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1.
BMC Med Educ ; 23(1): 403, 2023 Jun 03.
Artigo em Inglês | MEDLINE | ID: mdl-37268934

RESUMO

BACKGROUND: The number of ophthalmologists trained in Brazil has increased, but their satisfaction with the medical residency curriculum is unclear. The purpose of this study is to evaluate the satisfaction and self-confidence of graduates of a reference ophthalmology residency program in Brazil and to analyze whether there is a difference in these parameters among those who graduated in different decades. METHODS: This is a cross-sectional web-based study conducted in 2022 with 379 ophthalmologists who graduated from the Faculty of Medical Sciences of the State University of Campinas (UNICAMP), Brazil. We aim to obtain data on satisfaction and self-confidence in clinical and surgical practices. RESULTS: In total, 158 questionnaires were completed (41.68% response rate); 104 respondents completed their medical residency between 2010 and 2022, 34 between 2000 and 2009, and only 20 before 2000. Most respondents were satisfied or very satisfied with their programs (98.7%). Respondents reported insufficient exposure to low vision rehabilitation (62.7%), toric intraocular implants (60.8%), refractive surgery (55.7%), and orbital trauma surgery (84.8%), particularly among graduates before 2010. They also reported insufficient training in certain non-clinical areas, such as office management (61.4%), health insurance management (88.6%), and personnel and administration skills (74.1%). We found that respondents who graduated a long time ago had higher confidence in clinical and surgical practices. CONCLUSIONS: Brazilian ophthalmology residents and UNICAMP graduates expressed high levels of satisfaction with their residency training programs. Those who completed the program a long time ago appear to have more confidence in clinical and surgical practices. There were clinical and non-clinical areas with insufficient training identified for improvement.


Assuntos
Internato e Residência , Oftalmologia , Humanos , Oftalmologia/educação , Educação de Pós-Graduação em Medicina , Estudos Transversais , Currículo , Inquéritos e Questionários , Satisfação Pessoal , Competência Clínica
2.
Qual Life Res ; 29(7): 1731-1745, 2020 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-32246433

RESUMO

PURPOSE: Individuals with epidermolysis bullosa (EB) present with various clinical manifestations of different severities that affect quality of life (QoL). This systematic review synthesizes the current evidence about the QoL of individuals with EB. METHODS: We included observational studies with people of all age groups, both sexes, and any EB type. Studies with qualitative methodology, chapters of books, meeting proceedings, and abstracts were excluded. RESULTS: In this study, 12 articles comprising 745 individuals were included. More than half of the articles observed lower QoL in individuals with recessive dystrophic EB (RDEB) or junctional EB (JEB). Three articles indicated that EB affected QoL more in women than in men, and one article identified that children with EB suffered more than adults with the disease. Pain was frequently reported. Seven articles identified difficulty in sports, two identified a need for bathing assistance, and three identified eating difficulties. Additionally, participants reported that family relationships and friendships were affected, and they experienced feelings of anxiety and depression. Some of the instruments used evaluated QoL in general dermatologic conditions, and one was specific to EB. CONCLUSION: QoL is more affected in people who have RDEB and JEB. Regarding sex and age, women and children need special care in their monitoring. It is necessary that guidelines on pain management be more disseminated and put into practice. Future studies should use standardized specific instruments to assess the QoL in EB individuals, while considering the particularities of the different age groups.


Assuntos
Epidermólise Bolhosa/psicologia , Qualidade de Vida/psicologia , Estudos Transversais , Feminino , Humanos , Masculino
3.
Br J Dermatol ; 179(1): 42-49, 2018 07.
Artigo em Inglês | MEDLINE | ID: mdl-29168183

RESUMO

Individuals with epidermolysis bullosa (EB) may present with a broad spectrum of growth impairment and multiorgan disorders, with compromised nutritional status and quality of life. The provision of nutrients through a gastrostomy tube may minimize EB-related malnourishment but may also result in skin injuries and infections. In this systematic review we consider the current evidence about the effectiveness of gastrostomy in restoring nutritional status and improving quality of life in patients with EB. Seven studies (n = 146) met selection criteria and patients ranged in age from 6 weeks to 33 years of age. Although it is not a risk-free procedure, the placement of a gastrostomy tube is a feasible and safe alternative to provide nutritional support and to improve the quality of life of patients.


