To compare the effectiveness of nifedipine and glyceryl trjnjtrate patch jn prevention of preterm Labour

Objective: To assess the effectiveness of Nifedipine and Glyceryl trinitrate patch in prolonging the pregnancy for more than 48 hours

Methodology: This was a randomized control study. Fifty patients with preterm labour meeting the inclusion criteria were inducted in study and randomly allocated to the treatment group A [Nifedipine] and group B [Glyceryl trinitrate patch, GTN]. After taking consent from the patients, all the details were documented on a proforma and tocolysis was started with either of these tocolytics according to a preset protocol

Results: Nifedipine was found to be more effective than GTN, as prolongation of pregnancy beyond 48 hours was more frequent [74%] with nifedipine than GTN [40%] with P value <0.05 . Similarly prolongation beyond 7 days was also more frequent [32%] with nifedipine as compared with GTN [24%]. Most common adverse effect found with nifedipine was headache followed by palpitations and hypotension. GTN patch had a better side effect profile with most of the patients being asymptomatic. Fetal distress was noticed more in GTN group as compared with nifedipine

Conclusion: Nifedipine, as a tocolytic, is found to be more effective in pregnancy prolongation when compared with Glyceryl trinitrate but has frequent maternal adverse drug effects. Glyceryl trinitrate patch is well tolerated by the patients with preterm labour with relatively fewer side effects

Impacto dos stents e do sirolimus por via oral na vasomotilidade coronariana dependente e independente do endotelio / Impact of stenting and oral sirolimus on endothelium-dependent and independent coronary vasomotion

FUNDAMENTO: Não há consenso sobre o impacto do implante de stent sobre a função endotelial no longo prazo. Há relatos de disfunção endotelial aumentada com stent com sirolimus quando comparado com o stent metálico convencional (BMS). OBJETIVO: Este estudo visa a avaliar o impacto do BMS e o efeito do sirolimus por via oral sobre a função endotelial. MÉTODOS: Quarenta e cinco pacientes foram randomizados em três grupos: BMS + altas doses de sirolimus oral (dose inicial de 15 mg, seguida de 6 mg/dia durante quatro semanas); BMS + baixa dose de sirolimus (6 mg, seguida de 2 mg por dia durante quatro semanas) e BMS sem sirolimus. Mudanças na vasoconstrição ou vasodilatação, em um segmento de 15 milímetros começando pelo extremo distal do stent em resposta a acetilcolina e nitroglicerina, foram avaliadas por angiografia quantitativa. RESULTADOS: Os grupos apresentaram características angiográficas semelhantes. A variação percentual de diâmetro em resposta a acetilcolina foi semelhante em todos os grupos, nos dois momentos (p = 0,469). Quatro horas após o implante de stent, o segmento alvo apresentou uma disfunção endotelial que se manteve após oito meses em todos os grupos. Em todos os grupos, a vasomotricidade independente de endotélio em resposta a nitroglicerina foi semelhante, às quatro horas e aos oito meses, com diâmetro do segmento alvo aumentado após a infusão de nitroglicerina (p = 0,001). CONCLUSÃO: A disfunção endotelial esteve igualmente presente no segmento distal de 15 milímetros do segmento tratado, às 4 horas e aos 8 meses após implante do stent. O sirolimus administrado por via oral durante quatro semanas para evitar a reestenose não afetou o estado de vasomotricidade endotélio dependente e independente.

