RESUMO
Amnestic mild cognitive impairment (aMCI), an Alzheimer's disease prodrome, is characterized by cognitive and psychological symptoms, the latter aggravating prognosis. A mindfulness-based intervention (MBI) represents a promising non-pharmacological framework for Alzheimer's disease prevention. The Monitoring + Acceptance Theory (MAT) postulates that MBI improves cognition through monitoring, and psychological well-being, through acceptance. This single-blind preliminary randomized-controlled study investigated the effects of a MBI on anxio-depressive symptoms, quality of life, and memory, compared to a psychoeducation-based intervention in older adults with aMCI. The contribution of MAT components and of ruminations' reduction to intervention efficacy were examined. Participants assigned to both conditions experienced similar benefits regarding anxio-depressive symptoms and aging-related quality of life. General quality of life and memory remained unchanged. A partial support of the MAT and of ruminations reduction to the MBI's efficacy was found. The findings provide new insights on the effects and mechanisms of a MBI on aMCI symptoms.
Assuntos
Doença de Alzheimer/terapia , Disfunção Cognitiva/terapia , Atenção Plena/métodos , Qualidade de Vida , Idoso , Cognição , Depressão/diagnóstico , Feminino , Humanos , Masculino , Memória , Método Simples-CegoRESUMO
Since its discovery, the immunogenicity of the Dal blood type has not been further investigated. The aim of this study was to better characterize anti- Dal alloantibodies produced following sensitization of Dal-negative dogs, notably their rate of appearance, the agglutination titer over time, and their immunoglobulin class. A secondary objective was to obtain polyclonal anti- Dal alloantibodies to increase the availability of Dal blood typing. Of 100 healthy laboratory Beagles tested, 2 Dal-negative dogs were identified as recipients. Ten healthy Dal-positive dogs were investigated as potential blood donors. All dogs were extensively blood typed for DEA 1, 3, 4, 5, and 7, as well as for Dal. Then, the recipients were transfused uneventfully with 10 ml/kg of Dal-positive but otherwise compatible packed red blood cells. Posttransfusion blood samples were collected routinely over a minimum of 1 year. Using a gel column technology, anti- Dal alloantibodies were detected as early as 4 days posttransfusion and remained detectable 2 years posttransfusion, with maximum agglutination titers reached at 1 and 2 months posttransfusion. The immunoglobulin class was IgG. The immunogenicity and clinical significance of the Dal blood type were confirmed. The results support the recommendations that previously transfused dogs be crossmatched starting 4 days posttransfusion and for the animal's lifetime. The polyclonal anti- Dal antibodies produced will allow blood typing of a significant number of dogs, especially transfused dogs facing blood incompatibilities and canine blood donors.
Assuntos
Tipagem e Reações Cruzadas Sanguíneas/veterinária , Cães/imunologia , Imunização/veterinária , Isoanticorpos/imunologia , Animais , Transfusão de Sangue/veterinária , Cães/sangue , FemininoRESUMO
BACKGROUND: The Dal blood group system was identified a decade ago by the accidental sensitization of a Dal- Dalmatian with a Dal+ blood transfusion. Similar Dal-related blood incompatibilities have been suspected in other Dalmatians, Doberman Pinschers, and other breeds. OBJECTIVES: To determine the prevalence and mode of inheritance of the Dal antigen expression in dogs. ANIMALS: A total of 1130 dogs including 128 Dalmatians, 432 Doberman Pinschers, 21 Shih Tzus, and 549 dogs of other breeds including 228 blood donors were recruited from North America between 2008 and 2015. METHODS: Prospectively, dogs were blood typed for Dal applying a gel column technique using polyclonal canine anti-Dal sera. Pedigrees from 8 typed families were analyzed. RESULTS: The prevalence of the Dal+ blood type varied between 85.6 and 100% in Dalmatians and 43.3-78.6% in Doberman Pinschers depending on geographical area. Dal- dogs were identified mostly in Dalmatians (15/128; 11.7%), Doberman Pinschers (183/432; 42.4%), and Shih Tzus (12/21; 57.1%), and sporadically in mixed-breed dogs (3/122; 2.5%), Lhasa Apsos (1/6) and Bichon Frises (1/3). Only 6/245 (2.4%) blood donors were found to be Dal-, including 5 Doberman Pinschers. The mode of inheritance of the Dal+ phenotype was determined to be autosomal dominant. CONCLUSIONS AND CLINICAL IMPORTANCE: The high percentage of Dal- Doberman Pinchers, Dalmatians and Shih Tzus increases their risk of being sensitized by a blood transfusion from the common Dal+ donor. Extended Dal typing is recommended in those breeds and in dogs when blood incompatibility problems arise after initial transfusions.
