Background. Coronary revascularization with cardiopulmonary bypass has the potential risk of rena... more Background. Coronary revascularization with cardiopulmonary bypass has the potential risk of renal dysfunction related to the nonphysiologic nature of cardiopulmonary bypass. Recently, there has been a revival of interest in performing myocardial revascularization on the beating heart and we investigated whether this prevents renal compromise.Methods. A prospective, randomized, controlled trial was performed in 50 patients (45 males, mean age 61 ± 3.7 years) undergoing elective coronary artery bypass grafting. Patients were randomly assigned to conventional revascularization with cardiopulmonary bypass (on pump) or beating heart revascularization (off pump). Glomerular and tubular function were assessed up to 48 hours postoperatively.Results. There were no deaths, myocardial infarctions or acute renal failure in either group. Glomerular filtration as assessed by creatinine clearance and the urinary microalbumin/creatinine ratio was significantly worse in the on pump group (p < 0.0004 and 0.0083, respectively). Renal tubular function was also impaired in the on pump group as assessed by increased N-acetyl glucosaminidase activity (p < 0.0272).Conclusions. These results suggest that off pump coronary revascularization offers a superior renal protection when compared with conventional coronary revascularization with cardiopulmonary bypass and cardioplegic arrest in first time coronary bypass patients.
This paper is concerned with the simulation of the Par- tial Differential Equation (PDE) driven e... more This paper is concerned with the simulation of the Par- tial Differential Equation (PDE) driven evolution of a closed surface by means of an implicit representation. In most applications, the natu- ral choice for the implicit representation is the signed distance function to the closed surface. Osher and Sethian propose to evolve the distance function with a Hamilton-Jacobi equation. Unfortunately the solution to this equation is not a distance function. As a consequence, the practi- cal application of the level set method is plagued with such questions as when do we have to “reinitialize” the distance function? How do we “reinitialize” the distance function? Etc... which reveal a disagreement between the theory and its implementation. This paper proposes an al- ternative to the use of Hamilton-Jacobi equations which eliminates this contradiction: in our method the implicit representation always remains a distance function by construction, and the implementation does not differ from the theory anymore. This is achieved through the introduc- tion of a new equation. Besides its theoretical advantages, the proposed method also has several practical advantages which we demonstrate in two applications: (i) the segmentation of the human cortex surfaces from MRI images using two coupled surfaces [26], (ii) the construction of a hierarchy of Euclidean skeletons of a 3D surface.
We present a novel algorithm for recovering a smooth manifold of unknown dimension and topology f... more We present a novel algorithm for recovering a smooth manifold of unknown dimension and topology from a set of points known to belong to it. Numerous applications in computer vision can be naturally interpreted as instanciations of this fundamental problem. Recently, a non-iterative discrete approach, tensor voting, has been introduced to solve this problem and has been applied successfully to various applications. As an alternative, we propose a variational formulation of this problem in the continuous setting and derive an iterative algorithm which approximates its solutions. This method and tensor voting are somewhat the differential and integral form of one another. Although iterative methods are slower in general, the strength of the suggested method is that it can easily be applied when the ambient space is not Euclidean, which is important in many applications. The algorithm consists in solving a partial differential equation that performs a special anisotropic diffusion on an implicit representation of the known set of points. This results in connecting isolated neighbouring points. This approach is very simple, mathematically sound, robust and powerful since it handles in a homogeneous way manifolds of arbitrary dimension and topology, embedded in Euclidean or non-Euclidean spaces, with or without border. We shall present this approach and demonstrate both its benefits and shortcomings in two different contexts: (i) data visual analysis, (ii) skin detection in color images.
