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Di-(2-ethylhexyl) phthalate enhances atopic dermatitis-like skin lesions in mice.

Di-(2-ethylhexyl) phthalate (DEHP) has been widely used in polyvinyl chloride products and has become ubiquitous in the developed countries. DEHP reportedly displays an adjuvant effect on immunoglobulin production. However, it has not been elucidated whether DEHP is associated with the aggravation of atopic dermatitis. We investigated the effects of DEHP on atopic dermatitis-like skin lesions induced by mite allergen in NC/Nga mice. NC/Nga male mice were injected intradermally with mite allergen on their right ears. In the presence of allergen, DEHP (0, 0.8, 4, 20, or 100 microg) was administered by intraperitoneal injection. We evaluated clinical scores, ear thickening, histologic findings, and the protein expression of chemokines. Exposure to DEHP at a dose of 0.8-20 microg caused deterioration of atopic dermatitis-like skin lesions related to mite allergen; this was evident from macroscopic and microscopic examinations. Furthermore, these changes were consistent with the protein expression of proinflammatory molecules such as macrophage inflammatory protein-1alpha (MIP-1alpha) and eotaxin in the ear tissue in overall trend. In contrast, 100 microg DEHP did not show the enhancing effects. These results indicate that DEHP enhances atopic dermatitis-like skin lesions at hundred-fold lower levels than the no observed adverse effect level determined on histologic changes in the liver of rodents. DEHP could be at least partly responsible for the recent increase in atopic dermatitis.

Animals↗

A Rift Valley fever vaccine trial: 2. Serological response to booster doses with a comparison of intradermal versus subcutaneous injection.

A booster dose of a formalin-inactivated, cell culture-propagated Rift Valley fever vaccine (TSI-GSD-200) was administered without significant reactogenicity to 60 volunteers 18 months after they received a three dose primary series. Blood was drawn for serological testing prior to boosting and 10, 49, and 180 days thereafter. Neutralizing antibody response was prompt, being maximum on day 10 and considerably higher than the peak titres obtained on day 42 after the initial series. A marked decline in antibody titres was evident by day 180, as seen for the primary series, but residual titres were substantially higher. The initial series was given in doses of 1.0, 0.5, 0.3, or 0.1 ml and the immune status achieved with these injections was a major determinant of the response to boostering. Secondary responses were highly dependent in magnitude and duration on the prior immune status of the recipient. Evaluation of dose and route of recall inoculation showed 1.0 ml given subcutaneously (SC) to be equivalent to 0.1 ml administered intradermally (ID), though inference should be guarded due to the small sample size. Although 0.1 ml SC dose was inferior to either, it was modestly effective. Intradermal administration of vaccine may be useful for extending the small reserve of vaccine available for use in emergency.

Adult↗

The histopathology of pathergy: a chronologic study of skin hyperreactivity in Behçet's disease.

BACKGROUND: Many patients with Behçet's disease (BD) demonstrate hyperreactivity (pathergy), and the induced skin lesions may serve as a model for the disease. OBJECTIVE: This study examined the sequence of histopathologic changes after needle prick trauma. METHODS: Eight patients fulfilling the International Study Group Criteria for Behçet's Disease, two patients with recurrent aphthous stomatitis, and two healthy controls each underwent intradermal injections with subsequent biopsies at 0, 4, 24, and 48 h. Hematoxylin and eosin sections were evaluated in a blinded fashion according to 11 histopathologic criteria. RESULTS: At time zero, normal skin was seen. By 4 h, neutrophils were present usually admixed with lymphocytes (8 out of 10). The inflammatory cell density peaked by 24 h in 8 out of 10 patients and at 48 h in 2 out of 10 patients. Sparse leukocytoclasis was identifiable from 4 to 48 h, but was not associated with fibrin. True vasculitis (as evidenced by fibrin within vessel walls and/or intraluminal thrombi) was not seen. Intraepidermal pustules (IEPs) and polymorphonuclear (PMN) aggregates within the needle tract were seen as early as 4 h. The control patients and three out of eight of the BD patients failed to develop clinical lesions. Among this group histopathologic IEPs were lacking in all but two BD patients. CONCLUSIONS: These data suggest that early pathergy is mediated by PMNs and lymphocytes without vasculitis. Hyperchemotaxis may explain the rapid accumulation of PMNs along the injection site.

