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Biomedical subjects

B Agroyannis

Publications and source records attributed to B Agroyannis.

At least 37 records · Page 2Linked to original sources
PubMed1998

Management of claudication and hypertension by stent implantation in a renal transplant recipient.

Graft artery stenosis is one of the main causes of hypertension in renal transplant recipients. We present a rare case of severe common iliac artery stenosis, proximal to the graft artery, that was the cause of accelerated hypertension and claudication in a male renal transplant recipient. After percutaneous balloon angioplasty combined with a Palmaz stent implantation, a dramatic improvement of hypertension and claudication was observed during a 10-month follow-up period.

Adult↗
PubMed1998

Arteriovenous difference of blood ammonia in uremic patients under hemodialysis.

In this study the ammonia concentration was determined in arterial and venous blood samples pre- and posthemodialysis (HD) in 18 uremic patients and in 18 health subjects (controls). The mean values (+/- SD) of ammonia in the arterial blood of uremic patients pre-HD were 98.32 +/- 26.55; post-HD, 63.18 +/- 17.09; and in control group patients, 72.37 +/- 10.09 micrograms/dl. In venous blood they were pre-HD, 71.70 +/- 20.68; post-HD, 58.05 +/- 16.73; and in control patients, 74.46 +/- 12.0 micrograms/dl. According to our findings, the ammonia concentration in the arterial blood of uremic patients pre-HD exceeds the normal limits and is significantly higher (p < 0.001) than that post-HD and that of control patients. The ammonia contents of venous blood pre- and post-HD ranges were within normal values, but the post-HD range was significantly lower than the pre-HD range (p < 0.05) and the control range (p < 0.01). Comparison between ammonia levels from arterial and venous blood showed significant and positive arteriovenous differences pre-HD (p < 0.001), which disappeared post-HD and were not observed in the control patients. In conclusion, uremic patients under HD present pre-HD high levels of ammonia in arterial blood with a significantly positive arteriovenous difference. In contrast, the post-HD ammonia levels in arterial and venous blood are decreased, and the arteriovenous difference is not significant.

Ammonia↗
PubMed1998

Ammonia concentration in the renal veins in unilateral renal artery stenosis with hypertension.

We measured blood ammonia in pre-angioplasty samples from the renal veins, aorta and inferior vena cava of 15 patients with hypertension due to unilateral renal artery stenosis confirmed by arteriography. Patients with renal insufficiency or small kidneys were excluded. Mean ammonia values were microgram/dl: vein of affected kidney, 106.00 +/- 12.75; vein of unaffected kidney, 75.65 +/- 23.10; aorta 61.04 +/- 15.00; vena cava, 62.44 +/- 19.65. The value for the affected kidney was significantly higher than the other three values (p < 0.001). Mean +/- SD DTPA uptake (%) was 42.8 +/- 2.21 in the affected kidney and 56.53 +/- 3.64 in the unaffected kidney. This difference did not correlate significantly with that of the ammonia concentrations tau = -0.292).

Adult↗
PubMed1997

Alterations in echinocyte transformation and erythrocyte sedimentation rate during hemodialysis.

In 18 uremic patients under regular hemodialysis (HD) with bicarbonate dialysate, the echinocytes and erythrocyte sedimentation rates (ESR) were determined in 4 blood samples collected from the arterial line at 0, 45, 120, and 240 min (end-HD) in one HD session by a bioincompatible dialyzer and in another by a biocompatible one. In the HD session by a bioincompatible dialyzer, the mean values (+/- SEM) of echinocytes (%) at 0, 45, 120, and 240 min were 8.89 +/- 1.15, 20.77 +/- 2.35, 7.39 +/- 1.1, 5.27 +/- 0.66 and of ESR (mm/h) were 65.00 +/- 6.26, 47.05 +/- 3.89, 66.72 +/- 6.00, 68.44 +/- 5.92, respectively. According to these findings, echinocytes show a transient significant increase at 45 min HD in comparison to those at 0 (p < 0.001), 120 (p < 0.001), and 240 (p < 0.001) min while ESR shows a transient significant decrease at 45 min HD compared with the rates at 0 (p < 0.05), 120 (p < 0.05) and 240 (p < 0.01) min. In the HD sessions with the biocompatible dialyzer, the mean values (+/- SEM) of echinocytes at the aforementioned 4 time points were 8.55 +/- 1.10, 17.05 +/- 2.40, 17.05 +/- 1.19, and 5.11 +/- 0.75%, and the ESR values were 60.89 +/- 6.08, 44.33 +/- 4.18, 62.94 +/- 6.55, and 65.61 +/- 6.13 mm/h, respectively. These values also show a transient significant increase of echinocytes at 45 min HD in comparison with those at 0 (p < 0.01), 120 (p < 0.01), and 240 (p < 0.001) min, with a parallel transient decrease of ESR at 45 min HD as compared to the ones at 0 (p < 0.05), 120 (p < 0.05), and 240 (p < 0.05) min. Although the echinocytosis at 45 min HD was more prominent in HD by the bioincompatible than by the biocompatible dialyzer, the comparison between these values indicates no significant difference in the echinocytes or the ESR. In conclusion, uremic patients receiving HD exhibit echinocytes, the percentage of which shows a transient increase at 45 min HD that returns to about baseline at 120 min HD. In parallel with the changes in echinocytes, the ESR shows an inverse change at 45 min HD which returns to baseline at 120 min HD.