Assuntos
Epidermólise Bolhosa Distrófica/cirurgia , Gastrostomia , Estado Nutricional , Qualidade de Vida , Adolescente , Adulto , Criança , Pré-Escolar , Nutrição Enteral/métodos , Métodos Epidemiológicos , Epidermólise Bolhosa Distrófica/psicologia , Feminino , Humanos , Lactente , Masculino , Desnutrição/prevenção & controle , Desnutrição/psicologia , Adulto Jovem
4.
Eur J Clin Nutr ; 71(10): 1206-1211, 2017 10.
Artigo em Inglês | MEDLINE | ID: mdl-28537577

RESUMO

BACKGROUND/OBJECTIVES: C-reactive protein (CRP) is a marker of inflammation that has been shown to be predictive of cardiovascular diseases in adults. To evaluate the distribution of CRP as well as its association with metabolic syndrome and its components. SUBJECTS/METHODS: This is a cross-sectional study on adolescents aged 12-17, participants in the Study of Cardiovascular Risk in Adolescents (ERICA). Anthropometric, biochemical and blood pressure data were collected from 6316 adolescents, selected from a random sample of students in the cities of Brasilia, Fortaleza, João Pessoa, Manaus, Porto Alegre and Rio de Janeiro. Metabolic syndrome was defined by the criteria proposed by International Diabetes Federation for adolescent. Poisson regression model with robust variance, taking into consideration the study's complex sampling design, was used to determine multivariate-adjusted prevalence rate ratios expressing the relationship of metabolic syndrome with CRP. RESULTS: In adolescents with metabolic syndrome, CRP concentrations were five times higher (1.01 mg/l; interquartile range (IQR): 0.54-3.47) compared with those without metabolic syndrome (0.19 mg/l; IQR: 0.10-0.78). In multivariate Poisson regression analysis adjusted by sex, age and skin color, the prevalence of elevated CRP (>3.0 mg/l) was almost three times higher in adolescents with metabolic syndrome than in those without this condition (prevalence ratio (PR): 2.9; 95%CI: 2.0-4.3; P<0.001). Of the metabolic syndrome components, elevated waist circumference, low high-density lipoprotein-cholesterol and high triglycerides were significantly related to CRP in a graded (dose-response) manner. CONCLUSIONS: The association of CRP with metabolic syndrome and its components suggests that inflammation may be useful in assessing cardiovascular risk in adolescents.


Assuntos
Proteína C-Reativa/metabolismo , Síndrome Metabólica/epidemiologia , Obesidade Infantil/complicações , Adolescente , Serviços de Saúde do Adolescente , Antropometria , Brasil/epidemiologia , Criança , Estudos Transversais , Feminino , Humanos , Masculino , Síndrome Metabólica/sangue , Síndrome Metabólica/complicações , Prevalência , Fatores de Risco , Inquéritos e Questionários
5.
Braz J Med Biol Res ; 50(1): e5630, 2017 Jan 05.
Artigo em Inglês | MEDLINE | ID: mdl-28076453