Background. The internal thoracic artery (ITA) has become increasingly important in coronary arte... more Background. The internal thoracic artery (ITA) has become increasingly important in coronary artery bypass grafting due to the excellent long-term results. This study reviews its anatomic characteristics.Methods. The ITAs of 100 cadavers were examined and their origin, relation to the phrenic nerve, presence of lateral costal branch; origin of pericardiacophrenic arteries, length, level and type of ITA termination, relation with the transverse muscle of thorax, collateral parietal branches, and distance between the ITA and sternal margins were studied.Results. The ITA was present in all cases, originating directly from the subclavian artery or from a common trunk with other arteries. Its length was 20.4 cm on average, and the most frequent level of termination was at the sixth intercostal space, existing as a bifurcation in 93% and as a trifurcation in 7%. The pericardiacophrenic artery originated from the ITA in 89%. The lateral costal branch was present in 15% of the cases. The ITA was covered by the transverse muscle of the thorax for 7.5 cm (average) and was crossed anteriorly by the phrenic nerve in 70.0%.Conclusions. Information provided by this study may contribute to knowledge of its anatomic characteristics and in turn help prevent complications in ITA dissections.
Myocardial protection techniques during cardiac surgery have been largely investigated in the cli... more Myocardial protection techniques during cardiac surgery have been largely investigated in the clinical setting of coronary revascularisation. Few studies have been carried out on patients with left ventricular hypertrophy where the choice of delivery, and temperature of cardioplegia remain controversial. This study investigates metabolic changes and myocardial injury in hypertrophic hearts of patients undergoing aortic valve surgery using antegrade cold or warm blood cardioplegia. Thirty-five patients were prospectively randomised to intermittent antegrade cold or warm blood cardioplegia. Left ventricular biopsies were collected at 5min following institution of cardiopulmonary bypass, 30min after cross-clamping the aorta and 20min after cross-clamp removal, and used to determine metabolic changes during surgery. Metabolites (adenine nucleotides, amino acids and lactate) were measured using high pressure liquid chromatography and enzymatic techniques. Postoperative myocardial troponin I release was used as a marker of myocardial injury. Ischaemic arrest was associated with significant increase in lactate and alanine/glutamate ratio only in the warm blood group. During reperfusion, alanine/glutamate ratio was higher than preischaemic levels in both groups, but the extent of the increase was considerably greater in the warm blood group. Troponin I release was markedly (P&amp;amp;amp;amp;lt;0.05, Mean+/-SD) lower at 1, 24 and 48h postoperatively in the cold compared to the warm blood group (0.51+/-0.37, 0.37+/-0.22 and 0.27+/-0.19 vs. 0.75+/-0.42, 0.73+/-0.51 and 0.54+/-0.38ng/ml for cold vs. warm group, respectively). Cold blood cardioplegia is associated with less ischaemic stress and myocardial injury compared to warm blood cardioplegia in patients with aortic stenosis undergoing valve replacement surgery. Both cardioplegic techniques, however, confer sub-optimal myocardial protection.
Abstract. The nature of the enhanced blood fibrinolytic activity which is known to occur during c... more Abstract. The nature of the enhanced blood fibrinolytic activity which is known to occur during cardiopulmonary bypass is not understood. We show here that the cause is an increase in extrinsic (tissue-type) plasminogen activator.In six patients, the nature of the enhanced blood fibrinolytic activity that evolved during cardiopulmonary bypass was characterized by differential inhibition using the fibrin plate method and was shown to be C1-inactivator-resistant (extrinsic-activator activity). The C1-inactivator-resistant-activator activity was completely quenched by an antibody against extrinsic (tissue-type) plasminogen activator but not by antiurokinase, proving that the activity was due to the presence of extrinsic (tissue-type) plasminogen activator. The concentration of extrinsic (tissue-type) plasminogen activator increased during cardiopulmonary bypass and disappeared rapidly thereafter. Fibrinogen, plasminogen and α2-antiplasmin were not consumed during cardiopulmonary bypass, while no increase or occasionally a moderate one in fibrinogen degradation products occurred. This is in accord with the property of extrinsic (tissue-type) plasminogen activator which activates plasminogen predominantly at sites where fibrin is present and not in the free circulation.
