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Biomedical subjects

J Pinto

Publications and source records attributed to J Pinto.

119 records · Page 7Linked to original sources
PubMedDate not supplied

Acute ethanol exposure alters hepatic glutathione metabolism in riboflavin deficiency.

Since acute ethanol consumption and riboflavin deficiency each induces oxidative stress within tissues, we examined whether their combined effects compromise the major antioxidative system in liver, namely, reduced glutathione (GSH) metabolism. Four hours before sacrifice, half the riboflavin-deficient (RD) and riboflavin-sufficient (RS) rats were treated with ethanol (3 g/kg). Livers were excised and analyzed for GSH and enzymes that control its metabolism. In RD rats, GSH increased while glucose-6-phosphate dehydrogenase (G6PD) activity decreased. Ethanol had no effect on these measurements in RS rats. In RD rats, ethanol administration decreased GSH along with the activities of GSH peroxidase, glutathione reductase, and G6PD. These data suggest that riboflavin deficiency alone does not compromise hepatic GSH metabolism. By contrast, ethanol consumption together with riboflavin deficiency depletes hepatic GSH, blunts enzyme activities controlling GSH metabolism and may enhance alcohol-induced liver injury.

Animals↗
PubMedDate not supplied

Antimalarial properties of imipramine and amitriptyline.

Dietary riboflavin deficiency is known to diminish malarial parasitemia. In this study, we determined whether imipramine and amitriptyline, drugs which inhibit riboflavin metabolism, have antimalarial efficacy. In addition, we evaluated whether these drugs, like other antimalarial agents, increase the hemolytic response to ferriprotoporphyrin IX (FP). The growth of Plasmodium falciparum (FCR3) in the absence and presence of these drugs (10 to 75 microM) was measured by determining (3H)hypoxanthine uptake by intra-erythrocytic parasites for 48 h in RPMI 1640 medium. The uptake of (3H)hypoxanthine was significantly reduced in a dose-dependent manner by both imipramine and amitriptyline. The IC50 values of imipramine and amitriptyline at 48 h were 56 and 45 microM, respectively. Both drugs enhanced hemolysis induced by FP (10 or 20 microM). No hemolysis by these drugs was detected in the absence of FP. It is concluded that the tricyclic antidepressants, imipramine and amitriptyline, possess substantial antimalarial properties.

Amitriptyline↗
PubMedDate not supplied

Preferential killing of glucose-depleted HeLa cells by menadione and hyperthermia.

Energy deprivation of cancer cells increases sensitivity to killing by hyperthermia. Recent cell culture studies suggest that certain naphthoquinones, especially menadione (vitamin K3), have anti-tumour activity by interfering with the energy metabolism of cells, resulting in the inhibition of aerobic glycolysis. We therefore studied the cytotoxic effects of menadione in HeLa cells in combination with hyperthermia. The cell culture data show that the cytotoxicity is markedly increased in cells deprived of glucose in the medium at 37 degrees C after exposure to menadione. When cells were exposed to menadione (20-40 microM) and hyperthermia (41-42 degrees C), there was a dramatic potentiation of heat-induced cytotoxicity in cells deprived of glucose in the medium. These data suggest that glucose-deficient cancer cells could be selectively killed by the combined treatment of menadione and mild hyperthermia, both of which can be readily achievable in humans.

Cell Death↗
PubMedDate not supplied

[Acute interstitial nephritis induced by loratadine].

Loratadine is a second generation histamine H1 receptor antagonist, that has high potency antiallergic properties and is associated with low adverse effects compared with other antihistamines. Acute interstitial nephritis is a cause of acute renal failure that is most often induced by drugs or, less frequently, infection or sarcoidosis. Although the number of drugs associated with acute intersticial nephritis is too large, the antihistaminic loratadine have never been reported before. We report a case of an interstitial nephritis with acute renal failure that suggesting hypersensitivity reaction in a 77 old man who had received loratadine (10 mg/day) during ten days before his assessment to our hospital by disseminated pruritic syndrome. The initial suspect was rapidly progressive glomerulonephitis and renal biopsy was practice and treatment with corticosteroids were initiated (prednisone bolus of 500 mg three days and 1 mg/kg/day/later). The loratadine therapy was cessation. He exhibiting a slow and progressive improvement on renal function and one month later, urea and creatinine levels was normal and hematuria and proteinuria had disappeared. The corticosteroids therapy were progressive decreased until withdrawal. We think that this is an interesting case, basing in its clinical presentation and that it had never been reported before.

Acute Disease↗
PubMedDate not supplied

Behçet's disease in Portugal.

During the last decades 156 patients with Behçet's disease were diagnosed and studied in Portugal. Until 1966 only two cases were referred in Portugal. In 1978 we reported 23 cases (18 males and 5 females) with multisystemic involvement, not different from that reported in other publications elsewhere. In 1987, 17 cases were reported from the Oporto region, diagnosed during a period of 5 years. In the region of Coimbra 15 cases were diagnosed (6 males and 9 females). In the Lisbon area from 1969 until 1990, 123 cases were studied altogether, 76 during the last decade (35 males and 41 females). All the cases studied had oral ulcerations and a high incidence of ocular involvement (clinical and sub-clinical, 87%). HLA-B5 was detected in 50% of the patients. At least four cases were fatal, three died with neuro-Behçet. Steroids, colchicine and thalidomide were the main form of treatment, for the patients in the Lisbon area, but in some cases chlorambucil, cyclophosphamide, azathioprine, cyclosporine-A, fibrinolytic therapy, plasmapheresis and isovolemic hemodilution were also used.

Behcet Syndrome↗