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1.
Ann Ig ; 30(5 Supple 2): 99-110, 2018.
Artigo em Inglês | MEDLINE | ID: mdl-30374515

RESUMO

INTRODUCTION: Among the health professions with a long period of training, the students of the Nursing Bachelor's Degree are the most exposed to biological risk resulting from accidents, in particular with needles and cutting edges. The aim of the study was to estimate the frequency and the circumstances for the occurrence of needle stick injuries, as a knowledge base for targeted prevention interventions. METHODS: The study was carried out between May and July 2017 in 11 Universities in Italy and 1 in Albania (associated with the "Tor Vergata" University of Rome). An anonymous semi-structured questionnaire was proposed to 1st (second semester), 2nd and 3rd year students of Nursing Bachelor's Degree. RESULTS: A total of 2742 questionnaires were collected. The average age of participants was 22.9 years (median 22, range 19-60 years), 73% of whom were females. A total of 381 injuries were reported. Three hundred and sixteen students (11.8%) underwent at least 1 injury (12.7% among females, 9.7% among males); 41 students declared two or more injuries; four students did not report the number of injuries occurred. The first injury occurred, as an average, 17 days after the start of the internship (median 15 days) and, in 25% of the cases, during the first 9 days. The highest percentage of accidents occurred during the first internship (25.3% of the total) and decreased with the progress of the training path. The injuries occurred in 38% of cases during drug preparation, 24% when disposing of sharp devices, 15% while re-capping needles, 13% during blood sampling and 10% in other circumstances. In 51.2% of cases, the needle was not sterile. Among the nursing students who suffered a needle stick injury, 58.1% declared that they had performed the post-exposure prophylaxis. 96% of students stated to be vaccinated against Hepatitis B virus. Amongst the students who had their serological status checked (74%), 18% stated the antibody titre was not protective. 49.8% of students answered to have been trained in advance on the correct procedures to avoid needle stick and cutting edges injuries in each clinical ward attended, 41.2% referred that this occurred only in some wards and 10% in no ward at all. CONCLUSION: The results of this study show a high percentage of needle stick injuries in students of the Nursing Bachelor's Degree. Therefore, there is a need for careful reflection on the most effective methods of targeted training acquisition of knowledge, skills and behavioural models useful for the exercise of the profession.


Assuntos
Ferimentos Penetrantes Produzidos por Agulha/epidemiologia , Ferimentos Penetrantes Produzidos por Agulha/prevenção & controle , Escolas de Enfermagem/estatística & dados numéricos , Estudantes de Enfermagem/estatística & dados numéricos , Adulto , Albânia/epidemiologia , Feminino , Humanos , Internato e Residência/estatística & dados numéricos , Itália/epidemiologia , Masculino , Pessoa de Meia-Idade , Profilaxia Pós-Exposição/estatística & dados numéricos , Distribuição por Sexo , Adulto Jovem
2.
Biomacromolecules ; 2(2): 575-80, 2001.
Artigo em Inglês | MEDLINE | ID: mdl-11749223

RESUMO

Poly(lactic acid)-poly(ethylene glycol)-biotin (PLA-PEG-biotin) is a degradable polymer with protein resistant properties that can undergo rapid surface engineering in aqueous media to create biomimetic surfaces. Surface engineering of this polymer is dependent on biomolecular interactions between the biotin end group and the protein avidin. Given the vigorous conditions of synthesis, it is essential that the manufacture of the polymer does not alter the biotin structure or its molecular recognition. Equally, it is important that the incorporation of biotin does not adversely affect the physicochemical properties of the polymer. (1)H NMR provides evidence of biotin attachment and structural integrity. (1)H NMR, gel permeation chromatography (GPC), and differential scanning calorimetry (DSC) analysis shows there is no significant effect on bulk properties induced by the biotin end group. Surface plasmon resonance (SPR) and fluorescent spectroscopy studies using the 2-(4'-hydroxyazobenzene) benzoic acid (HABA)/avidin complex show that the biotin moieties binding capabilities are not impaired by the synthesis.


Assuntos
Biotina/química , Lactatos/química , Poliésteres/síntese química , Polietilenoglicóis/química , Polietilenoglicóis/síntese química , Avidina/química , Materiais Biocompatíveis/química , Varredura Diferencial de Calorimetria , Cromatografia em Gel , Espectroscopia de Ressonância Magnética , Espectrometria de Fluorescência , Ressonância de Plasmônio de Superfície , Propriedades de Superfície
3.
Ital Heart J ; 2(10): 751-6, 2001 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-11721719