Adult↗
PubMed1996

Echinocytic transformation and aggregation of red cells in uremic patients.

Isolated rabbit lungs were perfused with washed and resuspended human red blood cells (RBCs) in the presence of drugs known to change the shape and deformability of RBCs. With sodium salicylate (0.5-2 g/l), which causes echinocytosis and increases RBC deformability, lung diffusing capacity for O2 (DLO2) increased by 21%. When chlorpromazine, which induces stomatocytosis and stiffens RBCs, was given (50 mg/l), DLO2 decreased by 18% under chlorpromazine. Comparative experiments with hemoglobin solutions did not reveal any effect of those two drugs either on DLO2 or on pulmonary arterial pressure, which indicates that the effects of sodium salicylate and chlorpromazine were due to changes in RBC shape and deformability. It is concluded that RBC shape and deformability affect pulmonary artery pressure and oxygen diffusing capacity, which may have an influence on oxygen transfer to tissue and hence be of clinical relevance.

Animals↗
PubMed1996

Effect of smoking on ceruloplasmin and its ferroxidase activity in pregnant women.

This study deals with the effects of smoking on serum ceruloplasmin and its ferroxidase activity in pregnant women. The mean value (+/- SD) of serum ceruloplasmin in women smokers during pregnancy is significantly higher (p < 0.01) in comparison to that of nonsmokers, whereas the ferroxidase activity of ceruloplasmin in smokers is not significantly different from that of nonsmokers. These findings suggest that ceruloplasmin in women smokers loses part of its ferroxidase activity.

Adult↗
PubMed1996

Evaluation of the hypothalamic-pituitary axis in uremic males using dynamic tests. The possible role of testicular inhibin: a preliminary report.

Two dynamic tests (Gn-RH i.v. and clomiphene citrate-CC p.o.) were used to evaluate the hypothalamic-pituitary axis in hemodialysis patients and renal transplant recipients (recipients). In the Gn-RH test the gonadotropin secretion was maximally decelerated in hemodialysis patients while it was normal in recipients. During the CC test a decrease of gonadotropin secretion, chronically and quantitatively identical for both group, was found; while on the following test days an increase was noted, which was more accelerated in male recipients. In cases with uremia a strong negative feedback dominates at the pituitary level probably owing to testicular inhibin. The estrogenic feedback in uremia was intact, while the antiestrogenic feedback at the level of hypothalamus is partly impaired, owing to altered opioid metabolism.

Administration, Oral↗
PubMed1996

Oral glucose tolerance test after high-dose i.v. biotin administration in normoglucemic hemodialysis patients.

Abnormal glucose metabolism in uremia may result from a complex interplay between decreased insulin secretion and insulin resistance. Recent studies report beneficial effect of biotin administration in glucose metabolism in diabetic animals and in a small number of patients with diabetes mellitus. The aim of the present study was to evaluate the response of oral glucose tolerance test (OGTT) to the i.v. administration of large doses of biotin in hemodialysis patients. Eleven hemodialysis patients aged 56.90 +/- 11.20 (32-76) years on regular hemodialysis thrice a week for 2.72 +/- 1.79 (1-7) years were studied. Fasting venous plasma glucose, glucosylated hemoglobin (%GH), and plasma glucose concentration 2 h after the administration of a 75-g glucose load were measured before, and 2 weeks and 2 months after administration of 50 mg of biotin i.v. postdialysis, and after a 2-month washout period. During the study, dialysis schedule and patients' medication, diet, and dry weight were kept unchanged. OGTT was abnormal in 4 patients before biotin administration and became normal in 3 patients (75%). Our results offer support to the findings of other studies about the beneficial effect of biotin in experimental or clinical diabetes mellitus, and argue for the involvement of biotin in glucose metabolism.

Administration, Oral↗
PubMed1996

A cross-over study of a new low molecular weight heparin (Logiparin) in hemodialysis.

The safety and effectiveness of a low molecular weight heparin (LMWH) of 4500 +/- 1500 Daltons were evaluated in eight hemodialysis (HD) patients, in comparison with unfractionated heparin (UFH). In phase A of the study 3000 +/- 500 anti-factor Xa (AFXa) IU of LMWH were administered in bolus for the three consecutive HD sessions of a week. In phase B, 10000 +/- 2500 IU of UFH were administered to the same patients for the same time. Were observed no significant differences in hematocrit (Ht), platelets (Pt), fibronogen (FG) and prothrombin time (PT). Whole blood activated coagulation time (WBACT) was more prolonged with LMWH, 24 and 48 hours (start of next session) after administration (p < 0.05), and less prolonged at 5, 60, 120, 180, 240 min compared to UFH (p < 0.001). The activated partial thromboplastin time (APTT) and AFXa activity were more prolonged with UFH at 60 and 240 min (p < 0.001). The clinical effectiveness of the two preparations was similar as judged by thrombus formation and compression time. In conclusion, the present study found no real differences between LMWH and UFH, except for prolongation of WBACT 24 and 48 hours after the administration of LWMH. This probably indicates a cumulative effect of the LMWH and needs further investigation.

Adult↗