degrees C and 37 degrees C, the signal height of the strongly immobilized component exhibited reversible temperature-dependent changes, whereas that of the weakly immobilized component changed irreversibly at temperatures above 25 degrees C. The activation energy of the irreversible change was estimated to be 26 kcal per mol. The strongly immobilized component was derived from NEM-TEMPO which modified apolipoprotein A-I covalently, while the weakly immobilized component was derived from NEM-TEMPO noncovalently bound to HDL. The rate of binding of NEM-TEMPO to either the strongly binding or weakly binding sites and the number of the strongly binding sites in apolipoprotein A-I were estimated to be 125 M-1.day-1 and 1.78, respectively. The binding of NEM-TEMPO to the strongly binding sites was suppressed greatly by pretreatment of HDL with 2,4,6-trinitrobenzene sulfonic acid (TNBS). The slow reaction and suppression with TNBS suggest that NEM-TEMPO binds to some amino acid residue, probably a lysine residue, in apoprotein A-I. The strongly immobilized and weakly immobilized components were reduced almost completely by ascorbate at the same rate, 0.048 min-1 at pH 7.4 and at 4 degrees C.
Assuntos
Óxidos N-Cíclicos , Lipoproteínas HDL/sangue , Ácido Ascórbico , Sítios de Ligação , Fenômenos Químicos , Química , Espectroscopia de Ressonância de Spin Eletrônica , Eletroforese em Gel de Poliacrilamida , Humanos , Concentração de Íons de Hidrogênio , Oxirredução , Marcadores de Spin , Temperatura , Ácido TrinitrobenzenossulfônicoRESUMO
Selective labeling with N-(1-oxyl-2,2,6,6-tetramethyl-4-piperidinyl)-maleimide of human serum LDL has been performed. The spin-labeled LDL exhibited an ESR spectrum containing signals of a strongly immobilized component only. The signals were completely reversible between 4 degrees C and 37 degrees C and fairly stable at each temperature. The spin-labeled LDL which was prepared by the usual method exhibited an ESR spectrum containing signals of both strongly immobilized and weakly immobilized components (5, 6). The latter was unstable above 25 degrees C and changed irreversibly. The strongly binding site showed higher affinity for the nitroxide radical than the weakly binding site, and two kinds of the strongly binding site were demonstrated kinetically. The rate of binding of the nitroxide radical to the two kinds of strongly binding site were estimated to be 4.7 x 10(4) M-1 . day-1 and 0.16 x 10(4) M-1 . day-1 at pH 7.4 and 4 degrees C, respectively. Both the strongly immobilized and weakly immobilized radicals were reduced with ascorbate at the same rate. It was also shown on gel filtration of the SDS-treated LDL derivatives that the strongly immobilized component was on the apoprotein B moiety, whereas either noncovalent binding to LDL or binding to some small molecular species other than protein was suggested for the weakly immobilized component.
Assuntos
Lipoproteínas LDL/sangue , Sítios de Ligação , Espectroscopia de Ressonância de Spin Eletrônica , Temperatura Alta , Humanos , Modelos Químicos , Marcadores de Spin/síntese químicaRESUMO
N-(1-Oxyl-2,2,5,5-tetramethyl-3-pyrrolidinyl)maleimide (MSL) was incorporated into rat liver mitochondria and the nitroxide radical incorporated was found to decay considerably. The incorporation was blocked by a high concentration of NEM, but not by pCMB. Spin labeled fatty acid derivatives, 2-(3-carboxypropyl)-2-tridecyl-4,4-dimethyl-3-oxazolidinyloxyl (FSL1) and 2-(14-carboxytetradecyl)-2-ethyl-4,4-dimethyl-3-oxazolidinyloxyl (FSL2), were also incorporated and the nitroxide radical decayed. However, incorporation of FSL1 or FSL2 was not blocked by NEM or pCMB. The ESR spectrum of 3-carboxyl-2,2,5,5-tetramethyl-pyrroline-1-oxyl (CSL) did not change on reaction with the mitochondria. The labeled MSL exhibited an ESR spectrum composed of both strongly immobilized and weakly immobilized components. A similar reaction with FSL1 gave an ESR spectrum mainly composed of a strongly immobilized component, the weakly immobilized component was negligibly small, while FSL2 exhibited an ESR spectrum in which free-like signals of the nitroxide radical were predominant. The results suggest that MSL is labeled selectively in the mitochondrial membrane through those SH groups that are not reactive to pCMB, and the labeled nitroxide radical is reduced in situ. The mode of incorporation into the mitochondria differs between MSL and the other spin labeled reagents, and labeling of MSL at the binding site may precede reduction of the nitroxide radical. The incorporation of MSL was dependent on the concentration of MSL used. ADP-acceleration of mitochondrial oxygen uptake with succinate was inhibited by labeling the mitochondria with MSL without loss of the electron transferring activity.
