RESUMO
OBJECTIVES: Non-infectious aortitis often presents with non-specific symptoms leading to inappropriate diagnostic delay. We intend to describe the clinical spectrum and outcome of patients with aortitis diagnosed at a single centre. METHODS: We reviewed the clinical charts of patients diagnosed with non-infectious aortitis between January 2010 and December 2013 at the Rheumatology Division from a 1.000-bed tertiary teaching hospital from Northern Spain. The diagnosis of aortitis was usually based on FDG-PET-CT scan, and also occasionally on CT or MRI angiography or helical CT-scan. RESULTS: During the period of assessment 32 patients (22 women and 10 men; mean age 68 years [range, 45-87]) were diagnosed with aortitis. The median interval from the onset of symptoms to the diagnosis was 21 months. FDG-PET CT scan was the most common tool used for the diagnosis of aortitis. The underlying conditions were the following: giant cell arteritis (n=13 cases); isolated polymyalgia rheumatica (PMR) (n=11); Sjögren's syndrome (n=2), Takayasu arteritis (n= 1); sarcoidosis (n=1), ulcerative colitis (n=1), psoriatic arthritis (n=1), and large-vessel vasculitis that also involved the aorta (n=2). The most common clinical manifestations at diagnosis were: PMR features, often with atypical clinical presentation (n=23 patients, 72%); diffuse lower limb pain (n=16 patients, 50%); constitutional symptoms (n=12 patients, 37%), inflammatory low back pain (n=9 patients, 28%) and fever (n=7 patients, 22%). Acute phase reactants were increased in most cases (median erythrocyte sedimentation rate 46 mm/1st hour, and a median serum C-reactive protein 1.5 mg/dL). CONCLUSIONS: Aortitis is not an uncommon condition. The diagnosis is often delayed. Atypical PMR features, unexplained low back or limb pain, constitutional symptoms along with increased acute phase reactants should be considered 'red flags' to suspect the presence of aortitis.
Assuntos
Aorta/patologia , Aortite/diagnóstico , Idoso , Idoso de 80 Anos ou mais , Aorta/diagnóstico por imagem , Aortite/etiologia , Aortografia , Artrite Psoriásica/complicações , Sedimentação Sanguínea , Proteína C-Reativa/metabolismo , Estudos de Coortes , Colite Ulcerativa/complicações , Diagnóstico Tardio , Feminino , Fluordesoxiglucose F18 , Tomografia Computadorizada Quadridimensional , Arterite de Células Gigantes/complicações , Humanos , Angiografia por Ressonância Magnética , Masculino , Pessoa de Meia-Idade , Imagem Multimodal , Polimialgia Reumática/complicações , Tomografia por Emissão de Pósitrons , Compostos Radiofarmacêuticos , Estudos Retrospectivos , Sarcoidose/complicações , Síndrome de Sjogren/complicações , Arterite de Takayasu/complicações , Centros de Atenção TerciáriaRESUMO
OBJECTIVES: Henoch-Schönlein purpura nephritis (HSPN) and IgA nephropathy (IgAN) are related syndromes. In the present study we aimed to compare the clinical characteristics and outcome of a large and unselected series of patients diagnosed as having HSPN and IgAN. METHODS: Comparative study of a wide and unselected population of HSPN (142 patient) and IgAN (61 patients) from a teaching hospital of Northern Spain. RESULTS: All of the following comparisons were expressed between HSPN vs. IgAN, respectively. HSPN patients were younger (30.6±26.4 vs. 37.1±16.5 years, p<0.001). Precipitating events, usually an upper respiratory tract infection and/or drug intake, were more frequently observed in HSPN (38% vs. 23%, p=0.03). Extra-renal manifestations were also more common in HSPN than in IgAN; skin lesions (100% vs. 1.8%; p<0.001), gastrointestinal (62% vs. 7.4%; p<0.001), and joint involvement (61.3% vs. 3.6%; p<0.001). However, nephritis was less severe in HSPN, renal insufficiency (25% in HSPN vs. 63.4% in IgAN; p<0.001), nephrotic syndrome (12.5%, vs. 43.7%; p<0.001), and nephritic syndrome (6.8% vs. 10.7%; NS). Leukocytosis was more frequent in HSPN (22.5% vs. 8.2%; p=0.015) and anaemia in IgAN (12.7% in HSPN vs. 36% in IgAN, p<0.001). The frequency of corticosteroid (79.6% vs. 69%; NS) and cytotoxic drug (19% vs. 16.5%, NS) use was similar. The frequency of relapses was similar (38.6% in HSPN vs. 36.3% in IgAN). After a median follow-up of 120.8 (IQR; 110-132) months in HSPN and 138.6 (IQR; 117-156) in IgAN, requirement for dialysis (2.9% vs. 43.5%; p<0.001), renal transplant (0% vs. 36%, p<0.001) and residual chronic renal insufficiency (4.9% vs. 63.8%; p<0.001) was more frequently observed in patients with in IgAN. CONCLUSIONS: HSPN and IgAN represent different syndromes. IgAN has more severe renal involvement while HSPN is associated with more extra-renal manifestations.