To evaluate the continued efficacy and safety of alendronate (ALN) for up to 2 years in patients ... more To evaluate the continued efficacy and safety of alendronate (ALN) for up to 2 years in patients receiving glucocorticoids. This is a 12-month extension of a previously completed 1-year trial of daily ALN, performed to evaluate the effects of ALN over a total of 2 years in 66 men and 142 women continuing to receive at least 7.5 mg of prednisone or equivalent daily. All patients received supplemental calcium and vitamin D. The primary end point was the mean percentage change in lumbar spine bone mineral density (BMD) from baseline to 24 months. Other outcomes included changes in hip and total body BMD, biochemical markers of bone turnover, radiographic joint damage of the hands, and vertebral fracture incidence. The mean (+/-SEM) lumbar spine BMD increased by 2.8 +/- 0.6%, 3.9 +/- 0.7%, and 3.7 +/- 0.6%, respectively, in the groups that received 5 mg, 10 mg, and 2.5/10 mg of ALN daily (P &amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;lt; or = 0.001) and decreased by -0.8 +/- 0.6% in the placebo group (P not significant) over 24 months. In patients receiving any dose of ALN, BMD was increased at the trochanter (P &amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;lt; or = 0.05) and maintained at the femoral neck. Total body BMD was increased in patients receiving 5 or 10 mg ALN (P &amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;lt; or = 0.01). These 2 dose levels of ALN were more effective than placebo at all sites (P &amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;lt; or = 0.05). Bone turnover markers (N-telopeptides of type I collagen and bone-specific alkaline phosphatase) decreased 60% and 25%, respectively, during treatment with ALN (P &amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;lt; or = 0.05). There were fewer patients with new vertebral fractures in the ALN group versus the placebo group (0.7% versus 6.8%; P = 0.026). The safety profile was similar between treatment groups. Alendronate is an effective, well-tolerated therapy for the prevention and treatment of glucocorticoid-induced osteoporosis, with sustained treatment advantages for up to 2 years.
To evaluate the surgical outcome of preserved amniotic membrane transplantation (AMT) for ocular ... more To evaluate the surgical outcome of preserved amniotic membrane transplantation (AMT) for ocular surface reconstruction in chemical burn with limbal stem cell deficiency. Prospective, noncomparative, interventional case series. Twenty eyes of 20 consecutive patients with limbal stem cell deficiency secondary to ocular chemical injury. AMT with or without adjunctive limbal transplantation using limbal tissue from either the healthy contralateral eye (CLAU) or a living related donor (lr-CLAL). Reconstruction of corneal epithelium (clear appearance without epithelial defect, normal fluorescein permeability and the absence of conjunctiva-derived goblet cells on impression cytology), decrease in corneal vascularization and improvement in visual acuity. With a mean follow-up time of 19 months (range, 8-27 months), satisfactory ocular surface reconstruction was obtained in 15 eyes (75%), with reduced inflammation and vascularization of the ocular surface and a mean epithelialization time of 3.3 weeks. Success was observed in all cases of partial limbal stem cell deficiency (PLD) and in 68.75% (11 eyes) of cases of total limbal stem cell deficiency (TLD). Surgical failure was observed in five severe cases (31.25%). A significant visual improvement was observed in all cases after surgery, except for 2 eyes that maintained preoperative visual acuity. AMT seems to be an efficient adjunct for ocular surface reconstruction in chemical burns with PLD. When performed in conjunction with limbal stem cell transplantation, it is also effective in most cases of TLD.