Assuntos
Óxidos N-Cíclicos , Mitocôndrias Hepáticas/metabolismo , Marcadores de Spin , Animais , Cloromercurobenzoatos/farmacologia , Espectroscopia de Ressonância de Spin Eletrônica , Etilmaleimida/farmacologia , Técnicas In Vitro , Proteínas/metabolismo , Ratos , Ácido p-CloromercurobenzoicoRESUMO
Two recombinant mutants of porcine kidney D-amino acid oxidase [EC 1.4.3.3, DAO], in which Tyr(228) and His(307) are replaced with Phe and Leu, respectively, have been expressed in Escherichia coli and purified to apparent homogeneity. The molecular size and amino-terminal sequence of the two mutants were the same as those of the native DAO. Kinetic analysis revealed that the Michaelis constants of the Phe-228 and Leu-307 mutants for D-alanine were 71- and 10-fold and the inhibition constants for benzoate, a potent competitive inhibitor, were 1,189- and 18-fold greater than those of the native DAO, respectively. The maximum velocities of the Phe-228 and Leu-307 mutants were 66 and 58% that of the native DAO. The kinetically estimated dissociation constant of the Leu-307 mutant for FAD was 28-fold greater than that of the native DAO, whereas the value of the Phe-228 mutant was comparable to that of the native DAO. The Leu-307 mutant and the recombinant wild-type DAO were inactivated by D-propargylglycine (D-PG), a suicide substrate. However, the Phe-228 mutant was resistant to the inactivation. Absorption peaks of the Phe-228 mutant were blue-shifted about 10 nm from the corresponding peaks of the wild-type DAO, and the oxidized form was fully reduced by D-alanine without appearance of the purple intermediate.(ABSTRACT TRUNCATED AT 250 WORDS)
Assuntos
D-Aminoácido Oxidase/genética , Animais , Apoproteínas/genética , Apoproteínas/isolamento & purificação , Apoproteínas/metabolismo , Sequência de Bases , D-Aminoácido Oxidase/isolamento & purificação , D-Aminoácido Oxidase/metabolismo , DNA/genética , Escherichia coli/genética , Flavina-Adenina Dinucleotídeo/metabolismo , Rim/enzimologia , Cinética , Dados de Sequência Molecular , Peso Molecular , Mutagênese Sítio-Dirigida , Proteínas Recombinantes/genética , Proteínas Recombinantes/isolamento & purificação , Proteínas Recombinantes/metabolismo , SuínosRESUMO
In the presence of a spin trapping reagent, N-tert-butyl-alpha-phenylnitrone, anaerobic incubation of halothane (2-bromo-2-chloro-1,1,1-trifluoroethane) with a reconstituted cytochrome P-450 enzyme system of rabbit liver microsomes exhibited an electron spin resonance spectrum containing signals of a nitroxide radical, and all components of the reconstituted system were necessary to produce the nitroxide radical. Formation of 2-chloro-1,1,1-trifluoroethane, the product of anaerobic dehalogenation of halothane by the reconstituted system, was inhibited by N-tert-butyl-alpha-phenylnitrone. These results indicate that a radical intermediate of halothane is produced during the anaerobic dehalogenation reaction, and that the radical is trapped by N-tert-butyl-alpha-phenylnitrone to form a N-tert-butyl-alpha-phenylnitrone radical adduct.
