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Biomedical subjects

M J Matos

Publications and source records attributed to M J Matos.

6 recordsLinked to original sources
PubMed2001

Surgery for bronchiectasis.

OBJECTIVE: The incidence of bronchiectasis has declined markedly in developed countries. However, a reasonable number of patients still need surgery, despite aggressive physiotherapy and antibiotic therapy. We have reviewed our patients to clarify the benefits from surgery and to analyse the complications. MATERIAL AND METHODS: Between 1988 and 1999, we have operated on 119 patients with bronchiectasis, 71 female and 48 male, with a mean age of 42.2 years (range 11--77 years). Surgery was indicated because of unsuccessful medical therapy in 66 patients (55%), 31 (26%) had haemoptysis, 11 (9.2%) had lung abscess, 10 (8.4%) had lung masses, and three (2.5%) had pneumothorax. The most common manifestations were cough with sputum in 90 patients (76%), haemoptysis in 45 (38%) and recurrent infections in 57 (48%). The mean duration of the symptoms was 4 years (range 1--40 years). The lower lobes were diseased in 61 patients and bilateral disease was found in ten. The mean number of involved pulmonary segments was five (range 1-15). A lobectomy was performed in 75 patients (62%), a segmentectomy in 12 (10%), a pneumonectomy in nine (7.4%) and a bilobectomy in four (3.3%). Complete resection of the disease was achieved in 108 cases (91%). RESULTS: There was no operative mortality and perioperative morbidity occurred in 15 patients (15%), including temporary broncho-pleural fistulae in 7 (5.8%), and post-operative haemorrhage and atrial arrhythmias in four (3.3%) each. After a mean follow-up was 4.5 years, 73 patients (68%) of this group were asymptomatic, and 31 (29%) had meaningful clinical improvement, while only four (3.7%) maintained or worsened prior symptoms. The best clinical improvement occurred in patients with complete resection of the disease (P=0.008). There were no differences in the respiratory function, comparing pre- and post-operative data, with a 2-year of minimum interval. The VC was 91 and 89% and the FEV1 was 83% and 81% of expected, respectively before and after surgery, (P=NS). CONCLUSION: Surgery of pulmonary bronchiectasis has few complications and markedly improves symptoms in the great majority of patients, especially when complete resection of the disease is achieved. Pulmonary resection of bronchiectasis does not alter respiratory function.

Adult↗
PubMed2000

Synaptosomes isolated from Goto-Kakizaki diabetic rat brain exhibit increased resistance to oxidative stress: role of vitamin E.

Increased oxidative stress is believed to be an important factor in the development of diabetic complications. In this study, the effect of diabetes on the susceptibility of synaptosomes to oxidative stress, induced by the oxidizing system ascorbate/Fe2+, on the activity of antioxidant enzymes and on the levels of glutathione and vitamin E was investigated. Synaptosomes were isolated from brain of 29-weeks-old Goto-Kakizaki (GK) rats, a model of non-insulin dependent diabetes mellitus and from normal Wistar rats. Synaptosomes isolated from GK rats displayed a lower susceptibility to lipid peroxidation, as assessed by quantifying thiobarbituric acid reactive substances (TBARS), than normal rats (5.33 +/- 0.79 and 7.58 +/- 0.7 nmol TBARS/mg protein, respectively). In the absence of oxidants, no significant differences were found between the levels of peroxidation in synaptosomes of diabetic or control rats. Superoxide dismutase (SOD), glutathione peroxidase and glutathione reductase activities were unaltered in the brain of diabetic rats. There were no statistically significant differences in fatty acid composition of total lipids and reduced glutathione levels in synaptosomes of diabetic and control rats. The decreased susceptibility to membrane lipid peroxidation of diabetic rats synaptosomes correlated with a 1.3-fold increase in synaptosomal vitamin E levels. Vitamin E levels in plasma were also higher in diabetic rats (21.32 micromol/l) as compared to normal rats (15.13 micromol/l). We conclude that the increased resistance to lipid peroxidation in GK rat brain synaptosomes may be due to the increased vitamin E content, suggesting that diabetic animals might develop enhanced defense systems against brain oxidative stress.