Background. Tumor necrosis factor-α has been implicated in complications seen after cardiac opera... more Background. Tumor necrosis factor-α has been implicated in complications seen after cardiac operations with cardiopulmonary bypass. The release of tumor necrosis factor-α and its possible effects were studied in patients undergoing coronary artery bypass grafting with and without cardiopulmonary bypass.Methods. Twenty patients were studied, 10 with (group 1) and 10 without cardiopulmonary bypass (group 2). Serial blood samples were obtained before, during, and up to 48 hours after operation. Circulating tumor necrosis factor-α levels, leukocyte counts, and erythrocyte sedimentation rates were measured. Hemodynamic variables (blood pressure and heart rate), temperature, orotracheal intubation time, postoperative bleeding, and inotropic drug requirements were compared.Results. Serum levels of tumor necrosis factor-α were detected in 6 patients (60%) in group 1 and none in group 2. The patients in group 1 had more hypotension than those in group 2 (7.4 ± 1.0 mm Hg versus 8.5 ± 0.7 mm Hg), required more inotropic drugs (8 patients versus 1 patient), and had a higher heart rate (114 ± 8 beats per minute versus 98 ± 10 beats per minute), a higher temperature (37.1° ± 0.5°C versus 36.6° ± 0.3°C), increased postoperative bleeding (820 ± 120 mL versus 360 ± 84 mL), a longer orotracheal intubation time (13.6 ± 2.2 hours versus 9.3 ± 1.4 hours), and a more pronounced leukocytosis.Conclusions. Cardiopulmonary bypass induces the whole-body inflammatory response through the release of tumor necrosis factor α, resulting in adverse systemic effects.
Energy requirements to produce ethyl alcohol from three different crops in Brazil (sugarcane, cas... more Energy requirements to produce ethyl alcohol from three different crops in Brazil (sugarcane, cassava, and sweet sorghum) were calculated. Figures are presented for the agricultural and industrial phases. The industrial phase is always more energy-intensive, consuming from 60 to 75 percent of the total energy. Sugarcane is the more efficient crop for ethyl alcohol production, followed by sweet sorghum and cassava from a net energy viewpoint. The utilization of sweet sorghum stems might increase the total energy gain from this crop to almost the same level as sugarcane. Cassava has a lower energy gain at the present state of agriculture in Brazil.
Background. Coronary revascularization with cardiopulmonary bypass has the potential risk of rena... more Background. Coronary revascularization with cardiopulmonary bypass has the potential risk of renal dysfunction related to the nonphysiologic nature of cardiopulmonary bypass. Recently, there has been a revival of interest in performing myocardial revascularization on the beating heart and we investigated whether this prevents renal compromise.Methods. A prospective, randomized, controlled trial was performed in 50 patients (45 males, mean age 61 ± 3.7 years) undergoing elective coronary artery bypass grafting. Patients were randomly assigned to conventional revascularization with cardiopulmonary bypass (on pump) or beating heart revascularization (off pump). Glomerular and tubular function were assessed up to 48 hours postoperatively.Results. There were no deaths, myocardial infarctions or acute renal failure in either group. Glomerular filtration as assessed by creatinine clearance and the urinary microalbumin/creatinine ratio was significantly worse in the on pump group (p < 0.0004 and 0.0083, respectively). Renal tubular function was also impaired in the on pump group as assessed by increased N-acetyl glucosaminidase activity (p < 0.0272).Conclusions. These results suggest that off pump coronary revascularization offers a superior renal protection when compared with conventional coronary revascularization with cardiopulmonary bypass and cardioplegic arrest in first time coronary bypass patients.
This paper is concerned with the simulation of the Par- tial Differential Equation (PDE) driven e... more This paper is concerned with the simulation of the Par- tial Differential Equation (PDE) driven evolution of a closed surface by means of an implicit representation. In most applications, the natu- ral choice for the implicit representation is the signed distance function to the closed surface. Osher and Sethian propose to evolve the distance function with a Hamilton-Jacobi equation. Unfortunately the solution to this equation is not a distance function. As a consequence, the practi- cal application of the level set method is plagued with such questions as when do we have to “reinitialize” the distance function? How do we “reinitialize” the distance function? Etc... which reveal a disagreement between the theory and its implementation. This paper proposes an al- ternative to the use of Hamilton-Jacobi equations which eliminates this contradiction: in our method the implicit representation always remains a distance function by construction, and the implementation does not differ from the theory anymore. This is achieved through the introduc- tion of a new equation. Besides its theoretical advantages, the proposed method also has several practical advantages which we demonstrate in two applications: (i) the segmentation of the human cortex surfaces from MRI images using two coupled surfaces [26], (ii) the construction of a hierarchy of Euclidean skeletons of a 3D surface.