Adult↗

Delayed pressure urticaria histologically resembles cutaneous late-phase reactions.

In a recent study, all patients with delayed pressure urticaria (DPU) developed late cutaneous reaction (LCR) after intradermal injection of compound 48/80 and after skin testing with certain food antigens. In the present study, we analyzed the histologic changes in the pressure lesions and compared them with those found in normal skin injected with diluent and in LCR to 48/80. The study included five patients with DPU associated with chronic urticaria (CU) and four patients with CU but without DPU. Six to eight hours after pressure challenge and intradermal skin testing with 48/80 and diluent, skin biopsy specimens were obtained from the pressure lesions, the LCRs, and normal skin (diluent injection). Specimens were assessed by Giemsa staining of 1-micron sections and immunofluorescence of frozen sections. Total cells were counted in each specimen. Interstitial deposits of fibrin were observed by immunofluorescence in LCR and pressure lesions. The total numbers of infiltrating cells in the dermis among LCR sites and pressure lesions were not significantly different, while both LCR sites and pressure lesions contained significantly more infiltrating cells than did normal skin injected with saline diluent. The differential counts in LCR and DPU were mostly mononuclear cells. Infiltrates in the DPU and LCR were mostly perivascular. No histopathologic changes were seen at skin sites challenged with pressure in the control patients with CU without clinical manifestations of DPU. We conclude that lesions seen in DPU are morphologically similar to classic LCR.

Adult↗

Effect of forskolin on alterations of vascular permeability induced with bradykinin, prostaglandin E1, adenosine, histamine and carrageenin in rats.

The effect of the diterpene forskolin on vascular permeability alone and in combination with bradykinin, prostaglandin E1, adenosine or histamine has been investigated in rats. Vascular permeability in rat skin was measured using [125I]-labelled bovine serum albumin ([125I]BSA) as a tracer. In addition, the effect of forskolin on footpad edema induced by the injection of a mixture of 2% carrageenin was determined. Forskolin caused a marked potentiation of the increase in vascular permeability in rat skin elicited by the intradermal injection of histamine or bradykinin. However, forskolin caused a significant suppression of the prostaglandin E1-induced vascular permeability response and at a low concentration suppressed the response to adenosine. Forskolin greatly potentiated the footpad edema induced with carrageenin in rats. Intravenous administration of the enzyme bromelain, which reduces plasma kininogen levels, inhibited the footpad edema induced with carrageenin or with a mixture of carrageenin and forskolin. Parenteral administration of a prostaglandin synthetase inhibitor, indomethacin, suppressed the footpad edema induced with carrageenin, but did not inhibit the footpad edema induced with a mixture of carrageenin and forskolin. An antihistamine, cyproheptadine, had no effect on carrageenin-induced footpad edema either in the presence or absence of forskolin. These results suggest that both bradykinin and prostaglandins are essential for the development of carrageenin-induced footpad edema and that bradykinin plays an important role in the potentiative effect of forskolin on footpad edema induced with carrageenin in rats.

Adenosine↗

The kinetics of metaphase arrest in human psoriatic epidermis: an examination of optimal experimental conditions for determining the birth rate.