RESUMO

BACKGROUND: The aim of this study was to evaluate the effectiveness of glycoprotein (GP) IIb/IIIa receptor inhibitors in acute myocardial infarction (AMI) patients in case of unsuccessful and failed thrombolysis. METHODS: Eighty-four patients hospitalized within 4 hours of symptom onset were randomized (single blind) into two groups. Regardless of the group, placebo or GP IIb/IIIa inhibitors were administered to patients who did not present with reperfusion signs (failed thrombolysis) 30 min after starting thrombolysis and 30-60 min after the end of full thrombolysis in patients with pain recurrence and ST-segment elevation (unsuccessful thrombolysis). Reperfusion was assessed by the creatine kinase peak occurring within 12 hours, by the observation of rapid ST-segment reduction (50-70% within 1 hour) in the 12-lead ECG continuous tracing, by the rapid regression of pain and by the development of early ventricular arrhythmias. Group 1 patients (n = 42) received, during failed thrombolysis or after 30-60 min of effective thrombolysis but with pain recurrence and ST-segment elevation (unsuccessful thrombolysis), treatment with i.v. GP IIb/IIIa inhibitors, heparin according to the TIMI 14 trial, and aspirin. Group 2 patients (n = 42) received a full dose of recombinant tissue-type plasminogen activator (rt-PA 100 mg) and placebo either during failed thrombolysis or, after 30 min of effective thrombolysis but with pain recurrence and ST-segment elevation, and standard heparin treatment and aspirin. RESULTS: In group 1, 39 patients showed rapid reperfusion (4 +/- 3 min); 22 patients received rt-PA 65 mg and 20 patients received rt-PA 100 mg and subsequent GP IIb/IIIa inhibitor treatment. Coronary angiography, performed after 12-72 hours showed patency of the infarct-related artery in 39 patients whose clinical picture was suggestive of rapid reperfusion during administration of a bolus of GP IIb/IIIa inhibitors. In group 2, no patients showed reperfusion and they were submitted to rescue coronary angioplasty (p < 0.05). Side effects occurred in 3 cases in group 1 and in 2 cases in group 2. Patients receiving GP IIb/IIIa inhibitors showed a reduced incidence of stent treatment (p = NS) and a significant reduction in the occurrence of events (angina) within 30 days of treatment (p = NS). CONCLUSIONS: Our data suggest that in patients with AMI and failed thrombolysis, treatment with GP IIb/IIIa receptor inhibitors is feasible. The increase in the risk of bleeding was acceptable. The most important result was that this combination is safe.


Assuntos
Infarto do Miocárdio/tratamento farmacológico , Inibidores da Agregação Plaquetária/uso terapêutico , Complexo Glicoproteico GPIIb-IIIa de Plaquetas/antagonistas & inibidores , Tirosina/análogos & derivados , Abciximab , Adulto , Idoso , Idoso de 80 Anos ou mais , Anticorpos Monoclonais/uso terapêutico , Angiografia Coronária , Quimioterapia Combinada , Eptifibatida , Feminino , Humanos , Fragmentos Fab das Imunoglobulinas/uso terapêutico , Masculino , Pessoa de Meia-Idade , Reperfusão Miocárdica , Peptídeos/uso terapêutico , Projetos Piloto , Projetos de Pesquisa , Fatores de Risco , Método Simples-Cego , Terapia Trombolítica , Tirofibana , Ativador de Plasminogênio Tecidual/uso terapêutico , Tirosina/uso terapêutico
4.
Ital Heart J ; 2(8): 605-11, 2001 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-11577835

RESUMO

BACKGROUND: The goal of therapy in acute myocardial infarction (AMI) is the complete and timely restoration of coronary blood flow. Platelets have a pivotal role in the pathophysiology of AMI. The study was aimed at evaluating the safety and efficacy of the combination of 50 mg alteplase plus tirofiban vs 100 mg alteplase in AMI patients. METHODS: One hundred twenty patients (83 males, 37 females; mean age 54.3 +/- 8 years) were hospitalized for suspected AMI within 6 hours of the onset of symptoms. All patients presented pain and persistent ST-segment elevation, were suitable candidates for thrombolysis (1st episode) and were randomized (double blind) into two groups. Group A (n = 60,42 males, 18 females) received 50 mg alteplase (15 mg as bolus, followed by an infusion of 35 mg over 60 min) in combination with tirofiban (0.4 mcg/kg/min for 30 min followed by an infusion of 0.1 mcg/kg/min for 3 days). Group B (n = 60, 41 males, 19 females) received 100 mg of accelerated-dose alteplase alone. Reperfusion criteria were defined as follows: > 50% reduction in the ST-segment elevation; resolution of chest pain; double marker of creatine kinase (CK) and CK-MB activity 2 hours after the start of thrombolysis; reperfusion arrhythmias within the first 120 min of thrombolysis. The blood pressure, heart rate and ECG were continuously monitored. The mortality, re-AMI, recurrent angina, major and minor bleeding, and emergency bypass surgery or coronary angioplasty were checked. RESULTS: The groups were similar with regard to clinical data, risk factors, time elapsed from the onset of symptoms to thrombolytic therapy and AMI localization. Forty-seven patients (78.3%) from group A showed reperfusion (15-60 min) vs 25 patients (41.7%) from group B (43-105 min after the end of full-thrombolysis, p = 0.01). Group A patients showed an earlier CK peak and lower CK and CK-MB peaks than those in the control group (p = 0.0001, p = 0.011, p = 0.005, respectively). Nine patients (7.5%) died: 6 (10%) in group B and 3 (5%) in group A (p = NS). A non-fatal re-AMI occurred in 8 patients from group A and in 4 patients from group B (p = NS). Recurrent angina occurred in 27 patients (45%) from group A and in 11 (18.3%) from group B (p = 0.037). Twenty-three of these patients underwent urgent coronary angioplasty (17 from group A and 6 from group B) and 3 from group A and 1 from group B underwent urgent coronary artery bypass grafting (p = NS). The frequency of minor bleeding was higher in group A than in group B (56.7 vs 25%, p = 0.033). No major bleeding was observed in the study groups. At the predischarge echocardiogram, the ejection fraction was higher in group A than in group B (50 +/- 9 vs 44 +/- 7%, p = 0.001). CONCLUSIONS: Our data suggest that the combination of glycoprotein IIb/IIIa inhibitors plus alteplase is feasible in AMI patients and that the increased risk of bleeding is an acceptable risk considering the advantage in terms of the reduction in the extent of an AMI. In addition, this combination can allow one to gain time when it is necessary to perform mechanical revascularization in patients admitted to a hospital without an interventional cardiology laboratory or in those who have to be referred to another hospital for urgent coronary artery bypass grafting.