Assuntos
Glomerulonefrite por IGA/complicações , Vasculite por IgA/complicações , Rim/patologia , Nefrite/etiologia , Adolescente , Corticosteroides/uso terapêutico , Adulto , Idoso , Idoso de 80 Anos ou mais , Biomarcadores/sangue , Biópsia , Criança , Pré-Escolar , Progressão da Doença , Imunofluorescência , Glomerulonefrite por IGA/imunologia , Glomerulonefrite por IGA/terapia , Hospitais de Ensino , Humanos , Vasculite por IgA/diagnóstico , Vasculite por IgA/imunologia , Vasculite por IgA/terapia , Imunossupressores/uso terapêutico , Rim/imunologia , Transplante de Rim , Pessoa de Meia-Idade , Nefrite/diagnóstico , Nefrite/imunologia , Nefrite/terapia , Valor Preditivo dos Testes , Indução de Remissão , Diálise Renal , Estudos Retrospectivos , Espanha , Fatores de Tempo , Resultado do Tratamento , Adulto JovemRESUMO
Endometriosis is associated with a number of immunologic alterations. It has been suggested that autoimmune disorders could be more frequent in patients with endometriosis. The aim of this study is to ascertain whether the prevalence of two well-known autoimmune diseases [systemic lupus erythematosus (SLE) and Sjögren's syndrome (SS)] is increased in women with endometriosis. The clinical charts of four different populations assisted at the same hospital were manually revised: (i) SLE population (n = 120), (ii) SS (n = 22), (iii) endometriosis (n = 342) and (iv) control population (n = 501 consecutive unselected asymptomatic women). Among SLE women, the prevalence of endometriosis was 1.67% (2/120), similar to the 4.39% prevalence of the control group (22/501), the OR being 0.37 [95%CI 0.09-1.59]. Among SS women, the prevalence of endometriosis was 9.09 (2/22), also similar to the control group OR 2.17 [95%CI 0.48-9.90]. In the same way, when comparing endometriosis cases with asymptomatic women, similar frequencies of SLE (0.58% and 0.2%) and SS were found (0% and 0%). Women with endometriosis do not have an increased prevalence of SLE or SS.
Assuntos
Endometriose/epidemiologia , Lúpus Eritematoso Sistêmico/epidemiologia , Síndrome de Sjogren/epidemiologia , Adulto , Fatores Etários , Endometriose/complicações , Feminino , Humanos , Lúpus Eritematoso Sistêmico/complicações , Lúpus Eritematoso Sistêmico/fisiopatologia , Prontuários Médicos , Pessoa de Meia-Idade , Prevalência , Estudos Retrospectivos , Índice de Gravidade de Doença , Síndrome de Sjogren/complicaçõesRESUMO
A semi-industrial process (800-l fermentor) for lycopene production by mated fermentation of Blakeslea trispora plus (+) and minus (-) strains has been developed. The culture medium was designed at the flask scale, using a program based on a genetic algorithm; and a fermentation process by means of this medium was developed. Fermentation involves separate vegetative phases for (+) and (-) strains and inoculation of the production medium with a mix of both together. Feeding with imidazole or pyridine, molecules known to inhibit lycopene cyclase enzymatic activity, enhanced lycopene accumulation. Different raw materials and physical parameters, including dissolved oxygen, stirring speed, air flow rate, temperature, and pH, were checked in the fermentor to get maximum lycopene production. Typical data for the fermentation process are presented and discussed. This technology can be easily scaled-up to an industrial application for the production of this carotenoid nowadays widely in demand.