The optimum experimental conditions have been investigated for the measurement of the birth-rate in human psoriatic epidermis using the vinca alkaloids vinblastine and vincristine. The dose response characteristics of the two drugs were assessed over a 2.5 h collection period; although the dose response characteristics differed between the two agents, a dose of 1 microgram injected intradermally was considered to be optimal for both. The linearity of metaphase correction was assessed for both agents, taking biopsies for up to 10 h after injection. It was found that there was a delay period for up to an hour which must be avoided during the analysis to prevent an underestimate of the birth rate. However, linearity was then demonstrated for up to 4 h after injection. Metaphase degeneration was assessed by isolating a cohort of unlabelled cells in the G2 phase and tracing their fate over the next 10 h. It was found that the minimum life of an arrested metaphase was of the order of 4 h, and then metaphases degenerated at the rate of approximately 0.4% per hour. It is recommended that metaphase arrest experiments in psoriatic epidermis be confined to 4 h although, if required, correction factors are available to correct for experiments which are lengthened. Finally it is shown that flux into DNA synthesis exceeds the flux into mitosis by four or five times; several explanations are considered, and it is thought that the most likely explanation involves the death of psoriatic cells in the G2 phase.

DNA↗

Induction of delayed-type hypersensitivity to Leishmania major and the concomitant acceleration of disease development in progressive murine cutaneous leishmaniasis.

BALB/c mice injected intradermally with 10(5) or higher doses of formaldehyde-fixed promastigotes (FFP) of Leishmania major developed strong delayed-type hypersensitivity (DTH) to leishmanial antigens injected into the hind footpad 3 to 10 days later. The DTH peaked 15 to 18 h after footpad injection and disappeared by 48 h. This specific DTH correlated with the homing of 51Cr-labeled syngeneic bone marrow cells and the infiltration of proliferating cells to the site of antigen administration. Spleen cells from FFP-sensitized mice also gave significant proliferative response to FFP in vitro. The DTH was adoptively transferable by Lyt-1+2-L3T4+ T cells and was H-2 restricted. DTH could be substantially enhanced by pretreatment with cyclophosphamide or pertussigen. Such DTH enhancement was accompanied by concomitant exacerbation of disease progression after L. major infection. Mice injected intravenously with FFP developed substantial immunity to cutaneous leishmaniasis but specifically suppressed DTH reactivity. Treatment of mice with pertussigen before intravenous immunization, however, abolished the protection and reversed the suppression of DTH. These results therefore demonstrate that the early-appearing type of DTH is not involved in host protection but that it actually facilitates disease progression in cutaneous leishmaniasis. Further evidence, which also shows the nonspecific nature of this disease exacerbation, is provided by local cell transfer experiments. Splenic T cells from mice sensitized to keyhole limpet hemocyanin or FFP induced significantly larger lesions compared with normal T cells when they were transferred into the footpad together with specific antigen and L. major promastigotes.

Animals↗

Autoimmunity to collagen in adjuvant arthritis of rats.

Arthritis can be induced in rats by intradermal injection of oil containing bacterial derivatives (adjuvant-induced arthritis) or cartilage collagen (type II collagen-induced arthritis). It was of interest, therefore, to determine whether collagen functions as an autoantigen in rats with adjuvant arthritis. Blood mononuclear cells from the majority of rats with adjuvant arthritis exhibited enhanced thymidine incorporation to homologous types I and II collagens, as well as to purified protein derivative of tuberculin. In contrast, cells from rats remaining nonarthritic after injection of adjuvant did not respond to collagen, although they did react to tuberculin. Similar results were obtained with a radiometric ear assay used to quantify intradermal delayed-type hypersensitivity in vivo. Using passive hemagglutination, autoantibodies to these collagens and their denatured alpha-chains were frequently detected in the sera of rats late in the course of adjuvant arthritis. Rats with inflammation of a hindlimb induced by turpentine did not acquire sensitivity to collagen. These data indicate that autoimmunity to collagen is a common feature of adjuvant- and collagen-induced arthritis, both of which are considered to be mediated by immunologic mechanisms.

Animals↗

Sentinel lymph node detection by lymphoscintigraphy in malignant melanoma.

