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Biomedical subjects

M N Santos

Publications and source records attributed to M N Santos.

13 recordsLinked to original sources
PubMed2003

Short-term environmental impact of clam dredging in coastal waters (south of Portugal): chemical disturbance and subsequent recovery of seabed.

The physical and chemical changes in sediment and near bottom water caused by clam dredging were examined during July and September 1999, at two locations Vilamoura (VL) and Armona (AR), south coast of Portugal. Sediment cores and near bottom water were collected simultaneously before dredging (control samples) and within short time intervals (min-h) after dredging. After dredging operations, microphytobenthos coming from the path were accumulated in the re-worked sediment (ridge). Chlorophyll a in superficial sediment increased from 1.2 microg x g(-1) before dredging to 1.7 microg x g(-1) after dredging and these higher values remained for a few hours. However, the expected increase of chlorophyll a in near bottom water due to re-suspension was not observed. After sediment disturbance an instantaneous sorption of phosphorus onto iron oxides occurred in the upper sediment layers (from 2 to 3 micromol x g(-1) before dredging to 4-5 micromol x g(-1) after dredging). A microcosm experiment showed that after sediment disturbance HPO(4)(2-) dissolved in pore water decreased from 40 to 10 microM being simultaneously sorbed onto iron oxides formed in the top layer of sediment. The ammonium, nitrates, organic nitrogen, phosphate and silicate dissolved in pore water decreased immediately after dredging activity and simultaneously an increase in near bottom water was sporadically observed. Generally, the re-establishment of seabed was reached within a short time (min-h), at both stations (VL and AR).

Animals↗
PubMed1995

Experimental poisoning of cattle by the mushroom Ramaria flavo-brunnescens (Clavariaceae): a study of the morphology and pathogenesis of lesions in hooves, tail, horns and tongue.

Seven 2 to 7-mo-old calves were fed the mushroom Ramaria flavo-brunnescens. Clinical signs of toxicosis included salivation, nasal serous discharge, smoothing of the dorsum of the tongue, increased sensitivity in the hooves, reddening of the coronary bands, loss of the long hairs of the tip of the tail, softening of the base of the horns, and progressive weight loss. Affected calves either died or were euthanatized in extremis within 12-37 d from the initiation of feeding. Postmortem examination confirmed changes observed in the live calves. Histopathologic changes were marked in those structures where hard keratinization occurred and there normally is a high uptake of sulfur in the form of cystine during the keratinization process. Toxicosis appeared to alter the metabolism of sulfur-containing amino acids in keratinocytes, particularly cystine, with resultant strength loss in the molecular structure of hard keratin and loosening of the hooves, hairs and horns, and flattening of the lingual filiform papillae.

Animals↗
PubMed1991

Halofantrine in the treatment of acute uncomplicated falciparum malaria in the Philippines.

In an open clinical trial, thirty patients 14 to 44 years old and with acute uncomplicated falciparum malaria were given halofantrine hydrochloride 500 mg (2 tablets) 6-hourly for 3 doses, a total dose of 1500 mg. All 30 patients were cured, with a mean asexual parasite clearance time of 47.6 hours and mean fever clearance time of 36.6 hours. Post-dosing side-effects occurred in 6 patients consisting of mild to moderate headache, dizziness and abdominal muscle spasm. Drug-induced hemolysis did not occur in two G6PD deficient patients. Twenty-three out of 28 isolates tested (82%) were resistant to amodiaquine, 3 (11%) were resistant to the sulfadoxine-pyrimethamine combination, and all were sensitive to chloroquine, quinine and mefloquine by in vitro microtests. The study confirms the efficacy of halofantrine hydrochloride as a blood schizonticide in falciparum malaria.

Acute Disease↗
PubMed1987

Consequence of excess iodine supply in a Thoroughbred stud in southern Brazil.

Excessive iodine supply of at least 700 mg inorganic iodine in foals and of more than 350 mg iodine in pregnant and lactating mares cause a high incidence of goitres in the newborn and disorders in the long leg bones of foals. Elevated phosphorus and alkaline phosphatase content in the blood may indicate a severe disturbance in the bone metabolism. Of 39 pregnant mares 17 aborted and some of the mares also showed goitres. After withdrawal of the iodine supply normalization took place. Foals born more than 6 weeks later showed normal conditions. The goitres in the mares and the high blood levels of iodine decreased.