RESUMO

Previous studies have reported on the glucose and lipid-lowering effects of ferulic acid (FA) but its anti-obesity potential has not yet been firmly established. This study investigated the possible anti-obesitogenic effects of FA in mice fed a high-fat diet (HFD) for 15 weeks. To assess the antiobesity potential of FA, 32 male Swiss mice, weighing 20-25 g (n=6-8 per group) were fed a normal diet (ND) or HFD, treated orally or not with either FA (10 mg/kg) or sibutramine (10 mg/kg) for 15 weeks and at the end of this period, the body weights of animals, visceral fat accumulation, plasma levels of glucose and insulin hormone, amylase and lipase activities, the satiety hormones ghrelin and leptin, and tumor necrosis factor-α (TNF-α) and monocyte chemoattractant protein-1 (MCH-1) were analyzed. Results revealed that FA could effectively suppress the HFD-associated increase in visceral fat accumulation, adipocyte size and body weight gain, similar to sibutramine, the positive control. FA also significantly (P<0.05) decreased the HFD-induced elevations in serum lipid profiles, amylase and lipase activities, and the levels of blood glucose and insulin hormone. The markedly elevated leptin and decreased ghrelin levels seen in HFD-fed control mice were significantly (P<0.05) reversed by FA treatment, almost reaching the values seen in ND-fed mice. Furthermore, FA demonstrated significant (P<0.05) inhibition of serum levels of inflammatory mediators TNF-α, and MCH-1. These results suggest that FA could be beneficial in lowering the risk of HFD-induced obesity via modulation of enzymatic, hormonal and inflammatory responses.


Assuntos
Fármacos Antiobesidade/farmacologia , Ácidos Cumáricos/farmacologia , Ciclobutanos/farmacologia , Gordura Intra-Abdominal/efeitos dos fármacos , Obesidade/tratamento farmacológico , Tecido Adiposo/patologia , Animais , Dieta Hiperlipídica , Modelos Animais de Doenças , Masculino , Camundongos , Obesidade/patologia
6.
Phytomedicine ; 17(10): 740-3, 2010 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-20149612

RESUMO

The anti-inflammatory effect of physalin E, a seco-steroid isolated from Physalis angulata L. was evaluated on acute and chronic models of dermatitis induced by 12-O-tetradecanoyl-phorbol-13-acetate (TPA) and oxazolone, respectively, in mouse ear. The changes in ear edema/thickness, production of pro-inflammatory cytokines (TNF-alpha and IFN-gamma), myeloperoxidase (MPO) activity, and histological and immunohistochemical findings were analysed, as indicators of dermal inflammation. Similar to dexamethasone, topically applied Physalin E (0.125; 0.25 and 0.5 mg/ear) potently inhibited the TPA and oxazolone-induced dermatitis, leading to substantial reductions in ear edema/thickness, pro-inflammatory cytokines, and MPO activity. These effects were reversed by mifepristone, a steroid antagonist and confirmed by immunohistochemical and histopathological analysis. The data suggest that physalin E may be a potent and topically effective anti-inflammatory agent useful to treat the acute and chronic skin inflammatory conditions.


Assuntos
Anti-Inflamatórios/uso terapêutico , Dermatite de Contato/tratamento farmacológico , Physalis/química , Secoesteroides/uso terapêutico , Animais , Imuno-Histoquímica , Masculino , Camundongos , Oxazolona/toxicidade , Acetato de Tetradecanoilforbol/toxicidade
7.
Artigo em Inglês | MEDLINE | ID: mdl-11545362

RESUMO

The use of plants and microorganisms that can naturally volatilize selenium and remove it from the soil or water has been studied with promising results. It has been shown that selenium can be removed from soils by plant uptake and accumulation, plant volatilization, and removal in the rhizosphere. Preliminary studies indicated that Hydrilla verticillata Royle removed selenium by means of phytovolatilization. Therefore, studies were conducted to examine the volatile products produced during phytoremediation of selenium by hydrilla. Samples were obtained and analyzed by GC/MS. Organoselenium compounds found were dimethyl selenide, dimethyl diselenide, and diethyl diselenide.