AIMS AND BACKGROUND: Sentinel lymph node (SLN) detection is currently employed in patients with malignant melanoma (MM) to spare them unnecessary lymph node dissection. METHODS AND STUDY DESIGN: We investigated 241 patients (130 men and 111 women, median age, 50 years (range, 14-92) with MM (192 before and 51 after surgical biopsy); two of them had more than one melanoma lesion. In each patient approx. 10 MBq of 99mTc Nanocoll in 0.1 mL (Nycomed Amersham Sorin; particle size range, 3-80 nm) was injected intradermally around the MM lesion or surgical scar. Dynamic acquisition was performed for 20 minutes (20 frames/min) and the study was concluded within four hours of injection. Using an external radioactive marker, the skin over the SLN was marked with China ink. RESULTS: 294 SLNs were scintigraphically identified: 117 in the inguinal region, 147 in the axillae, four in the submandibular region, three in the laterocervical region and 23 at other sites. In two patients no drainage was detected. In 43 patients more than one sentinel node was identified. In 13 patients with lesions located in the trunk the tracer drained towards multiple lymph node stations or unexpected lymph nodes (nine cases). Histology and immunohistochemistry diagnosed MM in 25 SLNs; 19 were positive for metastasis with hematoxylin-eosin staining, five with Hmb45 and one with CD68 immunostaining. All 25 detected lymphatic basins were excised. In nine of these basins there was metastatic involvement of at least one other lymph node besides the SLN. During follow-up which ranged from six to 86 months, metastatic disease was found in only one patient with a histologically negative SLN six months after surgery. CONCLUSIONS: This study confirms the utility of scintigraphic SLN detection in patients with MM. In most of the cases the procedure led the surgeon to evaluate the drainage area, which is unpredictable for lesions in the trunk and may be difficult to delineate using only patent blue dye. Furthermore, in approximately 10% of cases we observed dual drainage from individual lesions, mainly those located on the trunk. We will proceed to compare the results obtained during follow-up with those of an investigational group of patients with melanoma who were not subjected to lymphoscintigraphy for SLN detection in order to obtain well-founded information on the prognostic value of this technique.

Adolescent↗

Intracisternal injection of opioids induces itch-associated response through mu-opioid receptors in mice.

We examined whether opioids, especially morphine, would centrally elicit scratching in mice and determined some characteristics of the scratch-inducing action of opioids. When intracisternally (i.c.) injected, morphine (0.1-3 nmol/mouse) produced a dose-dependent increase in scratching of the face, but not of the ears, head and body trunk. When injected intradermally into the rostral part of the back, morphine (at most potent i.c. dose of 3 nmol/mouse or higher) did not increase the scratching of the injected site. Facial scratching of the mouse induced by i.c. injection of morphine (0.3 nmol/mouse) was almost abolished by distraction and by naloxone (1 mg/kg, s.c.). [D-Ala2, N-Me-Phe4, Gly5-ol]Enkephalin (DAMGO) (0.03-2 nmol), but not [D-Pen2,5]enkephalin (DPDPE) and U-50,488, dose-dependently elicited facial scratching by i.c. injection. These results suggest that morphine and DAMGO increased facial scratching, probably mediated by central opioid mu-receptors in mice, and such scratching was due to a sensation, probably itching. The present animal model may be useful for analyzing opioid-mediated central itching.

3,4-Dichloro-N-methyl-N-(2-(1-pyrrolidinyl)-cycloh↗

Sentinel node biopsy as an indicator for pelvic nodes dissection in early stage cervical cancer.