We present a novel algorithm for recovering a smooth manifold of unknown dimension and topology f... more We present a novel algorithm for recovering a smooth manifold of unknown dimension and topology from a set of points known to belong to it. Numerous applications in computer vision can be naturally interpreted as instanciations of this fundamental problem. Recently, a non-iterative discrete approach, tensor voting, has been introduced to solve this problem and has been applied successfully to various applications. As an alternative, we propose a variational formulation of this problem in the continuous setting and derive an iterative algorithm which approximates its solutions. This method and tensor voting are somewhat the differential and integral form of one another. Although iterative methods are slower in general, the strength of the suggested method is that it can easily be applied when the ambient space is not Euclidean, which is important in many applications. The algorithm consists in solving a partial differential equation that performs a special anisotropic diffusion on an implicit representation of the known set of points. This results in connecting isolated neighbouring points. This approach is very simple, mathematically sound, robust and powerful since it handles in a homogeneous way manifolds of arbitrary dimension and topology, embedded in Euclidean or non-Euclidean spaces, with or without border. We shall present this approach and demonstrate both its benefits and shortcomings in two different contexts: (i) data visual analysis, (ii) skin detection in color images.
Background. The internal thoracic artery (ITA) has become increasingly important in coronary arte... more Background. The internal thoracic artery (ITA) has become increasingly important in coronary artery bypass grafting due to the excellent long-term results. This study reviews its anatomic characteristics.Methods. The ITAs of 100 cadavers were examined and their origin, relation to the phrenic nerve, presence of lateral costal branch; origin of pericardiacophrenic arteries, length, level and type of ITA termination, relation with the transverse muscle of thorax, collateral parietal branches, and distance between the ITA and sternal margins were studied.Results. The ITA was present in all cases, originating directly from the subclavian artery or from a common trunk with other arteries. Its length was 20.4 cm on average, and the most frequent level of termination was at the sixth intercostal space, existing as a bifurcation in 93% and as a trifurcation in 7%. The pericardiacophrenic artery originated from the ITA in 89%. The lateral costal branch was present in 15% of the cases. The ITA was covered by the transverse muscle of the thorax for 7.5 cm (average) and was crossed anteriorly by the phrenic nerve in 70.0%.Conclusions. Information provided by this study may contribute to knowledge of its anatomic characteristics and in turn help prevent complications in ITA dissections.
Myocardial protection techniques during cardiac surgery have been largely investigated in the cli... more Myocardial protection techniques during cardiac surgery have been largely investigated in the clinical setting of coronary revascularisation. Few studies have been carried out on patients with left ventricular hypertrophy where the choice of delivery, and temperature of cardioplegia remain controversial. This study investigates metabolic changes and myocardial injury in hypertrophic hearts of patients undergoing aortic valve surgery using antegrade cold or warm blood cardioplegia. Thirty-five patients were prospectively randomised to intermittent antegrade cold or warm blood cardioplegia. Left ventricular biopsies were collected at 5min following institution of cardiopulmonary bypass, 30min after cross-clamping the aorta and 20min after cross-clamp removal, and used to determine metabolic changes during surgery. Metabolites (adenine nucleotides, amino acids and lactate) were measured using high pressure liquid chromatography and enzymatic techniques. Postoperative myocardial troponin I release was used as a marker of myocardial injury. Ischaemic arrest was associated with significant increase in lactate and alanine/glutamate ratio only in the warm blood group. During reperfusion, alanine/glutamate ratio was higher than preischaemic levels in both groups, but the extent of the increase was considerably greater in the warm blood group. Troponin I release was markedly (P&amp;amp;amp;amp;lt;0.05, Mean+/-SD) lower at 1, 24 and 48h postoperatively in the cold compared to the warm blood group (0.51+/-0.37, 0.37+/-0.22 and 0.27+/-0.19 vs. 0.75+/-0.42, 0.73+/-0.51 and 0.54+/-0.38ng/ml for cold vs. warm group, respectively). Cold blood cardioplegia is associated with less ischaemic stress and myocardial injury compared to warm blood cardioplegia in patients with aortic stenosis undergoing valve replacement surgery. Both cardioplegic techniques, however, confer sub-optimal myocardial protection.
