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Biomedical subjects

A Tourkantonis

Publications and source records attributed to A Tourkantonis.

At least 73 records · Page 4Linked to original sources
PubMed1987

Effect of nifedipine in the protection of renal function during in situ preservation.

In an experimental study on six healthy dogs both kidneys were exposed and subjected to 1 h of ischaemia by clamping both renal vessels. To the left renal artery, 300 ml of cold (4 degrees C) Euro-Collins solution in which nifedipine (Bay a 1040--20 micrograms/kg per min) was diluted, was infused for 15 min. Simultaneously 300 ml of cold Euro-Collins solution plus 20 micrograms/kg per min of placebo (Bay a 1040--placebo) was infused in the right renal artery. The 1 h of ischaemia was divided in a 15-min period of cold ischaemia and 45 min of warm ischaemia, at the end of which both clamps were removed. During the 2 h (4 X 30 min) following the removal of the clamps, urine volume, urea and creatinine clearances, urine sodium concentration, sodium fractional excretion (%) and urine/plasma osmolality ratio measurements were made and results compared to the pre-ischaemia values. Both kidneys were then removed for histological study. The nifedipine group restored diuresis of 0.43 +/- 0.23 ml/min within 30 min, while this degree of diuresis (0.64 +/- 0.16 ml/min) was achieved by the placebo group at 120 min. Urine volume as well as creatinine and urea clearances of the nifedipine group were significantly higher in all studied periods compared to the placebo group (P less than 0.01 or P less than 0.025). Urine sodium and FENa (%) were not different between the two groups, and urine/plasma osmolality ratio was above 1.1 in all studied periods for both groups. The microscopic study did not show any significant differences between the two groups. We conclude that nifedipine is effective in the protection of renal function when it is administered during experimental in situ preservation.

Animals↗
PubMed1986

Serum and human milk IgA and zinc concentration after successful renal transplantation.

Although breast-feeding in renal transplant patients has been discouraged because of the potential risk to the infant from the immunosuppressive drugs, two of our patients chose to breast-feed their infants for 3-4 months period. Serum and human milk IgA and zinc concentration were measured by the immunodiffusion and atomic absorption spectrophotometry method, respectively. Human milk IgA and zinc levels were at the lower normal limits one week posttransplant and were found to be slightly decreased after three months of lactation. Although serum IgA and zinc levels were not measured to breast-feed infants they were both found to have normal blood counts, no increase in infections and above average growth rate.

Azathioprine↗
PubMed1985

Prophylactic treatment with cimetidine after renal transplantation.

17 consecutive patients who underwent renal transplantation during the period 1979-1981 and were at risk of gastrointestinal hemorrhage were treated prophylactically with the histamine H2-blocker cimetidine without antacids. The incidence of gastrointestinal bleeding, the number of rejection episodes and graft survival were compared with 17 patients, who had received renal transplant during the period 1976-1978 and had not received cimetidine. The incidence of gastrointestinal hemorrhage was not reduced in the cimetidine-treated patients. In addition, cimetidine treatment neither increased the total number of rejection episodes nor changed the long-term graft survival. The results of this study indicate that cimetidine does not appear to be superior to antacids in the prevention of gastrointestinal bleeding in renal transplant recipients.

Adult↗
PubMed1985

Effect of ticlopidine on coagulation and platelet functions during hemodialysis with cuprophan membranes.

The study is a comparison of two successive HD sessions on each patient. 60 min prior to the first session a placebo was administered orally, while to the second session 500 mg ticlopidine. Arterial blood samples for leucocyte and platelet counts, C3 complement, blood gases, beta-thromboglobulin (beta-TG) and platelet factor 4 (PF-4) measurement were taken before and 15, 30, 60, 120, 240 min during each HD session. Platelet aggregation (ADP 1 microM/ml) was also carried out pre and post-dialysis. It is suggested that ticlopidine: 1) prevents HD-induced complement activation and related phenomena, 2) normalize the increased plasma levels of platelet markers 3) inhibits the ADP-induced platelet aggregation.