Assuntos
Fibrinolíticos/uso terapêutico , Infarto do Miocárdio/tratamento farmacológico , Complexo Glicoproteico GPIIb-IIIa de Plaquetas/uso terapêutico , Terapia Trombolítica , Ativador de Plasminogênio Tecidual/uso terapêutico , Tirosina/análogos & derivados , Tirosina/uso terapêutico , Creatina Quinase/sangue , Quimioterapia Combinada , Estudos de Viabilidade , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Tirofibana
5.
Ital Heart J ; 2(2): 121-9, 2001 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-11256540

RESUMO

BACKGROUND: Recent evidence suggests that, via the mineralocorticoid receptors present in cardiovascular tissues, aldosterone exerts profibrotic effects, and that partial aldosterone escape occurs during ACE-inhibitor treatment. METHODS: A double-blind, randomized study was performed in order to evaluate the feasibility, tolerability, and the effects of the administration of 25 mg/day of canrenoate plus captopril versus captopril alone to patients with anterior acute myocardial infarction (AMI) unsuitable for or not receiving thrombolytic treatment and to patients in whom such treatment resulted or did not result in reperfusion. One hundred eighty-seven patients with anterior AMI were included in the present study. In all cases serum creatinine concentrations and serum K concentrations were < 2.0 mg/dl and < 5.5 mmol/l respectively. The patients were randomized in two groups: the canrenoate group included 94 patients who received captopril and 25 mg i.v. of canrenoate (1 mg/hour for the first 72 hours and then orally 25 mg/day) whereas the placebo group (93 patients) received captopril and placebo. On admission and on days 10, 90 and 180 all patients underwent echocardiography in order to determine the end-systolic volume (ESV), the ejection fraction (EF), the end-diastolic diameter, the E/A ratio, the E deceleration time as well as the isovolumetric relaxation time (IVRT) and the E and A peak velocities. RESULTS: Unreperfused patients did not show patency of the infarct-related artery whereas in reperfused patients this vessel was patent (7-10 days after AMI). The two groups were similar in age, sex, incidence of diabetes, smoking habits, hypertension, creatine kinase enzymatic peak, adjuvant therapy, baseline EF, ESV, and incidence of coronary artery bypass grafting/coronary angioplasty. Following 10 days of treatment (canrenoate group), only 9 patients presented with serum K and creatinine concentrations respectively > 5.5 mmol/l and > 2.0 mg/dl. Among those patients receiving canrenoate, the mitral E/A ratio was higher compared to the placebo group (p = 0.001) whereas the ESV was significantly reduced (p < 0.05). The deceleration time for reperfused patients receiving canrenoate was higher than that observed for reperfused patients in the placebo group. The intragroup EF was significantly increased (p = 0.042). Compared to the placebo group, the IVRT was significantly higher for unreperfused patients receiving canrenoate than in the placebo group (p = 0.001). Serum creatinine, blood urea and K levels as well as the incidence and extent of vessel disease were similar for both groups. No side effects were observed during the study period. CONCLUSIONS: Our data suggest that the combination of captopril plus canrenoate is feasible for the initial treatment of patients presenting with AMI. Besides, compared to captopril alone it is more efficacious in improving the E/A ratio, the ESV, the EF, and the IVRT.


Assuntos
Inibidores da Enzima Conversora de Angiotensina/uso terapêutico , Ácido Canrenoico/uso terapêutico , Captopril/uso terapêutico , Antagonistas de Receptores de Mineralocorticoides/uso terapêutico , Infarto do Miocárdio/tratamento farmacológico , Reperfusão Miocárdica/métodos , Idoso , Método Duplo-Cego , Quimioterapia Combinada , Estudos de Viabilidade , Feminino , Hemodinâmica , Humanos , Masculino , Pessoa de Meia-Idade , Infarto do Miocárdio/diagnóstico por imagem , Infarto do Miocárdio/fisiopatologia , Projetos Piloto , Terapia Trombolítica , Falha de Tratamento , Ultrassonografia
6.
Cardiovasc Drugs Ther ; 15(4): 309-14, 2001 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-11800414

RESUMO

BACKGROUND: Aldosterone exerts pro-fibrotic effects, acting via mineralo-corticoid reeptors in cardiovascular tissues. Aldosterone antagonism in combination with ACE inhibition may better protect against untoward effects of aldosterone than ACE inhibition alone. METHODS: In a double blind, randomised study the tolerability and efficacy of canreonate (25 mg/day) plus captopril versus captopril alone were evaluated in 187 patients with an acute anterior myocardial infarction (MI) and a serum creatinine concentration <2.0 mg/dL and a serum K concentration <5.0 mmol/L. Ninety-four patients received captopril and 25 mg canreonate (group A). Group B (93 patients) received captopril and placebo. At baseline and at 10 and 90 days after admission Doppler echocardiography was performed. RESULTS: Clinical and demographic aspects were similar in both groups. Also, baseline cardiac enzyme levels, left ventricular (LV) function and incidence of surgical interventions and angioplasty were comparable. Overall, creatinine, blood urea and serum K did not show significant differences between groups. However, in 9 patients in group A increases in serum K >5.5 mmol/dL and creatinine >2.0 mg/L were observed after 10 days of treatment. At 90 days, the mitral E/A ratio was higher (p = 0.001) and LV end systolic volume smaller (p = 0.021) inpatients treated with canreonate than in those receiving placebo. No further side effects were observed during the study period. CONCLUSIONS: Our data suggest that the combination of captopril plus canreonate is well tolerated following an acute myocardial infarction and has a beneficial effect on diastolic and systolic LV parameters and may decrease post-MI remodelling.


