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Objectives: During caries progression, dental pulp is increasingly pathologically affected. Since the accurate assessment of pulp is of vital importance in clinical decision-making, this study aimed to evaluate pulpal condition in the early stages of caries via laser Doppler (LD) flowmetry and histologic analysis and determine their agreement. Methods: Fourteen patients with severe dental crowding were included. Prior to extractions and orthodontic treatment, dental pulp condition of 52 premolars was evaluated via LD flowmetry. Teeth were assessed for the presence of caries and lesions were graded according to the International Caries Detection and Assessment System (ICDAS). After extractions, teeth were split and histologically stained for endothelial cells with anti–von Willebrand factor and Movat pentachrome for collagen. Volume densities of vessels (Vvasc) and collagen were calculated. Results: There was a significant negative correlation between LD flow and Vvasc of the dental pulp with ICDAS grade. Pulpal LD flow and Vvasc in teeth with the initial lesion were increased, decreasing with progressing stages of caries. A significant positive correlation between the the pulpal LD flow and Vvasc, and a negative correlation of LD flow with collagen fibre density were noted. Conclusions: Caries affects the physiology of the dental pulp, initially with increasing vascularity, and decreasing vascularity at later stges of caries progression. Collagen contents increase with grades of ICDAS. LD flow shows good agreement with the histologic constitution of the dental pulp. Use of clinical measurements of pulpal LD flow could provide a good noninvasive indication of pulpal vascular state and its health.

Objectives: During caries progression, dental pulp is increasingly pathologically affected. Since the accurate assessment of pulp is of vital importance in clinical decision-making, this study aimed to evaluate pulpal condition in the early stages of caries via laser Doppler (LD) flowmetry and histologic analysis and determine their agreement., Methods: Fourteen patients with severe dental crowding were included. Prior to extractions and orthodontic treatment, dental pulp condition of 52 premolars was evaluated via LD flowmetry. Teeth were assessed for the presence of caries and lesions were graded according to the International Caries Detection and Assessment System (ICDAS). After extractions, teeth were split and histologically stained for endothelial cells with anti-von Willebrand factor and Movat pentachrome for collagen. Volume densities of vessels (V vasc ) and collagen were calculated., Results: There was a significant negative correlation between LD flow and V vasc of the dental pulp with ICDAS grade. Pulpal LD flow and V vasc in teeth with the initial lesion were increased, decreasing with progressing stages of caries. A significant positive correlation between the the pulpal LD flow and V vasc , and a negative correlation of LD flow with collagen fibre density were noted., Conclusions: Caries affects the physiology of the dental pulp, initially with increasing vascularity, and decreasing vascularity at later stges of caries progression. Collagen contents increase with grades of ICDAS. LD flow shows good agreement with the histologic constitution of the dental pulp. Use of clinical measurements of pulpal LD flow could provide a good noninvasive indication of pulpal vascular state and its health., Competing Interests: Conflict of interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 The Authors. Published by Elsevier Inc. All rights reserved.)

Measuring brain electrical impedance (rheoencephalography) is a potential technique for noninvasive, continuous neuro-monitoring of cerebral blood flow autoregulation in humans. In the present rat study, we compared changes in cerebral blood flow autoregulation during CO2 inhalation measured by rheoencephalography to changes measured by laser Doppler flowmetry, an invasive continuous monitoring modality. Our hypothesis was that both modalities would reflect cerebral blood flow autoregulation.

