Biomedical subjects

Mario Díaz

Publications and source records attributed to Mario Díaz.

21 records · Page 2Linked to original sources

PubMed2002

Phenotype markers and function of neutrophils in children with hemolytic uremic syndrome.

The hemolytic uremic syndrome (HUS) is the most-common cause of acute renal failure in children. Several researchers have reported the presence of neutrophil (PMN) activating cytokines, such as interleukin-8 and tumor necrosis factor-alpha, in the sera of HUS patients. Moreover, PMN-derived products, such as elastase, were increased. These observations have lead to the hypothesis that activated PMN could act as mediators of endothelial damage. The objective of this investigation was to directly evaluate the activation status of peripheral PMN from children with HUS. For this purpose, 12 children with typical HUS were bled during the acute period, before dialysis and/or transfusion, and 8 of them were also bled after 1 month follow-up. Additionally, blood samples from healthy control children admitted for routine surgical procedures, chronic uremic children, and neutrophilic children with acute infections not related to HUS were collected and processed in an identical manner. The function and membrane activation markers of PMN from these groups were evaluated. We found that during the acute period of HUS, PMN had reduced expression of FcgammaRIII (CD16) and CD11b, were degranulated, and exhibited an impaired antibody-dependent cellular cytotoxicity. These parameters returned to normal after clinical recuperation. We conclude that PMN activation in HUS patients is a very early and transient event, and upon hospitalization before dialysis PMN show a phenotype and functional pattern of partial deactivation.

Adolescent↗

PubMed2002

Activation of Maxi Cl(-) channels by antiestrogens and phenothiazines in NIH3T3 fibroblasts.

The identification of alternative estrogen actions has been accumulating steadily over the past two decades. Typically, these novel actions are not directly related to nuclear transcriptional events but related to the interaction of estrogens with sites present at plasma membrane or cytosolic locations. These alternative effects, widely known as non-genomic effects, range from the modulation of plasma membrane ion channel activity to the regulation of different intracellular signalling cascades. In the present study we have investigated the modulation of a large conductance chloride channel (Maxi Cl(-)) by estrogens, non-steroidal triphenylethylene antiestrogens and phenothiazines in NIH3T3 fibroblasts and the dependence on guanosine triphosphate (GTP) of the Maxi Cl(-) activation. Our data identifies the non-steroidal antiestrogens toremifene and tamoxifen, and the phenothiazines chlorpromazine and triflupromazine as activators of Maxi Cl(-) channels. In contrast, 17 beta-estradiol and cAMP, added prior to the exposure to antiestrogens, prevent channel activation. The pure antiestrogen ICI 182780 did not activate the channel nor prevent its activation by non-steroidal antiestrogens. The activation of Maxi Cl(-) channels by toremifene and tamoxifen required the presence of intracellular nucleotides and was inhibited by the stable analog, GDP beta -S, suggesting the participation of a G-protein in the activation process. Little is known about the physiological relevance of Maxi Cl(-) channels. However, that fact that its regulation by estrogens and antiestrogens is shared by different cell types might imply a common role which needs to be identified.

3T3 Cells↗

PubMed2002

[Disulfiram neuropathy. Report of 3 cases].

Disulfiram is widely used for aversive treatment of alcoholism. Although it is well tolerated in most patients, one in 15,000 patients will develop peripheral neuropathy every year, which is frequently misdiagnosed as alcoholic neuropathy. Disulfiram neuropathy can be mild or severe, depending on diverse factors such as time of exposure and the dosage. Most patients will present with a motor-sensory neuropathy of the lower limbs, which tends to improve as disulfiram administration ceases, however some cases may remain with permanent sequelae. We report the clinical, laboratory and electrophysiological features of three patients who developed disulfiram neuropathy during treatment of alcoholism. Recovery was incomplete at 8 weeks after treatment cessation in all of them. No other findings justified the clinical features described in these patients. Considering the incidence of alcoholism and the wide use of disulfiram treatment in Chile, we suggest that disulfiram neuropathy is being underdiagnosed. We also stress the fact that disulfiram neuropathy could be avoided by using lower doses.

Adult↗