The purpose of this study was to investigate the feasibility of sentinel node frozen biopsy to minimize the extensive pelvic lymph nodes dissection in early stage cervical cancer patients on the basis that the risk of skip metastasis to the paraaortic area is negligible. Twenty-six patients with early stage cervical cancer were enrolled in this study. Technetium-99m colloid albumin (Tc(99m)) was injected intradermally around the tumor for allowing preoperative lymphoscintigraphy and intraoperative hand-held gama probe detection of seninel nodes. For visual detection, isosulfan blue dye was injected into the peritumoral sites before peritoneal opening. Postoperative morbidity and negative predictive value were the endpoints of this study. The 26 patients, ranging in age from 32 to 71 yr, underwent intraoperative sentinel nodes mapping. All the patients underwent complete pelvic lymph nodes dissection including para-aortic nodes. There was one case with positive non-sentinel nodes despite the negative sentinel node by frozen biopsy (negative predictive value, 95.2%). This new technique of sentinel node mapping is safe and simple to perform. Further clinical trials using the combination of Tc(99m) and isosulfan blue dye are warranted and this technique will make a true advance for less aggressive management of patients with early stage cervical cancer.

Adult↗

The neurogenic vasodilator response to endothelin-1: a study in human skin in vivo.

We have investigated the mediators and mechanisms underlying the vasodilator effects of the potent vasoactive peptide, endothelin-1 (ET-1) and its isomers ET-2 and ET-3 in human skin, in vivo, using cutaneous microdialysis to quantify the release of mediators within the dermal response and scanning laser Doppler imaging to measure changes in blood flux. The effects of local anaesthesia, inhibition of nitric oxide synthase (NOS) by L-NAME and ET receptor blockade on the ET-induced vascular response were also investigated. ET-1, -2 and -3 all caused a dose-dependent area of pallor surrounded by a long-lasting flare which was accompanied by a short-lived burning pruritus. The concentration of nitric oxide (NO) in dialysate collected within the pallor response to 5 microM ET-1 (1.43 +/- 0.64 microM, n = 5) was not significantly different from baseline levels collected prior to injection (0.86 +/- 0.38 microM) whilst that in the flare increased to reach a peak value of 2.28 +/- 0.61 microM at between 4 and 10 min after intradermal injection (P < 0.004). Pretreatment with local anaesthetic slowed the development of the flare and significantly reduced its size by up to 52% at 20 min after injection (P < 0.05) but had no significant effect on the central pallor. L-NAME, delivered by dialysis also caused a significant reduction in the ET-1-induced flare (P < 0.005). Bosentan, the non-selective ET(A)/ET(B) antagonist, when given by dialysis at the site of injection, reduced the area of both the ET-1-induced pallor and surrounding flare by 41 and 26%, respectively. No significant increase in tissue histamine was measured within either the pallor or flare response to ET-1, -2 or -3. Together these data confirm that the vasodilator response to endothelin-1 in human skin is neurogenic in origin and that it is in part mediated by the local release of nitric oxide. There appears to be little evidence for the involvement of mast cell-derived histamine in the initiation or modulation of ET-induced vasodilatation, in vivo.

Adult↗

The influence of long-term protein deprivation on in vivo phagocytic cell delivery to inflammatory lesions.

The effect of long-term protein deprivation and refeeding was assessed on the in vivo delivery of phagocytic leukocytes (PHAGS) to delayed-type hypersensitivity (DTH) reaction and a bacterial abscess. Male inbred Lewis rats sensitized to keyhole limpet hemocyanin (KLH) were fed either a normal diet or a 2% protein diet for 1, 6, and 10 weeks. Two additional groups were fed a 2% protein diet for 10 weeks but were refed with a normal diet for 1 or 4 weeks. At the end of each diet period rats were injected intradermally with KLH, Staphylococcus aureus 502A, and saline solution at different sites at from 1 to 24 hours. Technetium-99m-colloid labeled PHAGS (99PHAG) were injected intravenously and used to assess in vivo PHAG cell delivery. In normally fed rats the peak influx of 99PHAG was at 2 to 4 hours. After 1 week of protein-deficient diet there was a significant drop in early (2 to 4 hours) 99PHAG influx to both the DTH and bacterial reactions. After 10 weeks of protein deprivation (severe malnutrition) there was a further drop and a delay in the peak 99PHAG influx (from 2 to 4 hours, to 8 hours). A return to normal 99PHAG influx occurred only after 4 weeks of refeeding, and it coincided with a return to normal body weight and a normal DTH reaction. There was a direct correlation between total 99PHAG delivery to a DTH reaction and a bacterial abscess (rs = 0.87, Spearman rank; p less than 0.001). We conclude that both moderate and severe protein deprivation is associated with reduced in vivo phagocytic cell delivery to both a DTH reaction and a bacterial skin abscess, which can be restored with refeeding.