Adult↗
PubMed1985

Biocompatibility of cuprophan and cellulose acetate membranes. Prevention of dialysis hypoxemia and leucopenia by ticlopidine.

The study is a comparison of 4 successive hemodialysis (HD) sessions on each patient, 2 with cuprophan (CU) membrane (Gambro 120 M) and 2 with Cellulose acetate (CA) (Cordis Dow 3500). 60 minutes prior to the HD session placebo or Ticlopidine (500 mg) was administered orally to each patient. Leucocyte and platelet counts, serum C3 complement, arterial PO2, PCO2 and PH were measured before and 15, 30, 60, 120 and 240 minutes after the beginning of HD. Leucocyte count fell markedly within 15 minutes of both placebo HD sessions, but it was significantly lower (p less than 0.005) in CA than CU membrane. Ticlopidine prevented significantly (p less than 0.01) the HD-induced leucopenia. Slight changes in platelet count, either in placebo or Ticlopidine study were observed. Serum C3 complement increased significantly (p less than 0.05) at 15 minutes of CU placebo session and was also correlated (p less than 0.01) with the concurrent leucopenia. The arterial PO2 decreased 22% and 13.5% during HD with CU and CA membranes respectively, but it was preserved within normal limits by Ticlopidine. The arterial PH was increased up to 7.4 at the end of all HD sessions, while PCO2 showed only slight changes. We conclude that: 1) CA membrane is better tolerated than CU 2) HD-induced leucopenia and hypoxemia are prevented by Ticlopidine, probably by modulating the complement activation.

Adult↗
PubMed1985

Effect of hemodialysis on ceftazidime pharmacokinetics.

Ceftazidime, a new parenteral third generation cephalosporin, is widely used because of its broad aerobic gram-negative bacterial coverage and its apparent low risk of toxicity. To establish the effect of hemodialysis on the elimination kinetics of ceftazidime and to determine the supplementary dose of the drug after each dialysis session, we studied nine anuric patients with end stage chronic renal failure undergoing hemodialysis. After a single 1 g intravenous bolus injection of ceftazidime a two-compartment open model was used to calculate the pharmacokinetic parameters. The mean ceftazidime concentrations in hemodialysis patients were 64.3 micrograms/ml at the start of dialysis and 20.0 micrograms/ml at the end of dialysis session. A 4-h hemodialysis procedure reduced the area under concentration vs time curve from 795.1 mg/l X h to 175.8/l X h and the elimination half life of ceftazidime from 33.6 h to 3.3 h. Dialyzer clearance was 55.6 ml/min and 55% of the administered dose was recovered in the dialysate fluid. Hemodialysis patients should receive a supplemental dose equal to half their usual maintenance dose immediately after each dialysis session.

Adult↗
PubMed1985

Effect of zinc treatment on cell mediated immunity of chronic renal failure patients.

This study was performed on 13 normal subjects and 34 patients with chronic renal failure (CRF). Oral elemental zinc at a dose of 60 mg/day for four weeks was administered. Delayed type hypersensitivity (DTH) skin tests were performed using the multitest method. Monocyte accessory cell function (MAF) was tested by their ability to support T-cell colony growth in semi-solid cultures stimulated by staph-protein A (SpA). After zinc treatment a significant increase of DTH and MAF was found in all patients with advanced CRF in comparison with controls. These results provide evidence that zinc treatment may restore the impaired cellular mediated immunity of uraemia.

Adult↗
PubMed1985

Effect of pregnancy on the natural course of preexistent glomerular disease.

The clinical course of pregnancies in 3 patients with well defined glomerular diseases is described. Two women who had moderate renal insufficiency (serum creatinine greater than or equal to 1.6 mg/dl) at conception had also a dramatic progress to end-stage renal disease during pregnancy which in one case resulted in fetal loss. Glomerular diseases were focal glomerular sclerosis and poststreptococcal glomerulonephritis respectively. One patient with membranoproliferative glomerulonephritis was not affected. It is concluded that pregnancy can change the natural course of preexistent glomerular disease in patients with impaired renal function.