Abstract. The nature of the enhanced blood fibrinolytic activity which is known to occur during c... more Abstract. The nature of the enhanced blood fibrinolytic activity which is known to occur during cardiopulmonary bypass is not understood. We show here that the cause is an increase in extrinsic (tissue-type) plasminogen activator.In six patients, the nature of the enhanced blood fibrinolytic activity that evolved during cardiopulmonary bypass was characterized by differential inhibition using the fibrin plate method and was shown to be C1-inactivator-resistant (extrinsic-activator activity). The C1-inactivator-resistant-activator activity was completely quenched by an antibody against extrinsic (tissue-type) plasminogen activator but not by antiurokinase, proving that the activity was due to the presence of extrinsic (tissue-type) plasminogen activator. The concentration of extrinsic (tissue-type) plasminogen activator increased during cardiopulmonary bypass and disappeared rapidly thereafter. Fibrinogen, plasminogen and α2-antiplasmin were not consumed during cardiopulmonary bypass, while no increase or occasionally a moderate one in fibrinogen degradation products occurred. This is in accord with the property of extrinsic (tissue-type) plasminogen activator which activates plasminogen predominantly at sites where fibrin is present and not in the free circulation.
To evaluate the continued efficacy and safety of alendronate (ALN) for up to 2 years in patients ... more To evaluate the continued efficacy and safety of alendronate (ALN) for up to 2 years in patients receiving glucocorticoids. This is a 12-month extension of a previously completed 1-year trial of daily ALN, performed to evaluate the effects of ALN over a total of 2 years in 66 men and 142 women continuing to receive at least 7.5 mg of prednisone or equivalent daily. All patients received supplemental calcium and vitamin D. The primary end point was the mean percentage change in lumbar spine bone mineral density (BMD) from baseline to 24 months. Other outcomes included changes in hip and total body BMD, biochemical markers of bone turnover, radiographic joint damage of the hands, and vertebral fracture incidence. The mean (+/-SEM) lumbar spine BMD increased by 2.8 +/- 0.6%, 3.9 +/- 0.7%, and 3.7 +/- 0.6%, respectively, in the groups that received 5 mg, 10 mg, and 2.5/10 mg of ALN daily (P &amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;lt; or = 0.001) and decreased by -0.8 +/- 0.6% in the placebo group (P not significant) over 24 months. In patients receiving any dose of ALN, BMD was increased at the trochanter (P &amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;lt; or = 0.05) and maintained at the femoral neck. Total body BMD was increased in patients receiving 5 or 10 mg ALN (P &amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;lt; or = 0.01). These 2 dose levels of ALN were more effective than placebo at all sites (P &amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;lt; or = 0.05). Bone turnover markers (N-telopeptides of type I collagen and bone-specific alkaline phosphatase) decreased 60% and 25%, respectively, during treatment with ALN (P &amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;lt; or = 0.05). There were fewer patients with new vertebral fractures in the ALN group versus the placebo group (0.7% versus 6.8%; P = 0.026). The safety profile was similar between treatment groups. Alendronate is an effective, well-tolerated therapy for the prevention and treatment of glucocorticoid-induced osteoporosis, with sustained treatment advantages for up to 2 years.