Assuntos
Antígenos de Grupos Sanguíneos/genética , Cães/sangue , Animais , Antígenos de Grupos Sanguíneos/sangue , Tipagem e Reações Cruzadas Sanguíneas/veterinária , Feminino , Predisposição Genética para Doença , Masculino , Linhagem , Prevalência , Estados Unidos/epidemiologiaRESUMO
BACKGROUND: Metastatic spinal cord compression (mscc) is an oncologic emergency that, unless diagnosed early and treated appropriately, can lead to permanent neurologic impairment. After an analysis of relevant studies evaluating the effectiveness of various treatment modalities, the Comité de l'évolution des pratiques en oncologie (cepo) made recommendations on mscc management. METHOD: A review of the scientific literature published up to February 2011 considered only phase ii and iii trials that included assessment of neurologic function. A total of 26 studies were identified. RECOMMENDATIONS: Considering the evidence available to date, cepo recommends that cancer patients with mscc be treated by a specialized multidisciplinary team.dexamethasone 16 mg daily be administered to symptomatic patients as soon as mscc is diagnosed or suspected.high-loading-dose corticosteroids be avoided.histopathologic diagnosis and scores from scales evaluating prognosis and spinal instability be considered before treatment.corticosteroids and chemotherapy with radiotherapy be offered to patients with spinal cord compression caused by myeloma, lymphoma, or germ cell tumour without sign of spinal instability or compression by bone fragment.short-course radiotherapy be administered to patients with spinal cord compression and short life expectancy.long-course radiotherapy be administered to patients with inoperable spinal cord compression and good life expectancy.decompressive surgery followed by long-course radiotherapy be offered to appropriate symptomatic mscc patients (including spinal instability, displacement of vertebral fragment); andpatients considered for surgery have a life expectancy of at least 3-6 months.
RESUMO
Glycosaminoglycans (GAG) are essential extracellular matrix molecules which regulate tissue flexibility, a parameter that is reduced in airways of patients with asthma and chronic obstructive pulmonary disease (COPD). We investigated the expression of GAG and their metabolising enzymes in primary human airway smooth muscle cells (ASMC) obtained from healthy donors (controls) and patients with asthma or COPD. Total GAG synthesis was assessed by [(3)H]-glucosamine incorporation. GAG were isolated, purified, fractionated by electrophoresis and characterised using specific GAG-degrading enzymes. Secretion of hyaluronic acid (HA) by ASMC from patients with asthma or COPD was significantly decreased compared with controls. RT-PCR analysis and western blotting revealed that this decrease was associated with a significant reduction in the expression of HA synthase-1 and -2 and a significant increase of hyaluronidase-1. Furthermore, the expression of the HA receptor CD44 was significantly decreased, whereas the receptor for HA-mediated motility was not expressed in asthma or COPD. Our results indicate that there is a decreased expression of HA in asthma and COPD associated with a synergistic regulation of HA metabolising enzymes that may regulate the pathological airway remodelling in these lung diseases.
