摘要:

Laser Doppler fluxmetry was used to analyze local blood flux in the anterior tibial muscle and the skin of the calf simultaneously during 3 min of hyperventilation. Examinations were performed in 10 controls and 10 patients with a hyperventilation syndrome in order to evaluate a possible different vascular response to the provocation test. During hyperventilation, mean muscle blood flux increased in both groups. In controls, flux augmented from 23.4 ± 12.3 arbitrary units (AU) to 51.6 ± 28.3 AU (p < 0.05) and in patients from 21.6 ± 10.8 AU to 45.0 ± 26.4 AU (p < 0.05). The changes of skin blood flux during hyperventilation were not significant. The flux response did not differ significantly in controls and patients. Using the laser Doppler technique we were able to confirm muscular vasodilatation previously reported during short-term hyperventilation. Possible mechanisms include release of vasoactive substances and/or a stimulation of the autonomic nervous sys

ISSN:0167-6865    

DOI:10.1159/000179075

出版商:S. Karger AG    

年代:1995

数据来源: Karger

摘要:

We investigated by means of telethermography the contractile response of cutaneous vessels to recombinant erythropoietin (rHuEPO) and the effects of this hormone on the vasodilatation induced by either acetylcholine, which is endothelium-dependent, and nitroprusside, which is endothelium-indepen-dent. Experiments were carried out in 12 healthy volunteers. Graded doses of rHuEPO (25, 50, 500U/min), acetylcholine (7.5 and 15µg/min), sodium nitroprusside (3 and 10 µg/min), and saline solution (sodium chloride 0.9%) were infused in the dorsal pedal artery of the lower limb. rHuEPO reduced the cutaneous temperature in a dose-dependent manner compared to the saline solution, thus suggesting that the hormone causes vasoconstriction. In contrast graded doses of acetylcholine and nitroprusside provoked vasodilatation: in fact both increased the cutaneous temperature compared to controls in a dose-dependent manner. The infusion of vasoconstrictive doses of rHuEPO in association with acetylcholine (15 µg/min) reverted the increase in the cutaneous temperature induced by the endothelium-dependent vasodilator. In contrast rHuEPO administered in combination with nitroprusside failed to block the vasodilatation induced by the endothelium-independent vasodilator. Therefore our data suggest that rHuEPO exerts an indirect vasoconstrictive effect and that acetylcholine-induced vasodilatation, which is endothelium-dependent, is blunted by the vasoconstrictive activity of rHuEPO, thus demonstrating that the hormone may impair the synthesis of endothelial nitric oxi

ISSN:0167-6865    

DOI:10.1159/000179076

出版商:S. Karger AG    

年代:1995

数据来源: Karger

摘要:

In a total of 100 healthy subjects (36 males, 64 females) aged between 5 and 58 years, capillary microscopy of the nailfold was performed in all the fingers of both hands. The aim of this study was to determine whether capillary abnormalities, hitherto regarded as pathological, were to be found, and if so, to establish their frequency and nature. Capillary branchings – on average 4-5/person – were seen in 78% of the subjects investigated, and proved to be most common in digits IV and V of both hands. Of the subjects investigated, 94% showed meanderings, 64% tortuous loops, 25% hemorrhagic extravasations, and 19% apical dilatations of the capillaries. Only a single case of a giant loop was seen. Neither avascular fields, stasis nor reversion of blood flow were seen. Maricq’s venule index was increased in 3 subjects. These findings clearly indicate that the significance of deviating capillary patterns need to be reconsidered, for branchings or hemorrhagic extravasations can certainly be found in healthy sub

ISSN:0167-6865    

DOI:10.1159/000179077

出版商:S. Karger AG    

年代:1995

数据来源: Karger

摘要:

