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Results for “Skin Window Technique”

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PubMed1984

The effects of alpha- or beta-adrenergic receptor agonists and antagonists and calcium entry blockers on the spontaneous vasomotion.

The effects of systemic injections of vasoactive substances were studied in the micro-circulation of the hamster skin fold window preparation, which can be observed without anesthesia, exposure, and acute surgical procedures. The effects were characterized by the continuous measurement of the diameter of the arterial microvessels ranging from 100 to 8 micron. Power spectrum analysis was utilized to determine the frequency and the amplitude of the fundamental component of spontaneous diameter changes. Epinephrine and norepinephrine increased the frequency of vasomotion and reduced mean diameter at low dosages. Phentolamine reduced the frequency of vasomotion and increased mean diameter. Propranolol increased the frequency of vasomotion and did not significantly change mean diameter. Adenosine and verapamil suppressed vasomotion and increased mean diameter. These results are explained by postulating that low-dosage alpha-adrenergic receptor stimulation facilitates the spontaneous discharge of smooth muscle cells; beta-adrenergic receptor stimulation has the opposite effect, whereas beta-adrenergic receptor inhibition also enhances the vasomotor effect. Calcium entry blockers abolish the rhythmic discharge. This explanation of the activity of the various substances supports the hypothesis that the spontaneous vasomotion of the arterial microvessels is related to the intrinsic property of smooth muscle cells.

Adrenergic alpha-Agonists↗
PubMed1992

Activation of the coagulation pathway during ongoing allergic cutaneous reactions in humans.

The levels of histamine, fibrinopeptide A (FPA), and IgG were determined in chamber fluids overlying sites of antigen versus buffer incubation for up to 7 hours in seven atopic and four antigen-nonreactive subjects. Significant increases in histamine were observed at antigen versus buffer sites in the atopic subjects throughout the 7-hour period. FPA and IgG levels were higher in antigen than in buffer sites from 0 to 5 hours in the atopic subjects. Furthermore, FPA levels correlated with the magnitude of induration at 6 hours after antigen injection in atopic subjects. There were no differences in the levels of histamine, FPA, or IgG at antigen versus buffer sites in the skin test-negative subjects. We suggest that the combination of vascular leakage of proteins, induced by vasoactive mediator release, and activation of these proteins during ongoing cutaneous reactions is responsible for fibrin formation that contributes to the pathophysiology of late-phase allergic responses in the skin.

Adult↗
PubMed1990

Platelet activating factor-induced clinical and histopathologic responses in atopic skin and their modification by the platelet activating factor antagonist BN52063.

The clinical and histopathologic responses to intradermal platelet-activating factor (PAF-acether) in atopic subjects, without evidence of atopic dermatitis are documented. An immediate acute wheal and flare reaction was observed in all volunteers. Histopathologically, the reaction was characterized by a predominantly neutrophilic response, which was seen at 30 minutes and was maximal at 4 hours. Eosinophils were observed in the infiltrate as early as 30 minutes after injection, and were maximal by 12 hours. The specific PAF-acether antagonist BN52063 antagonized the acute flare response to intradermal PAF-acether but had little effect on cellular recruitment at the site of injection.

Adult↗
PubMed1993

Skin-window-induced inflammation in breast cancer patients: a study of macrophage migration.

A decreased number of macrophages has previously been demonstrated by means of skin-window assays in operable breast cancer patients. However, in this type of cellular inflammatory response, a varying intensity of cellular activation, cellular recruitment and macrophage chemotaxis exists. In this study, we performed skin windows after stimulation by a chemo-attractant (FMLP) and a recall antigen (Candidin-latex). Cellular responses were classified in 19 breast cancer patients according to the presence (A+) or absence (A0) of macrophage activation by comparison to healthy controls. In 13 A0 patients, the admixture of a cytokine (IFN alpha) and an immunomodulator (P40) to one agent or the other or both resulted in the restoration of macrophage functions. Our study shows that uniform cellular responses to chemo-attractants and antigens are observed in healthy and not immunocompromised individuals as assessed by skin-window tests. However, the cellular response recorded in immunodeficient cancer patients is altered. It also shows that the admixture to chemoattractants and antigens of particular cytokines or better still of an immunomodulator displaying a wide spectrum of activity offers a way of restoring macrophage functions. Individual responses to immunotherapy in clinical oncology may be related to such results.

