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C Saldanha

Publications and source records attributed to C Saldanha.

12 recordsLinked to original sources
PubMed1992

[Evaluation of blood esterases in Alzheimer's disease].

The aim of this work was to evaluate a possible correlation between erythrocyte acetylcholinesterase activity (AChE) and membrane fluidity expressed by fluorescence polarization of--1,6--diphenyl 1,3,5--hexatriene (DPH). Blood samples of 34 Alzheimer's patients (18F and 16M) were obtained and haemoglobin concentration, haematocrit, plasma (butyrylcholinesterase, BuChE) and erythrocyte (AChE) esterase activities and fluorescence polarization after introduction of DPH in erythrocyte membrane have been determined. Results were compared with values obtained from blood samples of 34 apparently healthy volunteers with the same age variation (53-82 years). There was no correlation between AChE activity and fluorescence polarization in the control group nor in the patients' group. There was a significant negative correlation (r = -0.82; p < 0.001) between mean corpuscular hemoglobin concentration (MCHG) and erythrocyte acetylcholinesterase activity in Alzheimer's patients. This correlation suggests that any variation of internal globular viscosity (or MCHG) may indirectly affect AChE enzymatic activity and consequently contribute to the loss of interrelation between AChE activity and membrane lipid fluidity, verified in the present work. A biological marker for Alzheimer's disease diagnosis remains to be discovered.

Acetylcholinesterase↗
PubMed1989

Coronary vascular responsiveness to 5-hydroxytryptamine before and after infusion of hyperkalemic crystalloid cardioplegic solution in the rat heart. Possible evidence of endothelial damage.

Using the isolated, Langendorff-perfused rat heart (n = 8 per group), we have studied the effects of 5-hydroxytryptamine and papaverine on coronary flow before and after a 30-minute infusion of hypothermic (20 degrees C), nonoxygenated cardioplegic solution containing potassium in a concentration of either 25 or 40 mmol/L. Before infusion of the 25 mmol/L potassium cardioplegic solution, both 5-hydroxytryptamine (1 x 10(-7) mol/L) and papaverine (5 x 10(-6) mol/L) caused similar increases in flow (+21.2% +/- 1.6% and +22.8% +/- 1.6%, respectively). After cardioplegia, the vasodilatory response to 5-hydroxytryptamine was completely lost and a slight vasoconstriction was observed (-0.2% +/- 1.2%). However, there was no significant change in the response to papaverine, which maintained a +23.7% +/- 1.4% vasodilation. With the cardioplegic solution containing a 40 mmol/L concentration of potassium, the initial responses to 5-hydroxytryptamine and papaverine were again similar (+21.5% +/- 2.5% and +24.1% +/- 3.0%, respectively). After cardioplegia, 5-hydroxytryptamine caused a significant vasoconstriction (-4.3% +/- 1.1%), whereas the response to papaverine was again maintained (+19.1% +/- 2.3%). The results of this study support the concept that hyperkalemic crystalloid cardioplegic solutions cause vascular damage possibly involving the endothelium or its function, which may adversely affect vascular responsiveness.

Animals↗
PubMed1988

Haematological changes in retinal vasculitis.

Two selected cases of retinal vasculitis, apparently of unknown aetiology, are reported; one case without any systemic or laboratory manifestation and the second case with a clinical picture similar to VKH syndrome and immunodepression. Both cases showed abnormal haematological parameters related to blood viscosity in the early and acute phases which could be manipulated by therapy. Reduction or near normalisation of these haemorrheological parameters coincided with clinical and angiographic improvement. The second case with severe immunodepression was found to be retrovirus HIV-2 positive.

Adult↗
PubMed1986

Particle-induced coronary vasoconstriction in the rat heart: pharmacological investigation of underlying mechanisms.

An isolated perfused rat heart preparation has been used in an attempt to define the mechanisms underlying the coronary vasoconstriction associated with the intraarterial infusion of cardioplegic solutions containing contaminant particles. Coronary infusion of commercially available intravenous solutions, compounded to create the St. Thomas' cardioplegic solution, resulted in a 40.3 +/- 1.9% decline in coronary flow rate at the end of a 20-minute period of infusion. Filtration of the solution through a 0.8 micron filter reduced this decline in flow rate to 23.4 +/- 2.3% of its control value. Inclusion of the 5HT2 receptor antagonist ketanserin (1.0 nanomoles/l), in the unfiltered cardioplegic solution, afforded the same protection as filtration. Inclusion of 5HT (0.1 micromole/l) in a filtered cardioplegic solution resulted in a reduction of coronary flow (49.7 +/- 1.9%) greater than that seen with the unfiltered solution. Studies with antagonists of the histamine receptor (mepyramine and cimetidine) and agonists and antagonists of adrenergic receptors suggested that, although involved in the control of vascular tone, these receptor systems are unlikely to be involved in the process of particle-induced vasoconstriction. Arguments are presented that 5 HT and its receptors may play a critical role and the hypothesis is advanced that particle-induced focal endothelial injury may be the primary lesion in a complex sequence of events leading to induction of transient vasoconstriction.

Animals↗
PubMedDate not supplied

[Evaluation of interests, experiences and chemistry knowledge among students admitted to the Lisboa Medical School en 1989/1990].

Selected medical students for undergraduate medical courses in Portugal exhibit each year substantial deficiencies in chemistry. The group of students admitted to the Faculty of Medicine of Lisbon in 1989/1990 were selected by admission criteria apparently more restrictive than before. The aim of this study was to evaluate the quality of the theoretical knowledge in chemistry showed by those students before learning biochemistry. Eight-four of the admitted students were invited to participate in the study, by replying to an anonymous questionnaire on chemistry. A second questionnaire to identify a variety of personal/social factors was completed by the same students some days later. The results obtained have confirmed a clearly insufficient chemical background, in spite of the high scores achieved by those students in chemistry and other science subjects on the application. The majority of the students here studied declared financial security, live with their families, study at home, and report scarce outside distractions. It may be concluded that the new admission criteria to the faculties of medicine do not select students with better academic performances on chemistry than before. Otherwise, the sociocultural characteristics of the entrants do not fulfill the expectations that could contrast them clearly with average groups of students.

Chemical Phenomena↗
PubMedDate not supplied

Evidence for anti-inflammatory effect of normal circulating plasma cortisol.

Joint pain and tenderness increased significantly during metyrapone tests in 21 patients with rheumatoid arthritis who had never received corticosteroid therapy and who had no evidence of endocrine disease. This observation implies that the normal circulating plasma corticol exerts an anti-inflammatory effect.

Anti-Inflammatory Agents↗