The effects of a clinically used purified micronized flavonoid fraction (S5682) containing 90% diosmin and 10% hesperidin on increased microvascular permeability induced by histamine, bradykinin and leukotriene B4 (LTB4) were investigated by intravital microscopy in the cheek pouch preparation of diabetic hamsters. We also investigated the effects of S 5682 on macromolecular permeability increase and leukocyte adhesion during ischemia-reperfusion using the same preparation. Diabetes was induced by an intraperitoneal injection of streptozotocin (50 mg/kg). S 5682, suspended in 10% lactose solution, or vehicle (10% lactose) was administered orally for 25 days at 20 mg/kg/day (10 mg/kg twice a day), starting 5 days after the streptozotocin injection. Fluorescein isothiocyanate-labelled dextran (molecular weight 150,000) was given intravenously, 30 min after completion of the cheek pouch preparation. The leukocytes were stained by continuous intravenous infusion of acridine orange (0.5 mg/kg/min). Histamine (2 µM), bradykinin (1 µM), and LTB4 (0.01 µM), applied topically for 5 min, increased the number of fluorescent vascular leakage sites in postcapillary venules. A temporary ischemia (duration: 30 min) with total circulatory arrest of the cheek pouch was obtained by clamping the neck of the everted pouch. The maximum number of leaky sites (per cm2 in the prepared area) which occurs either at 5 min after the beginning of each topical application or 10 min after the onset of reperfusion was quantified in UV light microscopy. The results from 60 animals divided into ten groups of 6 animals each are presented as means ± SEM. In comparison with vehicle, S 5682 significantly inhibited the macromolecular permeability increasing the effect of histamine (343.8 ± 18.5 vs. 91.0 ± 8.2 leaks/cm2; p < 0.001), bradykinin (347.0 ± 14.6 vs. 110.3 ± 8.5 leaks/cm2; p < 0.001) and LTB4 (323.0 ± 15.5 vs. 161.3 ± 13.8 leaks/cm2; p < 0.001). At reperfusion, after 30 min ischemia, S 5682 significantly decreased the observed macromolecular permeability (168.5 ± 19.7 vs. 52.7 ± 6.3 leaks/cm2; p < 0.01). Flavonoid-treated animals also tended to have a lower number of leukocytes adhering to the venular endothelium (104.8 ± 11.0 vs. 75.8 ± 9.7/6 mm2 0.05). These results demonstrate that oral administration of S 5682 for 25 days at 20 mg/kg body weight/day has a protective effect on leakage of macromolecules after application of permeability-increasing substances and during ischemia-reperfusion in the cheek pouch microvasculature of diabetic hamsters. In conclusion, the present data illustrating the inhibitory effect of a clinically relevant dose of S 5682 on the inflammatory processes induced in this in vivo model of microcirculation may serve as a rational basis to explain its clin

ISSN:0167-6865    

DOI:10.1159/000179078

出版商:S. Karger AG    

年代:1995

数据来源: Karger

摘要:

Leukocyte adhesion (LA) to the endothelium of postcapillary venules is considered to be an important step in the inflammatory response. The recruitment of blood leukocytes into sites of inflammation involves a well-coordinated and dynamic sequence of events in which several cellular adhesion molecules (CAMs) and chemotactic cytokines play an active role. The aim of the present study was to elucidate receptor-mediated interaction in mesenteric venules of leukocyte rolling/adhesion and plasma leakage. We applied intravital microscopic techniques, with the help of an analogous video image processing system, to measure changes in the microvascular integrity. Rat monoclonal antibodies (MoAb) to different CAMs were administered before inflammatory stimuli were applied. Topical application of different doses of either lipopolysaccharide (LPS), fMet-Leu-Phe, zymosan, complement C5a, TNF-α, interleukin-1β (IL-1β), IL2 or IL-6 resulted in a dose-dependent increase in LA. The injection of a MoAb (1 mg/kg), 15 min prior to the LPS challenge, resulted in (1) total inhibition of LA, when MoAb to rat L-selectin, LFAl-β and VLA-4 were used, (2) a moderate effect with LFA-1β and Mac-1 MoAb, and (3) only a weak influence on LA by the MoAb to rat ICAM-1 (1 mg/kg). No effects were seen with IgGl control MoAb. LA in acute models of inflammation can be regarded as a consequence of time-dependent differential effects of CAMs, as observed through the application of different

ISSN:0167-6865    

DOI:10.1159/000179079

出版商:S. Karger AG    

年代:1995

数据来源: Karger

摘要:

This study is designed to explore the effect of adrenal glucocorticoids on arteriolar behavior under steady state conditions in spontaneously hypertensive rats (SHR) compared with their normotensive controls, the Wistar Kyoto (WKY) rats. Mesenteric arterioles were observed by intravital microscopy under general anesthesia and arteriolar diameters were measured. At the end of each experiment, papaverine was topically applied to determine maximum diameter of the vessels for which arteriolar tone was computed. The adrenal contribution to the atypical arteriolar tone in SHR was explored by subjecting them to bilateral adrenalectomy with or without glucocorticoid replacement therapy. Adrenalectomy led to a reduction in the elevated blood pressure in SHR to normotensive levels, which could be restored to its hypertensive level by treatment with dexamethasone. Adrenalectomy had no significant effect on blood pressure in WKY rats, although administration of dexamethasone but not aldosterone did lead to an elevation of the blood pressure in sham-operated WKY. Arteriolar tone in SHR was set at a higher steady state level than in WKY rats. In adrenalectomized SHR, tone fell to the levels observed in WKY rats. This decrease in arteriolar tone in the adrenalectomized SHR could in turn be restored to the hypertensive levels with dexamethasone but not aldosterone. Our results suggest that the enhancement of arteriolar tone, as well as the high blood pressure in SHR, may be related to the above normal levels of adrenal glucocorticoids present in the bloodstream.

ISSN:0167-6865    

DOI:10.1159/000179080

出版商:S. Karger AG    

年代:1995

数据来源: Karger

摘要:

Rhythmic variations in blood flow have been observed in various vascular beds, including brain. We have characterized fluctuations of the microcirculation in different locations in the brain, and studied the response to changes in arterial carbon dioxide tension, arterial pressure, and cerebrospinal fluid pressure. Laser Doppler flowmetry was performed in 20 pentobarbital-anesthetized pigs. Flow probes were positioned on the brain surface and 3, 10, and 20 mm into the cerebral tissue. The protocol included carbon dioxide breathing, hemorrhagic hypotension, and infusion into the cisterna magna. Twenty-five periods of low-frequency oscillations (4.5/min) were found in 10 pigs with superimposed spindle-shaped rhythmic variations (0.5/min) of the amplitude in 7. There were no rhythmic changes in arterial pressure or intracranial pressure. Rhythmic activity was most often seen in the probe positioned 20 mm into the brain and was often seen in several probes at the same time. Animals with rhythmic oscillations before interventions had lower cerebral perfusion pressure and arterial pressure, lower heart rate, and higher laser Doppler signal than the others. Blood loss often initiated oscillations. High intracranial pressure tended to abolish preexisting oscillations. Hypercapnia always abolished preexisting oscillations. Oscillations were more frequent if the cerebral perfusion pressure was in the low range of cerebral autoregulation, occurred more often in the cerebral locations with relatively high local flow, were most likely to be localized, and therefore probably caused by local metabolic or myogenic variations.

ISSN:0167-6865    

DOI:10.1159/000179081

出版商:S. Karger AG    

年代:1995

数据来源: Karger

摘要:

While changes in blood flow associated with simple intestinal obstruction have been studied extensively, little is known about blood flow changes associated with strangulation obstruction. Closed loop strangulation was produced in anesthetized cats by means of a baby pressure gasket. Intestinal blood flow was measured by transit time flowmetry. Blood pressure was measured in a carotid artery and in veins of a closed loop of small intestine. The gasket pressure was increased stepwise in 10 mm Hg increments after which the intestinal venous pressure was kept constant at 50 mm Hg for 5 h. Increasing gasket pressure was followed by a corresponding increase in venous pressure in the closed bowel loop. Blood flow in the closed loop decreased with increasing venous pressure and was closely related to the arteriovenous perfusion pressure under stepwise increase of the gasket pressure and during prolonged periods with increased venous pressure. At constant elevated venous pressure the intestinal blood flow was determined by the arterial pressure. The vascular resistance in the closed loop increased exponentially with increasing venous pressure and especially at very low blood flow. In conclusion, we have found that strangulation obstruction is associated with increased venous pressure in the closed loop which contributes to maintaining intestinal blood flow during the obstruction.

ISSN:0167-6865    

DOI:10.1159/000179082

出版商:S. Karger AG    

年代:1995

数据来源: Karger

ISSN:0167-6865    

DOI:10.1159/000179083

出版商:S. Karger AG    

年代:1995

数据来源: Karger

ISSN:0167-6865    

DOI:10.1159/000179084

出版商:S. Karger AG    

年代:1995

数据来源: Karger