Assuntos
Sistema Enzimático do Citocromo P-450/metabolismo , Halotano/metabolismo , Microssomos Hepáticos/enzimologia , Anaerobiose , Animais , Óxidos N-Cíclicos , Espectroscopia de Ressonância de Spin Eletrônica , Radicais Livres , Indicadores e Reagentes , Óxidos de Nitrogênio , CoelhosRESUMO
The injection of neostigmine into the hippocampus of anesthetized rats increased the mean arterial blood pressure (17% of baseline after 60 min injection) and decreased the heart rate (24% of baseline after 60 min injection). These changes were blocked by the co-administration of methylatropine into the hippocampus. Intrahippocampal injection of neostigmine stimulated the secretion of epinephrine and norepinephrine. Adrenodemedullation did not suppress the increase in blood pressure and the decrease in heart rate. It is concluded that the stimulation of muscarinic cholinoceptive neurons in the hippocampus evokes a hypertensive response via an increase in sympathetic drive to the heart and peripheral vasculature, with bradycardia possibly mediated via the parasympathetic system.
Assuntos
Derivados da Atropina/farmacologia , Pressão Sanguínea/efeitos dos fármacos , Frequência Cardíaca/efeitos dos fármacos , Hipocampo/efeitos dos fármacos , Neostigmina/farmacologia , Animais , Bradicardia/fisiopatologia , Epinefrina/sangue , Cinética , Masculino , Norepinefrina/sangue , Ratos , Ratos Endogâmicos , Receptores Colinérgicos/fisiologia , Receptores Muscarínicos/fisiologiaRESUMO
Anaesthetic concentration is very important for the quantitative treatment of anaesthesia theory. Traditionally concentration values have been derived from the water/gas partition coefficient. However, the values from many investigators show discrepancies. This study reports the accurate solubility of methoxyflurane (9.1 mM), halothane (18.0 mM), enflurane (11.9 mM) and isoflurane (13.5 mM) in water at 25.0 degrees C using 19F NMR spectroscopy. The method has advantages in that the dissolved molecule in solution can be separately quantified from undissolved anaesthetic. Saturated solutions of the anaesthetic agents were prepared in situ in a NMR tube to avoid pressure and temperature changes in the solution.
Assuntos
Anestésicos/química , Anestésicos/análise , Flúor , Espectroscopia de Ressonância Magnética/métodos , Solubilidade , Temperatura , ÁguaRESUMO
This article describes the presence of two new forms of a thrombin-like enzyme, both with apparent molecular masses of 38 kDa, in Bothrops atrox venom. Both share the ability to cleave fibrinogen into fibrin and to digest casein. Both present identical K(m) on the substrate BApNA. Their N-terminal amino acid sequences are identical for 26 residues, sharing 80% homology with batroxobin and flavoxobin. Two groups of monoclonal antibodies (mAbs) raised against the purified enzyme forms recognized different epitopes of the putative corresponding enzymes present in B. atrox crude venom. On Western blotting analysis of B. atrox crude venom, mAbs 5DB2C8, 5AA10 and 5CF11, but not mAbs 6CC5 and 6AD2-G5, revealed two or more protein bands ranging from 25 to 38 kDa. By immunoprecipitation assays, the 6AD2-G5 mAb was able to precipitate protein bands of 36-38 kDa from B. atrox, B. leucurus, B. pradoi, B. moojeni, B. jararaca and B. neuwiedii crude venoms. Fibrinogen-clotting activity was inhibited when the same venom specimens were pre-incubated with mAb 6AD2-G5, except for B. jararaca and B. neuwiedii.