Background and aim Decreased vascular reactivity in atherosclerosis was previously shown. In our study, it was aimed to demonstrate the decreased vascular functions in both microvascular and macrovascular tissues and to estimate any correlation between them. Methods Twenty-five control outpatients with no coronary artery disease (CAD) history and 26 outpatients with CAD history were enrolled in the study. Local cutaneous post-occlusive reactive hyperemia (PORH) responses after three minutes of brachial occlusion with a pneumatic cuff were recorded noninvasively by a Perimed Periflux 5010 laser Doppler flow system. Aortic distensibility and stiffness indexes were recorded noninvasively by a two-dimensional Doppler echocardiography machine (Vivid S6 GE Medical System, Horten, Norway). Results Except for the medication history of subjects, there were no significant demographic differences between the CAD and control groups. Peak flow (PF), resting flow (RF) and biological zero(BZ) laser Doppler measurements were not decreased, but PF-RF/RF (%), PF-BZ/BF (%), hyperemia repayment and PORH indexes were significantly decreased in the CAD group ( P = 0.005, P = 0.024, P = 0.017, P = 0.006, respectively) with laser Doppler measurements. Aortic strain (%) and aortic distensibility (cm3/dyn-1) measurements were significantly decreased in the CAD group ( P = 0.005, P = 0.013). However, there was no correlation between microvascular indexes (hyperemia repayment index, PORH index) and macrovascular indexes (aortic strain and aortic distensibility). Discussion Different corrupted vascular tonus regulator systems in arteries of varying diameter, different major reactive responses to the stimuli or, finally, the lack of a number of subjects to obtain a significant level may be responsible for the irrelevant correlation analysis. Conclusion The differences in arterial beds (both aorta and microcirculation) may be examined to assess the cardiovascular risk in patients with history of CAD. [ABSTRACT FROM AUTHOR]

Background: An increasing number of studies support the hypothesis that endothelial dysfunction due to reduced availability of nitric oxide plays a key role in initiation, development and progression of essential hypertension. The aim of our study was to determine whether the ingestion of L-arginine actually improves microvascular function in normotensive subjects with a family history of hypertension.Methods: 30 normotensive healthy men, aged 20–30 years, were divided into two groups according to the family history of hypertension. We measured ECG, heart rate, systolic and diastolic arterial pressure, cardiac output, stroke volume, total peripheral resistance (Task Force Monitor) and laser Doppler (LD) flux in the microvessels of the skin on the forearm at rest, before and after the administration of 0.9 g L-arginine. The endothelium-dependent vasodilation was assessed by iontophoresis of acetylcholine and the endothelium-independent vasodilation by iontophoresis of sodium nitroprusside.Results: After the ingestion of L-arginine the heart rate and the cardiac output statistically significantly decreased in both groups (paired t-test, p Conclusions: In subjects with a family history of hypertension L-arginine improved endothelial function. This justifies L-arginine as a potential agent for the prevention and/or treatment of arterial hypertension.

Introduction: Morphological abnormalities of microvessels are described in psoriasis. However, there are conflicting data as to whether their function is also altered. Objective: Our aim was to study the morphology and function of the lymphatic capillaries of psoriatic skin. Methods: Morphology and permeability of initial lymphatics were studied by microlymphography and densitometry in 20 patients. Perfusion was studied by laser Doppler fluxmetry. Results: Permeability of lymphatics in plaques was increased by 7.6% compared to unafflicted skin (p < 0.001). Lymphatic vessel density and the extension of dye in lymphatic networks were not significantly different between involved and uninvolved areas. Both sites showed a wide range of diameters of lymphatics. The median laser Doppler flux in plaques was increased by 144% (91-380%) compared to unaffected skin (p < 0.001). Conclusions: Increased permeability of lymphatics and increased blood flow was demonstrated in vivo in psoriatic skin lesions. These findings may reflect the local inflammatory process and may be used as markers when studying new therapeutic approaches for psoriasis. © 2013 S. Karger AG, Basel [ABSTRACT FROM AUTHOR]

