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C Saldanha

Publications and source records attributed to C Saldanha.

At least 19 recordsLinked to original sources

Effects of low-fat milk enriched with phytosterols on plasma cholesterol concentrations and hemorheological parameters of Wistar rats.

Clinical and experimental studies have shown that the use of phytosterol esters as a food ingredient reduces the plasma concentrations of cholesterol and LDL cholesterol, not affecting the HDL cholesterol levels. Based on the use of phytosterols as a food ingredient, we have conducted a 30-day feeding study with Wistar rats, drinking low-fat milk containing phytosterols, in order to evaluate the plasma cholesterol concentrations and the hemorheological parameters. Throughout the study, clinical observations, body weights and food and milk consumption were measured and at the end of the feeding period, blood samples were collected for biochemical and hemorheological determinations. There were no clinical changes, alterations in growth, food or milk consumption. In the plasma cholesterol and HDL concentrations there were no significant differences, but LDL levels decreased about 70%. In the hemorheological parameters, significant changes were observed in plasma viscosity and in membrane fluidity in all experimental groups. The blood viscosity and the erythrocyte deformability show significant improvements with the ingestion of the phytosterols enriched milk. With these results we conclude that phytosterols maintain their cholesterol lowering properties when incorporated in milk and can be considered a hypolipemic food component.

Animals↗

Phytosterols in milk as a depressor of plasma cholesterol levels: experimental evidence with hypercholesterolemic Portuguese subjects.

Plant sterols have been reported to decrease plasma concentrations of cholesterol without any side effects. To evaluate the effects on plasma cholesterol concentrations and the hemorheological parameters, we performed a study with hypercholesterolemic patients (n = 19) treated with phytosterol-enriched milk (2 g/day). Hypercholesterolemic patients (n = 15) of matched age drinking equal type of milk but without phytosterols were used as control group. Concentrations of total cholesterol, HDL-C, LDL-C and hemorheological parameters were measured in the beginning, after 15 and 30 days of milk intake. After 15 days of beverage intake, hypercholesterolemic subjects treated with phytosterol-enriched milk showed a significant decrease in plasma concentrations of total cholesterol and LDL-C by 9.62% (p < 0.05) and 12.20% (p < 0.05), respectively. After 30 days, a little increase in the total cholesterol and LDL-C concentrations were observed. In the hypercholesterolemic control group there were nonsignificant changes between plasma concentrations of total cholesterol, HDL-C and LDL-C during the study. The evaluation of plasma viscosity and erythrocyte aggregation shows no changes statistically significant during the study for both groups studied. The results obtained during the study show a positive effect with the phytosterol-enriched milk as plasma cholesterol-lowering as combined treatment for hypercholesterolemia.

Adult↗

The relation between the erythrocyte nitric oxide and hemorheological parameters.

We stimulated human erythrocytes obtained from patients with hypercholesterolemia (HC; n = 42), renal transplantation (RT; n = 18) and hypertension (HT; n = 10) with acetylcholine (ACh 10 microM) and measured the amperometric NO production, comparing with the NO levels achieved on erythrocytes of healthy persons (n = 27). We also measured the hemoglobin, hematocrit, erythrocyte aggregation, erythrocyte deformability, plasma viscosity and fibrinogen concentration from human blood samples. The erythrocytes NO levels were of 2.5 +/- 0.7 nM (P = 0.038, HC), 2.4 +/- 1.1 nM (RT) and 2.2 +/- 0.8 nM (HT) against the 2.0 +/- 0.8 nM for the control groups. For each group and at each shear stress value, the erythrocytes deformability decreases with the increase of the NO concentration after ACh stimulation. We observed a significant increase of the control values on the erythrocyte aggregation results on each patient group. Besides the lower erythrocyte deformability obtained on HC, RT and HT blood samples, the erythrocytes produced higher NO levels after ACh stimulation than the healthy ones. The power of erythrocyte hemorheological behaviour could be compensated by the NO production at the presence of acetylcholine. We can hypothesises that cholinergic drugs could be used as co-adjuvants of specific therapeutics compounds on these studied diseases.

Acetylcholine↗

Personality, manual preference and neuroendocrine reactivity in hirsute subjects.