Assuntos
Asma/metabolismo , Asma/patologia , Ácido Hialurônico/metabolismo , Miócitos de Músculo Liso/metabolismo , Doença Pulmonar Obstrutiva Crônica/metabolismo , Doença Pulmonar Obstrutiva Crônica/patologia , Adulto , Asma/etiologia , Estudos de Casos e Controles , Técnicas de Cultura de Células , Feminino , Glucuronosiltransferase/fisiologia , Humanos , Hialuronan Sintases , Hialuronoglucosaminidase/fisiologia , Masculino , Pessoa de Meia-Idade , Doença Pulmonar Obstrutiva Crônica/etiologia , Adulto JovemRESUMO
BACKGROUND: Airway remodelling is a key feature of asthma and chronic obstructive pulmonary disease (COPD). The remodelling process involves the deposition of extracellular matrix (ECM) proteins within the airways. Current therapies for asthma and COPD consist of inhaled corticosteroids and long-acting beta(2)-agonists (LABA). However, their effect on airway remodelling is not well understood so far. OBJECTIVE: In this study we investigated the effect of fluticasone and salmeterol, either alone or in combination, on fibronectin and tenascin-C protein, isoform, and mRNA levels in primary human lung fibroblasts. METHODS: In our model, fibroblasts cultured in serum-free medium represented a non-inflammatory condition and stimulation with 5% fetal calf serum and/or TGF-beta(1) mimicked a pro-fibrotic environment with activation of tissue repair. Using these two different conditions, the effects of fluticasone and salmeterol on fibronectin and tenascin-C protein and mRNA levels were analysed by immunoblotting and semi-quantitative RT-PCR. RESULTS: In both conditions, fluticasone increased fibronectin transcript and protein levels, whereas it decreased those of tenascin-C. Salmeterol neither affected fibronectin and tenascin-C synthesis significantly nor did it influence the effect of fluticasone when applied in combination. Furthermore, we found that treatment with fluticasone had an opposite effect on extra domain A and B containing fibronectin isoforms generated by alternative splicing compared with total fibronectin transcript levels, whereas tenascin-C isoforms were not differently modulated by fluticasone. CONCLUSIONS: Our results indicate that standard therapies for inflammatory lung disorders influence ECM protein composition and relative expression levels. In contrast to corticosteroids, LABA did not significantly alter the expression of tenascin-C and fibronectin in cultures of primary human lung fibroblasts.
Assuntos
Agonistas Adrenérgicos beta/farmacologia , Albuterol/análogos & derivados , Androstadienos/farmacologia , Broncodilatadores/farmacologia , Fibronectinas/biossíntese , Pulmão/efeitos dos fármacos , Tenascina/biossíntese , Corticosteroides/farmacologia , Albuterol/farmacologia , Células Cultivadas , Matriz Extracelular/metabolismo , Fibroblastos/efeitos dos fármacos , Fibroblastos/metabolismo , Fluticasona , Humanos , Pulmão/metabolismo , Isoformas de Proteínas/biossíntese , Xinafoato de Salmeterol , Fator de Crescimento Transformador beta1/farmacologiaRESUMO
BACKGROUND: The Canadian Clinical Practice Guidelines (CPGs) for the management of asthmatic patients were last published in 1999, with updates in 2001 and June 2004. Large disparities exist in the implementation of these guidelines into clinical practice. OBJECTIVE: The present study evaluated the knowledge of Quebec-based primary care physicians regarding the CPGs, as well as patient outcomes before and after introducing physicians to a new clinical tool--a memory aid in the form of a self-inking paper stamp checklist summarizing CPG criteria and guidelines for assessing asthmatic patient control and therapy. The primary objective of the present study was to assess whether the stamp would improve physicians' knowledge of the CPGs, and as a secondary objective, to assess whether it would decrease patient emergency room visits and hospitalizations. METHODS: A prospective, randomized, controlled study of 104 primary care physicians located in four Quebec regions was conducted. Each physician initially responded to questions on their knowledge of the CPGs, and was then randomly assigned to one of four groups that received information about the CPGs while implementing an intervention (the stamp tool) aimed at supporting their decision-making process at the point of care. Six months later, the physicians were retested, and patient outcomes for approximately one year were obtained from the Régie de l'assurance maladie du Québec. RESULTS: The stamp significantly improved physicians' knowledge of the CPGs in all Quebec regions tested, and reduced emergency room visits and hospitalizations in patients who were followed for at least one year. CONCLUSION: A paper stamp summarizing CPGs for asthma can be used effectively to increase the knowledge of physicians and to positively affect patient outcomes.