Assuntos
Coagulação Sanguínea/efeitos dos fármacos , Bothrops , Venenos de Crotalídeos/enzimologia , Fibrinogênio/química , Trombina/isolamento & purificação , Animais , Western Blotting , Venenos de Crotalídeos/farmacologia , Eletroforese em Gel de Poliacrilamida , Isoenzimas/isolamento & purificação , Isoenzimas/farmacologia , Testes de Precipitina , Trombina/químicaRESUMO
Adult white leghorn hens hyperimmunised with Brazilian snake venoms of the genus Bothrops and/or Crotalus produced antibodies capable of recognising, combining with and neutralising the toxic and lethal components of the venoms. The antibodies were first detected by an enzyme-linked immunosorbent assay two weeks after starting the immunisation schedule, reached the highest titres by the third week and remained high for at least 24 weeks. These antibodies are transferred to the egg yolk from which they were isolated as enriched IgY preparations by a combination of methods using positive and negative precipitation with sodium sulphate and/or caprylic acid. The yolk-derived IgY preparations contained antibodies which blocked the phospholipase A2-dependent haemolytic activity of both venoms and the haemorrhagic activity of Bothrops venom, and neutralised the toxic lethal activities of the venoms with good efficacy. The median effective dose (ED50) of the IgY anti-Bothrops venom was 592.5 microliters/2LD50 and, 1.0 ml neutralised 0.0675 mg of venom. The ED50 of the IgY anti-Crotalus venom was 457.5 microliters/3LD50 and 1.0 ml neutralised 0.075 mg of venom.
Assuntos
Antivenenos/imunologia , Bothrops , Venenos de Crotalídeos/imunologia , Venenos de Crotalídeos/toxicidade , Crotalus , Venenos de Serpentes/imunologia , Animais , Formação de Anticorpos , Antivenenos/biossíntese , Galinhas/imunologia , Gema de Ovo , Ensaio de Imunoadsorção Enzimática , Imunoglobulinas/análise , Imunoglobulinas/imunologiaRESUMO
The broad background resonance observed in the in vivo 31P NMR spectra of adult murine heads was investigated in terms of phosphorus atoms in bone and membrane phospholipids. The broad background resonance was found to be weak in a juvenile and increase with advance of age. Fractionation of adult gerbil heads showed that the broad signal was derived from bone and membrane, of which myelin is the major component. The two origins of the broad background resonance exhibited considerably different line shapes in spectra, which enabled us to extract the membrane component from an intact murine head spectrum (sequential subtraction method). By the use of this method, the development of membrane in gerbil brain at various age grades could be estimated. The membrane component was shown to be suppressed in a mutant mouse, jimpy, which has a deficiency in myelin formation ability. Furthermore, the value of T1 of the membrane component was estimated to be 0.9 sec, which was in good agreement with previously reported values for excised brain.
Assuntos
Química Encefálica , Encéfalo/crescimento & desenvolvimento , Animais , Osso e Ossos/química , Osso e Ossos/metabolismo , Encéfalo/metabolismo , Extratos Celulares/química , Membrana Celular/química , Membrana Celular/metabolismo , Feminino , Gerbillinae , Espectroscopia de Ressonância Magnética/métodos , Masculino , Camundongos , Camundongos Jimpy , Camundongos Mutantes Neurológicos , Bainha de Mielina/química , Bainha de Mielina/metabolismo , Couro Cabeludo/química , Crânio/químicaRESUMO
We present a case of primitive urethral carcinoma in a male. The diagnosis was established with physical exploration when we observed papillomatous formations in the fossa navicularis upon everting the meatus. The interest of this case lies in the rare nature of primitive urethral tumours, in its localization at anterior urethra level, and in its transitional histological strain, as transitional ones are usually located at prostatic and not anterior urethra level as in this case that we submit.