Behavioral and neuroendocrine differences may be postulated in hirsute subjects since central effects of gonadal steroids are well established. We conducted a controlled clinical study with 25 consecutive young hirsute participants compared with 20 consecutive controls. Neuropsychological evaluation included the Minnesota Multiphasic Personality Inventory (MMPI) and the Edinburgh Inventory of Manual Preference (EIMP). Neuroendocrine reactivity was assessed by the adrenocorticotropic hormone (ACTH) and cortisol responses to corticotropin releasing hormone (CRH). Hirsute participants presented a flattened personality profile with lower neurotic triad scores--146 +/- 20 versus 166 +/- 28. Left-hand preference was more common in hirsute participants--4/21 versus 0/20. Decreased ACTH [area under the curve (AUC)--36 +/-2 8 vs. 72 +/- 63 pg/ml h] and cortisol (AUC--18 +/- 4 vs. 25 +/- 10 microg/dl h) responses to CRH were found in the hirsute group. In the hirsute group, higher manual preference scores were associated with lower ACTH responses to CRH, while the opposite association was found in the control group. In the hirsute group, the hyporeactive hypothalamic-pituitary-adrenal (HPA) axis was associated with lower behavior-deviant scores, while in the control group, the hyporeactive HPA axis was associated with more psychopathology. We conclude that personality and HPA axis reactivity are different in hirsute female participants when compared with controls, with a trend for differences regarding handedness. Personality and handedness are differently associated with HPA reactivity. Distinctive features in hirsute participants are probably established very early during ontogenic development.

Adrenocorticotropic Hormone↗

Fluorescent probes DPH, TMA-DPH and C17-HC induce erythrocyte exovesiculation.

An experimental approach has been developed to study human erythrocyte vesiculation, using the fluorescent probes diphenylhexatriene (DPH), trimethylamino-diphenylhexatriene (TMA-DPH) and heptadecyl-hydroxycoumarin (C17-HC). Acetylcholinesterase (AChE) enzyme activity measurements confirmed the presence of exovesicles released from erythrocyte membranes labeled with DPH, TMA-DPH or C17-HC. The fluorescence intensity and anisotropy values obtained showed that the amphiphilic probes TMA-DPH and C17-HC are preferentially incorporated in the exovesicles (when compared with DPH). There is a significant decrease of the cholesterol content of the exovesicle suspensions with time, independently of the fluorescence probe used, reaching undetectable cholesterol levels for the samples incubated for 48 hr. The ratios between the concentration of cholesterol released in the exovesicles after 1 hr incubation with DPH, TMA-DPH or C17-HC and the probe concentration used in the incubation were 84.7, 3.82 and 0.074, respectively. The size of the released vesicles was evaluated by dynamic light scattering spectroscopy. Some hypotheses are proposed that could explain the resemblance and differences between the results obtained for erythrocytes labeled with each probe, considering the present knowledge of membrane vesiculation mechanisms, lipid microdomains (rafts), erythrocyte membrane phospholipid asymmetry and AChE inhibition by TMA-DPH and C17-HC. This work demonstrates that the fluorescent probes DPH, TMA-DPH and C17-HC induce rapid erythrocyte exovesiculation; their use can lead to new methodologies for the study of this still poorly understood mechanism.

Cell Membrane↗

Biochemical, biophysical and haemorheological effects of dimethylsulphoxide on human erythrocyte calcium loading.

The studies using dimethylsulphoxide (DMSO) and/or the 4-bromo-calcium ionophore A23187 (Br-A23187) often neglect the precise knowledge of some of their biochemical, biophysical and haemorheological effects. The aim of the present study was to evaluate these effects on erythrocytes after whole blood incubations with DMSO or Br-A23187 dissolved in DMSO. There were no significant differences between the different aliquots in the values of P(50), pH, erythrocyte deformability, erythrocyte membrane fluidity, haemoglobin and intracellular Ca(2+) concentrations ([Ca(2+)](i)). Aliquots with DMSO (independently of the presence of Br-A23187 or added Ca(2+)) had lower erythrocyte aggregation indexes and higher plasma concentrations of K(+)], Na(+)] and Ca(2+) than the aliquots without DMSO (independently of the presence of added Ca(2+)). Aliquots with added calcium (without the presence of Br-A23187 in DMSO) had a significantly higher erythrocyte acetylcholinesterase activity. Our data shows that calcium loading, the usual objective of Br-A23187 incubations, cannot be fulfilled with the studied experimental conditions. The coherence between our results and those obtained by other authors with different biological systems and different modulators of the rise on [Ca(2+)](i) suggests a non-specific effect of DMSO, disabling the action of the modulator. It can be reasoned that the decreased erythrocyte aggregation (without significant changes on the deformability or membrane fluidity) can result either from the decrease of the hydrogen bonding contribution to erythrocyte aggregation or the increased ionic strength influence on the erythrocyte membrane surface.

