ISSN:0167-6865    

DOI:10.1159/000179242

出版商:S. Karger AG    

年代:1997

数据来源: Karger

摘要:

The role of leukocytes (WBCs) and platelets (PLTs) in the pulmonary circulation may be important in the development of monocrotaline (MCT)-induced pulmonary hypertension in rats. We investigated the changes in WBCs and PLTs in the pulmonary microvasculature during the development of chronic pulmonary hypertension in MCT rats by real-time confocal scanning laser microscopy. The number of WBCs sequestered in the pulmonary microvasculature increased significantly from day 7 after MCT injection, but no further increase occurred from days 14-28. The number of PLTs sequestered in the pulmonary microvasculature increased significantly from day 7 after MCT injection, and reached a peak on day 14. However, the number of PLTs sequestered on days 21 and 28 after MCT injection was significantly lower than on day 14. These findings suggest that PLTs mainly contribute to the initial and middle stages of the development of MCT-induced pulmonary hypertension in rats, while WBCs mainly contribute to the middle and late stages.

ISSN:0167-6865    

DOI:10.1159/000179243

出版商:S. Karger AG    

年代:1997

数据来源: Karger

摘要:

The reproducibility of laser Doppler flowmetry (LDF) in measuring the perfusion of the dental pulp was investigated. A second aim was to establish if the LDF signal from the dental pulp can be influenced by physiological stimuli, e.g. postural changes. A third aim was to apply the technique to clinical measurements of pulp perfusion in patients undergoing orthodontic therapy. A custom splint to position the probe was fabricated for 10 subjects, and measurements of pulpal perfusion in the maxillary six anterior teeth were repeated on eight occasions with the subject seated. Further, measurements of the dental pulp perfusion in one tooth were repeated with the subject in a standing and supine position. Mean perfusion (arbitrary perfusion units) for individual teeth varied from 2.7 for a central incisor to 15.5 for a lateral incisor. Perfusion was greatest for lateral incisors and least for central incisors. Pulpal perfusion was significantly higher in a supine than in a standing or sitting position. Initial clinical experience with LDF encourages further investigation of its potential as a diagnostic tool for determining pulp vitality. Preliminary experimental results suggest that LDF will be a valuable source indicating pulpal response to orthodontic therapy with fixed appliances.

ISSN:0167-6865    

DOI:10.1159/000179244

出版商:S. Karger AG    

年代:1997

数据来源: Karger

摘要:

In immunological reactions, leukocytes need to travel from the intravascular space through the vessel wall into the surrounding tissue. The first step in this process is leukocyte rolling, which has often been studied in anesthetized animals. In this study, we investigated the effect of pentobarbital, Hypnorm and both components of the latter, fentanyl and fluanisone, on this primary leukocyte-endothelial cell interaction. Using intravital brightfield video microscopy, observations were made in postcapillary venules in the intact skin of the nailfold of trained conscious Lewis rats. Subsequently, the animals were anesthetized and observations were made in vivo. Leukocyte rolling was significantly elevated after injection of Hypnorm or fentanyl, while pentobarbital and fluanisone had no effect. None of the anesthetics affected leukocyte rolling velocity. Blood flow was significantly increased only after injection of Hypnorm and fluanisone. No correlation existed between the relative changes in leukocyte rolling and concomitant changes in blood flow. The results show that the level of leukocyte rolling can be affected by anesthetics. These changes are probably not mediated by changes in local hemodynamics. Pentobarbital anesthesia does not influence leukocyte rolling. Therefore, pentobarbital is a suitable anesthetic for observation of leukocyte rolling in skin. Hypnorm significantly increases the level of rolling in skin venules. This effect seems to be caused mainly by fentanyl.

ISSN:0167-6865    

DOI:10.1159/000179245

出版商:S. Karger AG    

年代:1997

数据来源: Karger

摘要:

The systemic effect of heparin fractions with mean molecular masses of 2.5, 5.0 and 16.4 kD on angiogenesis induced by vascular endothelial growth factor isoform 165 was studied using the truly quantitative rat mesenteric-window angiogenesis assay. The angiogenic treatment with 5 ml of VEGF165 at 480 pM was given intraperitoneally on days 0-4 and heparin fractions were given subcutaneously on days 0-13; animals were sacrificed on day 14. As the overlaps between the molecular mass distributions of the three fractions were relatively small, they essentially represent three different populations of heparin molecules. The doses of the heparins given were equal in terms of weight, but different in terms of the number of molecules and biologic activity. Angiogenesis was assessed in terms of vascularized area (VA), a measurement of microvascular spatial extension, and microvascular length (MVL), a measurement of microvascular density, using technically independent variables and image analysis. The total microvascular length was computed from VA × MVL. Treatment with the 5.0-kD fraction suppressed angiogenesis significantly in statistical terms compared with treatment with 2.5- and 16.4-kD heparins and the saline in controls. Interestingly, the 2.5-kD heparin fraction which was used here has previously been shown statistically significantly to suppress angiogenesis mediated by basic fibroblast growth factor in the same experimental system. Our data thus suggest that the systemic angiosuppressive effect of heparin in different mammalian angiogenic reactions is distinctly related to structural features such as molecular size

ISSN:0167-6865    

DOI:10.1159/000179246

出版商:S. Karger AG    

年代:1997

数据来源: Karger

摘要:

The use of intravital microscopy as a tool for studying the microcirculation has increased greatly over the last several decades. Early microscopes provided the first pictures of the microcirculation, but were cumbersome to use and subjected the tissue to a high light intensity, a problem which has recently become the subject of much discussion. The goal of this project was therefore to build a more ergodynamic microscope which minimizes the light exposure to the tissue. The automation of the microscope controls provides a platform on which other options can be built into the microscope, such as an autofocus feature. Furthermore, the use of the Optimas software also opens the possibility for on-line data processing.