Assuntos
Plantas , Selênio/análise , Selênio/química , Poluição da Água/prevenção & controle , Biodegradação Ambiental , Monitoramento Ambiental , Cromatografia Gasosa-Espectrometria de Massas , Compostos Orgânicos/análise , Selênio/farmacocinética , Volatilização
8.
Braz. j. med. biol. res ; 34(6): 797-801, Jun. 2001. ilus
Artigo em Inglês | LILACS | ID: lil-285856

RESUMO

In this study, the behavioral and electroencephalographic (EEG) analysis of seizures induced by the intrahippocampal injection in rats of granulitoxin, a neurotoxic peptide from the sea anemone Bunodosoma granulifera, was determined. The first alterations occurred during microinjection of granulitoxin (8 µg) into the dorsal hippocampus and consisted of seizure activity that began in the hippocampus and spread rapidly to the occipital cortex. This activity lasted 20-30 s, and during this period the rats presented immobility. During the first 40-50 min after its administration, three to four other similar short EEG seizure periods occurred and the rats presented the following behavioral alterations: akinesia, facial automatisms, head tremor, salivation, rearing, jumping, barrel-rolling, wet dog shakes and forelimb clonic movements. Within 40-50 min, the status epilepticus was established and lasted 8-12 h. These results are similar to those observed in the acute phase of the pilocarpine model of temporal lobe epilepsy and suggest that granulitoxin may be a useful tool not only to study the sodium channels, but also to develop a new experimental model of status epilepticus.


Assuntos
Animais , Masculino , Ratos , Comportamento Animal/efeitos dos fármacos , Eletroencefalografia/métodos , Neurotoxinas/toxicidade , Peptídeos/toxicidade , Anêmonas-do-Mar , Convulsões/induzido quimicamente , Venenos de Cnidários/toxicidade , Hipocampo/efeitos dos fármacos , Microinjeções , Ratos Wistar , Convulsões/fisiopatologia , Fatores de Tempo
9.
Braz J Med Biol Res ; 34(6): 797-801, 2001 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-11378671

RESUMO

In this study, the behavioral and electroencephalographic (EEG) analysis of seizures induced by the intrahippocampal injection in rats of granulitoxin, a neurotoxic peptide from the sea anemone Bunodosoma granulifera, was determined. The first alterations occurred during microinjection of granulitoxin (8 microg) into the dorsal hippocampus and consisted of seizure activity that began in the hippocampus and spread rapidly to the occipital cortex. This activity lasted 20-30 s, and during this period the rats presented immobility. During the first 40-50 min after its administration, three to four other similar short EEG seizure periods occurred and the rats presented the following behavioral alterations: akinesia, facial automatisms, head tremor, salivation, rearing, jumping, barrel-rolling, wet dog shakes and forelimb clonic movements. Within 40-50 min, the status epilepticus was established and lasted 8-12 h. These results are similar to those observed in the acute phase of the pilocarpine model of temporal lobe epilepsy and suggest that granulitoxin may be a useful tool not only to study the sodium channels, but also to develop a new experimental model of status epilepticus.


Assuntos
Comportamento Animal/efeitos dos fármacos , Eletroencefalografia/efeitos dos fármacos , Neurotoxinas/toxicidade , Peptídeos/toxicidade , Anêmonas-do-Mar , Convulsões/induzido quimicamente , Animais , Venenos de Cnidários/toxicidade , Eletroencefalografia/métodos , Hipocampo/efeitos dos fármacos , Masculino , Microinjeções , Neurotoxinas/administração & dosagem , Peptídeos/administração & dosagem , Ratos , Ratos Wistar , Convulsões/fisiopatologia , Fatores de Tempo
10.
Invest Ophthalmol Vis Sci ; 41(11): 3399-401, 2000 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-11006230

RESUMO

PURPOSE: To evaluate the efficiency of mitomycin C (MMC) in limiting the postoperative inflammatory response and scarring after strabismus surgery. METHODS: A prospective, two-stage, masked, controlled trial was conducted. In the first stage, the inflammatory response at the extraocular muscle reattachment site was increased after inferior rectus recession in eight rabbits. In the second stage, MMC (0.4 mg/ml) was applied during surgery to the eyes of 22 rabbits with inferior rectus recession. As a control, contralateral eyes were treated with saline solution. Seven weeks later, exenteration was performed, and the sites of muscle reattachment were processed for histologic examinations. The sums of the areas of the granulomas in the extraocular muscle reattachment sites of control and treated eyes were compared. RESULTS: There was no significant inhibitory effect of MMC on the inflammatory response of treated eyes compared with that of control eyes. CONCLUSIONS: The intraoperative use of MMC (0.4 mg/ml) was not effective in controlling the postoperative inflammatory response in rabbit eyes after extraocular muscle surgery. These data do not support the hypothesis that MMC reduces postoperative adhesions after strabismus surgery.


