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Biomedical subjects

S Cala

Publications and source records attributed to S Cala.

11 recordsLinked to original sources
PubMed2000

Are convective methods superior to diffusive dialytic methods?

The principle of convective elimination is the passage of solutes through the membrane carried by water flux, so the elimination of all substances for which membrane is permeable is equal to water. This results in uniform clearances of small, medium and large molecules. Dialytic methods with exclusive or considerable convective elimination are hemofiltration, hemodiafiltration and high-flux hemodialysis. Only by convective methods, middle (MM 300-15,000 D) and large molecules (MM > 1-15,000 D) are cleared. Standard low-flux hemodialysis does not eliminate a considerable amount of medium and large molecules, in contrast to outstanding efficiency in small molecule removal. Clinical significance of larger molecule removal was analyzed in 4 studies prominent for a great number of patients included, very long observation times, or prospective, multicentric randomized design. In 3 studies, dialytic methods with convective elimination were connected with a mortality decrease by 10% to 39% (statistically significant in 2 studies). Dialysis amyloidosis morbidity was lowered by 42%-50% when convective methods were used. Results of the presented studies support the conclusion that dialytic methods with convective elimination are beneficial for survival and prevention of dialysis amyloidosis, irrespective of the biochemical characteristics and complement activation by the membrane used.

Diffusion↗
PubMed1994

Hepatitis C and hepatitis B virus infection in hemodialysis patients and staff: a two year follow-up.

To estimate the prevalence of antibodies to the hepatitis C virus ((HCV) and hepatitis virus (HBV) and the presence of infection, 101 patients receiving renal replacement therapy and 75 staff members caring for them were tested. Evaluation included detailed history, screening for anti-HCV antibody, HBV markers and liver enzymes 38% of patients were anti-HCV positives and 15 (40%) of these had antibodies to the hepatitis B core antigen indicating previous hepatitis B infection. Positive markers indicating HBV infection only, accounted for another 18% of patients. All staff members were anti-HCV negative, although 34 (45%) were anti-HBc positive. Age, sex and history of blood transfusions did not influence the prevalence of anti-HCV and anti-HBC in patients. There was, however, a significant difference in the prevalence of anti-HCV and anti-HBc positivity between polytransfused and occasionally transfused patients (p < 0.05). During a 24-months follow-up a decline was observed in HBs antigen carriers from 20% to 10% and in HBc antibody carriers from 47% to 33%. At the same time, regardless of accurate preventive measures, an increase in incidence of anti-HCV seropositivity from 30% to 38% was detected.

Female↗
PubMed1990

Negative effect of uraemia and cuprophane haemodialysis on natural killer cells.

The evidence indicating the important role of natural killer (NK) cells in immune surveillance against tumours and certain infections is accumulating. Uraemic and dialysed patients are known to be at greater risk of infections and malignant diseases. NK cells were analysed in patients with advanced uraemia, and in patients treated with different dialysis techniques. Number of NK cells was morphologically identified as large granular lymphocytes in blood smears. NK activity was determined as mononuclear cell cytotoxicity against K562 cells. In a group of uraemic patients, large granular lymphocyte number was reduced to 39%, and NK activity to 41%-52% of control values. Large granular lymphocyte number and NK activity in patients haemodialysed on cuprophane membranes was significantly reduced, compared to corresponding values in controls and uraemic patients, declining to 17% and 8%-16% of respective control values. In a group of patients treated by CAPD, and in a group haemodialysed on polyacrylonitrile membranes, NK activity was close to values in the uraemic group, but significantly greater than those of cuprophane-haemodialysed patients. Haemodialysis on cuprophane membranes has an additional negative effect on NK cells, which are already seriously depressed by the uraemic state.

Adult↗
PubMed1989

Localization of ARPP-90, a major 90 kiloDalton basal ganglion-enriched substrate for cyclic AMP-dependent protein kinase, in striatonigral neurons in the rat brain.

Cyclic AMP-regulated phosphoproteins with specific cellular localizations in brain represent important targets through which this second messenger system can mediate or modulate distinct neurotransmitter signals. This study reports that two cyclic AMP-regulated phosphoproteins (Mr 90,000 and 93,000) found in brain share several properties, including similar isoelectric points and similar phosphopeptide maps. This protein doublet is particularly enriched in the forebrain basal ganglia, but it can also be found in the substantia nigra, a brainstem region which is a major target for fibers from the forebrain basal ganglia. Quinolinic acid lesions of neurons in the neostriatum decrease the levels of the 90/93 kDa phosphoprotein doublet to about the same extent as they reduce the levels of DARPP-32, a phosphoprotein specifically enriched in striatonigral medium-sized spiny neurons. These reductions are seen in both the neostriatum and the substantia nigra. Therefore, within the basal ganglia, the 90/93 kDa phosphoprotein doublet, termed adenosine 3':5'-monophosphate-regulated phosphoprotein, Mr = 90,000 (ARPP-90), is largely, if not solely, present in striatonigral cells and fibers. The specific localization in these neurons suggests that ARPP-90 could be important in receptor-regulated, cyclic AMP-mediated functions in the striatonigral neurons.

Animals↗
PubMedDate not supplied

[Which patients should be treated with plasma exchange? Indications for plasma exchange therapy].

What is the current opinion on therapeutic plasma exchange, after 20 years of clinical use for numerous patients and disease states? Principles of rational therapy have broken through into the field of therapeutic plasmapheresis during the last decade. Efficacy proven by controlled clinical trials is the prerequisite for determining indications. Superiority of plasma exchange over other therapeutic modalities has been established for only a limited number of rare diseases. Plasma exchange treatment is still actual for plasmatic hyperviscosity syndromes in the course of haematological and rheumatological diseases. Indications for therapeutic plasma exchange in nephrology are narrowed to some forms of Goodpasture's syndrome, rapidly progressive glomerulonephritis with antineutrophil cytoplasmic antibodies and renal insufficiency, and thrombotic thrombocytopenic purpura/haemolytic uraemic syndrome. Plasma exchange therapy is indicated for severe forms of Guillain-Barré syndrome and myasthenia gravis. Therapeutic benefit of plasma exchange was not found by controlled clinical trials in patients with rheumatoid arthritis, systemic lupus erythematosus, polymyositis, dermatomyositis, multiple sclerosis and rejection of kidney allotransplant.

Humans↗