Assuntos
Asma/terapia , Médicos de Família , Guias de Prática Clínica como Assunto , Humanos , Estudos Prospectivos , QuebequeRESUMO
This experiment assessed the effect of neonatal ventral hippocampus lesions in rats, a heuristic approach to model schizophrenia, on continuous delayed alternation and conditional discrimination learning performance before and after complete cerebral maturation. Delays (0, 5, 15, and 30 s) were introduced in the tasks to help dissociate between a hippocampal and a prefrontal cortex dysfunction. At postnatal day (PND) 6 or 7, rats received bilateral microinjections of ibotenic acid or phosphate-buffered saline in the ventral hippocampus. From PND 26 to PND 35, rats were tested on the alternation task in a T-maze; from PND 47 to PND 85, the same rats were tested in the discrimination task where a stimulus and a response location had to be paired. Deficits in ventral hippocampus-lesioned rats were observed in both tasks whether a delay was introduced before a response or not. Impaired performance regardless of delay length, combined with high rates of perseverative errors, suggested a post-lesional prefrontal cortex dysfunction which persisted from the juvenile stage into adulthood. Premature cognitive impairments could not be predicted on the basis of the neurodevelopmental animal model of schizophrenia. Nevertheless, they appear consistent with accounts of premorbidly compromised memory, both immediate and delayed, in subgroups of schizophrenia patients.
Assuntos
Transtornos Cognitivos/fisiopatologia , Hipocampo/fisiopatologia , Transtornos da Memória/fisiopatologia , Córtex Pré-Frontal/fisiopatologia , Esquizofrenia/fisiopatologia , Psicologia do Esquizofrênico , Envelhecimento/fisiologia , Animais , Animais Recém-Nascidos , Aprendizagem da Esquiva/efeitos dos fármacos , Aprendizagem da Esquiva/fisiologia , Transtornos Cognitivos/etiologia , Denervação , Modelos Animais de Doenças , Feminino , Hipocampo/crescimento & desenvolvimento , Hipocampo/patologia , Ácido Ibotênico/efeitos adversos , Masculino , Aprendizagem em Labirinto/efeitos dos fármacos , Aprendizagem em Labirinto/fisiologia , Transtornos da Memória/etiologia , Vias Neurais/crescimento & desenvolvimento , Vias Neurais/patologia , Vias Neurais/fisiopatologia , Neurotoxinas/efeitos adversos , Córtex Pré-Frontal/crescimento & desenvolvimento , Ratos , Ratos Sprague-Dawley , Esquizofrenia/complicaçõesRESUMO
Pregnant C57BL/6 mice were chronically treated with 0, 4, 6, or 8 ppm of methylmercury chloride (MeHg) in drinking water during fetal and early postnatal development. Four behavioral functions were analyzed in female and male offspring between the age of 6 and 12 weeks: motor coordination learning on the rotarod; training to spatial alternation in the standard T maze followed by a working memory test with delays; spontaneous locomotion and rearings in the open field; reference and working memory assessment in the modified T maze [Behav. Neurosci. 102 (1988) 635]. Chronic perinatal treatment with MeHg resulted in moderate brain levels of mercury near birth which rapidly decreased during nursing. MeHg exerted an effect on the performance of females, but not of males, on two of the four measurements. All treated females exhibited less locomotion than control mice when the open field was new, but not in the following four sessions when the environment was becoming increasingly familiar. Working memory was impaired in females treated with 6 and 8 ppm of MeHg in the modified T maze, but not on the test with delays in the standard T maze. Taken together, these results show that chronic exposure to MeHg during fetal and postnatal development had sex-dependent effects on horizontal exploration and on working memory in the modified T maze, and no effects on motor coordination learning and reference memory.