Assuntos
Antimetabólitos/uso terapêutico , Granuloma/prevenção & controle , Mitomicina/uso terapêutico , Músculos Oculomotores/patologia , Complicações Pós-Operatórias/prevenção & controle , Estrabismo/cirurgia , Animais , Cicatriz/patologia , Cicatriz/prevenção & controle , Granuloma/patologia , Cuidados Intraoperatórios/métodos , Músculos Oculomotores/cirurgia , Complicações Pós-Operatórias/patologia , Coelhos
11.
Braz J Med Biol Res ; 32(1): 51-4, 1999 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-10347768

RESUMO

A new metalloendopeptidase was purified to apparent homogeneity from a homogenate of normal human liver using successive steps of chromatography on DEAE-cellulose, hydroxyapatite and Sephacryl S-200. The purified enzyme hydrolyzed the Pro7-Phe8 bond of bradykinin and the Ser25-Tyr26 bond of atrial natriuretic peptide. No cleavage was produced in other peptide hormones such as vasopressin, oxytocin or Met- and Leu-enkephalin. This enzyme activity was inhibited by 1 mM divalent cation chelators such as EDTA, EGTA and o-phenanthroline and was insensitive to 1 microM phosphoramidon and captopril, specific inhibitors of neutral endopeptidase (EC 3.4.24.11) and angiotensin-converting enzyme (EC 3.4.15.1), respectively. With M(r) 85 kDa the enzyme exhibits optimal activity at pH 7.5. The high affinity of this endopeptidase for bradykinin (Km = 10 microM) and for atrial natriuretic peptide (Km = 5 microM) suggests that it may play a physiological role in the inactivation of these circulating hypotensive peptide hormones.


Assuntos
Fator Natriurético Atrial/metabolismo , Bradicinina/metabolismo , Fígado/enzimologia , Metaloendopeptidases/isolamento & purificação , Metaloendopeptidases/metabolismo , Adulto , Ativação Enzimática , Humanos
12.
Braz. j. med. biol. res ; 32(1): 51-4, Jan. 1999. ilus, tab
Artigo em Inglês | LILACS | ID: lil-226212

RESUMO

A new metalloendopeptidase was purified to apparent homogeneity from a homogenate of normal human liver using successive steps of chromatography on DEAE-cellulose, hydroxyapatite and Sephacryl S-200. The purified enzyme hydrolyzed the Pro7-Phe8 bond of bradykinin and the Ser25-Tyr26 bond of atrial natriuretic peptide. No cleavage was produced in other peptide hormones such as vasopressin, oxytocin or Met- and Leu-enkephalin. This enzyme activity was inhibited by 1 mM divalent cation chelators such as EDTA, EGTA and o-phenanthroline and was insensitive to 1 µM phosphoramidon and captopril, specific inhibitors of neutral endopeptidase (EC 3.4.24.11) and angiotensin-converting enzyme (EC 3.4.15.1), respectively. With Mr 85 kDa, the enzyme exhibits optimal activity at pH 7.5. The high affinity of this endopeptidase for bradykinin (Km = 10 µM) and for atrial natriuretic peptide (Km = 5 µM) suggests that it may play a physiological role in the inactivation of these circulating hypotensive peptide hormones


Assuntos
Humanos , Adulto , Fator Natriurético Atrial/metabolismo , Bradicinina/metabolismo , Fígado/enzimologia , Metaloproteases/isolamento & purificação , Metaloproteases/metabolismo , Ativação Enzimática
13.
Binocul Vis Strabismus Q ; 13(3): 181-4, 1998.
Artigo em Inglês | MEDLINE | ID: mdl-9780414