Adjuvants, Immunologic↗
PubMedDate not supplied

Functional abnormalities of monocytes/macrophages in HIV1-infected patients as demonstrated by the skin window procedure.

Skin window (SW) tests were performed in ten HIV1-infected patients and in ten healthy volunteers. The chemotaxis of monocytes/macrophages is weakened in AIDS patients, since the number of monocytes/macrophages attracted by the SW stimulus decreases in HIV1-infected subjects during the observation time, whereas the number increases in control individuals. HLA-DR expression decreases faster in AIDS patients than in healthy volunteers. Giant cell formation occurs and disappears earlier in HIV1-infected patients than in healthy control individuals. The results suggest that, at least in part, the impairment of chemotaxis and other functional abnormalities of mononuclear phagocytes are caused by their accelerated aging in HIV1-infected patients.

Acquired Immunodeficiency Syndrome↗
PubMed1990

Quantitative analysis of neovascularization of different PTFE-implants.

The process of neovascularization was analyzed in vivo in different expanded polytetrafluoroethylene (e-PTFE) implants which are frequently used in cardio-thoracic and vascular surgery. We have used the model of the hamster dorsal skinfold chamber which allows quantitative analysis of the microcirculation by means of intravital fluorescence microscopy. Pieces of approximately 1 mm2 of the cardiovascular patch (CVP, fibril length: 30 microns; n = 21), surgical membrane (SM, fibril length: 1 micron; n = 16), and soft tissue patch (STP, fibril length: 22 microns; n = 12) were implanted into the skinfold chambers. On day 10 after implantation, the functional density of newly formed microvessels was significantly (P less than 0.05) higher in CVP (145.0 +/- 10.9 cm-1) as compared to SM (688 +/- 13.9 cm-1) and STP (86.9 +/- 21.2 cm-1). In addition, CVP revealed a larger zone of neovascularization (311.6 +/- 19.4 microns) and the tightest integration (dynamic breaking strength: 17.9 +/- 3.0 cN/mm2) into the perigraft tissue, while SM demonstrated only few microvessels and no integration (6.0 +/- 1.9 cN/mm2) into the perigraft. None of the three different PTFE-implants revealed transmural ingrowth of capillaries. The internodal distance of PTFE implants seems to be the most important factor for neovascularization. Surgical membrane used for the replacement of passive biological membranes demonstrated, as is its purpose, little neovascularization and no integration into the perigraft tissue.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed2006

Vascular-specific quantification in an in vivo Matrigel chamber angiogenesis assay.

The study of angiogenesis as a therapeutic target requires reliable in vivo assays that can provide physiologically relevant data. A murine in vivo Matrigel-based angiogenesis assay is presented here which includes the quantitative assessment of vascular-specific indicators of neovascularization. Matrigel containing 175 ng/ml bFGF is encapsulated in synthetic chambers which are implanted subcutaneously in C57/B16J mice. Ex vivo implants can be imaged to qualitatively view perfused vasculature within the chambers, or histologically processed to confirm the presence of vascular-specific tissue within the Matrigel. Viable cells are recovered from the excised chambers and quantified cytometrically using endothelial cell-specific markers CD34 and CD144, and for a marker of nucleated cells, Hoechst 33342. Thalidomide, 200 mg/kg/day, was tested using the assay and was found to inhibit angiogenesis by 46%. Angiogenesis inhibitors secreted by LL/M27 tumors were also characterized, where tumor-bearing mice showed a 73% inhibition of angiogenesis compared to tumor-free controls. Analysis of the number of nucleated cells in these samples failed to show a strong correlation with the number of endothelial cells, indicating that quantification of nonvascular-specific tissue in in vivo angiogenesis assays may not be sufficient. This new assay provides an objective, comprehensive determination of the vasculature-specific response of both endogenous and exogenous angiogenesis inhibitors in vivo, and also creates new opportunities for obtaining primary murine endothelial cells.