Abstract: Background: Necrotizing enterocolitis (NEC) alters intestinal microvascular control mechanisms causing significant vasoconstriction. Our prior work with intraperitoneal 2.5% dextrose solution demonstrated increased intestinal perfusion in experimentally induced NEC. In the current study, we examine whether a buffered solution with lower glucose and osmolar loads similarly increases intestinal blood flow. We hypothesized that buffered 1.5% dextrose solution would increase ileal blood flow compared with baseline in NEC. Methods: We randomly assigned pregnant Sprague-Dawley rats to control (n = 103) or NEC (n = 123) groups, by litter. We induced NEC by previously published methods. Control pups were vaginally delivered and dam-fed. We used laser Doppler flowmetry to evaluate perfusion in the terminal ileum at 12, 24, 48, 72, or 96 h after delivery at baseline and after application of topical 1.5% dextrose solution. We evaluated differences between groups and time points by analysis of variance and Tukey post hoc test. Results: Baseline blood flow in the terminal ileum increased with gestational age in both groups (P < 0.05). Control groups had significantly greater baseline blood flow than NEC groups (P < 0.05), and topical application of buffered 1.5% dextrose solution increased blood flow compared with baseline in both groups at all time points (P < 0.05). Conclusions: Topical 1.5% dextrose solution significantly enhanced blood flow in the terminal ileum to the same degree as 2.5% dextrose solution. Thus, the use of buffered 1.5% dextrose solution might be more beneficial in treating clinical NEC, because it places a lower glucose and osmotic load on NEC-injured intestine. [Copyright &y& Elsevier]

Abstract: Purpose: Endothelin-1, prostaglandins (PGs), and nitric oxide (NO) have been implicated in the intestinal microvascular dysfunction of necrotizing enterocolitis (NEC). We hypothesized that direct peritoneal resuscitation (DPR) dilates the intestinal microvasculature and improves blood flow independent of these mechanisms. Methods: Rat pups were assigned by litter to experimental NEC or CONTROL groups. Laser Doppler flowmetry evaluation of intestinal microvascular blood flow was studied at baseline, with mediator blockade (endothelin-A receptor, endothelin-B receptor, PG synthesis, or NO synthase) and with DPR. Repeated-measures analysis of variance test was applied with Tukey-Kramer honestly significant difference test (P < .05). Results: At baseline, NEC animals demonstrated significantly decreased ileal blood flow as compared with CONTROLs (P < .05). Endothelin-A receptor and PG inhibition increased flow in the intestinal microvasculature, but this was significantly augmented by the addition of DPR (P < .05). Blockade of NO synthase decreased intestinal blood flow, which was overcome with addition of DPR (P < .05). Conclusion: Ileal blood flow was significantly reduced in NEC animals as compared with CONTROLs. The addition of DPR to the peritoneum increased ileal blood flow significantly in all groups in spite of blockade of these known vasoactive mechanisms. Direct peritoneal resuscitation may be a novel strategy to improve intestinal blood flow in NEC. [Copyright &y& Elsevier]

Abstract: The aim of the present study was to investigate the effect of quantitatively measured cold perception (CP) thresholds on microcirculatory response to local cooling as measured by direct and indirect response of laser-Doppler (LD) flux during local cooling at different temperatures. The CP thresholds were measured in 18 healthy males using the Marstock method (thermode placed on the thenar). The direct (at the cooling site) and indirect (on contralateral hand) LD flux responses were recorded during immersion of the hand in a water bath at 20°C, 15°C, and 10°C. The cold perception threshold correlated (linear regression analysis, Pearson correlation) with the indirect LD flux response at cooling temperatures 20°C (r=0.782, p<0.01) and 15°C (r=0.605, p<0.01). In contrast, there was no correlation between the CP threshold and the indirect LD flux response during cooling in water at 10°C. The results demonstrate that during local cooling, depending on the cooling temperature used, cold perception threshold influences indirect LD flux response. [Copyright &y& Elsevier]