RESUMO

PURPOSE: To determine the effectiveness of grading such surgery according to the magnitude of the V pattern and inferior oblique muscle overaction (IOOA). METHODS: We retrospectively reviewed all 53 cases we operated since 1984 for V pattern with IOOA, who had undergone graded inferior oblique recession, recessed according to the anatomical recession table of Apt and Call, ranging from 8mm for V pattern of 12 PD with +1 IOOA to 12mm for 30+ PD with +3 IOOA. RESULTS: A "satisfactory outcome" (defined as = V pattern of 8 PD or less) was observed in 75% of the cases with a preoperative V pattern less than 20 PD, in 70% of those with a preop' V pattern between 20 PD and 29 PD, and in 57% of those with a preop' V pattern greater than 29 PD. There were no overcorrections. All unsatisfactory outcomes were undercorrections. CONCLUSIONS: The principle of grading this surgery is supported and affirmed by these results. However, the results also suggest a need to increase the amount of surgery for all categories and add anterior transposition for larger V patterns.


Assuntos
Músculos Oculomotores/cirurgia , Estrabismo/cirurgia , Adolescente , Adulto , Criança , Pré-Escolar , Humanos , Lactente , Estudos Retrospectivos , Resultado do Tratamento
14.
Braz. j. med. biol. res ; 31(10): 1335-8, Oct. 1998. ilus
Artigo em Inglês | LILACS | ID: lil-223996

RESUMO

A neurotoxic peptide, granulitoxin (GRX), was isolated from the sea anemone Bunodosoma granulifera. The N-terminal amino acid sequence of GRX is AKTGILDSDGPTVAGNSLSGT and its molecular mass is 4958 Da by electrospray mass spectrometry. This sequence presents a partial degree of homology with other toxins from sea anemones such as Bunodosoma caissarum, Anthopleura fuscoviridis and Anemonia sulcata. However, important differences were found: the first six amino acids of the sequence are different, Arg-14 was replaced by Ala and no cysteine residues were present in the partial sequence, while two cysteine residues were present in the first 21 amino acids of other toxins described above. Purified GRX injected ip (800 µg/kg) into mice produced severe neurotoxic effects such as circular movements, aggressive behavior, dyspnea, tonic-clonic convulsion and death. The 2-h LD50 of GRX was 400 ñ 83 µg/kg


Assuntos
Animais , Camundongos , Neurotoxinas/química , Peptídeos/toxicidade , Anêmonas-do-Mar , Sequência de Aminoácidos , Venenos de Cnidários
15.
J Pediatr Ophthalmol Strabismus ; 35(3): 162-5, 1998.
Artigo em Inglês | MEDLINE | ID: mdl-9627878

RESUMO

BACKGROUND: Assessment of the causes of childhood blindness is important to develop preventive and therapeutic strategies that can reduce the incidence of visual impairment. METHODS: A retrospective survey of the clinical records of 395 consecutive children younger than 14 years of age who were attended by the Low Vision Service of State University of Campinas (UNICAMP) was conducted. Data on the age distribution, the causes of low vision, the types of low vision aids prescribed, the follow up of their use, and improvement in visual acuity were obtained. RESULTS: Congenital bilateral toxoplasmic macular scars, optic atrophy, and congenital cataracts were the major causes of low vision in this population. The optical aid most frequently prescribed was a telescope. The improvement of visual acuity with the use of aids was highly significant.