Assuntos
Carotenoides/biossíntese , Cruzamentos Genéticos , Fungos/metabolismo , Reatores Biológicos , Biotecnologia/métodos , Fermentação , Fungos/genética , Licopeno , Oxigênio/metabolismoRESUMO
The chromatographic behaviour of binary and ternary mixtures of several phenethylamines (phenylephrine, phenylpropanolamine, ephedrine, pseudoephedrine and methoxyphenamine) and antihistamines (pheniramine, carbinoxamine, doxylamine, chlorpheniramine, dexchlorpheniramine, dexbrompheniramine, diphenhydramine, tripolidine, azatadine and phenyltoloxamine), found in cough-cold pharmaceutical preparations, was studied using C8, C18 and cyano columns, micellar mobile phases of sodium dodecyl sulfate (SDS) and pentanol and UV detection. Using a C8 column and mobile phases of 0.05 mol l-1 SDS-6% v/v pentanol or 0.15 mol l-1 SDS-2% v/v pentanol at pH 7, more than 30 different phenethylamine-antihistamine combinations can be resolved in < 15 min. Intra- and inter-day repeatabilities and reproducibilities evaluated at three different drug concentrations (0.5, 5 and 25 micrograms ml-1, n = 10) were below 1.6, 2.5 and 2.4%, respectively. The drug amounts found in 18 formulations agreed with those declared by the manufacturers within the tolerance limits, and with those obtained using a mobile phase of 55% v/v methanol at pH 7. No interference was observed from other accompanying drugs such as acetylsalicylic acid, ascorbic acid, betamethasone, bromhexine, caffeine, codeine, dextromethorphan, paracetamol, prednisolone, salicylamide and tartrazine. The proposed procedure has the advantage over the conventional aqueous-organic procedure of using a small amount of organic solvent, which is highly retained in the SDS solution. The efficiencies are also greater. On the other hand, in the micellar system, the retentions of phenethylamines and antihistamines are similar, although the compounds can be easily resolved. In contrast, using the methanol-water mobile phase, the phenethylamines are weakly retained, whereas the antihistamines usually show a high retention.
Assuntos
Antagonistas dos Receptores Histamínicos H1/análise , Descongestionantes Nasais/análise , Fenetilaminas/análise , Cromatografia , Antagonistas dos Receptores Histamínicos H1/química , Descongestionantes Nasais/química , Fenetilaminas/química , Sensibilidade e EspecificidadeRESUMO
BACKGROUND: The genus Salmonella is one of the main causes of foodborne and waterborne illness worldwide. It is a major public health concern almost entirely due to S. enteritidis. However, outbreaks caused by Salmonella ohio are rare. We have not found any reference about salmonellosis by S. ohio whose origin was water of a drinking fountain. METHODS: An epidemiological survey was carried out to investigate the origin of the outbreak, and information was sought on personal details, symptoms, contact with others who had ill as well as a history of eating. Fecal specimens and water samples were cultured for bacterial pathogens including Salmonella. Salmonella isolates obtained were characterized by stereotyping. RESULTS: A total of 101 persons were exposed. 87 of these were interviewed, but only 59 of these were affected (attack rate: 67.8%), including 56 children and 3 adults. Syndrome was not severe, in general, persisting for a period of 2 days, in average. S. ohio was isolated from the water and from 2 of the 13 stool specimens analysed. CONCLUSIONS: The outbreak was caused by consumption of water from a drinking fountain which was contaminated by S. ohio. This fountain had not a chlorination system. An outbreak due to S. ohio whose origin is the consumption of water from a drinking fountain is described for the first time in this paper. It can be concluded the importance of keeping a good epidemiological control system to investigate and prevent outbreaks. The control of drinking fountains is also important, to prevent its contamination.