Acetylcholine-induced endothelium-dependent vasodilation in conduit arteries primarily depends on nitric oxide (NO). However, the biochemical mediators in the microvasculature remain less well defined. We tested whether prostaglandins and NO are responsible for cutaneous acetylcholine-mediated vasodilation and if they interact to modulate vasodilation. We measured skin blood flow (SBF) using laser Doppler flow (LDF) with intradermal microdialysis in the calves of 23 healthy volunteers. We examined the response of SBF to different doses of acetylcholine (0.01-100 mM), the nonisoform-specific NO synthase inhibitor, nitro-L-arginine (NLA, 10 mM), the nonspecific cyclo-oxygenase (COX) inhibitor, ketorolac (Keto, 10 mM), and combined NLA + Keto. NLA had no effect on baseline SBF, while Keto increased baseline SBF by approximately 150%. The increase was blunted with combined NLA + Keto. SBF increased by approximately 700% with the highest acetylcholine concentration and reduced by approximately 60% by NLA. Ketorolac alone also reduced the response to acetylcholine, although the reduction varied between 10 and 20% at differing acetylcholine doses. NLA plus ketorolac reduced the responses to different doses of acetylcholine by some 30%, which was intermediate to NOS or COX inhibition alone. These data suggest that cutaneous acetylcholine-mediated endothelium-dependent vasodilation is highly NO-dependent and is also strongly related to the interactions of NO with prostaglandins. [ABSTRACT FROM AUTHOR]

Background: Ropivacaine is primarily a local anesthetic, but it also acts as a vasoactive agent. Case reports have described a critical reduction in blood flow when higher concentrations of ropivacaine were used for peripheral-nerve blocks. One hypothesis is that local application of ropivacaine in tissues supplied by end arteries reduces tissue blood flow because of arterial vasoconstriction. Methods: Rats were anesthetized by inhalation of isoflurane. The tail vessels were carefully dissected from the ventral side near the radix. Randomly, normal saline, prilocaine 0.5%, prilocaine 0.5% with epinephrine 1:200,000, ropivacaine 0.2%, ropivacaine 0.5%, or ropivacaine 0.75% was applied directly to the artery. Blood flow in the tail was continuously measured by use of laser Doppler flowmetry distal to the surgical site. Changes in temperature in the tail were detected by use of infrared thermography. Results: Blood flow decreased after the application of ropivacaine at all concentrations in comparison with normal saline (P < .01 at t = 10 minutes, P < .001 at t = 20, 30, and 40 minutes). This effect was most pronounced at t = 30 minutes for ropivacaine 0.5% (with a 64.5% decrease in blood flow). Prilocaine 0.5% with epinephrine 1:200,000 reduced blood flow by up to 44.7% (t = 20 minutes, P < .001). In comparison with the placebo, the application of ropivacaine 0.5% and 0.75%, as well as prilocaine 0.5% with epinephrine 1:200,000, caused a significant reduction in tail temperature (P < .001 at t = 20, 30, and 40 minutes). No alteration in blood flow or temperature was seen after application of prilocaine 0.5%. Conclusions: The application of ropivacaine directly to a rat’s tail artery diminished blood flow and lowered regional skin temperature. These effects were dose related. The use of ropivacaine at higher concentrations can, therefore, not be recommended if tissues supplied by end arteries might be affected. [Copyright &y& Elsevier]

Abstract: In order to evaluate hemodynamics and blood flow during rest-associated apnea in young elephant seals (Mirounga angustirostris), cardiac outputs (CO, thermodilution), heart rates (HR), and muscle blood flow (MBF, laser Doppler flowmetry) were measured. Mean apneic COs and HRs of three seals were 46% and 39% less than eupneic values, respectively (2.1±0.3 vs. 4.0±0.1 mL kg−1 s−1, and 54±6 vs. 89±14 beats min−1). The mean apneic stroke volume (SV) was not significantly different from the eupneic value (2.3±0.2 vs. 2.7±0.5 mL kg−1). Mean apneic MBF of three seals was 51% of the eupneic value. The decline in MBF during apnea was gradual, and variable in both rate and magnitude. In contrast to values previously documented in seals during forced submersions (FS), CO and SV during rest-associated apneas were maintained at levels characteristic of previously published values in similarly-sized terrestrial mammals at rest. Apneic COs of such magnitude and incomplete muscle ischemia during the apnea suggest that (1) most organs are not ischemic during rest-associated apneas, (2) the blood O2 depletion rate is greater during rest-associated apneas than during FS, and (3) the blood O2 store is not completely isolated from muscle during rest-associated apneas. [Copyright &y& Elsevier]