Abscess↗

PGD2 is an intermediate in agonist-stimulated nitric oxide release in rabbit skin microcirculation.

We investigated the role of endogenous prostaglandins and NO in the blood flow response of skin microcirculation in vivo. Test agents were injected intradermally in anesthetized rabbits and changes in skin blood flow measured with a laser-Doppler flow probe. Skin blood flow increased 75% at 7.33, 6.77, 11.63, 10.30, 10.55, 8.20, and < 7 -log mol/site with acetylcholine, ATP, bradykinin, prostaglandin D2 (PGD2), prostaglandin E2 (PGE2), NO gas in solution, and nitroprusside respectively. Co-injection of indomethacin (3 x 10(-9) mol/site) or NG-nitro-L-arginine methyl ester (L-NAME; 10(-7) mol/site) with either acetylcholine or bradykinin abolished the effects. This suggests a link between NO and prostaglandin release. Arachidonic acid increased blood flow, which was inhibited by indomethacin, L-NAME, or the PGD2-receptor antagonist BW-A868C. Blood flow responses to either intradermal acetyl-choline or bradykinin, but not to NO in solution, were abolished by co-injection with BW-A868C. PGD2-mediated vasodilation was abolished by L-NAME or BW-A868C, but not by indomethacin. There was no evidence of a link between NO and prostaglandin release in precontracted rabbit aortic rings in vitro. The results suggest that, in the microcirculation of rabbit skin, acetylcholine- and bradykinin-mediated vasodilation involve the arachidonic acid-PGD2-NO pathway.

Acetylcholine↗

Hypersensitivity reaction against patent blue during sentinel lymph node removal in three melanoma patients.

BACKGROUND: In order to identify the sentinel lymph node (SLN) in melanoma patients intradermal injection of a radiocolloid tracer and a blue dye are commonly used. Life-threatening side effects such as allergic reactions to the injected dye have been described. We report 3 cases with systemic allergic reactions. METHODS: Three patients suffering from systemic reactions such as hypotension and rash during SLN biopsy were tested for sensitisation against patent blue and methylene blue with skin prick, scratch, and intradermal test. RESULTS: All 3 patients showed positive skin tests to patent blue confirming allergic reaction to the injected dye. In addition, all patients showed positive skin tests with methylene blue indicating immunologic cross-reactivity between patent blue and methylene blue. CONCLUSIONS: Although allergic reactions to blue dye during SLN biopsy are rare, they may be life threatening. It is important that the attending anesthetist is aware of this.

Adult↗

Prolonged maintenance of capsaicin-induced hyperalgesia by brief daily vibration stimuli.

This study tests the hypothesis that central sensitization initiated by nociceptive input can be maintained by repeated brief innocuous peripheral inputs. Capsaicin was injected intradermally into the hind paw of adult rats. Three different types of daily cutaneous mechanical stimulations (vibration, soft brush, or pressure) were applied to the capsaicin-injected paw for a period of 2 weeks. Daily stimulation consisted of a 10-s stimulation repeated every 30s for 30 min. Foot withdrawal thresholds to von Frey stimuli applied to the paw were measured once a day for 4 weeks. The capsaicin-only group (control rats without daily stimulation) showed hyperalgesia lasting for 3 days. In contrast, hyperalgesia persisted for 2 weeks in the group that received vibration stimulation. Neither the soft brush nor the pressure group showed a significant difference in mechanical threshold from the control group (capsaicin only). The vibration-induced prolonged hyperalgesia was significantly reduced by systemic injection of ifenprodil, an NMDA-receptor antagonist, but it was not influenced by either an AMPA-receptor blocker or a reactive oxygen species (ROS) scavenger. Furthermore, a dorsal column lesion did not interfere with the prolongation of hyperalgesia. Data suggest that vibration-induced prolongation of hyperalgesia is mediated by spinal NMDA-receptors, and a similar mechanism may underlie some forms of chronic pain with no obvious causes, such as complex regional pain syndrome type 1 (CRPS-1).