Assuntos
Comportamento Animal/efeitos dos fármacos , Intoxicação do Sistema Nervoso por Mercúrio/fisiopatologia , Compostos de Metilmercúrio/administração & dosagem , Complicações na Gravidez , Efeitos Tardios da Exposição Pré-Natal , Animais , Comportamento Animal/fisiologia , Encéfalo/metabolismo , Feminino , Fígado/metabolismo , Masculino , Aprendizagem em Labirinto/efeitos dos fármacos , Aprendizagem em Labirinto/fisiologia , Intoxicação do Sistema Nervoso por Mercúrio/complicações , Intoxicação do Sistema Nervoso por Mercúrio/metabolismo , Compostos de Metilmercúrio/farmacocinética , Camundongos , Camundongos Endogâmicos C57BL , Atividade Motora/efeitos dos fármacos , Atividade Motora/fisiologia , Gravidez , Fatores SexuaisRESUMO
In the present experiment, sham-operated (SH) and fornix-transected (FX) rats were trained on a new nonspatial, odor-guided task. On each session, eight odor pairs were presented twice. On the first occurrence of a pair, rats were reinforced for pushing the container (go response) in which the olfactory stimuli were placed. On the second occurrence, they were not reinforced and had to refrain from responding (no-go response) to be scored as success. Rats were first trained to criterion on odor pairs made of replicates of the same odor (S pairs). Then they were trained to criterion on pairs made of different odors, each member of the pair overlapping with that of another pair (O pairs) and finally, on pairs of different odors with no overlap (NO pairs). The results showed that the number of sessions to reach criterion was significantly higher in FX than in SH rats during training on O pairs, but not during training on S or on NO pairs. These findings are consistent with the configural (Rudy and Sutherland, 1995: Hippocampus 5:375-389) or relational (Eichenbaum et al., 1994: Behav Brain Sci 17:449-518) account of the hippocampal memory function.
Assuntos
Sinais (Psicologia) , Fórnice/lesões , Hipocampo/fisiopatologia , Deficiências da Aprendizagem/fisiopatologia , Transtornos da Memória/fisiopatologia , Condutos Olfatórios/fisiologia , Olfato/fisiologia , Animais , Fórnice/fisiopatologia , Fórnice/cirurgia , Aprendizagem/fisiologia , Deficiências da Aprendizagem/etiologia , Deficiências da Aprendizagem/patologia , Masculino , Memória/fisiologia , Transtornos da Memória/etiologia , Transtornos da Memória/patologia , Modelos Neurológicos , Desempenho Psicomotor/fisiologia , Ratos , Ratos Long-EvansRESUMO
Pregnant C57BL/6 mice were orally given daily doses of 4 or 6 mg/kg of methylmercury chloride (MeHg) or vehicle during either gestational days 7-9 (GD7-9) or days 12-14 (GD12-14). Their female offspring were tested between 6 and 16 weeks of age on a variety of behavioral tasks. Motor coordination on the rotarod and visual discrimination learning in the Y maze were not affected by administration of MeHg either at GD7-9 or at GD12-14. In the open field, the total number of square crossings was lower in mice treated with 4 and 6 mg/kg of MeHg at GD12-14 than in control mice whether the environment was new or familiar, but prenatal administration of MeHg at GD7-9 had no effect on this measure. Administration of MeHg either at GD7-9 or at GD12-14 had no effect on the percentage of central square crossings or on the frequency of rearings in the open field. On spatial alternation training in the T maze, both treated groups in Condition GD7-9 and the group treated with 6 mg/kg at GD12-14 required more sessions to reach the learning criterion than their respective vehicle groups. When spatial alternation was tested with delays, treated groups did not differ from their respective control groups. In the radial arm maze, the performance of mice treated at GD7-9 was normal, but reference memory and working memory were impaired by administration of MeHg at GD12-14. In mice treated with 4 mg/kg of MeHg, reference memory was impaired only on the first block of trials, whereas in mice treated with 6 mg/kg, the deficit persisted on all blocks of trials. Overall, these results indicate that prenatal administration of MeHg at GD12-14 had more detrimental effects on behavioral performance than administration at GD7-9. It reduced locomotor activity and impaired reference memory for egocentric and allocentric spatial information as well as working memory for places.