Assuntos
Inibidores da Enzima Conversora de Angiotensina/uso terapêutico , Ácido Canrenoico/uso terapêutico , Captopril/uso terapêutico , Antagonistas de Receptores de Mineralocorticoides/uso terapêutico , Infarto do Miocárdio/tratamento farmacológico , Idoso , Método Duplo-Cego , Quimioterapia Combinada , Feminino , Humanos , Injeções Intravenosas , Masculino , Pessoa de Meia-Idade , Reperfusão Miocárdica/métodos
7.
J Biomater Sci Polym Ed ; 11(3): 319-31, 2000.
Artigo em Inglês | MEDLINE | ID: mdl-10841282

RESUMO

The advancement of elastomeric patterning techniques in recent years has significantly enhanced our ability to spatially control biomaterial surface chemistry at the micrometre level. The application of this technology to the patterning of biomolecules onto solid surfaces has created many potential applications including the development of advanced biosensors, combinatorial library screening and the formation of tissue engineering templates. In this paper, we describe the direct patterning of protein by microcontact printing. An important consideration for the fabrication of protein micropatterns intended for these applications is the nature of the protein immobilization to a substrate. To date, the patterning of proteins by direct microcontact printing (microCP) has relied on the non-covalent adsorption to a substrate. Ideally, the proteins need to be firmly anchored onto a surface without adversely effecting their activity. Here, the high affinity avidin-biotin receptor-ligand interaction has been exploited to form arrays of avidin molecules onto a polymeric substrate expressing biotin moieties. This has created a generic technique by which any biotinylated species can be subsequently immobilized into defined patterns. Utilizing atomic force microscopy (AFM), the patterned surfaces have been characterized to molecular resolution. The micropatterned sample supported cell adhesion when biotin-(G)11-GRGDS was bound to the avidin bearing arrays.


Assuntos
Materiais Biocompatíveis/química , Proteínas/química , Células 3T3 , Adsorção , Animais , Avidina , Biotina , Adesão Celular , Elastômeros , Corantes Fluorescentes , Teste de Materiais , Camundongos , Microscopia de Força Atômica , Rodaminas , Propriedades de Superfície
8.
Cardiovasc Drugs Ther ; 13(5): 423-8, 1999 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-10547222

RESUMO

Reperfusion may prevent or reduce the development and extent of necrosis, but may also lead to an increase in reperfusion damage. Experimental studies performed in various animal models of myocardial ischemia have demonstrated the anti-ischemic properties of trimetazidine (TMZ) and have suggested that TMZ has antioxidant properties, without any direct hemodynamic effects. Our study was aimed at investigating the effects of TMZ before thrombolysis in acute anterior myocardial infarction and included 81 patients, hospitalized within 4 hours of the onset of symptoms. Patients were randomly (double-blind) subdivided in two groups The first group (40 patients, Group A, TMZ-pretreatment), received 40 mg TMZ orally about 15 minute before thrombolysis and, subsequently, 20 mg every 8 hours. The second group (41 patients, Group B) received placebo before thrombolysis. Ventricular arrhythmias (VA) due to reperfusion were evaluated in the first 2 hours. VA occurred in 15 of patients in group A, versus 29 in group B, p<0.05. Creatine kinase (CK) normalization time was achieved after 55.7+/-12.5 hours in group A, versus 61.2+/-12.1 hour in group B, p = 0.048. CK peak was 1772+/-890 in group A vs. 2285+/-910 Ul/l in group B, (p = 0.012). In the follow-up (range 6-22 months), there were 4 deaths, two patients in each group. After 180 days from treatment, the TMZ group showed a smaller end systolic volume than the placebo group (echocardiographic data), 46.2+/-12 and 52.8+/-13 ml/m2, respectively, p = 0.037. Our data suggest that TMZ probably reduces reperfusion damage and/or infarct size in patients with anterior AMI subjected to thrombolysis and affects the post-AMI remodeling. Our data must be interpreted with caution because of the selection of patients. These findings require further extensive trials.


Assuntos
Infarto do Miocárdio/tratamento farmacológico , Terapia Trombolítica , Trimetazidina/uso terapêutico , Vasodilatadores/uso terapêutico , Idoso , Análise de Variância , Angioplastia Coronária com Balão , Ponte de Artéria Coronária , Creatina Quinase/metabolismo , Método Duplo-Cego , Quimioterapia Combinada , Feminino , Hemodinâmica/efeitos dos fármacos , Humanos , Masculino , Pessoa de Meia-Idade , Infarto do Miocárdio/classificação , Reperfusão Miocárdica
9.
Heart ; 81(6): 606-11, 1999 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-10336919