Assuntos
Surtos de Doenças , Gastroenterite/microbiologia , Infecções por Salmonella/epidemiologia , Salmonella/isolamento & purificação , Microbiologia da Água , Abastecimento de Água , Adulto , Pré-Escolar , Fezes/microbiologia , Feminino , Humanos , Masculino , Saúde da População Rural , Infecções por Salmonella/microbiologia , Infecções por Salmonella/transmissão , Espanha/epidemiologiaRESUMO
The primary structure of recombinant human (h) insulin-like growth factor-I (IGF-I) epitopes recognized by a panel of 28 monoclonal antibodies (mAbs) is characterized. Pairwise mAb epitope mapping defines eight 'epitopic clusters' (I-VIII) which cover nearly the entire solvent-exposed IGF-I surface. Monoclonal antibody reactivity with 32 overlapping synthetic peptides and with IGF-I mutants is used to associate these epitopic clusters with the probable primary IGF-I sequences recognized. Epitopic cluster I involves residues in the C-domain and the first alpha-helix of the A-domain; clusters II, V and VII involve principally the B-domain; clusters III and IV map to amino acid sequences (55-70) and (1-13) respectively; cluster VI includes the A- and B-domains; and cluster VIII involves mainly the C-terminal part of the B-domain. Data indicate that this mAb panel defines 14 distinct IGF-I epitopes. The specific inhibition of HEL 92.1.7 IGF-I-promoted proliferation by these mAbs was explored. Direct correlation between mAb affinity and inhibitory activity was observed except in the case of clusters III- and VIII-specific mAbs. Finally, the combination of epitopic cluster I and II mAbs detect 0.5-10 ng/ml hIGF-I in a sandwich immunoassay, with no IGF-II crossreactivity. These anti-IGF-I mAbs are, therefore, useful for both the inhibition of IGF-I mitogenic activity and for the quantification of this growth factor. The potential use of this mAb panel in tumor cell growth control is discussed.
Assuntos
Anticorpos Monoclonais , Mapeamento de Epitopos , Fator de Crescimento Insulin-Like I/imunologia , HumanosRESUMO
OBJECTIVE: To estimate the prevalence of safety-belt use in a telephone survey and an observational survey. PATIENTS AND METHODS: Observational survey. Trained interviewers studied 4,067 front-seat occupants, at ten intersections of Madrid, according to "National Highway Traffic Safety Administration" guidelines. TELEPHONE SURVEY: We selected 433 front seat occupants from the Madrid city residential telephone directory. The questionnaire was completed by trained interviewers. RESULTS: Prevalence by the observational survey was 58.5%, and was significantly higher at interurban intersections (OR = 2.1) than city intersections. In the telephone survey, the overall prevalence was 94% at interurban area and 64% at city area and it was associated with no history of lines and positive opinion of effectiveness of safety belts. CONCLUSIONS: The safety belt prevalence observed is low, especially in the urban area. The telephone survey overestimates the safety belt use, but contributes with useful information for planning strategies.