Adult↗
PubMed1984

The effects of canrenoate K on corticosteroid biosynthesis in nephrectomized dogs.

There is evidence from in vitro experiments that spironolactone not only antagonises the peripheral effects of aldosterone but also inhibits the production of corticosteroids by the adrenals. However relevant data from clinical studies are contradictory probably because spironolactone action on the kidneys also activates other mechanisms, such as renin secretion and potassium retention, which are potent stimulants of the adrenal cortex and thus tend to compensate for the inhibition. To determine the inhibitory effect of spironolactone on the adrenals in isolation, three groups of nephrectomized dogs were studied. Steroidogenesis was stimulated either by angiotensin II, potassium, or ACTH infusion. Potassium canrenoate was administered i.v. bolus at the beginning of the experiment. All the groups showed a similar marked decrease in plasma renin activity (PRA). Plasma aldosterone and cortisol were stimulated by the appropriate stimulus but their increase was blunted after the canrenoate K administration. The altered response between the subgroups was statistically significant (P less than 0.05). Plasma progesterone increased after the administration of canrenoate K. The response difference between the respective subgroups was again statistically significant (P less than 0.05). Canrenoate K was rapidly eliminated from the systemic circulation. These data indicate that canrenoate K causes a partial inhibition of aldosterone and cortisol stimulated secretion but augments the plasma levels of the precursor progesterone, as would be expected following inhibition of specific steps of corticosteroid biosynthesis.

Adrenal Cortex Hormones↗
PubMed1984

HLA antigens in pityriasis versicolor.

The distribution of 30 HLA antigens was studied in 48 patients with Pityriasis Versicolor and 134 controls. No significant deviations were found in the patient group after correction for the number of antigens tested.

Cytotoxicity, Immunologic↗
PubMed1984

Diagnostic value of serum ferritin in primary hepatocellular carcinoma.

The diagnostic value of serum ferritin levels was evaluated in 19 patients with biopsy-proven primary hepatocellular carcinoma (PHC) and 26 patients with chronic liver disease (CLD). Serum ferritin levels were significantly elevated in PHC, as compared with CLD and controls (p less than 0.0005). Similarly, serum ferritin/SGOT ratio, an index of increased ferritin production, was significantly higher in PHC than in CLD and controls. Serum alpha-fetoprotein (alpha-FP) was higher in PHC than in CLD (p less than 0.0025). No significant correlation was noted between serum ferritin and alpha-fetoprotein or SGOT in PHC and CLD. 17 of 19 patients with PHC had serum ferritin values over 450 ng/ml (sensitivity 88%). By contrast, only 10 of 17 patients with PHC (59%) demonstrated alpha-FP levels over 25 ng/ml, compatible with the diagnosis of PHC. 9 of these 10 patients had ferritin levels over 450 ng/ml, within the distribution of values for PHC. Conversely, 7 of 17 patients with PHC (40%) had normal levels of alpha-FP (false-negative). However, 6 of these patients (86%) had ferritin levels over 450 ng/ml, consistent with values in PHC. In this study, the overall sensitivity of serum ferritin in PHC was higher than that of alpha-FP (88 versus 59%) and its specificity 85 versus 68% for alpha-FP. These data indicate that serum ferritin may be utilized as a useful diagnostic marker in the evaluation of patients with PHC.

Adult↗
PubMed1984

Clinical experience with long-term nitrendipine treatment in essential hypertension.