Acetylcholinesterase↗

Hemorheological effects of sodium fluorescein in rats.

Sodium fluorescein is widely used in clinical practice for the study of the retinal circulation by angiography. It has been reported several hemorheological and microvascular abnormalities induced by this compound. The aim of this work was to analyse the hemorheological effects of intravenous sodium fluorescein in an animal model. Twenty male 10-16 weeks-old Wistar rats were used, under systemic anaesthesia. The animals were divided in 2 groups of 10 each: (1) intravenous injection of sodium fluorescein (14 mg/kg of body weight)--Group NaF, (2) controls (injection of NaCl 0.9%)--Group CTRL. A blood sample was drawn by aortic puncture after 60 minutes and hemorheological parameters determined: hematocrit, hemoglobin, metahemoglobin, carboxyhemoglobin, plasma viscosity, erythrocyte deformability, membrane fluidity and acetylcholinesterase activity. In the Group NaF there was a 20% reduction of the AChE activity (p<0.05) and an increase in PV (p<0.05). Concerning hemoglobin status, a three-fold increase in COHb (p<0.001) was shown. In conclusion, the NaF injection in the animal model produces hemorheological abnormalities similar to those reported in the human.

Animals↗

Progression to 100% off-pump coronary artery bypass with the Octopus 1 dual holder.

BACKGROUND: Can off-pump coronary artery bypass grafting become the routine standard in all elective primary coronary artery bypass grafting (CABG) operations? This paper shows how this aim has been achieved during one year in 130 off-pump cases performed through a sternotomy. This strategy allows for full revascularization (up to six grafts) without the disadvantage of cardiopulmonary bypass. The study introduces a variant of the Octopus stabilizer, a single Octopus 1 arm (Medtronic, Inc., Minneapolis, MN) with a dual holder. MATERIALS AND METHODS: From November 1998 through February 2000, 130 patients underwent coronary artery bypass grafting through a sternotomy off-pump utilizing a stabilizer and CO2 blower. The stabilizer most frequently used to achieve this was a single Octopus 1 arm equipped with a dual holder to accommodate two straight suction pods. The holder allowed increased flexibility and manipulation of the suction pods with an equivalent of seven degrees' freedom of motion at the dual holder junction. Techniques for carrying out total revascularization are discussed. The progress of proportion of elective primary CABG revascularization performed off-pump is shown and results are compared with published reviews of the literature for off-pump coronary revascularization. RESULTS: Patient demographics included: age range 32 to 87, mean 61.3; female sex: 17%; ejection fraction < 50%: 54%; presence of left main stem disease: 17%. Overall Parsonnet risk score ranged 0-31, with a mean of 8.8. Graft numbers carried out were: 34 x 2, 34 x 3, 32 x 4, 25 x 5 and 5 x 6 anastomoses respectively. The mean number of distal anastomoses was 3.6 +/- 1.0. There was extensive coverage of the lateral aspect of the heart (153 circumflex territory grafts, 33%). Radial artery, left internal mammary artery or saphenous vein sequential (jump) grafts were used in 26 cases (20%). Apart from general experience, the use of the dual holder and wide opening of the right pleura were the two important factors allowing freedom for multi-vessel lateral and posterior wall grafting. Thirteen Genzyme (Genzyme Surgical Products, Inc., Cambridge, MA) and ten Octopus 2 (or 2+) stabilizers were used, mostly for two or three grafts. The remainder were carried out using the Octopus 1 (dual holder: 83). In the first three-month period, 31% of cases were off-pump compared to the last three-month period, when 96% were off-pump. In the last two months we performed 100% of all 27 cases referred off-pump. There were no deaths, strokes or myocardial infarctions. Ventricular arrhythmia occurred in two cases. Conversions to bypass were undertaken twice. Two unexpected renal failures occurred, neither of which were from the 13 patients with preoperative incipient renal failure, of whom none suffered a rise in postoperative creatinine of greater than 30%. The results compare favorably with published results despite having a large mean number of grafts of 3.6. CONCLUSION: Off-pump surgery with full revascularization has now become feasible for all primary elective coronary artery graft operations.

Adult↗

Beta-estradiol effect on erythrocyte aggregation--a controlled in vitro study.