Assuntos
Cintos de Segurança/estatística & dados numéricos , Adulto , Fatores Etários , Coleta de Dados , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Fatores Sexuais , Espanha , Inquéritos e Questionários , TelefoneRESUMO
BACKGROUND: The description of a community measles epidemic and the activities developed to control the same is presented. Vaccination efficacy was studied by a cases and controls study. METHODS: The study period of the epidemic was from August 1994 to March 1995 and the intervention was performed from January to March 1995. The activities were developed in two phases: the first directed at a descriptive study and control of the outbreak and in the second phase a cases and controls study was designed to evaluate vaccination efficacy (VE%) versus measles. RESULTS: A total of 325 cases of measles were registered over a period of 29 weeks. The greatest attack rate was found in the age group of 5 to 9 years with 5-91 cases/100. The surveillance system and the priorization of activities protocol designed for control of the outbreak were found to be useful. The result of the cases and controls study demonstrated VE% to be 93.5% (84.3-97.3%). CONCLUSIONS: Rapid intervention in the outbreaks of measles is considered fundamental to avoid propagation of the same among the susceptible population. The surveillance system versus the disease should therefore be optimized. Although vaccination efficacy was found to be good, the high rates of attack found in the theoretically vaccinated groups lead to the recommendation of the introduction of a second dosis of the vaccine and to vaccinate the existing non vaccinated sets.
Assuntos
Surtos de Doenças , Vacina contra Sarampo , Sarampo/epidemiologia , Sarampo/prevenção & controle , Adolescente , Adulto , Estudos de Casos e Controles , Criança , Pré-Escolar , Feminino , Humanos , Lactente , Masculino , Avaliação de Programas e Projetos de Saúde , Estudos Retrospectivos , Espanha/epidemiologiaRESUMO
BACKGROUND: The aim of this study was to describe an epidemic outbreak of mass hysteria among adolescents which occurred after the immunisation with vaccine against hepatitis B and to determine the association with social variables related to the students. SUBJECTS AND METHODS: All the available information was evaluated and a questionnaire was designed, which included sociodemographic, clinics and school environment variables. A case-control study was conducted. The data were analyzed and outbreak rate and odds ratio with their respective CI (95%) were calculated. RESULTS: 18 cases (among a set of 74 students of seventh of EGB) were clustered in time (10.30-11 h) and space (class of seventh B). There was a clear association between the cases and the female sex (odds ratio = 5.4; CI 95% 1.3 - 23.8). As for the sociological variables there was a association with increasing household members (odds ratio = 5.3; CI 95% 1.3 - 23.4) and with lower educational levels of the father (odds ratio = 10.6; CI 95% 1.2 - 239.9). Among the affected a more unfavorable opinion of the school was detected. CONCLUSIONS: This outbreak fulfils 8 of the 11 criteria classically admitted as usual characteristics of a mass psychogenic illness episode. The sensorial transmission remains demonstrated supporting the hypothesis of a chain reaction.
Assuntos
Surtos de Doenças , Vacinas contra Hepatite B , Histeria/epidemiologia , Vacinação , Adolescente , Fatores Etários , Análise por Conglomerados , Feminino , Humanos , Histeria/etiologia , Masculino , Razão de Chances , Fatores Sexuais , Fatores Socioeconômicos , Espanha/epidemiologia , Inquéritos e QuestionáriosAssuntos
Infecções Oportunistas Relacionadas com a AIDS/transmissão , Infecção Hospitalar , Resistência Microbiana a Medicamentos , Resistência a Múltiplos Medicamentos , Mycobacterium tuberculosis/efeitos dos fármacos , Tuberculose/transmissão , Infecções Oportunistas Relacionadas com a AIDS/epidemiologia , Infecções Oportunistas Relacionadas com a AIDS/microbiologia , Adulto , DNA Bacteriano/análise , Feminino , Humanos , Transmissão de Doença Infecciosa do Paciente para o Profissional , Isoniazida/uso terapêutico , Masculino , Mycobacterium tuberculosis/genética , Mycobacterium tuberculosis/isolamento & purificação , Rifampina/uso terapêutico , Espanha/epidemiologia , Tuberculose/tratamento farmacológico , Tuberculose/epidemiologia , Tuberculose/microbiologiaRESUMO
The 8-37 fragment of human calcitonin gene-related peptide [(8-37)hCGRP] antagonizes the effects of calcitonin gene-related peptide (CGRP) and amylin in a number of tissues. We have studied the influence of (8-37)hCGRP on the effects of both CGRP and amylin on insulin secretion. In the perfused rat pancreas, homologous CGRP and amylin, at 75 pM, exerted comparable inhibitory effects on the insulin response to 9 mM glucose (ca. 70%; P < 0.025). These effects were antagonized by (8-37)hCGRP (1 microM). Our results suggest that CGRP and amylin act on the B-cell, at least in part, through a common receptor.