BACKGROUND: There is no consensus regarding the impact of stenting on long-term endothelial function. There have been reports of increased endothelial dysfunction with sirolimus-eluting stents as compared to bare metal stenting (BMS). OBJECTIVE: This study aims to assess the impact of BMS and the effect of oral sirolimus on endothelial function. METHODS: Forty-five patients were randomized into three groups: BMS + high-dose oral sirolimus (initial dose of 15 mg, followed by 6 mg/day for four weeks); BMS + low-dose sirolimus (6 mg followed by 2 mg daily for four weeks); and BMS without sirolimus. Changes in vasoconstriction or vasodilation in a 15 mm segment starting at the distal stent end in response to acetylcholine and nitroglycerin were assessed by quantitative angiography. RESULTS: The groups had similar angiographic characteristics. The percent variation in diameter in response to acetylcholine was similar in all groups at the two time points (p = 0.469). Four hours after stenting, the target segment presented an endothelial dysfunction that was maintained after eight months in all groups. In all groups, endothelium-independent vasomotion in response to nitroglycerin was similar at four hours and eight months, with increased target segment diameter after nitroglycerin infusion (p = 0.001). CONCLUSION: The endothelial dysfunction was similarly present at the 15 mm segment distal to the treated segment, at 4 hours and 8 months after stenting. Sirolimus administered orally during 4 weeks to prevent restenosis did not affect the status of endothelium-dependent and independent vasomotion.

[Comparison of the analgesic effect of nitroglycerin added to lidocaine and lidocaine alone in the intravenous regional anesthesia]

Intravenous regional anesthesia is easy to administer, reliable, and cost effective so it is notable for limb surgery. Slow onset, tourniquet pain, and minimal postoperative pain are this methods limitation. This study evaluate the effect of adding nitroglycerine to lidocaine on sensory and motor block onset time, tourniquet pain, first time of analgesic requirement and dose of opiate. In a randomized, double blinded, clinical trial thirty patients of 18 to 60 years old ASA class I,II undergoing upper limb surgery were randomly allocated into group A [3mg/kg lidocaine diluted with saline to total volume of 40ml] and group B [300 micro g nitroglycerine added to 3mg/kg lidocaine diluted with saline to total volume of 40ml]. Sensory and motor block onset time, tourniquet pain, first time of analgesic requirement, dose of opiate, hemodynamic changes and complications have been recorded and assessed. Sensory block onset time, motor block onset time, tourniquet pain and analgesic requirement were significantly lower in group B than group A. The first time of analgesic requirement was longer in group B than group A. No complication was seen in both groups. Addition of nitroglycerine to lidocaine to intravenous regional anesthesia can hastens the onset time of sensory and motor block and decreases tourniquet pain and opioid

[ effect of transdermal TNG on the level of spinal anesthesia in knee arthroscopic surgery]

One of the problems with the implementation of spinal anesthesia is not to achieve an appropriate sensory level and sensory level decline before the end of operation that can cause pain and stress for the patient and surgeon dissatisfaction. In this study, the effects of transdermal TNG on the level of spinal anesthesia in knee arthroscopy patients were investigated. In a randomized clinical trial 46 patients randomly allocated in two groups of TNG or placebo. All of patients were premedicated with 10 mg diazepam before operation and then spinal anesthesia was performed with 1.5cc lidocaine 5%. After 20 minutes, one group received a transdermal placebo and the second group received transdermal TNG. The level of sensory block was measured by a blunt needle and alcohol swab. After 20 minutes a two level increase of sensory level in 82.6% of patients in the TNG group was observed but only 4.3%of the placebo group showed this raise. [p<0.05]. In spinal anesthesia, transdermal TNG can increase the sensory level via some theoretical mechanisms

Flebitis postinfusión en catéteres venosos periféricos: Una actualización del arte / Post infusion phlebitis in peripheral venous catheters; An actualization of the art

Las diferentes patologías y su manejo actual hacen que la terapia endovenosa sea frecuentemente utilizada en un gran número de pacientes admitidos en unidades de hospitalización, y más aún, sean fundamentales en las unidades de cuidados intensivos. No obstante, pesar de los beneficios, su utilización no está exenta de complicaciones, siendo una de las más frecuentes la flebitis post infusión o flebitis química, asociándose a una alta incidencia (alrededor de un 15 a 80% de los pacientes con accesos venosos periféricos) y se atribuye principalmente a la irritación provocada por medicamentos administrados por esta vía. Es responsabilidad de enfermería la instalación de una vía venosa periférica y sus cuidados, por lo que es de suma importancia conocer los signos y síntomas de flebitis para su detección precoz y, además, formas de prevención y su manejo una vez que esté presente. Sin embargo, pese a que existen numerosos estudios referentes a su prevención y tratamiento, aún no hay resultados concluyentes que permitan recomendar una medida determinada.