Angiogenesis Inhibitors↗
PubMed1990

Photodynamic therapy with chloroaluminum sulfonated phthalocyanine in the rat window chamber.

The efficacy of photodynamic therapy tumor destruction is dependent upon both the interruption of the tumor vasculature and the resultant production of unstable oxygen species causing cellular oxidation and death. Chloroaluminum sulfonated phthalocyanine (CASP) is a recently developed photosensitizer. In order to study the direct vascular effects of CASP on a non-tumor system, a rat window chamber was utilized. Twelve rats were implanted with the window chamber, and were divided into two groups of six. Three rats served as controls for each group (receiving light alone, CASP alone, or no treatment). The remaining 6 rats received 10 mg/kg CASP intravenously 4 days after chamber placement. Photoactivation with light was performed 24 hours after injection (power density 200 mW/cm2, irradiance 100 J/cm2, lambda = 675 nm). Utilizing integrating sphere measurements and image analysis, marked vascular changes in the form of initial vasospasm followed by vaso-constriction and loss of chamber neovascularization were noted in the CASP-PDT group. The control groups exhibited no significant changes. Manipulation of the chamber vasculature at strategic time-points may translate into improved response rates for photodynamic therapy in a tumor model.

Animals↗
PubMed1995

Infrared video imaging of subsurface vessels: a feasibility study for the endoscopic management of gastrointestinal bleeding.

The feasibility of infrared video imaging of subsurface vessels in the stomach was investigated both experimentally and in more detail using computer simulations of light propagation. Infrared video imaging was first attempted in several experimental situations. Images of a human arm illuminated with infrared light (wavelength > 700 nm) revealed subcutaneous venous structures not revealed by visible light (wavelength of 500 to 600 nm). An infrared-sensitive video endoscope was used to view both a human arm and normal stomach wall. Infrared illumination within the stomach enhanced only the larger subsurface vessels. Infrared transillumination of a rat skin flap window chamber allowed video recording of images during injection of an absorbing dye, indocyanine green, into the blood volume and showed that indocyanine green can enhance the contrast in infrared images of small vessels. Computer simulations of vessels of varying depths and sizes indicated successful detection was possible by infrared imaging. Computer simulations demonstrated that the shadow caused by an imaged subsurface vessel has two characteristics: (1) the central loss of reflectance, which indicates the size of the vessel, and (2) the full-width half-maximum of the reflectance loss, which indicates the depth of the vessel. The simulations further suggested that images of small vessels can be dramatically enhanced (68-fold) by indocyanine green, which attenuates the transmittance of scattered light from behind the vessels to the surface for observation. On the other hand, indocyanine green enhances the contrast of large vessels to a lesser degree (2.6-fold). The ultimate goal is to develop an endoscopic video imaging system capable of capturing reflected light from the stomach wall.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1976

Defective neutrophil motility in children with measles.

The random migration and chemotactic ability of neutrophils from ten patients with uncomplicated measles was found to be grossly impaired when compared to a group of normal children. Chemotaxis to endotoxin activated serum and to hydrolysed casein was markedly depressed, but serum from measles patients, when activated by endotoxin, generated and chemotactic activity and did not contain leukotactic inhibitors. The defect in neutrophil motility was confirmed in vivo by abnormal Rebuck skin windows. The defect was temporary, and recovery of normal chemotaxis was observed by the eleventh day after the onset of the rash.

Cell Movement↗
PubMed1977

Xanthogranulomatous pyelonephritis in children.

Xanthogranulomatous pyelonephritis in children, contrary to adult onset, rarely is associated with non-function or calcification. The lesion is predominantly on the left side in children. There appears to be a normal humoral but temporarily impaired cellular immune response in addition to sustained depression of polymorphonuclear chemotaxis. The etiology of this is uncertain but may be attributed partially to hyperosmolarity of serum and urine, and to leukocyte specific antinuclear antibodies. The presence of leukocyte specific antinuclear antibody or cold agglutining may interfere with normal phagocyte chemotaxis requiring tissue macrophages to produce a xanthogranulomatous reaction to bacterial invasion.

Cell Movement↗