Animals↗
PubMed2000

Lipid composition and dynamics of cell membranes of Bacillus stearothermophilus adapted to amiodarone.

Bacillus stearothermophilus, a useful model to evaluate membrane interactions of lipophilic drugs, adapts to the presence of amiodarone in the growth medium. Drug concentrations in the range of 1-2 microM depress growth and 3 microM completely suppresses growth. Adaptation to the presence of amiodarone is reflected in lipid composition changes either in the phospholipid classes or in the acyl chain moieties. Significant changes are observed at 2 microM and expressed by a decrease of phosphatidylethanolamine (relative decrease of 23.3%) and phosphatidylglycerol (17.9%) and by the increase of phosphoglycolipid (162%). The changes in phospholipid acyl chains are expressed by a decrease of straight-chain saturated fatty acids (relative decrease of 12.2%) and anteiso-acids (22%) with a parallel increase of the iso-acids (9.8%). Consequently, the ratio straight-chain/branched iso-chain fatty acids decreases from 0. 38 (control cultures) to 0.30 (cultures adapted to 2 microM amiodarone). The physical consequences of the lipid composition changes induced by the drug were studied by fluorescence polarization of diphenylhexatriene and diphenylhexatriene-propionic acid, and by differential scanning calorimetry. The thermotropic profiles of polar lipid dispersions of amiodarone-adapted cells are more similar to control cultures (without amiodarone) than those resulting from a direct interaction of the drug with lipids, i.e., when amiodarone was added directly to liposome suspensions. It is suggested that lipid composition changes promoted by amiodarone occur as adaptations to drug tolerance, providing the membrane with physico-chemical properties compatible with membrane function, counteracting the effects of the drug.

Adaptation, Physiological↗
PubMed1999

Decreased susceptibility to lipid peroxidation of Goto-Kakizaki rats: relationship to mitochondrial antioxidant capacity.

The respiratory function and the antioxidant capacity of liver mitochondrial preparations isolated from Goto-Kakizaki non-insulin dependent diabetic rats and from Wistar control rats, with the age of 6 months, were compared. It was found that Goto-Kakizaki mitochondrial preparations presented a higher coupling between oxidative and phosphorylative systems, compared to non-diabetic preparations. Goto-Kakizaki mitochondria presented a lower susceptibility to lipid peroxidation induced by ADP/Fe2+, as evaluated by the formation of thiobarbituric acid substances. The decreased susceptibility to peroxidation in diabetic rats was correlated with an increase in mitochondrial vitamin E (alpha-tocopherol) content and GSH/GSSG ratio. Moreover, the glutathione reductase activity was significantly increased, whereas the glutathione peroxidase was decreased. Superoxide dismutase activity was unchanged in diabetic rats. Fatty acid analyses showed that the content in polyunsaturated fatty acids of Goto-Kakizaki mitochondrial membranes was significantly higher compared to controls. These results indicate that the lower susceptibility to lipid peroxidation of mitochondria from diabetic rats was related to their antioxidant defense systems, and may correspond to an adaptative response of the cells against oxidative stress in the early phase of diabetes.

Animals↗
PubMed1990

Composition and organization of sarcolemmal fatty acids in cultured neonatal rat cardiomyocytes.

This paper describes studies on the fatty acid composition of individual phospholipids of the neonatal rat cardiomyocyte as well as in the gas-dissected sarcolemma derived from those cells. There is a sarcolemmal fatty acid asymmetry between the two leaflets of the membrane, which results from an asymmetric phospholipid distribution and particular fatty acid composition of each phospholipid class. The cytoplasmic leaflet is shown to be more unsaturated than the outer one. The phospholipids preferring the inner sarcolemmal leaflet (PE, PS, and PI) are particularly rich in two fatty acids, stearic acid and arachidonic acid. The implications of the data in current models for Ca2+ binding and for disruption of sarcolemma following ischemia and reperfusion damage are discussed.

Animals↗