摘要:

In vivo suppression of neovascularization by in situ administration of human recombinant interferon α2a (hrlFN-α2a) was tested on the chick embryo area vasculosa (AV). Methylcellulose discs, each containing 5 IU of hrlFN-α2a were implanted onto the AV at Hamburger-Hamilton (HH) stage 13, and inhibition of blood vessel growth was morphometrically evaluated between HH stages 20 and 27. Our results show: (i) a decreased extent of the AV; (ii) a decreased AV total vessel length; (iii) modified percent ratios of different classes of AV vessels having a definite length. The observed effects of treating with hrlFN-α2a are likely attributable to inhibition of endothelial cell proliferat

ISSN:0167-6865    

DOI:10.1159/000179169

出版商:S. Karger AG    

年代:1996

数据来源: Karger

摘要:

Using direct visualization techniques, we recently confirmed earlier histologic studies that leukocytes accumulate primarily in the coronary capillaries of ischemic hearts during early reperfusion. The purpose of this study was to determine if pentoxifylline (PTX) would reduce leukocyte trapping in postischemic hearts. Isolated rat hearts were subjected to 30 min of 37 °C, no-flow ischemia. Hearts were initially reperfused with diluted whole blood containing fluorescent leukocytes. At 5, (R5), 20, and 35 min of reperfusion, the deposition of leukocytes in the coronary capillaries and venules was observed directly using intravital fluorescence microscopy. Three groups were studied: a non-ischemic control group (group I) and postischemic groups reperfused with diluted whole blood treated with vehicle group II or PTX (5 mM; group III). Postischemic reperfusion with unactivated blood caused a significant trapping of leukocytes in coronary capillaries throughout reperfusion (R5, group I = 2.0 ± 0.3 vs. group II = 5.7 ± 0.6 leukocytes/capillary field, p < 0.05). The addition of PTX reduced capillary leukocyte trapping below control values throughout reperfusion (R5, group III = 1.6 ± 0.2 leukocytes/capillary field, p < 0.05). At R5, there was no statistically significant difference in leukocyte accumulation in venules for all groups (group I = 1.5 ± 0.6, group II = 3.2 ± 0.4, group III = 3.3 ± 0.4 leukocytes/100 µm venule). During the reperfusion period, leukocyte persistence in the capillaries of postischemic hearts (36%) was greater than in the venules (13%). These data indicate that early in reperfusion after myocardial ischemia, leukocyte trapping occurs primarily in the coronary capillaries. PTX reduced early leukocyte trapping in the capillaries. The results also demonstrate that during reperfusion, the mechanisms affecting capillary retention are more persistent than those in the venule. These findings suggest that attempts to attenuate the damaging potential of early leukostasis in capillaries consider the biophysical properties of the le

ISSN:0167-6865    

DOI:10.1159/000179170

出版商:S. Karger AG    

年代:1996

数据来源: Karger

摘要:

Oxygen and carbon dioxide are known to be heterogeneously distributed in tissues. Extracellular skeletal muscle tissue pH (pHt) also exhibits a spatial variability in vitro, but this has not been examined in vivo. pHt distributions in resting skeletal muscle and the effect of the dispersion of pHt on ischemia and normoxic hypercarbia was therefore studied in an animal model with a multichannel pH microelectrode. Under resting conditions and spontaneous breathing, local pHt (from all animals, n = 10) was found to vary between 6.96 and 7.68 (range), and 70% of the values were within a pH of 7.00-7.32. In each animal the maximum pHt differences (maximum range between the 6 channels of the microelectrode) found were 0.32 ± 0.11 pH units (mean ± SD). During tissue acidosis, induced by ischemia, no significant change in the local pHt differences in each animal was seen. During normoxic hypercarbia a 2-fold increase in pHt variability within each animal was noticed (p < 0.01), which suggests that carbon dioxide and buffering effects of the blood are significant factors for the pHt distribution. The pHt distribution range found is of similar magnitude as previously described in in vitro studies on skeletal muscle. Locally varying pHt levels may be of importance as they will affect cellular H+ extrusion, membrane potential and volume control of different cell populations differentl

ISSN:0167-6865    

DOI:10.1159/000179171

出版商:S. Karger AG    

年代:1996

数据来源: Karger

摘要:

Flow behavior of erythrocytes in microvessels and glass capillaries with an inner diameter of 10-50 µm was compared in relation to erythrocyte deformation and erythrocyte aggregation. This study was focused on the formation of a marginal cell-free layer, and the thickness was determined using an image processor. Human erythrocytes were perfused through a part of microvascular networks isolated from rabbit mesentery and through glass capillaries. Erythrocyte deformability was modified by treating erythrocytes with diamide, diazene-dicarboxylic acid bis[N, N-dimethylamide], and erythrocyte aggregation was accelerated by adding dextran (with a molecular weight of 70,400) to the perfusion medium. The thickness of the cell-free layer increased with an increase of the inner diameter of flow channel, with lowering the hematocrit, and with increasing the flow velocity of erythrocytes, in both microvessels and glass capillaries. Furthermore, the thickness of cell-free layer decreased with decreasing erythrocyte deformability, while it increased with accelerating erythrocyte aggregation. However, the alteration of the cell-free layer in response to the changes of these hemorheological conditions was more sensitive in microvessels than in glass capillaries. The present study concludes that flow behavior of erythrocytes in microvessels is qualitatively similar to, but quantitatively different from those in glass capillaries, as far as evaluated by the change of the thickness of the marginal cell-free layer

ISSN:0167-6865    

DOI:10.1159/000179172

出版商:S. Karger AG    

年代:1996

数据来源: Karger

摘要:

The assessment of completeness of a sympathectomy can be objectively recorded and documented by dermofluorography. This method enables measurement of increased skin perfusion which leads to an earlier appearance time and steeper initial rise in fluorescence of intravenously administered sodium fluorescein. The most significant parameters are the quotients of the average appearance time and the initial rise in fluorescence of the untreated versus treated leg. Following a successful lumbar sympathectomy, these parameters were outside 3 standard deviations of the values obtained from healthy test persons.

ISSN:0167-6865    

DOI:10.1159/000179173

出版商:S. Karger AG    

年代:1996

数据来源: Karger

ISSN:0167-6865    

DOI:10.1159/000179174

出版商:S. Karger AG    

年代:1996

数据来源: Karger

ISSN:0167-6865    

DOI:10.1159/000179175

出版商:S. Karger AG    

年代:1996

数据来源: Karger

ISSN:0167-6865    

DOI:10.1159/000179176

出版商:S. Karger AG    

年代:1996

数据来源: Karger