RESUMO

OBJECTIVE: To verify the efficacy of the combination of captopril (75 mg day) and losartan (25 mg/day) in early postinfarction phases of reperfused anterior acute myocardial infarction. DESIGN AND PATIENTS: 99 patients, hospitalised for suspected anterior acute myocardial infarction within four hours from the onset of symptoms, were randomised into two groups: group A included 50 patients who received captopril 75 mg/day and placebo; group B included 49 patients who received captopril 75 mg/day within three days of admission plus losartan 12.5 mg, as a first dose, and 25 mg/day successively. An additional 23 patients with anterior acute myocardial infarction received losartan 25 mg alone and acted as controls (group C) to check the effects of losartan on plasma angiotensin II (AII) concentrations. Noradrenaline (norepinephrine) (NA) and AII plasma concentrations were measured on the third and 10th day after admission in 93 patients (35 from group A, 35 from group B, and 23 from group C). 90 days after admission patients underwent echocardiography to determine end systolic volume (ESV) and ejection fraction (EF). RESULTS: Patients in groups A and B were similar with regard to age, sex, creatine kinase peak, EF, ESV, and risk factors. Group B (captopril plus losartan) patients showed a significant reduction in mean (SD) systolic blood pressure within the group (basal 128 (10) mm Hg; 10 days after admission 105 (9) mm Hg, p < 0.001), and in comparison with group A (captopril) patients (basal 127 (11) mm Hg; 10 days after admission 116 (10) mm Hg, p < 0. 001). Diastolic blood pressure was also lower in group B patients versus group A (66 (11) v 77 (11) mm Hg). Group C (losartan) patients also showed a significant reduction in systolic blood pressure (131 (13) mm Hg down to 121 (12) mm Hg, p < 0.001). Neither NA nor AII plasma concentrations in groups A and B differed significantly in basal samples (NA 673 (138) v 675 (141) pg/ml; AII 12.77 (4.79) v 12.65 (4.71) pg/ml) or 10 days after admission (NA 283 (93) v 277 (98) pg/ml; AII 5.31 (2.25) v 6.09 (3.31) pg/ml). However, patients in group C had higher plasma concentrations of AII (14.79 (5.7) pg/ml on the third day and 7.98 (4.92) pg/ml on the 10th day) than patients in either group A or B (p = 0.006). After 90 days following treatment, group B (captopril plus losartan) patients had a smaller ESV than patients in group A (captopril) and group C (losartan). CONCLUSION: The data suggest that the combination of captopril plus losartan is feasible in the early treatment of acute myocardial infarction patients, and it appears that this combination has more effect on ESV than captopril alone in the short term.


Assuntos
Inibidores da Enzima Conversora de Angiotensina/uso terapêutico , Antiarrítmicos/uso terapêutico , Anti-Hipertensivos/uso terapêutico , Losartan/uso terapêutico , Infarto do Miocárdio/tratamento farmacológico , Idoso , Angiotensina II/sangue , Pressão Sanguínea/efeitos dos fármacos , Captopril/uso terapêutico , Quimioterapia Combinada , Feminino , Seguimentos , Hemodinâmica/efeitos dos fármacos , Humanos , Masculino , Pessoa de Meia-Idade , Infarto do Miocárdio/sangue , Infarto do Miocárdio/fisiopatologia , Norepinefrina/sangue , Projetos Piloto , Método Simples-Cego
10.
Chem Rev ; 99(11): 3181-98, 1999 Nov 10.
Artigo em Inglês | MEDLINE | ID: mdl-11749514
11.
FASEB J ; 12(14): 1447-54, 1998 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-9806753

RESUMO

Controlling receptor-mediated interactions between cells and template surfaces is a central principle in many tissue engineering procedures (1-3). Biomaterial surfaces engineered to present cell adhesion ligands undergo integrin-mediated molecular interactions with cells (1, 4, 5), stimulating cell spreading, and differentiation (6-8). This provides a mechanism for mimicking natural cell-to-matrix interactions. Further sophistication in the control of cell interactions can be achieved by fabricating surfaces on which the spatial distribution of ligands is restricted to micron-scale pattern features (9-14). Patterning technology promises to facilitate spatially controlled tissue engineering with applications in the regeneration of highly organized tissues. These new applications require the formation of ligand patterns on biocompatible and biodegradable templates, which control tissue regeneration processes, before removal by metabolism. We have developed a method of generating micron-scale patterns of any biotinylated ligand on the surface of a biodegradable block copolymer, polylactide-poly(ethylene glycol). The technique achieves control of biomolecule deposition with nanometer precision. Spatial control over cell development has been observed when using these templates to culture bovine aortic endothelial cells and PC12 nerve cells. Furthermore, neurite extension on the biodegradable polymer surface is directed by pattern features composed of peptides containing the IKVAV sequence (15, 16), suggesting that directional control over nerve regeneration on biodegradable biomaterials can be achieved.


Assuntos
Materiais Biocompatíveis , Engenharia Biomédica , Poliésteres/química , Polietilenoglicóis/química , Animais , Biodegradação Ambiental , Bovinos , Movimento Celular , Células Cultivadas , Microscopia de Força Atômica , Microscopia de Fluorescência , Células PC12 , Ratos
12.
J Biomater Sci Polym Ed ; 9(5): 507-18, 1998.
Artigo em Inglês | MEDLINE | ID: mdl-9648030

RESUMO

In designing polymers that can act as tissue engineering templates it is beneficial to consider methods of mimicking the natural support structures used by the human body to guide the behavior and development of cells within tissues. The well-known RGD cell adhesion ligand provides a simple mechanism of creating polymer surfaces that mimic the extracellular matrix. This paper considers the methods that have been used to attach such motifs to synthetic polymers. In general there are two strategies: the formation of polymer-peptide hybrid molecules, or the immobilization of the ligand on the fabricated surface of the polymer. The three major synthetic strategies of creating polymer-peptide hybrids are reviewed.


Assuntos
Materiais Biocompatíveis/síntese química , Matriz Extracelular , Peptídeos/química , Polímeros/química , Adesão Celular , Comunicação Celular , Humanos , Ligantes , Modelos Biológicos , Engenharia de Proteínas
13.
Biotechnol Bioeng ; 58(5): 529-35, 1998 Jun 05.
Artigo em Inglês | MEDLINE | ID: mdl-10099289

RESUMO

We describe the development of a novel biodegradable polymer designed to present bioactive motifs at the surfaces of materials of any architecture. The polymer is a block copolymer of biotinylated poly(ethylene glycol) (PEG) with poly(lactic acid) (PLA); it utilizes the high-affinity coupling of the biotin-avidin system to undergo postfabrication surface engineering. We show, using surface plasmon resonance analysis (SPR) and confocal microscopy that surface engineering can be achieved under aqueous conditions in short time periods. These surfaces interact with cell surface molecules and generate beneficial responses as demonstrated by the model study of integrin-mediated spreading of endothelial cells on polymer surfaces presenting RGD peptide adhesion sequences.