Different pathologies and their current management make intravenous therapy frequently used for the majority of patients admitted to hospital units and are even more critical in intensive care units. Still, despite of the benefits, Its use is not free of complications, being one of the most frequent post infusion phlebitis or chemical phlebitis, associated with a high incidence (around 15 to 80% of patients with peripheral venous access) and is mainly attributed to the irritation caused by medication administered by this route. Is responsibility of nursing staff the installation of peripheral venous catheters and its care, so it is important to recognize the signs and symptoms of phlebitis for early detection and also forms of prevention and handling this once it is present. However, while there are numerous studies concerning the prevention and treatment, there are no conclusive results yet to recommend a particular measure.

Treatment of ethanol-induced acute pulmonary hypertension and right ventricular dysfunction in pigs, by sildenafil analogue (UK343-664) or nitroglycerin.

In patients at risk for sudden ethanol (ETOH) intravascular absorption, prompt treatment of pulmonary hypertension (PHTN) will minimise the risk of cardiovascular decompensation. We investigated the haemodynamic effects of intravenous ETOH and the pulmonary vasodilatory effects of a sildenafil analogue (UK343-664) and nitroglycerin (NTG) during ETOH-induced PHTN in pigs. We studied pulmonary and systemic haemodynamics, and right ventricular rate or time derivate of pressure rise during ventricular contraction ( =dP/dT), as an index of contractility, in 23 pigs. ETOH was infused at a rate of 50 mg/kg/min, titrated to achieve a twofold increase in mean pulmonary arterial pressure (MPAP), and then discontinued. The animals were randomised to receive an infusion of 2 ml/kg ( n = 7) normal saline, a 500-microg/kg bolus of UK343-664 ( n = 8), or NTG 1 microg/kg ( n = 8); each was given over 60 seconds. Following ETOH infusion, dP/dT decreased central venous pressure (CVP), and MPAP increased significantly, resulting in significantly increased pulmonary vascular resistance (PVR). Within 2 minutes after treatment with either drug, CVP, heart rate (HR), and the systemic vascular resistance-to-pulmonary vascular resistance (SVR/PVR) ratio returned to baseline. However, at that time, only in the UK343-664 group, MPAP and dP/dT partially recovered and were different from the respective values at PHTN stage. NTG and UK343-664 decreased PVR within 2 minutes, from 1241+/-579 and 1224+/-494 dyne . cm/sec 5 , which were threefold-to-fourfold increased baseline values, to 672+/-308 and 538+/-203 dyne . cm/sec 5 respectively. However, only in the UK343-664 group, changes from baseline PVR values after treatment were significant compared to the maximal change during target PHTN. Neither drug caused a significant change in SVR. In this model of ETOH-induced PHTN, both UK343-664 and NTG were effective pulmonary vasodilators with a high degree of selectivity. However, the changes from baseline values of PVR, and the partial recovery of systemic pressure and RV contractility compared to the maximal change during target PHTN, were significant only in the sildenafil analogue group.

Effects of combined sildenafil-nitric oxide donor on defibrillation efficacy.