The purpose of this in vitro study was to assess the effect of 17beta-estradiol on hemorheologic parameters, namely on erythrocyte aggregation and deformability and membrane fluidity. Blood samples from 65 women (aged 57 +/- 4 years) undergoing postmenopausal hormone replacement therapy were obtained and were incubated for 5 min in absence and presence of 17beta-estradiol 10(-5) M. The measured parameters were the erythrocyte aggregation (EAI) and deformability (EI), the acetylcholinesterase activity (AChE), the plasma pH and osmolality and the erythrocyte membrane fluidity assessed by fluorescence polarization with two probes 1,6-diphenyl-1,3,5-hexatriene (DPH) and (1-(4-(trimethylamino)-phenyl)-6-phenyl-1,3,5-hexatriene (TMA-DPH). Data analysis was performed using t-Student and Pearson correlation analysis. A statistically significant decrease of the EAI (15.8 +/- 3.02 vs 13.45 +/- 2.3; p<0.001) and an increase of the EI (51.39 +/- 5.64 vs 52.06 +/- 5.36; p<0.01) at shear stress of 30 Pa in presence of 17beta-estradiol 10(-5) M was obtained. There was a decrease in membrane fluidity in 45 blood samples (DPH) and in the other 20 an increase, when beta-estradiol 10(-5) M was present. In vitro beta-estradiol 10(-5) M decreased erythrocyte aggregation in blood samples of postmenopausal women undergoing hormone therapy, which could prevent high blood viscosity and, consequently, cardiovascular events.

Acetylcholinesterase↗

Effects of acetylcholine and spermineNONOate on erythrocyte hemorheologic and oxygen carrying properties.

PURPOSE OF THE STUDY: To determine the effects of acetylcholine and spermineNONOate--a NO donor--on RBC membrane and oxygen carrying properties. MATERIAL AND METHODS: Aliquots of venous blood from eleven healthy subjects were incubated with ACh 10(-3) M, ACh 10(-5) M, spermineNONOate 10(-5) M and spermineNONOate 10(-4) M. The following parameters were determined: erythrocyte aggregation and deformability, hematocrit, plasma pH, osmolality, K(+), Na(+), Ca(2+) concentrations, hemoglobin, oxyhemoglobin, carboxyhemoglobin and methemoglobin concentrations, oxygen saturation of hemoglobin, oxygen and carbon dioxide partial pressures and p50. RESULTS: In presence of ACh there is an increase of erythrocyte deformability, decrease of erythrocyte aggregation, plasma pH, K(+) and Na(+) concentration, increase of Ca(2+) concentration and p50. In presence of spermineNONOate there is an increase of erythrocyte deformability, plasma pH, decrease of Na(+) and Ca(2+) concentration, increase of metHb concentration and decrease of p50. CONCLUSION: Acetylcholine and spermineNONOate are able to induce changes on RBC membrane and oxygen carrying properties.

Acetylcholine↗

Red blood cell membrane integrity in primary open angle glaucoma: ex vivo and in vitro studies.

PURPOSE: There is increasing evidence that abnormal perfusion of the optic nerve head is an important factor involved in the pathophysiology of glaucoma. Transport and distribution of oxygen to the tissues takes place through the erythrocyte membrane. Red blood cell (RBC) acetylcholinesterase (AChE) is a marker of RBC membrane integrity. The aim of this study was to find out whether RBC membrane integrity is preserved in primary open angle glaucoma (POAG), and whether it is modified by the use of topical timolol maleate and pilocarpine. METHOD: RBC AChE activity was determined ex vivo by Kaplan's spectrophotometric method in 19 POAG patients undergoing topical treatment for glaucoma with timolol, pilocarpine or a combination of the two drugs, and compared with that in 20 controls. To assess the effect of antiglaucomatous therapy in our findings, we carried out an in vitro study in 26 non-glaucomatous patients in which we measured RBC AChE activity after incubation of blood with either timolol maleate, pilocarpine or a combination of the two drugs, using the same spectrophotometric method. RESULTS: There was a significant increase in RBC AChE enzyme activity in POAG patients compared with the control group (p < 0.002). However, timolol and pilocarpine, individually or in combination, have the opposite effect, significantly decreasing RBC AChE activity (p < 0.05). CONCLUSION: This change in RBC AChE enzyme activity could suggest alterations in RBC membrane integrity in primary open angle glaucoma. Whether or not this finding has implications regarding the microcirculation at the optic nerve head needs to be investigated further.

Acetylcholinesterase↗

Sodium fluorescein influence on the hemorheological profile of non-insulin dependent diabetes mellitus patients.