Although microvascular complications are frequent in diabetes, the pathogenesis underlying these morbidities remains unclear. Chronic inflammation appears to play a role both in the development of vascular dysfunction and diabetes. Evaluation of microvascular status in the prediabetic stages would provide a better insight into the natural progression of the disease, both from the vascular and metabolic perspective. Microvascular function was assessed in sixty rhesus monkeys using laser Doppler fluximetry. These included monkeys who had been calorie-restricted (CR); normal non-diabetic ad libitum fed (N) monkeys; Prediabetic (PreDM) monkeys with either impaired fasting glycemia, glucose intolerance or insulin resistance; and overtly diabetic monkeys (DM) with fasting glucose levels above 126 mg/dl. Body weight, per cent body fat, fasting glucose and insulin levels, glucose disposal rate during an intravenous glucose tolerance test (Kglucose), and insulin sensitivity (M-rate) as assessed by the euglycemic, hyperinsulinemic clamp procedure were measured. Routine clinical chemistry and hematology were also performed. Our results show that in prediabetes, dermal microvascular flow is characterized by an increase in response to thermogenic provocation. We further show that this paradoxical increase is significantly and highly correlated with circulating high sensitivity CRP levels. The study demonstrates that both mild chronic inflammation and elevated skin microvascular perfusion precede overt diabetes. [ABSTRACT FROM AUTHOR]

ABSTRACT: Transanal advancement flap repair has been advocated as the treatment of choice for transsphincteric pen-anal fistulas, because it enables the healing of almost all fistulas without sphincter damage and consequent continence disturbance. After initial promising reports, recently less favorable results have been reported. It remains unclear why there is such a large variety in the reported healing rates. Recently, it has been suggested that impaired wound healing caused by a diminished rectal mucosal perfusion in patients who smoke may lead to the breakdown of the advancement flap in patients undergoing flap repair for perianal fistulas. This study was designed to investigate the difference in blood flow in rectal mucosa between patients who smoke and those who do not smoke. Furthermore, we assessed the impact of the creation of a mucosa advancement flap and the difference in blood flow in the flap between smoking and nonsmoking patients. Between July 2001 and July 2002, 23 consecutive patients (19 males; median age, 46 (range, 26-69) years) with a perianal fistula of cryptoglandular origin underwent surgery for a perianal fistula. Among them were 13 patients who smoked cigarettes. All patients underwent intraoperative laser Doppler flowmetry. Median blood flow before transanal advancement flap repair was 35 (range, 8-70) volts in patients who did not smoke. In patients who smoked the median blood flow before transanal advancement flap repair was 18 (range, 7-3 5) volts. Blood flow was significantly lower in patients who smoked (P = 0.0 18; Mann-Whitney). In conclusion, it seems likely that impaired wound healing caused by a diminished rectal mucosal perfusion is a contributing factor in the breakdown of advancement flaps in patients who smoke cigarettes. [ABSTRACT FROM AUTHOR]