Assuntos
Envelhecimento/fisiologia , Desenvolvimento Embrionário e Fetal , Aprendizagem/efeitos dos fármacos , Compostos de Metilmercúrio/toxicidade , Atividade Motora/efeitos dos fármacos , Efeitos Tardios da Exposição Pré-Natal , Desempenho Psicomotor/efeitos dos fármacos , Envelhecimento/efeitos dos fármacos , Animais , Encéfalo/metabolismo , Desenvolvimento Embrionário e Fetal/efeitos dos fármacos , Comportamento Exploratório/efeitos dos fármacos , Feminino , Idade Gestacional , Fígado/metabolismo , Compostos de Metilmercúrio/farmacocinética , Camundongos , Camundongos Endogâmicos C57BL , Gravidez , Percepção Espacial/efeitos dos fármacos , Distribuição TecidualRESUMO
The NS3 serine protease enzyme of the hepatitis C virus (HCV) is essential for viral replication. Short peptides mimicking the N-terminal substrate cleavage products of the NS3 protease are known to act as weak inhibitors of the enzyme and have been used as templates for the design of peptidomimetic inhibitors. Automated solid-phase synthesis of a small library of compounds based on such a peptidomimetic scaffold has led to the identification of potent and highly selective inhibitors of the NS3 protease enzyme.
Assuntos
Inibidores Enzimáticos/síntese química , Proteínas não Estruturais Virais/antagonistas & inibidores , Técnicas de Química Combinatória , Inibidores Enzimáticos/farmacologia , Humanos , Mimetismo Molecular , Oligopeptídeos/síntese química , Oligopeptídeos/farmacologia , Biblioteca de Peptídeos , Relação Estrutura-AtividadeRESUMO
Nine rhesus monkeys were trained on visual, tactual, and crossmodal (tactual-visual) versions of delayed nonmatching-to-sample (DNMS). They then received bilateral aspiration lesions of the anterior rhinal cortex or bilateral excitotoxic lesions of the amygdala or were retained as unoperated controls. Monkeys with anterior rhinal cortex lesions displayed a persistent deficit on crossmodal DNMS as well as a deficit on tactual DNMS. In contrast, monkeys with amygdala lesions exhibited only a transient impairment on crossmodal DNMS, and their difficulty appeared to be related to inadvertent damage to the anterior rhinal cortex. The present findings support the idea that the rhinal cortex is important for the formation and retrieval of stimulus-stimulus associations across sensory modalities.
Assuntos
Tonsila do Cerebelo/fisiologia , Aprendizagem por Associação/fisiologia , Córtex Entorrinal/fisiologia , Macaca mulatta/fisiologia , Rememoração Mental/fisiologia , Reconhecimento Visual de Modelos/fisiologia , Desempenho Psicomotor/fisiologia , Tato/fisiologia , Animais , Mapeamento Encefálico , Condicionamento Operante/fisiologia , Masculino , Vias Neurais/fisiologia , Resolução de Problemas/fisiologia , Privação Sensorial/fisiologiaRESUMO
Structure-activity studies on a hexapeptide N-terminal cleavage product of a dodecamer substrate led to the identification of very potent and highly specific inhibitors of the HCV NS3 protease/NS4A cofactor peptide complex. The largest increase in potency was accomplished by the introduction of a (4R)-naphthalen-1-yl-4-methoxy substituent to the P2 proline. N-Terminal truncation resulted in tetrapeptides containing a C-terminal carboxylic acid, which exhibited low micromolar activity against the HCV serine protease.