ISSN:0167-6865    

DOI:10.1159/000179247

出版商:S. Karger AG    

年代:1997

数据来源: Karger

摘要:

This technical report describes the production and installation of a newly developed, one-piece, light-weight (0.6 g) access plexiglass chamber for the dorsal skin fold of the mouse.

ISSN:0167-6865    

DOI:10.1159/000179248

出版商:S. Karger AG    

年代:1997

数据来源: Karger

摘要:

To evaluate whether the microsphere method, including the necessary surgical procedures, for blood flow determination creates hemodynamic stress and a secondary reduction in small intestinal perfusion, we monitored the small intestinal perfusion with laser Doppler (LD) fluxmetry in 3 groups of Sprague-Dawley rats. Group I was studied during two microsphere injections without manipulation, group II was subjected to mesenterial-root occlusion during the second injection, and for group III, vasodilatation with papaverine preceded the second injection. While cardiac output and kidney blood flow were constant at the two microsphere injections, mean blood pressure (p < 0.05) and hematocrit (p < 0.01) significantly decreased in all 3 groups. Blood glucose increased significantly (p < 0.01). LD values also declined significantly (p < 0.05) between the start and end of experiments. In group I, the initial values of 9.5 perfusion units (PU) (5-23) decreased to 6.5 PU (3-12), in group II, 10.5 PU (5-24) decreased to 7.0 PU (4-15) and in group III, 9.0 PU (5-13) decreased to 5.5 PU (4-12). In conclusion, these findings suggest that the microsphere technique with two injections of spheres and reference sample withdrawals may affect the perfusion of the small intestine in the Sprague-Dawley rat.

ISSN:0167-6865    

DOI:10.1159/000179249

出版商:S. Karger AG    

年代:1997

数据来源: Karger

摘要:

The distribution of blood flow in the heart muscle is very heterogeneous and shows a self-similar fractal pattern, extending to small spatial scales. It is very likely that local oxygen consumption is more or less proportional to local blood flow and that local aerobic metabolism also is very heterogeneous. It is not yet clear whether local metabolism is heterogeneous in origin and the distribution of flow has secondarily adapted to metabolism, or, the other way around, whether flow is primarily heterogeneous because of the irregular structure of the coronary tree and flow has adapted to metabolism. Little is known yet about the developmental and adaptive mechanisms which bring about mutual adjustment between vascular growth and local metabolic demand, and genes and growth factors involved in shaping the structure of the coronary tree have only begun to be identified. Fractal and nonlinear dynamic mathematical models generate complex heterogeneous structures from simple nonlinear deterministic rules which are recursively applied. Such nonlinear models may thus help to explain the generation of large vascular trees regulated by synergy of a limited number of genes and signaling molecules. This may explain the relative regularity of space filling of the vascular tree and the asymmetry of branching and flow distribution in the tree.

ISSN:0167-6865    

DOI:10.1159/000179250

出版商:S. Karger AG    

年代:1997

数据来源: Karger

摘要:

Synergetic concepts allow to identify emergent coordination phenomena between interacting physiological systems, for example between the cutaneous microcirculation, the sympathetic nervous system and the cardiac and pulmonary systems. The temporal patterns (oscillations of various frequencies) that are found in the data obtained with laser-Doppler anemometers (LDA; e.g. Periflux 2 used in the study) can be investigated by simultaneous recording of photoplethysmographic data obtained in the identical region of interest, as well as in cutaneous regions treated with vasoparalytic procedures which permit to record the dynamics of the arterial system. These strategies were applied to studies in the cutaneous microcirculation (volar side of the index fingers) as well as to mucosal microcirculation (maxillar gingiva) in healthy subjects and in patients suffering from autonomic dysfunction (cutaneous microcirculation) or gingivitis. By this procedure, it could be corroborated that – contrary to popular notions – the temporal fluctuations in the LDA records do not necessarily reflect myogenic vasomotion, but can have multiple causes. In a confirming recent study [Schmid-Schönbein et al., J Auton Nerv Syst, 57, 136-140, 1996], we have demonstrated that the LDA fluctuations under conditions of normal ambient temperature and hand position most likely reflect neurogenic vasoconstriction. Under exceptional conditions, different patterns emerge. Prolonged exposure to ambient temperature (18°C) leads to marked vasoconstriction, with occasional vasodilator escape (‘miniature hunting reaction’). Normal subjects under gravitational load and in warm environment (28°C ambient) silence their neurogenetic vasoconstriction reactions, which allows sinusoidal vasomotion to dominate. A similar phenomenon is seen in neuropathic patients at 21-24°C (presumably due to structural defects). Fluctuations in LDA signal taken from the healthy gingiva are entrained to arterial, those taken from inflamed gingiva to respiratory activity. The theory and practice of nonlinear analysis is discussed, and data compression procedures allowing to portray characteristic temporal patterns for future diagnostic procedures ar

ISSN:0167-6865    

DOI:10.1159/000179251

出版商:S. Karger AG    

年代:1997

数据来源: Karger