BACKGROUND: A previous study demonstrated that supra-therapeutic concentration of sildenafil citrate attenuates defibrillation efficacy. However, the effect of combined sildenafil and NTG administration on defibrillation efficacy is not known. OBJECTIVE: The present study investigated whether sildenafil administration at the therapeutic level increases the defibrillation threshold (DFT) when combined with NTG. MATERIAL AND METHOD: Twenty-four pigs (20-25 kg) were randomized into four groups. After the control DFT was obtained, a stock solution of 50-mg (group 1, therapeutic concentration) and 100-mg (group 2, supratherapeutic concentration) of sildenafil, and 100-mL of saline (groups 3 and 4) were infused at 2 mL/min. Then, NTG was administered in groups 1-3 at 5 microg/min, with an increment of 5 microg/min every 5 min. The DFT was determined again after NTG was infused for 20 minutes. RESULTS: In group 1, the DFT (402 +/- 33V, 11 +/- 2J) was not different from the control (404 +/- 28V, 11 +/- 2J). In group 2, the DFT (521 +/- 18V, 19 +/- 1J) was higher (p < 0.004) than that in the control group (444 +/- 31V, 14 +/- 2J). Saline did not alter the DFT either individually or in combination with NTG. CONCLUSION: Supratherapeutic dose of sildenafil-NTG combination significantly increased the DFT (17% of peak voltage, 37% of total energy). This effect on DFT appears to be driven by sildenafil and not NTG.

Preventive effects of nitroglycerine on glucocorticoid-induced osteoporosis in growing rats / 华中科技大学学报（医学）（英德文版）

The preventive effects of nitroglycerine (NG) on glucocorticoid-induced osteoporosis in growing rats were studied. Three-month-old female Wistar rats were randomly divided into control group (CON), dexamethasone group (DXM), DXM plus a low dose NG group (NG-L), DXM plus a middle dose NG group (NG-M) and DXM plus a high dose NG group (NG-H), 8 rats in each group. The rat model of osteoporosis was developed by intramuscular injection of dexamethasone twice a week. NG 0.2, 0.4 and 1.0 mg/kg was administered by oral gavages to the treatment groups every day for 12 weeks. Rats in CON group and DXM group were treated with normal saline of the same amount. After the treatment, the bone mineral density (BMD) and bone metabolism-associated biochemical markers were determined. Compared with CON group, BMD of lumbar spine and femur in DXM group was decreased significantly (P<0.05 and P<0.01 respectively), blood BGP levels and NO levels reduced (both P<0.01), and TRAP level increased (P<0.05). As compared with DXM group, BMD, serum BGP and NO were increased, and TRAP decreased in NG-L group and NG-M group, but had no significant difference in comparison to CON group. All the markers other than serum NO and TRAP levels had no significant difference between NG-H group and DXM group. It was concluded that low or middle doses of NG could prevent glucocorticoid-induced bone loss in growing rats, but high dose of NG could not. Supplement with NO donor could be considered as a preventive treatment for glucocorticoid-induced osteoporosis in a developing skeleton.

Hemodynamic effects of inhaled nitroglycerin in patients with pulmonary hypertension undergoing mitral valve replacement surgery

There has been a renewed interest in nitric oxide donor drugs such as nitroglycerin, delivered by the inhalational route for treatment of pulmonary arterial hypertension [PHT], since the presence of [PHT] affects the prognosis of the patients. Aim of this study was to investigate the postoperative hemodynamic effects of nitroglycerin inhalation on patients with [PHT] undergoing mitral valve replacement surgery. Twenty-two patients who diagnosed as having pulmonary hypertension [mean pulmonary artery pressures >25 mmHg] and underwent mitral valve replacement surgery were included in the study. Basal systemic and pulmonary hemodynamics were recorded in postoperative period at [T0] before inhalation of nitroglycerin. Then 2.5 microg/kg/min nitroglycerin liquid nebulized by 2 l/min gas flow of 40% oxygen and air mixture were given to the patients. Thereafter, the same parameters were measured at the first [T1], second [T2], and fourth [T3] hours after the beginning of nitroglycerin inhalation and one hour after the end of treatment [T4]. With respect to heart rate, mean arterial pressure, systemic vascular resistance, cardiac index, mixed venous oxygen saturation and arterial carbon dioxide tension, there were no statistically significant differences at T0, T1, T2, T3, or T4. On the other hand, the mean pulmonary artery pressure, pulmonary vascular resistance and intrapulmonary shunt fraction decreased significantly, whenever the PaO2/FiO2 ratio increased significantly at T1, T2 and T3 when compared to that of T0 and T4. The results of the present study suggest that nitroglycerin inhalation causes a significant decrease in both mean pulmonary artery pressure and pulmonary vascular resistance in patients with pulmonary hypertension undergoing mitral valve replacement surgery without decreasing mean arterial pressure and systemic vascular resistance thus can be used as a therapeutic modality during postoperative course