To evaluate the surgical outcome of preserved amniotic membrane transplantation (AMT) for ocular ... more To evaluate the surgical outcome of preserved amniotic membrane transplantation (AMT) for ocular surface reconstruction in chemical burn with limbal stem cell deficiency. Prospective, noncomparative, interventional case series. Twenty eyes of 20 consecutive patients with limbal stem cell deficiency secondary to ocular chemical injury. AMT with or without adjunctive limbal transplantation using limbal tissue from either the healthy contralateral eye (CLAU) or a living related donor (lr-CLAL). Reconstruction of corneal epithelium (clear appearance without epithelial defect, normal fluorescein permeability and the absence of conjunctiva-derived goblet cells on impression cytology), decrease in corneal vascularization and improvement in visual acuity. With a mean follow-up time of 19 months (range, 8-27 months), satisfactory ocular surface reconstruction was obtained in 15 eyes (75%), with reduced inflammation and vascularization of the ocular surface and a mean epithelialization time of 3.3 weeks. Success was observed in all cases of partial limbal stem cell deficiency (PLD) and in 68.75% (11 eyes) of cases of total limbal stem cell deficiency (TLD). Surgical failure was observed in five severe cases (31.25%). A significant visual improvement was observed in all cases after surgery, except for 2 eyes that maintained preoperative visual acuity. AMT seems to be an efficient adjunct for ocular surface reconstruction in chemical burns with PLD. When performed in conjunction with limbal stem cell transplantation, it is also effective in most cases of TLD.
Background. Tumor necrosis factor-α has been implicated in complications seen after cardiac opera... more Background. Tumor necrosis factor-α has been implicated in complications seen after cardiac operations with cardiopulmonary bypass. The release of tumor necrosis factor-α and its possible effects were studied in patients undergoing coronary artery bypass grafting with and without cardiopulmonary bypass.Methods. Twenty patients were studied, 10 with (group 1) and 10 without cardiopulmonary bypass (group 2). Serial blood samples were obtained before, during, and up to 48 hours after operation. Circulating tumor necrosis factor-α levels, leukocyte counts, and erythrocyte sedimentation rates were measured. Hemodynamic variables (blood pressure and heart rate), temperature, orotracheal intubation time, postoperative bleeding, and inotropic drug requirements were compared.Results. Serum levels of tumor necrosis factor-α were detected in 6 patients (60%) in group 1 and none in group 2. The patients in group 1 had more hypotension than those in group 2 (7.4 ± 1.0 mm Hg versus 8.5 ± 0.7 mm Hg), required more inotropic drugs (8 patients versus 1 patient), and had a higher heart rate (114 ± 8 beats per minute versus 98 ± 10 beats per minute), a higher temperature (37.1° ± 0.5°C versus 36.6° ± 0.3°C), increased postoperative bleeding (820 ± 120 mL versus 360 ± 84 mL), a longer orotracheal intubation time (13.6 ± 2.2 hours versus 9.3 ± 1.4 hours), and a more pronounced leukocytosis.Conclusions. Cardiopulmonary bypass induces the whole-body inflammatory response through the release of tumor necrosis factor α, resulting in adverse systemic effects.
Energy requirements to produce ethyl alcohol from three different crops in Brazil (sugarcane, cas... more Energy requirements to produce ethyl alcohol from three different crops in Brazil (sugarcane, cassava, and sweet sorghum) were calculated. Figures are presented for the agricultural and industrial phases. The industrial phase is always more energy-intensive, consuming from 60 to 75 percent of the total energy. Sugarcane is the more efficient crop for ethyl alcohol production, followed by sweet sorghum and cassava from a net energy viewpoint. The utilization of sweet sorghum stems might increase the total energy gain from this crop to almost the same level as sugarcane. Cassava has a lower energy gain at the present state of agriculture in Brazil.
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