Sodium fluorescein angiography is a widely used technology in ophthalmology, which allows us to visualise the chorioretinal microcirculation. Previous reports showed a prolongation of the retinal circulation time along with erythrocyte hyperaggregation and a decrease of erythrocyte acetylcholinesterase activity and a possible interference with the erythrocyte's membrane fluidity. The aim of the present work is to investigate the influence of sodium fluorescein on the hemorheological profile of a group of 23 non-insulin dependent diabetes mellitus (NIDDM) patients undergoing routine retinal angiography. Thirty minutes after the endovenous administration of the fluorescein there was: (I) an increase of whole blood viscosity (p = 0.015), erythrocyte elongation index (EEI, p < 0.05), whole blood pH (p < 0.001), methemoglobin (p < 0.001) and carboxyhemoglobin (p < 0.001) concentrations; (II) no variation of plasma osmolality and erythrocyte aggregation index (EAI); (III) a decrease of the erythrocyte acetylcholinesterase activity, p < 001; (IV) no variation in membrane lipid fluidity, although 1,6-diphenyl-1,3,5-hexatriene (DPH) correlated directly with the EEI, while 1,4-trimethyl-phenyl-1,3,5-hexatriene (TMA-DPH) and EAI correlated inversely, suggesting that the decreasing EEI (lower erythrocyte deformablity) might be associated with an increased rigidity of the external polar region and fluidification of the hydrophobic region of the erythrocyte membrane, with an increasing EAI. In conclusion, the endovenous administration of sodium fluorescein in NIDDM patients during the retinal angiography procedure interferes with the erythrocyte membrane and possibly with the microcirculatory blood flow.

Angiography↗

Impairment of the erythrocyte membrane fluidity in survivors of acute myocardial infarction. A prospective study.

Erythrocytes have to constantly adapt themselves to the varying circulatory system shear stress forces and capillaries diameter. Membrane lipid and protein content have an important role in determining the erythrocyte shape and are main determinants of the membrane solid and fluid behaviour which enables the erythrocyte to respond to the outer environment modifications. Membrane fluidity is an inverse index of membrane microviscosity. The aim of the present work is to evaluate prospectively in three periods of time (discharge, after 6 months and one year later) in survivors of an acute myocardial infarction (AMI) the erythrocyte membrane fluidity (outer and inner bilayer) and establish a relation with the cardiovascular events or need of coronary revascularization during a two year clinical follow up. Sixty survivors of acute myocardial infarction were recruited during 1994-96 and were prospectively studied in three periods (discharge, 6 months and after one year), and were compared with a control group (n = 36). Membrane lipid fluidity was determined by means of fluorescence polarisation with two probes: 1,6-diphenyl-1,2,5-hexatriene (DPH) and 1,4-trimethylamine 6-phenyl hexa-1,3,5-triene (TMA-DPH), for the characterisation of the hydrophobic and external polar region, respectively. The hydrophobic region was more rigidified (p < 0.01) in the erythrocytes from AMI patients, in relation to the control group. During the time of the study there was a progressive erythrocyte membrane rigidification (DPH p < 0.001; TMA-DPH p < 0.001). We found no relation between erythrocyte membrane fluidity and the coronary risk factors, cardiovascular events or the need of coronary revascularization during the clinical follow-up. In conclusion, after the myocardial infarction erythrocyte membrane of AMI survivors becomes more rigid with time, which could contribute to the decreased erythrocyte deformability and the increased blood viscosity previously described in this group of patients.

Aged↗

Ethanol and erythrocyte membrane interaction: a hemorheologic perspective.

Previous studies have documented structural and functional changes induced by ethanol-erythrocyte membrane interaction. In order to perform an in vitro study on the effect of different ethanol concentrations on erythrocyte hemorheologic properties, blood samples were collected from 21 male donors at the Hospital of Santa Maria. Whole blood aliquots were incubated with ethanol solutions of rising concentrations. The following parameters were measured: erythrocyte aggregation, haemoglobin, carboxyhaemoglobin and methaemoglobin concentrations, hematocrit, plasma osmolality and erythrocyte membrane fluidity (fluorescence polarisation probes TMA-DPH and DPH). With ethanol blood concentrations of 45 mM a rise in plasma osmolality (0.352 Osm/kg H2O vs 0.310 Osm/kg H2O; p < 0.001) was verified. With 67 mM concentration a decrease of erythrocyte aggregation (11.03 vs 12.81; p < 0.05) and an increase in plasma osmolality (0.380 Osm/kg H2O vs 0.310 Osm/kg H2O; p < 0.001) were obtained. In conclusion, ethanol only changes erythrocyte aggregation for a concentration of 67 mM. These data could lead to future changes in therapeutic approaches to situations such as alcoholic coma.

Adult↗