Assuntos
Materiais Biocompatíveis , Endotélio Vascular/citologia , Lactatos , Polietilenoglicóis , Polímeros , Animais , Aorta , Biotinilação , Bovinos , Técnicas de Cultura de Células/instrumentação , Técnicas de Cultura de Células/métodos , Movimento Celular , Células Cultivadas , Endotélio Vascular/fisiologia , Fluoresceína-5-Isotiocianato , Microscopia Confocal , Microscopia de Fluorescência , Propriedades de Superfície
14.
J Biomed Mater Res ; 35(4): 513-23, 1997 Jun 15.
Artigo em Inglês | MEDLINE | ID: mdl-9189829

RESUMO

The design of biomaterials containing specific ligands on the surface offers the possibility of creating materials that can interact with and potentially control mammalian cell behavior. Biodegradable materials further provide the significant advantage that the polymer will disappear in vivo, obviating long-term negative tissue responses as well as the need for retrieval. In earlier studies we synthesized and characterized arginine-glycine-aspartic acid (RGD) peptide-modified poly(lactic acid-co-lysine) (PLAL). In this study, both bulk properties and surface features have been characterized, with a focus on surface analysis as a means of interpreting observed changes in cell behavior. Bulk peptide attachments were performed using 1,1'-carbonyldiimidazole (CDI). Amino groups were measured using colorimetric assays and X-ray photoelectron spectroscopy (XPS). Peptides were measured by incorporating iodine into the peptide as a distinct elemental marker for use with XPS. Typical samples contained 13 +/- 4 pmol/cm2 of amino groups and 4 +/- 0.2 pmol/ cm2 of peptides, as calculated from XPS measurements of nitrogen and iodine. The wettability and crystallinity of the samples were determined by contact angles and differential scanning calorimetry, respectively. Wettability and crystallinity were not altered by the incorporation of lysine or peptides. After incubating bovine aortic endothelial (BAE) cells for 4 h on surfaces with RGD-containing peptides, the mean spread cell area increased from 77 +/- 2 microns2 to 405 +/- 29 microns2 compared to 116 +/- 11 microns2 on poly(lactic acid), 87 +/- 4 microns2 on PLAL, and 105 +/- 4 microns2 on surfaces with RDG-containing (control) peptides. The significance of this work is that the first synthetic interactive, resorbable biomaterial has been developed, and use of this material to control cell behavior has been demonstrated.


Assuntos
Materiais Biocompatíveis/química , Oligopeptídeos/química , Polilisina/química , Polímeros/química , Animais , Varredura Diferencial de Calorimetria , Bovinos , Adesão Celular , Movimento Celular , Células Cultivadas , Colorimetria , Endotélio Vascular/citologia , Temperatura Alta , Microscopia Eletrônica de Varredura , Espectrometria por Raios X
15.
G Ital Cardiol ; 27(12): 1256-63, 1997 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-9470059

RESUMO

BACKGROUND: Suppression of the formation of angiotensin II (A II) is thought to be a major contributor to the hemodynamic response to angiotensin-converting enzyme inhibition (ACE-inhibitor) therapy. However, during ACE-inhibitor treatment, A II plasma levels may also recover through tissue chymase. This study has attempted to verify the feasibility, safety and tolerability of a combined treatment using captopril (75 mg/day) and losartan (25 mg/day), and to ascertain its ability to reduce the formation and action of A II in the early post-infarction phase of reperfused anterior myocardial infarction (AMI). METHOD: Forty-four patients hospitalized for suspected AMI within 4 hours of the onset of symptoms, who were suitable for thrombolysis (first episode), in Killip class I-II, reperfused, treated with 75 mg/day of captopril within 3 days of admission and with a blood pressure level of more than 120 mmHg, were randomized (single-blind) into two groups that were similar with regard to age, sex, blood pressure, CK peak, ejection fraction, end-systolic volume and risk factors. Group A (22 subjects: 6 women/16 men) received captopril (75 mg/day) and placebo, while group B (22 subjects: 5 women/17 men) was given captopril (75 mg/day) plus losartan, initially at 12.5 mg and then at 25 mg/day thereafter (BP > 110 mmHg). Norepinephrine (NE) and A II plasma levels were measured on the third and tenth day after admission. RESULTS: Ten days after admission, group B (captopril plus losartan) showed a significant decrease in blood pressure (BP) on an intragroup level (p < 0.001) as well as in comparison with group A (p < 0.001), with values of 108 + 6.4 and 118 + 11 mmHg respectively. At the same time interval, NE and A II values did not show significant differences within or between groups. CONCLUSIONS. For the first time, our data suggest that a combined captopril-losartan treatment is feasible and that it has no particular side effects. In addition, it shows no significant increase of A II that would be produced by losartan alone.