Assuntos
Antivirais/síntese química , Hepacivirus/efeitos dos fármacos , Hepacivirus/enzimologia , Oligopeptídeos/síntese química , Inibidores de Serina Proteinase/síntese química , Proteínas não Estruturais Virais/antagonistas & inibidores , Animais , Antivirais/química , Antivirais/farmacologia , Catepsina B/antagonistas & inibidores , Quimotripsina/antagonistas & inibidores , Desenho de Fármacos , Humanos , Cinética , Elastase de Leucócito/antagonistas & inibidores , Modelos Moleculares , Conformação Molecular , Oligopeptídeos/química , Oligopeptídeos/farmacologia , Elastase Pancreática/antagonistas & inibidores , Conformação Proteica , Serina Endopeptidases/metabolismo , Inibidores de Serina Proteinase/química , Inibidores de Serina Proteinase/farmacologia , Relação Estrutura-Atividade , SuínosRESUMO
In macaque monkeys, aspiration but not excitotoxic lesions of the medial temporal lobe limbic structures, the amygdala and hippocampus, produce a severe impairment in visual recognition memory. Furthermore, certain ventromedial cortical regions, namely the rhinal (i.e., entorhinal and perirhinal) cortex, are now known to be critical for visual recognition memory. Because the route taken by temporal cortical efferent fibers, especially perirhinal efferents, passes nearby the amygdala, it is possible that inadvertent damage to these fibers is produced by the aspirative but not the excitotoxic process, thereby accounting at least in part for the different behavioral outcomes of the two types of lesion. To test this idea, we assessed the integrity of the rhinal corticothalamic projection system after aspiration lesions of the amygdala. Three rhesus monkeys with unilateral amygdala removals received bilaterally symmetrical injections of a retrograde fluorescent tracer into the medial portion of the mediodorsal nucleus of the thalamus. Retrogradely labeled cells were identified using conventional fluorescence microscopy techniques. In all three cases, the rhinal cortex of the intact hemispheres contained moderate numbers of retrogradely labeled cells. By contrast, the rhinal cortex of the amygdalectomized hemispheres consistently contained few retrogradely labeled cells, and a direct comparison of the two hemispheres showed this difference to be statistically significant. A similar asymmetric pattern was observed for area TE but not for the cortex lining the dorsal bank of the superior temporal sulcus, nor for the rostral cingulate motor area, which was examined as a control. The results indicate that aspiration lesions of the amygdala not only remove the cell bodies of the amygdala, as intended, but also inadvertently disrupt projection fibers arising from cells in the rhinal cortex and area TE that pass nearby or through the amygdala en route to the thalamus. Behavioral studies examining the effects of aspiration lesions of the amygdala in nonhuman primates need to take these findings into consideration.
Assuntos
Tonsila do Cerebelo/fisiopatologia , Córtex Cerebral/fisiopatologia , Sistema Límbico/fisiopatologia , Sucção , Transmissão Sináptica/fisiologia , Tálamo/fisiopatologia , Animais , Encefalopatias/etiologia , Encefalopatias/fisiopatologia , Mapeamento Encefálico , Inalação , Macaca mulattaRESUMO
Hexapeptide DDIVPC-OH is a competitive inhibitor of the hepatitis C virus (HCV) NS3 protease complexed with NS4A cofactor peptide. This hexapeptide corresponds to the N-terminal cleavage product of an HCV dodecapeptide substrate derived from the NS5A/5B cleavage site. Structure-activity studies on Ac-DDIVPC-OH revealed that side chains of the P4, P3 and P1 residues contribute the most to binding and that the introduction of a D-amino acid at the P5 position improves potency considerably. Furthermore, there is a strong preference for cysteine at the P1 position and conservative replacements, such as serine, are not well tolerated.
Assuntos
Hepacivirus/enzimologia , Oligopeptídeos/farmacologia , Serina Endopeptidases/metabolismo , Inibidores de Serina Proteinase/farmacologia , Sequência de Aminoácidos , Dados de Sequência Molecular , Oligopeptídeos/química , Inibidores de Serina Proteinase/química , Relação Estrutura-Atividade , Especificidade por SubstratoRESUMO
Replacement of the C-terminal carboxylic acid functionality of peptide inhibitors of hepatitis C virus (HCV) NS3 protease (complexed with NS4A peptide cofactor) by activated carbonyl groups does not produce any substantial increase in potency. These latter inhibitors also inhibit a variety of other serine and cysteine proteases whereas the carboxylic acids are specific. Norvaline was identified as a chemically stable replacement for the P1 residue of Ac-DDIVPC-OH which was also compatible with activated carbonyl functionalities.