Aims/hypothesis. Insulin possesses vasodilatory actions that may be important in regulating its access to insulin-sensitive tissues. Our study aims to directly measure changes in response to insulin in the human skeletal muscle microcirculation. Measurement was by an implanted laser Doppler probe. Methods. We investigated changes in intramuscular and skin microvascular perfusion in 12 healthy individuals during a hyperinsulinaemic and a control clamp. We determined leg blood flow with plethysmography, finger skin functional capillary recruitment with capillaroscopy, endothelium-(in)dependent vasodilation by iontophoresis of acetylcholine and sodium nitroprusside, and leg intramuscular reactive hyperaemia and vasomotion with laser Doppler measurements. Results. Compared to the control study, hyperinsulinaemia (416±82 pml/l) caused: (i) an increase in leg blood flow (1.0±1.0 vs 0.1±0.6 ml·min-1·100 ml, p<0.05); (ii) an increase in finger skin capillary recruitment (14.9 ±10.1 vs -5.6±11.0%, p<0.01); (iii) no change in baseline laser Doppler perfusion either in finger skin or leg muscle; (iv) a tendency to increase acetylcholine-mediated vasodilation (475±534 vs 114±337%, p=0.07) with no change in sodium-nitroprusside-mediated vasodilation (p=0.2) in finger skin; (v) an increase in intramuscular reactive hyperaemia (423±507 vs 0±220%, p<0.01); and (vi) a decrease in time needed to reach peak intramuscular perfusion (-3.6±3.0 vs 1.1±3.1 s, p<0.01). In addition, hyperinsulinaemia induced an increase in intramuscular vasomotion by increasing the contribution of frequencies between 0.01 and 0.04 Hz (p<0.05 for all), which probably represents increased endothelial and neurogenic activity. Conclusions/interpretation. Physiological hyperinsulinaemia not only stimulates total blood flow and skin microvascular perfusion, but also augments human skeletal muscle microvascular recruitment and vasomotion as detected directly by laser Doppler measurements. [ABSTRACT FROM AUTHOR]

Ghrelin, leptin and adiponectin are three hormones which are frequently associated with metabolism, obesity and appetite. Recently, it has been shown that they may possess other physiologic roles, specially in connection with the circulation. Ghrelin infusion increases forearm blood‐flow in a dose‐dependent manner. Leptin has been shown to be involved not only in thermogenesis but angiogenesis as well. Adiponectin, apart from its insulin‐sensitizing action, appears to modulate inflammation by inhibiting monocyte adhesion to endothelial cells. Six monkeys, which had been classified as being in the pre‐diabetic state, where administered a triglyceride lowering regimen. Microvascular function was assessed using a laser Doppler flow‐meter during a temperature provocation test. Percent change in flow from baseline following temperature elevation, as well as percent change in flow/degree rise in temperature were used to evaluate microvascular reserve and reactivity. Using univariate analysis, it appears that increased perfusion is significantly correlated with adiponectin, followed by leptin. Flow was also positively correlated with ghrelin, but the relationship did not attain significance. As expected, flow was also negatively and significantly correlated with fibrinogen. Trends show that flow was also negatively correlated to circulating triglyceride levels (p=0.08). The data indicate that the three hormones appear to possess microvascular actions that may impact on their other physiologic functions. [ABSTRACT FROM AUTHOR]

Objective: To evaluate effects of lung recruitment maneuvers on gastric mucosal perfusion, systemic circulation, and lung mechanics in patients with acute lung injury.Design: Prospective observational clinical study. SETTING. General intensive care unit of university hospital.Patients and Participants: Fourteen patients with acute lung injury (ten in the main study group and four in a validation group). INTERVENTIONS. Three 2-min-long recruitment maneuvers (RM) with transient increases in mean airway pressure to 35 cmH(2)O (RM1 and RM2) and 44 cmH(2)O (RM3).Measurements and Results: Measurements of systemic hemodynamics, gastric mucosal perfusion (laser Doppler flowmetry), and lung mechanics were performed immediately before, at the end of, and 3 min after each RM. Cardiac index decreased during all RMs while mean arterial pressure decreased only during RM3. Gastric mucosal perfusion was not significantly changed during any of the RMs. When comparing values obtained before the first RM with values after the third RM there was a significant decrease in cardiac index ( P=0.043) and a non-significant ( P=0.051) decrease in gastric mucosal perfusion. There were no significant changes in systemic oxygenation or lung mechanics after three RMs, even though four patients showed marked transient increases in systemic oxygenation during RMs.Conclusions: In this study of ten patients there were no significant changes in gastric mucosal perfusion during lung recruitment maneuvers. There was, however, a trend towards gradual decreases in gastric mucosal perfusion. [ABSTRACT FROM AUTHOR]