Noninvasive evaluation of endothelial function and arterial mechanics in overweight adolescents.

OBJECTIVE: To evaluate endothelial function and arterial mechanics in apparently healthy overweight adolescents. Design: Analytical observational study. SETTING: Tertiary hospital. METHODS: 40 asymptomatic, normotensive and non-smoking adolescents (11 to 18 years old) were evaluated. Of these 20 were overweight or obese as per International Obesity Task Force criteria while 20 were controls. High resolution ultrasonography was performed to measure flow mediated and Glyceryltrinitrate induced dilation in brachial artery, and arterial mechanics in common carotid artery. RESULTS: Overweight adolescents had significantly lower ratio of flow mediated dilation to Glyceryltrinitrate mediated dilation (0.40 plusminus 0.41 versus 0.61 plusminus 0.17; P = 0.039). On age and sex adjusted multiple regression analysis, the ratio of flow mediated to Glyceryltrinitrate mediated dilation had a significant negative association with body mass index (P = 0.012) and mean skin fold thickness (P = 0.011). However, for mean skin fold thickness, flow mediated dilation also had a significant negative association (P = 0.027). None of the measures of arterial mechanics were significantly different amongst overweights and controls, or significantly associated with either body mass index or mean skin fold thickness. CONCLUSION: Endothelial function can be mildly impaired in apparently healthy adolescents who are overweight (assessed by body mass index) or adipose (assessed by skin fold thickness). The use of overweight for screening adolescents likely to develop coronary artery disease is therefore justified. Skin fold thickness is a better indicator than Body Mass Index for predicting endothelial function.

Nitratos orgánicos en su segundo siglo / Organic nitrates in their second century

Se hizo una revisión actualizada de los nitratos orgánicos que tienen casi un siglo y medio de introducidos en la terapéutica de la cardiopatía isquémica. Este grupo de drogas induce la formación de óxido nítrico en la célula del músculo liso arterial y así provoca un aumento en los niveles de guanosín monofosfato cíclico, que a su vez, reduce las concentraciones citosólicas de ión calcio lo que causa vasodilatación principalmente venosa. La reducción del retorno venoso al corazón disminuye el trabajo cardiaco y el consumo de oxígeno miocárdico. Su eficacia clínica está ampliamente demostrada, por lo que continúan siendo medicamentos de primera línea en el tratamiento de diversas afecciones cardiacas. Un efecto adverso muy importante es la tolerancia, la cual ha llevado a la búsqueda de combinaciones terapéuticas de nitratos para lograr su reducción. No obstante, parece ser que lo fundamental es lograr un período libre de nitratos, reducir la dosis a la mínima y evitar algunas formas farmacéuticas de larga duración que provocan la aparición de este evento. Parece razonable asumir que ocurra tolerancia cruzada entre nitratos, lo que restaría eficacia al tratamiento de las crisis anginosas. Otro efecto adverso es el síndrome de supresión que puede ser causa de un aumento de la frecuencia y gravedad de las crisis isquémicas

Uso de la nitroglicerina local en el tratamiento de la fisura anal / Local application of nitroglycerin in the anal fissure treatment