Assuntos
Inibidores da Enzima Conversora de Angiotensina/uso terapêutico , Captopril/administração & dosagem , Losartan/administração & dosagem , Infarto do Miocárdio/tratamento farmacológico , Idoso , Angiotensina II/sangue , Angiotensina II/efeitos dos fármacos , Quimioterapia Combinada , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Infarto do Miocárdio/sangue , Norepinefrina/sangue , Projetos Piloto , Método Simples-Cego , Fatores de Tempo
16.
Biomaterials ; 18(21): 1417-24, 1997 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-9375843

RESUMO

The quantification of functional amino (NH2) groups on poly(lactic acid-co-lysine):(poly(L-lactic acid (PLAL:PLA) blends was performed using a colorimetric assay based on the reaction of sulpho-succinimidyl-4-O-(4,4'-dimethoxytrityl)-butyrate (sulpho-SDTB) with primary amino groups. The colorimetric assay was used to assess the available reactive sites for coupling of biologically active species to PLAL. Blends were created that contained from 10 to 70 wt% poly(lactic acid-co-lysine). Bulk lysine contents within the blends were determined by amino acid analysis and ranged from 9.1 micromol g(-1) to 52.9 micromol g(-1) for blends created using PLA of 100000g mol(-1) molecular weight. Surface amino group concentrations on the same set of blends ranged from 0.23 to 1.45 nmol cm(-2). Similar surface amino groups concentrations were measured on blends using 50000, 200000 and 300000g mol(-1) poly(lactic acid). Non-specific interactions of the colorimetric assay reagents with the PLAL-containing blends were measured on blends prepared from epsilon-amino protected PLAL and 100000g mol(-1) PLA. The presence of amino groups within the top 50 angstroms was confirmed by X-ray photoelectron spectroscopy.


Assuntos
Aminoácidos/análise , Ácido Láctico/química , Polilisina/química , Polímeros/química , Colorimetria/métodos , Lisina/análise , Poliésteres , Polímeros/análise , Próteses e Implantes
17.
G Ital Cardiol ; 26(6): 673-80, 1996 Jun.
Artigo em Italiano | MEDLINE | ID: mdl-8803588

RESUMO

BACKGROUND: Studies showed that endothelin-1 (ET-1) was increased in the acute myocardial infarction (AMI). Experimental studies reported that captopril was able to reduce ET-1 secretion. In addition increased levels of ET-1 were reported as a negative prognostic index. The study was aimed to verify whether captopril was able to reduce plasma ET-1 levels in the acute and subacute phases of AMI. METHODS: Forty five patients, hospitalized for suspected anterior AMI within 4 h since the onset of symptoms, suitable for thrombolysis (first episode), in Killip class 1-2, were randomized (double blind) into two groups: Group A (23 patients, pts), 7 females and 16 males, received captopril 6.25 mg orally (as first dose) 2-4 h after starting thrombolysis, and the doses of captopril were successively increased up to 25 mg every 8 h. Group B: (22 pts), 5 females and 17 males, received placebo after thrombolysis. All the patients met the reperfusion criteria. RESULTS: The two groups were similar for age, sex, CK peak, ejection fraction, end systolic volume and risk factors. Plasma ET levels were checked on admission, and 2, 12, 24, 48, 72 hours, after starting thrombolysis. Mean concentrations of ET +/- SD: Group A: basal 1.50 +/- 0.67, at 2 h 2.31 +/- 1.24, 12 h 1.84 +/- 1.45, 24 h 1.30 +/- 0.72, 48 h 0.95 +/- 0.50, 72 h 0.60 +/- 0.15 fmol/ml (p < 0.001). Group B: basal 1.58 +/- 0.83, at 2 h 2.38 +/- 1.35, 12 h 2.33 +/- 1.71, 24 h 1.80 +/- 1.41, 48 h 1.46 +/- 0.88, 72 h 0.93 +/- 0.44 fmol/ml (p < 0.001). Difference between the two groups was significant at 48 h (p < 0.05), and 72 h (p < 0.001). CONCLUSIONS: Our data suggest that captopril affects plasma endothelin levels in the acute and subacute phases of AMI. In addition, our results seem to be an additional support to the beneficial effects of early captopril treatment in patients with AMI.


Assuntos
Inibidores da Enzima Conversora de Angiotensina/uso terapêutico , Captopril/uso terapêutico , Endotelina-1/sangue , Infarto do Miocárdio/sangue , Administração Oral , Creatina Quinase/sangue , Método Duplo-Cego , Feminino , Humanos , Isoenzimas , Masculino , Pessoa de Meia-Idade , Infarto do Miocárdio/tratamento farmacológico , Infarto do Miocárdio/enzimologia , Terapia Trombolítica , Fatores de Tempo
18.
Int J Cardiol ; 51(2): 131-5, 1995 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-8522408

RESUMO

Studies showed that endothelin-1 (ET-1) was increased in the acute myocardial infarction (AMI). Experimental studies reported that captopril was able to reduce ET-1 secretion, and that ET-1 was increased during reperfusion. This study was aimed to verify if captopril was able to reduce plasma ET-1 during thrombolysis in AMI. Seventy-three patients, hospitalized for suspected AMI within 4 h from the onset of symptoms suitable for thrombolysis (1st episode), Killip class 1-2, were randomized (double blind) into two groups: group 1 (37 pts), 8 F/29 M, received captopril, 6.25 mg, orally 15 min before thrombolysis. Group 2: (36 pts) 8 F/28 M, received placebo before thrombolysis. All patients met the reperfusion criteria. Plasma ET-1 were checked on admission, at 1 h and at 2 h, after starting thrombolysis. Group 1 contained ten unstable angina, 17 anterior and ten inferior AMIs. Group 2 contained ten unstable angina, 16 anterior and ten inferior AMIs. Mean concentrations of ET-1: Unstable angina: group 1, basal--4.56, at 1 h--4.47, 2 h--5.89 pg/ml; group 2: basal--4.17, at 1 h--4.59, 2 h--5.24 pg/ml. Inferior AMI: group 1: basal--6.87, 1 h--7.75, 2 h--8.47; group 2: basal--6.34, 1 h--6.68, 2 h--7.98 pg/ml. Anterior AMI: group 1: basal--7.17, 1 h--7.93, 2 h--10.76 pg/ml (between basal and 2-h samples P < 0.05); group 2: basal--7.46, 1 h--7.51, 2 h--10.74 pg/ml. Differences between the two groups were not significant. Our data suggest that captopril does not affect plasma ET-1 during thrombolysis.