Assuntos
Baixa Visão/epidemiologia , Pessoas com Deficiência Visual/estatística & dados numéricos , Adolescente , Distribuição por Idade , Catarata/complicações , Catarata/congênito , Criança , Pré-Escolar , Óculos , Seguimentos , Humanos , Incidência , Lactente , Atrofias Ópticas Hereditárias/complicações , Prescrições , Prognóstico , Estudos Retrospectivos , Toxoplasmose Congênita/complicações , Baixa Visão/etiologia , Baixa Visão/reabilitação , Acuidade Visual
16.
Braz J Med Biol Res ; 31(10): 1335-8, 1998 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-9876306

RESUMO

A neurotoxic peptide, granulitoxin (GRX), was isolated from the sea anemone Bunodosoma granulifera. The N-terminal amino acid sequence of GRX is AKTGILDSDGPTVAGNSLSGT and its molecular mass is 4958 Da by electrospray mass spectrometry. This sequence presents a partial degree of homology with other toxins from sea anemones such as Bunodosoma caissarum, Anthopleura fuscoviridis and Anemonia sulcata. However, important differences were found: the first six amino acids of the sequence are different, Arg-14 was replaced by Ala and no cysteine residues were present in the partial sequence, while two cysteine residues were present in the first 21 amino acids of the other toxins described above. Purified GRX injected i.p. (800 micrograms/kg) into mice produced severe neurotoxic effects such as circular movements, aggressive behavior, dyspnea, tonic-clonic convulsion and death. The 2-h LD50 of GRX was 400 +/- 83 micrograms/kg.


Assuntos
Neurotoxinas/química , Neurotoxinas/toxicidade , Peptídeos/toxicidade , Anêmonas-do-Mar , Sequência de Aminoácidos , Animais , Venenos de Cnidários , Camundongos , Dados de Sequência Molecular
17.
Braz. j. med. biol. res ; 30(10): 1153-6, Oct. 1997. tab, graf
Artigo em Inglês | LILACS | ID: lil-201530

RESUMO

A new metalloendopeptidase was purified to apparent homogeneity from a homogenate of normal human brain using successive steps of chromatography on DEAE-Trisacryl, hydroxylapatite and Sephacryl S-200. The purified enzyme cleaved the Gly(33)-Leu(34) bond of the 25-35 neurotoxic sequence of the Alzheimer Beta-amyloid 1-40 peptide producing soluble fragments without neurotoxic effects. This enzyme activity was only inhibited by divalent cation chelators such as EDTA, AGTA and o-phenanthroline (1 mM) and was insensitive to phosphoramidon and captopril (1 muM concentration), specific inhibitors of neutral endopeptidase (EC 3.4.24.11) and angiotensin-converting enzyme (EC 3.4.15.1), respectively. The high affinity of this human brain endopeptidase for Beta-amyloid 1-40 peptide (Km = 5 muM) suggests that it may play a physiological role in the degradation of this substance produced by normal cellular metabolism. It may also be hypothesized that the abnormal accumulation of the amyloid Beta-protein in Alzheimer´s disease may be initiated by a defect or an inactivation of this enzyme.


Assuntos
Adulto , Humanos , Doença de Alzheimer/fisiopatologia , Peptídeos beta-Amiloides , Encéfalo/enzimologia , Endopeptidases/análise , Técnicas In Vitro
18.
Braz. j. med. biol. res ; 30(10): 1157-62, Oct. 1997. ilus, tab
Artigo em Inglês | LILACS | ID: lil-201531