Assuntos
Amiloide/farmacologia , Peptídeo Relacionado com Gene de Calcitonina/farmacologia , Glucose/antagonistas & inibidores , Insulina/metabolismo , Pâncreas/efeitos dos fármacos , Fragmentos de Peptídeos/farmacologia , Amiloide/antagonistas & inibidores , Animais , Peptídeo Relacionado com Gene de Calcitonina/antagonistas & inibidores , Secreção de Insulina , Polipeptídeo Amiloide das Ilhotas Pancreáticas , Masculino , Pâncreas/metabolismo , Perfusão , Ratos , Ratos WistarRESUMO
Islet amyloid polypeptide (IAPP), also called amylin, has been localized in the B-cell secretory granule and is co-secreted with insulin. We have investigated the effect of synthetic amidated rat amylin on the insulin release evoked by 9 mM glucose in the isolated, perfused rat pancreas. Amylin, in a range of 75 nM-75 pM, significantly inhibited this insulin response in a dose-dependent manner. The correlation between the logarithm of amylin concentrations and the percentages of inhibition was highly significant (r = 0.98, P < 0.01). The lowest effective amylin concentration tested (75 pM) is within the range of amylin levels reported for the effluent of the perfused rat pancreas. Finally, pre-infusion of the rat pancreas with a high amylin concentration (75 nM) did not alter the insulin response to glucose, thus excluding a toxic effect of amylin on the B-cell. These observations support the concept that amylin plays a role in the control of insulin secretion.
Assuntos
Amiloide/farmacologia , Insulina/metabolismo , Ilhotas Pancreáticas/efeitos dos fármacos , Animais , Relação Dose-Resposta a Droga , Glucose/farmacologia , Técnicas In Vitro , Secreção de Insulina , Polipeptídeo Amiloide das Ilhotas Pancreáticas , Ilhotas Pancreáticas/metabolismo , Masculino , Ratos , Ratos WistarRESUMO
Pancreatic polypeptide (PP) secretory cells are abundant in the islets of Langerhans. Results concerning the effects of exogenous PP on islet-cell secretion are controversial. This might be due in part to species specificity, given that most reports refer to studies performed using PP of bovine, porcine, or human origin in a heterologous animal model. Thus, we have investigated the influence of synthetic rat PP (80 nmol/L) on unstimulated insulin, glucagon, and somatostatin release, and on the responses of these hormones to glucose (11 mmol/L) and to arginine (3.5 mmol/L) in a homologous animal model, the perfused rat pancreas. Infusion of rat PP (rPP) reduced unstimulated insulin release by 35% (P = .03), and the insulin responses to glucose by 65% (P = .029) and to arginine by 50% (P = .026), without modifying glucagon output. rPP did not affect somatostatin secretion, either in unstimulated conditions or in the presence of 11 mmol/L glucose. However, it induced a clear-cut increase in somatostatin release during 3.5 mmol/L arginine infusion. Our observation that rPP inhibited insulin secretion without affecting glucagon and somatostatin output points to a direct effect of PP on B-cell function. However, during aminogenic priming of the D cell, the inhibition of insulin output induced by rPP was accompanied by an increase in somatostatin release. Thus, in this circumstance, it might be considered that the blocking effect of PP on B-cell secretion could be, at least in part, mediated by a D-cell paracrine effect.