Assuntos
Inibidores da Enzima Conversora de Angiotensina/uso terapêutico , Captopril/uso terapêutico , Endotelinas/sangue , Infarto do Miocárdio/terapia , Reperfusão Miocárdica , Terapia Trombolítica , Administração Oral , Angina Instável/sangue , Angina Instável/terapia , Inibidores da Enzima Conversora de Angiotensina/administração & dosagem , Pressão Sanguínea , Captopril/administração & dosagem , Creatina Quinase/sangue , Método Duplo-Cego , Eletrocardiografia , Feminino , Frequência Cardíaca , Humanos , Isoenzimas , Masculino , Infarto do Miocárdio/sangue , Placebos , Proteínas Recombinantes , Fatores de Tempo , Ativador de Plasminogênio Tecidual/uso terapêutico
19.
Int J Cardiol ; 43(1): 43-50, 1994 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-8175218

RESUMO

Several experimental studies carried out on animals and on isolated heart preparations show that captopril can reduce post-ischemic reperfusion injury. Our study was aimed at investigating the effects of captopril before thrombolysis in acute myocardial infarction (AMI) and included 259 patients, hospitalized within 4 h of the onset of symptoms. Patients were randomly subdivided into two groups: the first group (131 patients, Group A, pretreatment) received 6.25 mg captopril orally about 15 min before i.v. administration of urokinase (2 million), the second group (128 patients, Group B, late-treatment), received captopril about 3 days after thrombolytic treatment. Captopril doses were later increased in both groups according to blood pressure. All patients were subdivided according to the localization of infarction. Anterior AMI was shown by 166 patients (84 from Group A and 82 from Group B); 93 patients showed inferior AMI (47 from Group A and 46 from Group B). Ventricular hyperkinetic arrhythmias (VHAs) due to reperfusion were evaluated during the first 2 h. VHAs occurred in 11.9% of patients with anterior AMI in Group A vs. 37.8% in Group B (P < 0.001). CK peak normalization time in the group with anterior AMI was achieved after 58 +/- 2 h in Group A vs. 71 +/- 2 h in Group B (P < 0.001). CK peak was 1719 +/- 152 in Group A vs. 2184 +/- 164 U/l in Group B, (P < 0.039). Late arrhythmias, higher than Lown's Class 2 were found to occur in 15.4% of patients with anterior AMI of Group A vs. 31.7% in Group B (P < 0.022), at predischarge Holter test.(ABSTRACT TRUNCATED AT 250 WORDS)


Assuntos
Captopril/administração & dosagem , Infarto do Miocárdio/tratamento farmacológico , Traumatismo por Reperfusão/prevenção & controle , Terapia Trombolítica , Arritmias Cardíacas/etiologia , Feminino , Seguimentos , Humanos , Masculino , Pessoa de Meia-Idade , Revascularização Miocárdica , Traumatismo por Reperfusão/complicações , Fatores de Tempo
20.
Int J Cardiol ; 42(3): 225-30, 1993 Dec 31.
Artigo em Inglês | MEDLINE | ID: mdl-8138330

RESUMO

UNLABELLED: The study aimed at checking effects exerted by captopril (C) on human myocardial ACE system as well as the role played by tissue ACE inhibition in reducing reperfusion damage. A human experimental model was used during cardioplegia due to aorto-coronary-by-pass (CABG). Fifty-four patients with coronary artery disease affecting 3 vessels having suffered from acute myocardial infarction anterior (AMI-ant), homogeneous as far as ejection fraction (35-55%), number of grafts (3), clamping time, age and sex, were randomised in a double blind experiment, and were given captopril or placebo (P). A total of 4 mg/l Captopril was mixed into the cardioplegic solution with blood according to the method of Buckberg (Buckberg GD. J Thorac Cardiovasc Surg 1987; 93: 127-139). Eight samples (blood/perfusate) were obtained from each patients and norepinephrine (NE), epinephrine (E) were assayed using an HPLC technique. Angiotensin I was assayed by RIA. CK was also assayed (units/ml). Blood/perfusate samples were taken during CABG: (1) pre-pump; (2) pump sample; (3) pump preclamping; (4) coronary sinus; (5) coronary sinus sample during reperfusion; (6) coronary sinus during warm reperfusion; (7) after clamping sample; (8) after decanulation; RESULTS: Captopril group (29 patients): angiotensin I: (1) 8.15; (2) 7.0; (3) 7.31; (4) 8.45; (5) 8.93; (6) 8.73; (7) 9.07; (8) 9.40; versus placebo: (1) 7.09, (2) 7.43; (3) 7.80; (4) 9.31; (5) 9.01; (6) 8.35; (7) 8.85; (8) 8.07 ng/ml, probability, not significant.(ABSTRACT TRUNCATED AT 250 WORDS)


Assuntos
Captopril/uso terapêutico , Parada Cardíaca Induzida , Traumatismo por Reperfusão Miocárdica/prevenção & controle , Angiotensina I/sangue , Ponte de Artéria Coronária , Creatina Quinase/sangue , Método Duplo-Cego , Epinefrina/sangue , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Norepinefrina/sangue
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