Summary It has been known since the nineteenth century that oxygen is taken up by the human skin. With a newly developed sensor it became possible to examine the influence of the vascular supply on the oxygen flux into the skin, tcJ(O2). tcJ(O2) was measured optically by determining the oxygen partial pressure difference, ΔpO2 across a diffusion test membrane, which itself was brought into close contact to the skin surface. Under these conditions ΔpO2 is proportional to the tcJ(O2). The skin perfusion was varied by the application of a hyperemizing ointment on the abdomen of 12 volunteers and by suprasystolic occlusion at the thigh of 20 volunteers. The tcJ(O2) was measured at a temperature of 33°C of the humid skin. It was compared with the skin perfusion monitored by laser Doppler flow, and the capillary oxygen supply measured by transcutaneous partial pressure of oxygen, tcpO2, at an electrode temperature of 37°C. The transcutaneous O2 flux produced a distinct ΔpO2 of 81.8 ± 8.2 Torr (abdomen) and 72.8 ± 12.3 Torr (ankle). In hyperemic skin on the abdomen the O2 flux was reduced (ΔpO2 = 57.7 ± 10.6 Torr). The tcpO2 increased from 8.7 ± 10.7 to 35.1 ± 16.9 Torr. During suprasystolic occlusion, ΔpO2 increased by 6.4 ± 2.3 Torr, whereas laser Doppler flow and tcpO2 decreased significantly. These results indicate that the total oxygen supply of the epidermis and the upper dermis is guaranteed even if the perfusion varies. [ABSTRACT FROM AUTHOR]

The aim of the study was to test the irritancy of 6 antiseptics in an open exposure model. The following agents were tested in their normal use concentrations using open exposures, 2 × daily for 4 days in 20 subjects: chlorohexidine 4% (CH), chlorhexidine 0.5% in ethanol 70% (CE), ethanol 70% (ET), iodine 1% in ethanol 70% (IE). povidine-iodine 10% (PI) and sodium hypochlorite 0.25% (SH). Responses were evaluated by visual scoring, subjective irritancy scoring, stratum corneum hydration (Corneometer), transepidermal water loss and laser Doppler flowmetry. Exposure to SH had to be discontinued after 4 applications because of severe subjective irritation. The same held true for IE (7 applications), whereas the other agents were exposed 8 ×. All evaluation methods showed SH to be significantly more irritating than IE, which was in turn more irritating than CH CE, Et and PI. Thus, it can be concluded that CH, CE, Et and PI were non-irritating in this open exposure model. [ABSTRACT FROM AUTHOR]

Objectives: Cold stimulation causes a finger skin vasoconstrictor response, which is regulated by stimulation of α-adrenergic receptors and is reduced by administration of prazosin. The purpose of this study was to investigate, using a laser Doppler flowmeter, whether the decrease in the finger skin vasoconstrictor response to cold stimulation produced by administration of two different α-adrenoceptor antagonists, prazosin and urapidil, was correlated with the corresponding plasma drug concentration, and whether this method could be used to evaluate the relative potency of these α-adrenoceptor antagonists in human subjects. Method: In thirteen healthy male subjects (20-42 y), finger tip skin blood flow was measured during cold stimulation before and 1, 2, 3, 6, and 9 h after administration of placebo, prazosin (1 mg) or urapidil (60 mg). Results: Both prazosin and urapidil significantly decreased the vasoconstrictor response to cold stimulation. The degree of the decrement in the response indicated by the reduction ratio was significantly correlated with the plasma concentration of prazosin and urapidil. The α-adrenoceptor blocking activity of prazosin estimated by the regression lines was about 130-times more potent than that of urapidil. Conclusion: These findings suggest that the cold stimulation response of finger skin vasoconstriction may be used to evaluate the relative α-adrenoceptor blocking potency of drugs. [ABSTRACT FROM AUTHOR]