RESUMO

Two intramolecularly quenched fluorogenic peptides containing oaminobenzoyl (Abz) and ethylenediamine 2,4-dinitrophenyl (EDDnp) groups at amino- and carboxyl-terminal amino acid rsidues, Abz-Darg-Arg-Leu-EDDnp (Abz-DRRL-EDDnp) and Abz-DArg-Arg-Phe-EDDnp (Abz-DRRF-EDDnp), were selectively hydrolyzed by neutral endopeptidase (NEP, enkephalinase, neprilysin, EC 3.4.24.11) at the Arg-Leu and Arg-Phe bonds, respectively. The kinetic parameters for the NEP-catalyzed hydrolysis of Abz-DRRL-EDDnp and Abz-DRRF-EDDnp were Km = 2.8muM, Kcat = 5.3 min-1, Kcat/Km = 2 min-1 muM-1 and Km = 5.0 muM, Kcat = 7.0 min-1, Kcat/Km = 1.4 min-1 muM-1, respectively. The high specificity of these substrates was demonstrated by their resistance to hydrolysis by metalloproteases [thermolysin (EC 3.4.24.2), angiotensin-converting enzyme (ACE;EC 3.4.24.15)], serineproteases [trypsin (EC 3.4.21.4), alpha-chymotrypsin (EC 3.4.21.1)] and proteases present in tissue homogenates from kidney, lung, brain and testis. The blocked amino- and carboxyl-terminal amino acids protected these substrates against the action of aminopeptidases, carboxypeptidases and ACE. Furthermore, DR amino acids ensured total protection of Abz-DRRL-EDDnp and Abz-DRRF-EDDnp against the action of thermolysin and trypsin. Leu-EDDnp and Phe-EDDnp were resistant to hydrolysis by alpha-chymotrypsin. The high specifity of these substrates suggests their use for specific NEP assays in crude enzyme preparations.


Assuntos
Ratos , Animais , Técnicas In Vitro , Metaloproteases , Neprilisina/fisiologia , Serina Proteases , Substratos para Tratamento Biológico
19.
Braz J Med Biol Res ; 30(2): 187-90, 1997 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-9239303

RESUMO

We have studied the metabolism of diglycine and triglycine in the isolated non-filtering rat kidney. Kidneys from adult male Wistar Kyoto rats weighing 250-350 g were perfused with Krebs-Henseleit solution containing either 1 mM diglycine or triglycine. The analysis of the peptide residues and their components was performed using an amino acid microanalyzer utilizing ion exchange chromatography. Diglycine was degraded to a final concentration of 0.09 mM after 120 min (91%); this degradation occurred predominantly during the first hour, with a 56% reduction of the initial concentration. The metabolism of triglycine occurred similarly, with a final concentration of 0.18 mM (82%); during the first hour there was a 67% reduction of the initial concentration of the tripeptide. Both peptides produced glycine in increasing concentrations, but there was a slightly lower recovery of glycine, suggesting its utilization by the kidney as fuel. The hydrolysis of triglycine also produced diglycine, which was also hydrolyzed to glycine. The results of the present study show the existence of functional endothelial or contraluminal membrane peptidases which may be important during parenteral nutrition.


Assuntos
Glicilglicina/metabolismo , Oligopeptídeos/metabolismo , Insuficiência Renal/metabolismo , Animais , Masculino , Ratos , Ratos Wistar
20.
Braz. j. med. biol. res ; 30(2): 187-90, Feb. 1997. tab, graf
Artigo em Inglês | LILACS | ID: lil-188425

RESUMO

We have studied the metabolism of diglycine and triglycine in the isolated non-filtering rat kidney. Kidneys from adult male Wistar Kyoto rats weighing 250-350 g were perfused with Krebs-Henseleit solution containing either 1 mM diglycine or triglycine. The analysis of the peptide residues and their components was performed using an amino acid microanalyzer utilizing ion exchange chromatography. Diglycine was degraded to a final concentration of 0.09 mM after 120 min (91 per cent); this degradation occurred predominantly during the first hour, with a 56 per cent reduction of the initial concentration. The metabolism of triglycine occurred similarly, with a final concentration of 0.18 mM (82 per cent); during the first hour there was a 67 per cent reduction of the initial concentration of the tripeptide. Both peptides produced glycine in increasing concentrations, but there was a slightly lower recovery of glycine, suggesting its utilization by the kidney as fuel. The hydrolysis of triglycine also produced diglycine, which was also hydrolyzed to glycine. The results of the present study show the existence of functional endothelial or contraluminal membrane peptidases which may be important during parenteral nutrition.


Assuntos
Ratos , Animais , Masculino , Dipeptídeos/metabolismo , Glicina/metabolismo , Insuficiência Renal/metabolismo , Cromatografia , Glicina/análogos & derivados , Ratos Wistar
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