La fisura anal (FA) es una entidad común, que produce dolor anal en la defecación, en que participa una isquemia relativa del canal anal, asociado a una hipertonicidad esfinteriana. La aplicación tópica de Glicerolato de Trinitrina (GT) produce relajación del esfínter interno, llevando a la cicatrización de la FA en un plazo de 4 a 6 semanas. Se realizó un estudio prospectivo en el que se trataron 19 pacientes con FA con GT al 0,2 por ciento usando en forma tópica tres veces al día. La desaparición del dolor se evidenció en 17 pacientes (89,5 por ciento), en promedio a los 15 días de tratamiento. La cicatrización de la FA ocurrió en 14 pacientes (73,7 por ciento), en promedios a los 22 días. No cicatrizaron 5 pacientes (26,3 por ciento). Este estudio muestra que la mayoría de los pacientes portadores de FA pueden ser tratados con GT al 0,2 por ciento en forma tópica y aquellos en quienes fracasa el tratamiento o presentan intolerancia al medicamento debieran ser sometidos a cirugía convencional

Vasodilatadores en arterias radiales humanas aisladas / Vasodilators in isolated human radial arteries

Este trabajo se diseñó para evaluar la efectividad de diversos vasodilatadores aplicados tópicamente para prevenir la hiperreactividad de las arterias radiales (AR) implantadas como bypass aortocoronario. De cada uno de los remanentes de AR provenientes de 20 pacientes operados se obtuvieron 4 anillos que se incubaron por 30 minutos en condiciones control (n = 20) o en presencia de 30 µM de diltiazem (DILT, n = 6), mibefradil (MIBE, n = 4) o mezcla de verapamil + nitroglicerina (VP-NTG, n = 6). La subsiguiente exposición a CIK 80 mM (en ausencia de vasodilatadores) provocó una contracción sostenida en los anillos control, que fue atenuada en un 35 ñ 9 por ciento por DILT, 48 ñ 13 por ciento por VP-NTG y 69 ñ 20 por ciento por MIBE (p < 0.05). La preincubación con vasodilatadores provocó también la disminución de frecuencia e intensidad de contracciones rítmicas espontáneas de la AR. En anillos almacenados en frío por 24 hs y luego reestimulados con CIK 80 mM el efecto depresor fue aun evidente: DILT 53 ñ 6 por ciento, VP-NTG 46 ñ 14 por ciento y MIBE 61 ñ 9 por ciento (p < 0.05). El efecto del MIBE fue más intenso y persistente que el de DILT o VP-NTG, aún a concentraciones que provocan un igual efecto depresor inicial. Se concluye que la exposición a vasodilatadores durante un período equivalente a la duración de la preparación de la AR a implantar produce una atenuación de la reactividad arterial que proporcionaría una protección adicional contra el espasmo durante el postoperatorio inmediato.

Increased basal tone and hyperresponsiveness to acetylcholine and ergonovine in spasm related coronary arteries in patients with variant angina: basal coronary artery tone in patients with variant angina

In patients with variant angina, previous data have been inconclusive as to whether basal coronary artery tone is elevated at the spastic and non-spastic sites. Thus, the purpose of this study was to assess the basa coronary artery tone and the responsiveness to acetylcholine (Ach) and ergonovine (Erg) in patients with variant angina. We compared the basal coronary artery tone and the constrictive responses to Ach and Erg between 31 patients (Group 1) with variant angina in whom spasm was provoked by the low doses of Ach (intracoronary 20 micrograms) or Erg(intravenous 50 micrograms) and 35 patients (Group 2) provoked by higher doses of Ach (intracoronary 100 micrograms) or Erg (intravenous cumulative dose of 350 micrograms), and 26 control subjects. Patients with variant angina in whom spasm was provoked by low doses of Ach or Erg, had a higher incidence of mixed disease, multi-vessel spasm and higher disease activity. The basal coronary artery tone at the spastic and nonspastic sites of spasm related artery was significantly more elevated in Group 1 than that in Group 2 (44+/- 17 vs 14 +/- 11% and 26 +/- 14 vs 16 +/- 10% respectively, P< 0.05), but not in the nonspasm related artery, The magnitudes of vasoconstrictive responses to Ach and Erg at the nonspastic sites were also greater in Group 1 than those in Group 2 and the control groups (Ach; 40 +/- 20 vs 26+/- 11, 27 +/- 12%: Erg; 37 +/- 18 vs 12 +/- 8, 13 +/- 10% respectively, P< 0.05). However, the basal coronary artery tone was not elevated at the spastic and nonspastic sites in Group 2 compared to the in control subjects. These findings suggest that the basal coronary artery tone is increased in patients with variant angina with higher disease activity at the spastic sites and nonspastic sites of the spasm-related artery, and this may be related to the occurrence of coronary artery spasm.