6-Cyano-7-nitroquinoxaline-2,3-dione↗

The extension of the Shwartzman phenomenon to the mouse and some ecological determinants of the single-injection reaction.

The localized Shwartzman reaction has been demonstrated in a highly inbred mouse strain (BSVS). This reaction was produced with marked regularity in these mice by administration of relatively small doses of bacterial endotoxin or other Shwartzman-active agents. It is considered the equivalent of the phenomenon described in the rabbit inasmuch as it has conformed to all the operational and histopathological aspects of the classical reaction that have been tested, including elicitation by various endotoxins, heterologous preparation and provocation, inhibition by anticoagulants, and provocation by antigen-antibody complexes. A reaction similar to the above but differing in its manner of production was also investigated and has been termed the single-injection Shwartzman reaction. This phenomenon was identical with the normal Shwartzman reaction in all ways except for the fact that it was elicited with but a single intradermal injection of bacterial endotoxin. In investigating the lesion it has been demonstrated that inapparent in the gross, but elicitible infection of the lungs with a Gram-negative microflora was uniformly associated with single-injection reactivity. Because of this constant association it has been suggested that a causal relationship exists between the infected state and the skin reaction, not on the basis of known immunological events but on the basis of the Shwartzman mechanism in which the lung flora, demonstrably excited by the preparative injection, appears to mediate natural "endogenous" provocation of the lesion at the prepared skin sites.

Animals↗

Roles of leukocytosis and cysteinyl leukotriene in polymorphonuclear leukocyte-dependent plasma extravasation.

The PMN-dependent plasma extravasation is a major mechanism of permeability enhancement in acute inflammation. To reveal the pathophysiological significance of the PMN-dependent plasma extravasation, we prepared a systemic leukocytotic guinea pig model by a daily injection of recombinant human (rh)G-CSF. The extent of the PMN-dependent plasma extravasation, regarded as the late-phase permeability induced by an intradermal injection of zymosan-activated guinea pig plasma (ZAP) or of rhC5a, clearly correlated to the circulating PMN number. The augmentation of local response following the systemic response seemed to be the characteristic feature of the PMN-dependent plasma extravasation. We then revealed the molecular mechanism of the PMN-dependent plasma extravasation. Neither the antihistaminic agent diphenhydramine, nor the bradykinin B2 receptor antagonist, HOE140, affected the ZAP-induced, late-phase extravasation. In contrast to this, pretreatment with an antagonist of cysteinyl leukotriene (cys-LT) 1 receptor, pranlukast, significantly reduced the late-phase extravasation. Similarly, it was reduced by pretreatment with a 5-lipoxygenase inhibitor, MK-886, indicating the participation of cys-LTs in the PMN-dependent plasma extravasation. Histologically, pretreatment with pranlukast or MK-886 did not affect the ZAP-induced PMN infiltration. Consistently, a combined treatment with pranlukast and diphenhydramine completely suppressed the early-phase extravasation. As pranlukast pretreatment did not affect plasma extravasation induced by mast cell degranulation, and depletion of platelets did not influence the pranlukast-inhibitable plasma extravasation induced by rhC5a injection, cys-LTs are most likely produced by transcellular biosynthesis involving PMNs and vascular wall cells.

Adrenergic beta-Antagonists↗