Fifty-one patients with essential hypertension, 22 males and 29 females with a mean age of 51 (range, 28 to 65 years), were studied for more than 12 months in a controlled clinical trial with nitrendipine, a new calcium antagonist agent. No differences in age, severity of hypertension, and other risk factors between the two sexes were detected. Forty-four of 51 patients completed the study, and 38 (86.4%) achieved a normalization of blood pressure. Mean systolic blood pressure decreased from 196.0 +/- 12.9 mm Hg (means +/- SD) during placebo to 171.2 +/- 9.5 mm Hg (12.6%, p less than 0.001) after 12 months. Mean diastolic blood pressure at the same time decreased from 109.0 +/- 5.2 mm Hg to 88.5 +/- 3.6 mm Hg (18.8%, p less than 0.001). Heart rate also decreased slightly but significantly (p less than 0.01) after the fifth week. A significant change in weight was not observed throughout the trial. Plasma potassium remained unchanged during the year, and plasma sodium after a transient increase (p less than 0.001) in the fifth week returned very close to basal levels in the sixth month. Side-effects were observed in 17 patients, 5 of whom had to leave the trial, but in the rest they were usually mild and transient. These were mainly frontal and occipital headache, facial flushing, ankle and pretibial oedema, and dizziness. No relationship was detected between side-effects and body weight or plasma sodium disturbances. Preliminary data on a separate group of 27 elderly patients (66-83 years) showed a better and faster effect of nitrendipine given in low doses.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1983

Pharmacokinetics of ceftazidime in patients undergoing peritoneal dialysis.

The pharmacokinetics of ceftazidime were studied in 12 patients during peritoneal dialysis. In five patients given 1 g iv the mean serum levels (mg/l) at 0.25, 2 and 12 h after starting peritoneal dialysis were 50.6 +/- 11.2, 35.6 +/- 3.7 and 22.7 +/- 7.9, respectively. The mean ceftazidime peak level was 13.2 +/- 5.5 mg/l in peritoneal effluent, approximately 3 h after start of dialysis. The peritoneal clearance was 9 ml/min and the mean half-life during and after peritoneal dialysis was 8.7 +/- 3.1 h and 26.9 +/- 11 h, respectively. In four patients, 1 g ceftazidime was given via an intraperitoneal catheter. The mean serum levels (mg/l) at 0.25, 2 and 8 h were 14.2 +/- 3.1, 40.0 +/- 13.0 and 32.5 +/- 6.4 respectively. In three patients given ceftazidime 200 mg, in 21 dialysate treatments each with 12 cycles, mean serum levels increased from 1.3 +/- 1.5 mg/l at 1 h to 25.3 +/- 3.1 mg/l at 12 h. Mean levels in the dialysis effluent were 47.2 +/- 14.3 mg/l and the mean percentage of the dose recovered in the effluent was 47.1%. We concluded that (1) 1 g ceftazidime as an iv bolus maintained serum and peritoneal effluent levels adequate to treat patients; (2) its peritoneal absorption produced high ceftazidime levels in serum; (3) in infected patients undergoing peritoneal dialysis ceftazidime may be given either by the intravenous or intraperitoneal route.

Ceftazidime↗
PubMed1983

Adrenal responsiveness during and after intermittent haemodialysis.

ACTH and cortisol were measured by radioimmunoassay in 15 patients undergoing long term haemodialysis. Also a basal ACTH stimulation test was done by administration of 250 micrograms of Synachten (Synthetic ACTH, CIBA foundation) and the results compared with those of normal controls and end-stage chronic renal failure patients (CRF). All 15 had been receiving intermittent haemodialysis three times weekly for 5 hours on a twin coil dialyser. The duration of dialysis was from 6 to 20 months and the mean value of pre - dialysis serum creatinine was 1093 +/- 182 mumol/l. Both hormones had significantly risen in the middle and at the end of dialysis (p less than 0.005), While they had fallen back to normal mean levels 24 hours after dialysis. The Synachten stimulation test showed that adrenal response was within normal limits in both groups of patients, but dialysis patients responded significantly better (p less than 0.05) than patients with end stage CRF. We concluded that the adrenal responsiveness is within normal limits during and after regular haemodialysis and our likely explanation is a fall in plasma volume produced by the extracorporeal circulation and the increased turnover of cortisol during haemodialysis.

Adrenocorticotropic Hormone↗