Transdermal glyceryl trinitrate (nitroglycerin) in healthy persons: acute effects on skin temperature and hemodynamic orthostatic response

MATERIAIS E METODOS: Em 63 pessoas, antes e após aplicaçäo tópica de discos de nitroglicerina ou glicerina como placebo, foram avaliadas: a temperatura cutâneaem ambos os antebraços e as relaçöes hemodinâmicas em posiçäo supina e ortostática. RESULTADOS: As respostas foram as seguintes: 1. Uma hora após aplicaçäo unilateral (no antebraço esquerdo) houve aumento da temperatura cutânea também no antebraço direito, indicando efeito sistêmico; esse efeito era mais acentuado e prolongado em mulheres obesas. 2. A fototermo-reaçäo (eritema) induzida com luz ultravioleta (UV) foi menor no antebraço esquerdo, sugerindo que a nitroglicerina age mais sobre arteríolas do que sobre capilares do sistema vascular. 3. A aplicaçäo transdérmica de nitroglicerina causou uma moderada reaçäo ortostática com diminuiçäo da pressäo arterial e aumento da freqüência cardíaca. A duraçäo do Qtc no ECG era prolongada. 4. Foram observadas as seguintes reaçöes individuais em posiçäo supina: em 7 homens houve uma reaçäo adversa com aumento da pressäo média em +12 por cento e aumento da freqüência cardíaca em +10 por cento; a mesma reaçäo (simpática?) foi descrito por Murell em 1879, após nitroglicerina v.o. Em homens fumantes e aqueles com hipertensäo e diabetes em membros próximos da família, o efeito hipotensor após nitroglicerina transdérmica era acentuado em posiçäo supina.

Tolerância aos nitratos orgânicos / Tolerance to organic nitrates

Este trabalho apresenta uma síntese dos principais mecanismos envolvidos no desenvolvimento de tolerância ao uso dos nitratos e orienta a melhor maneira de minimizar o problema na prática clínica

Effect of vasoactive drugs on muscle fibre types and capillares

The effect of nitroglycerin, nifedipine, diltiazem or propranolol on fibre types and capillaries was studied in extensor digitorum longus (EDL) and soleus (S) muscles of the rat. In EDL muscle nifedipine increased the proportion of type I fibres (7.9 percent +/- 1.7 vs. 4.7 percent +/- 2.7). Nitroglycerin and dialtiazem decreased IIB fibres (40.7 percent +/- 10.6 and 37.3 percent +/- 14.6 respectively vs. 52.3 percent +/- 9.4). Propranolol increased IIB fibres to 66.3 percent +/- 8.1, while reducing IIA fibres (25.3 percent +/- 6.6 vs. 42.2 percent +/- 6.9). No changes in fibre type proportion were found in S muscle. Capillary density was increased in EDL by nitroglycerin (965 +/- 171 vs. 818 +/- 98 cap/mm2). Propranolol had a dual effect on this parameter, decreasing it in EDL to 570 +/- 85 and augmenting it in S (754 +/- 117 vs. 601 +/- 121). No change was found in capillary to fibre ratio with any of the drugs either in EDL or S muscles. In EDL all the drugs except propranolol, which had the opposite effect, decreased the area of IIA fibre per capillary around 20 percent this effect can be interpreted as a reduction of diffusion distance from blood to fibre