Assuntos
Hepacivirus/enzimologia , Oligopeptídeos/síntese química , Oligopeptídeos/farmacologia , Inibidores de Serina Proteinase/síntese química , Inibidores de Serina Proteinase/farmacologia , Proteínas não Estruturais Virais/antagonistas & inibidores , Cisteína/química , Cisteína/farmacologia , Relação Estrutura-AtividadeRESUMO
The development of peptidomimetic inhibitors of the human cytomegalovirus (HCMV) protease showing sub-micromolar potency in an enzymatic assay is described. Selective substitution of the amino acid residues of these inhibitors led to the identification of tripeptide inhibitors showing improvements in inhibitor potency of 27-fold relative to inhibitor 39 based upon the natural tetrapeptide sequence. Small side chains at P1 were well tolerated by this enzyme, a fact consistent with previous observations. The S2 binding pocket of HCMV protease was very permissive, tolerating lipophilic and basic residues. The substitutions tried at P3 indicated that a small increase in inhibitor potency could be realized by the substitution of a tert-leucine residue for valine. Substitutions of the N-terminal capping group did not significantly affect inhibitor potency. Pentafluoroethyl ketones, alpha,alpha-difluoro-beta-keto amides, phosphonates and alpha-keto amides were all effective substitutions for the activated carbonyl component and gave inhibitors which were selective for HCMV protease. A slight increase in potency was observed by lengthening the P1' residue of the alpha-keto amide series of inhibitors. This position also tolerated a variety of groups making this a potential site for future modifications which could modulate the physicochemical properties of these molecules.
Assuntos
Antivirais/síntese química , Citomegalovirus/efeitos dos fármacos , Inibidores de Proteases/síntese química , Antivirais/farmacologia , Citomegalovirus/enzimologia , Humanos , Inibidores de Proteases/farmacologia , Relação Estrutura-AtividadeRESUMO
We have been investigating the potential of a new class of antiviral compounds. These peptidomimetic derivatives prevent association of the two subunits of herpes simplex virus (HSV) ribonucleotide reductase (RR), an enzyme necessary for efficient replication of viral DNA. The compounds disclosed in this paper build on our previously published work. Structure-activity studies reveal beneficial modifications that result in improved antiviral potency in cell culture in a murine ocular model of HSV-induced keratitis. These modifications include a stereochemically defined (2,6-dimethylcyclohexyl)amino N-terminus, two ketomethylene amide bond isosteres, and a (1-ethylneopentyl)amino C-terminus. These three modifications led to the preparation of BILD 1351, our most potent antiherpetic agent containing a ureido N-terminus. Incorporation of the C-terminal modification into our inhibitor series based on a (phenylpropionyl)valine N-terminus provided BILD 1357, a significantly more potent antiviral compound than our previously published best compound, BILD 1263.
Assuntos
Antivirais/farmacologia , Dipeptídeos/farmacologia , Inibidores Enzimáticos/farmacologia , Oligopeptídeos/farmacologia , Ribonucleotídeo Redutases/antagonistas & inibidores , Simplexvirus/efeitos dos fármacos , Ureia/análogos & derivados , Animais , Antivirais/química , Células Cultivadas , Dipeptídeos/química , Inibidores Enzimáticos/química , Ceratite Herpética/tratamento farmacológico , Espectroscopia de Ressonância Magnética , Camundongos , Oligopeptídeos/química , Simplexvirus/enzimologia , Estereoisomerismo , Relação Estrutura-Atividade , Ureia/química , Ureia/farmacologiaRESUMO
We have been investigating peptidomimetic inhibitors of herpes simplex virus (HSV) ribonucleotide reductase (RR). These inhibitors bind to the HSV RR large subunit and consequently prevent subunit association and subsequent enzymatic activity. This report introduces a new series of compounds that contain an extra nitrogen (a ureido function) at the inhibitor N-terminus. This nitrogen improves inhibitor binding potency 50-fold over our first published inhibitor series. Evidence supports that this improvement in potency results from a new hydrogen-bonding contact between the inhibitor and the RR large subunit. This report also provides evidence for the bioactive conformation around two important amino acid residues contained in our inhibitors. A tert-butyl group, which contributes 100-fold to inhibitor potency but does not directly bind to the large subunit, favors an extended beta-strand conformation that is prevalent in solution and in the bound state. More significantly, the bioactive conformation around a pyrrolidine-modified asparagine residue, which contributes over 30 000-fold to inhibitor potency, is elucidated through a series of conformationally restricted analogues.