Assuntos
Glucagon/metabolismo , Insulina/metabolismo , Ilhotas Pancreáticas/metabolismo , Polipeptídeo Pancreático/farmacologia , Somatostatina/metabolismo , Animais , Arginina/farmacologia , Glucose/farmacologia , Secreção de Insulina , Ilhotas Pancreáticas/efeitos dos fármacos , Cinética , Masculino , Perfusão , Ratos , Ratos Endogâmicos , Fatores de TempoRESUMO
The identification of pancreastatin in pancreatic extracts prompted the investigation of its effects on islet cell function. However, in most of the investigations to date, pig pancreastatin was tested in heterologous species. Since there is great interspecies variability in the amino acid sequence of pancreastatin, we have investigated the influence of rat pancreastatin on insulin, glucagon and somatostatin secretion in a homologous animal model, namely the perfused rat pancreas. During 5.5 mM glucose infusion, pancreastatin (40 nM) inhibited insulin secretion (ca. 40%, P less than 0.025) as well as the insulin responses to 10 mM arginine (ca. 50%, P less than 0.025) and to 1 nM vasoactive intestinal polypeptide (ca. 50%; P less than 0.05). Pancreastatin failed to significantly modify glucagon or somatostatin release under any of the above experimental conditions. In addition, a lower pancreastatin concentration (15.7 nM) markedly suppressed the insulin release evoked by 11 mM glucose (ca. 85%, P less than 0.05). Our present observations reinforce the concept that pancreastatin is an effective inhibitor of insulin secretion, influencing the B-cell function directly and not through an A-cell or D-cell paracrine effect.
Assuntos
Glucagon/metabolismo , Antagonistas da Insulina/farmacologia , Pâncreas/metabolismo , Hormônios Pancreáticos/farmacologia , Somatostatina/metabolismo , Animais , Arginina/fisiologia , Cromogranina A , Glucose/fisiologia , Insulina/metabolismo , Secreção de Insulina , Masculino , Pâncreas/efeitos dos fármacos , Perfusão , Ratos , Ratos Endogâmicos , Peptídeo Intestinal Vasoativo/fisiologiaRESUMO
We have investigated the effect of a high concentration (750 nM) of synthetic amidated rat amylin on unstimulated somatostatin and insulin secretion as well as on the response of these hormones to arginine. Amylin consistently reduced insulin output but it did not significantly modify somatostatin release. These findings indicate that the inhibitory effect of amylin on insulin secretion is not mediated by a D-cell paracrine effect.
Assuntos
Amiloide/farmacologia , Insulina/metabolismo , Somatostatina/metabolismo , Animais , Arginina/farmacologia , Antagonistas da Insulina , Secreção de Insulina , Polipeptídeo Amiloide das Ilhotas Pancreáticas , Masculino , Ratos , Ratos Endogâmicos , Somatostatina/antagonistas & inibidoresRESUMO
Amylin, a 37-amino acid polypeptide, is the main component of amyloid deposits in the islets of Langerhans, and has been identified in the B-cell secretory granules. We have investigated the effect of rat amylin on the insulin and glucagon release by the isolated, perfused rat pancreas. Amylin infusion at 750 nM, markedly reduced unstimulated insulin release (ca. 50%, P less than 0.025), whereas it did not modify glucagon output. At the same concentration, amylin also blocked the insulin response to 9 mM glucose (ca. 80%, P less than 0.025) without affecting the suppressor effect of glucose on glucagon release. The inhibitory effect of amylin on glucose-induced insulin secretion was confirmed by lowering the amylin concentration (500 nM) and increasing the glucose stimulus (11 mM); again, no effect of amylin on glucagon release was observed. Finally, amylin, at 500 nM, reduced the insulin response to 3.5 mM arginine (ca. 40%, P less than 0.025) without modifying the secretion of glucagon elicited by this amino acid. It can be concluded that, in the rat pancreas, the inhibitory effect of homologous amylin on unstimulated insulin secretion, as well as on the insulin responses to metabolic substrates (glucose and arginine), favours the concept of this novel peptide as a potential diabetogenic agent.