Animals↗
PubMed1986

Circulating immune complexes in sickle cell anaemia.

Circulating immune complexes were investigated in sera of 100 patients with sickle cell anaemia (SCA) in different clinical stages, using inhibition of complement-dependent rosette formation (EAC rosette inhibition), anticomplementary activity, polyethylene glycol 6000 precipitation, immunoconglutinin titre, total haemolytic complement, C4 and C3d. A high positivity was observed in patients with hepatic crisis (75%) and cases with leg ulcers (43%) compared with painful crisis (12%) and asymptomatic (7%) patients. These results provide evidence for the presence of circulating immune complexes during leg ulcers and hepatic crisis in SCA.

Adolescent↗
PubMed1982

Circulating immune complexes in paroxysmal nocturnal hemoglobinuria.

Circulating immune complexes were investigated in sera of 13 patients with paroxysmal nocturnal hemoglobinuria. A significant inhibition was observed in the complement-dependent rosette formation (EAC) in 6 cases; 2 patients presented an increased anticomplementary activity; antilymphocyte antibodies were demonstrated in 2 patients. The levels of C3d and immunoconglutinins were also increased; there were no differences in the total hemolytic complement between patients and normal controls. There was a significant correlation between C3d and immunoconglutinins with the inhibition of the EAC rosette formation test. These results provide evidence for the presence of circulating immune complexes in paroxysmal nocturnal hemoglobinuria.

Adult↗
PubMed1982

Cell-mediated immunity in chronic myelocytic leukemia.

14 patients with chronic myelocytic leukemia were evaluated immunologically; no difference was found in mean lymphocyte percentage and absolute number between patients and healthy subjects. 4 cases (28.5%) showed decreased percentage of T lymphocytes, while only 2 cases (14.2%) had decreased absolute T lymphocyte values. PHA transformation was decreased in 57% of the patients. Spontaneous transformation in the short-term cultures exceeded the normal range in 65% of the cases. All patients skin tested were found to be reactive. Most of the patients had defective cellular immune response in vitro, probably related with a qualitative defect in T lymphocyte subpopulations. It cannot be completely excluded that part of the observed lymphocyte depression was due to the busulfan.

Adult↗
PubMed1980

Immunologic dysfunction in Sickle cell anaemia.

Selected cellular immune parameters were studied in 20 patients with sickle cell anaemia (SCA). A moderate absolute lymphocytes was observed in SCA patients compared with the control group. There was no significant difference between patients and controls in the mean E-rosette percentage and absolute number. PHA transformation was decreased in 50% of SCA patients, and some of them showed cutaneous anergy. It was suggested that imparied cell-mediated immunity is another factor to be included among defective SCA host-defense mechanism.

Adolescent↗
PubMed1976

Solanum malacoxylon toxicity: inhibition of bone resorption.

Young rabbits on high (0.57%) or low (0.24%) calcium were given an aqueous extract of Solanum malacoxylon (S.m.) leaves (20 g dried leaves/200 ml distilled water) intragastrically at 0, 12 and 36 hours. On bothe diets S.m. induced progressive hypophosphatasemia but serum calcium and phosphorus underwent only minor changes. In rabbits necropsied at 0, 12, 36, 60, 84 and 108 hours, S.m. was shown to have a negative effect on the resorbing osteocytes. With retarded osteocytic osteolysis, osteopetrosis resulted. Further regressive changes in the osteocytes resulted in osteonecrosis which was observed within 12 hours after administration of S.m. extract. The osteonecrosis, combined with retarded apposition, later resulted in osteopenia. It was concluded that the recommended dietary calcium for growing rabbits--about 0.6%--is too high. Whereas the histologic appearance of bone in rabbits fed low calcium was normal, bones from rabbits on high calcium showed retarded resorption and the rabbits had a relative hypophosphatasemia.

Alkaline Phosphatase↗