[Determination of urinary NAG to detect renal ischemia-reperfusion injury and the protective effect of Allopurinol]. / Ischaemia-reperfusiós vesekárosodás és az Allopurinol védo hatásának kimutatása vizelet NAG követésével.

We analysed the effect of ischemia-reperfusion injury to renal parenchyma after unilateral renal artery clamping using urinary N-acetyl-beta-D-glucosaminidase (NAG) that is a sensitive parameter of early renal tubular injury. In the study 60 mongrel dogs were divided into 3 groups: in the 1st group the left renal artery was clamped for 45 minutes, in the 2nd group Allopurinol was administered before the clamping, the 3rd was the control group, where only laparotomy and closure of the abdomen was performed. Urinary NAG activity referring to urinary creatinine (NAG index) was determined before the operation, at the beginning of the reperfusion, in the 60th and 120th minute of the reperfusion then 1, 2, 3 and 5 days after the operation. The highest NAG indices relating to injury of the proximal tubuli were found at the beginning of the reperfusion, in the 60th and 120th minutes of the reperfusion, then NAG returned to preoperative level in each group. Significantly higher NAG indices were found in the ischemia-reperfusion group compared to the group with Allopurinol pretreatment. Renal ischemia-reperfusion injury and the protective effect of Allopurinol could be detected by lysosomal NAG enzyme. The injury of the tubular function was reversible so it could be a change in tubular function.

[The importance of hemorheological examinations in experimental limb ischemia-reperfusion injuries]. / A haemorheologiai vizsgálatok jelentosége kísérletes végtagi ischaemiareperfusiós károsodások kapcsán.

Rheological properties of the blood are determined by several factors and if they change it may be diagnostic for many diseases. It is well-known that during ischemia and reperfusion different free-radical liberating pathways are inducted besides the local physical and metabolical changes. These processes may harm red blood cells by increasing their rigidity and impairing their deformability. In ischemia-reperfusion models measurements of erythrocyte deformability is important. Characteristic alterations were observed in both rat and dog hind limb ischemia-reperfusion with vascular clamping on femoral vessels for 1 or 3 hours. Erythrocyte deformability was significantly impaired on the postoperative 1st-3rd days. The acute limb ischemia-reperfusion experimental models seem suitable for further in vivo rheological studies.

Hemorheological follow-up after splenectomy and spleen autotransplantation in mice.

We previously reported on a spleen autotransplantation model in mice, with spleen function studies at 6 weeks. The present study was undertaken to investigate long-term hemorheological functions. A/J and BALB/c inbred mice were divided into four groups: control, sham surgery (SH), splenectomy (SE), and spleen autotransplantation (AU). Hematological and hemorheological parameters were determined. Leukocyte counts in the SE and AU groups were significantly higher than in controls, while hematocrit levels were markedly lower. Mean erythrocyte volume did not change significantly. Platelet counts in the AU group were significantly lower, and red blood cell deformability was significantly worse in the SE group. The AU group also had increased cell transit time, but it was less than that in the SE group. The SE group showed the highest fibrinogen levels. We conclude that there are some consistent differences in hematological parameters between splenectomy and spleen autotransplantation. These data suggest that spleen autotransplantation may partially restore hemorheological functions following splenectomy.

Measurement of erythrocyte deformability and methodological adaptation for small-animal microsurgical models.

Measuring erythrocyte deformability with bulk filtrometers is common, but there are problems with standardization and sample quantity in small laboratory animals. In this study, blood was drawn from mice, rats, and dogs, and then erythrocyte suspensions at 1-5% hematocrit were prepared. Bulk filtrometers with a 5- or 3-microm pore-diameter filter were used to determine the initial relative filtration rate (IRFR) and relative cell transit time (RCTT). Hematological composition was also tested. In all species, the highest IRFR values occurred at 1% hematocrit, and the lowest values at 5%. In mice and rats, RCTT values were lowest at 1% and highest at 5% using a 5-microm filter, whereas in dogs, RCTT was elevated at 1-2%. Using a 3-microm filter, each species showed the same phenomena under 3%. RCTT values may become distorted above a certain cell-size/pore-size ratio. In mice and rats, 1% suspension is applicable for bulk filtrometry, but only using 5-microm filters.