Assuntos
Amiloide/farmacologia , Arginina/farmacologia , Glucose/farmacologia , Antagonistas da Insulina/farmacologia , Insulina/metabolismo , Pâncreas/efeitos dos fármacos , Animais , Glucagon/metabolismo , Técnicas In Vitro , Polipeptídeo Amiloide das Ilhotas Pancreáticas , Masculino , Ratos , Ratos EndogâmicosRESUMO
Results of studies on the effects of exogenous galanin on islet cell secretion are controversial. Until recently, only pig galanin has been available, and structural dissimilarities among the galanin molecules of different species might have contributed to discrepancies among the study results. Thus, we investigated the influence of synthetic rat galanin (50 nM) on unstimulated insulin, glucagon, and somatostatin release and on the responses of these hormones to arginine (10 mM), glucose (16.6 mM), and vasoactive intestinal polypeptide (VIP; 1 nM) in a homologous animal model, the perfused rat pancreas. In addition, the effect of an equimolar concentration of pig galanin on arginine-induced islet cell secretion was examined. Infusion of rat galanin reduced unstimulated insulin release (approximately 60%, P less than 0.01) and the insulin responses to arginine (approximately 30%, P less than 0.025), glucose (100%, P less than 0.01), and VIP (approximately 80%, P less than 0.025). Galanin also inhibited unstimulated somatostatin secretion (approximately 15%, P less than 0.05) and virtually abolished the somatostatin output evoked by arginine, glucose, and VIP. Conversely, rat galanin increased unstimulated glucagon output (approximately 20%, P less than 0.05), potentiated the glucagon response to arginine (approximately 50%, P less than 0.05) and VIP (approximately 90%, P less than 0.05), and counteracted the suppressor effect of glucose on alpha-cell secretion. Pig galanin inhibited the insulin output elicited by arginine (approximately 45%, P less than 0.05) but did not affect the somatostatin and glucagon responses to the aminogenic stimulus. In conclusion, the opposite effects of galanin on insulin and glucagon secretion favor the concept of galanin as a diabetogenic agent. Galanin also behaves as a potent inhibitor of somatostatin release. Finally, the importance of using homologous galanin to study the biological activity of this peptide must be emphasized.
Assuntos
Glucagon/metabolismo , Insulina/metabolismo , Pâncreas/metabolismo , Peptídeos/farmacologia , Somatostatina/metabolismo , Animais , Arginina/farmacologia , Relação Dose-Resposta a Droga , Galanina , Glucose/farmacologia , Secreção de Insulina , Masculino , Pâncreas/efeitos dos fármacos , Peptídeos/administração & dosagem , Perfusão , Ratos , Ratos Endogâmicos , Peptídeo Intestinal Vasoativo/farmacologiaAssuntos
Glucagon/metabolismo , Hipoglicemiantes/farmacologia , Imidazóis/farmacologia , Insulina/metabolismo , Ilhotas Pancreáticas/efeitos dos fármacos , Animais , Técnicas In Vitro , Secreção de Insulina , Ilhotas Pancreáticas/metabolismo , Masculino , Ratos , Ratos Endogâmicos , Somatostatina/metabolismoRESUMO
Pancreastatin is a 49-amino acid straight chain molecule isolated from porcine pancreatic extracts. In the perfused rat pancreas, this peptide has been shown to inhibit unstimulated insulin release and the insulin responses to glucose, arginine, and tolbutamide. To further explore the influence of pancreastatin on islet cell secretion, the effect of synthetic porcine pancreastatin (a 2-micrograms priming dose, followed by constant infusion at a concentration of 15.7 nmol/L) was studied on the insulin, glucagon, and somatostatin responses to 1 nmol/L vasoactive intestinal peptide (VIP), 1 nmol/L gastric inhibitory peptide (GIP), and 1 nmol/L 26 to 33 octapeptide form of cholecystokinin (8-CCK). The effect of pancreastatin on the insulin and somatostatin secretion elicited by glucagon (20 nmol/L) was also examined. Pancreastatin infusion consistently reduced the insulin responses to VIP, GIP, and 8-CCK without modifying glucagon or somatostatin release. It also inhibited the insulin release but not the somatostatin output induced by glucagon. These observations broaden the spectrum of pancreastatin as an inhibitor of insulin release. The finding that pancreastatin does not alter glucagon or somatostatin secretion supports the concept that it influences the B cell directly, and not through an A cell or D cell paracrine effect.