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Emigration and accumulation of PMN-leukocytes induced by endotoxin, interleukin 1 and other chemotactic substances.

This publication describes polymorphonuclear leukocyte (PMN) emigration and accumulation, which is prerequisite for their defensive function in infected tissues. The extravasated PMNs can kill microorganisms, but in this process they also release proteolytic enzymes and other cell constituents which can alter and even injure the tissues, primarily the microcirculation. In the first part of the paper in vivo quantitation of the acute inflammatory reaction is described with emphasis on PMN emigration and accumulation. With 51Cr-labeled PMNs the kinetics of their emigration induced by a number of chemotaxins and chemotaxinigens was found to be similar, peaking in 1-4 hour old lesions and returning to baseline values thereafter. The most potent substance tested was endotoxin, which induced a PMN influx at a molar concentration a least 3 orders of magnitude lower than the other substances tested, implying the these substances are not the primary endogenous mediators of endotoxin induced inflammation. Next we describe an observation which shed considerable light on the mechanisms underlying PMN emigration. When a chemotaxin or endotoxin was injected intradermally and after varying periods of time reinjected into the same site, the PMN influx into those sites was diminished, compared to sites not previously injected, i. e. injected for the first time. This tachyphylaxis or diminished responsiveness was attributed to a downregulation of receptors, presumably on endothelial cells, coupled to a facilitatory mechanism. Other mechanism proposed to terminate emigration of PMNs during inflammatory reaction were unlikely, based on our experimental findings. Endotoxin is not chemotactic in vitro but it induces PMN emigration when injected intradermally. Hence the third part of the publication deals with PMN emigration induced by interleukin 1 and its significance for endotoxin-induced inflammation. IL 1 is the only chemotaxin which induces PMN accumulation at a concentration comparable to that of endotoxin and considerably lower than the other chemotaxins. There was cross tachyphylaxis between endotoxin and IL 1 and vice versa. The PMN influx into IL 1 sites injected 6 hours earlier with IL 1 or with endotoxin was diminished compared to IL 1 sites injected into normal skin. Sites injected first with IL 1 and then with a low dose of endotoxin also exhibited cross tachyphylaxis. FMLP or LTB4 injected into sites pretreated with endotoxin did not exhibit cross tachyphylaxis, i. e. the PMN influx was similar to sites injected for the first time with these chemotaxins.(ABSTRACT TRUNCATED AT 400 WORDS)

Animals↗

Interdigital skin test for evaluation of delayed hypersensitivity and cutaneous basophil hypersensitivity in young chickens.

A skin test to assess T-cell mediated delayed hypersensitivity (DH) and cutaneous basophil hypersensitivity (CBH) was evaluated in the interdigital skin of young chickens. Three-day-old chickens were sensitized with Mycobacterium tuberculosis, and the DH reaction was elicited in the interdigital skin in 10-, 17-, 24-, and 31-day-old chickens by intradermal injection of tuberculin. Cutaneous basophil hypersensitivity was elicited in the interdigital skin of 10- and 14-day-old chickens by a single intradermal injection of phytohemagglutinin-P (200 micrograms). The effect of immunosuppression on the results of interdigital skin test for DH and for CBH was evaluated in chickens that were treated with dexamethasone daily for 4 days before testing. The DH reaction, as indicated by a significant (P less than 0.01) increase in the mean interdigital skin thickness, was detectable in 10-day-old chickens and was consistently evident in 17-, 24-, and 31-day-old chickens. The DH response in the interdigital skin of 24-day-old chickens was comparable with that elicited in the standard wattle test. The CBH reaction, as indicted by a significant increase (P less than 0.005) in skin thickness, was evident in the interdigital skin of 10- and 14-day-old chickens. Treatment with dexamethasone significantly decreased (P less than 0.01) the DH and CBH reactions. Results of the study indicated that the interdigital skin test may be used to evaluate normal and suppressed cell-mediated DH and CBH reactions in chickens as young as 10 and 14 days old.

Animals↗

Local action of some antibacterial substances against Corynebacterium ovis in guinea-pig skin.

When a suspension of living Corynebacterium ovis was injected intradermally in guinea-pigs, a lesion of roughly circular outline developed within 24 hr. Lesions of smaller diameter arose if benzylpenicillin, dequalinium, hedaquinium, cetrimide, or oxytetracycline were injected at the identical site, either before, with, or after C. ovis. Evidence has been obtained that such reductions of lesion diameter are due to direct action of drugs on bacteria and not to antitoxic or anti-inflammatory actions. Lesion diameters became less as drug dosage increased up to a limit, and these reductions provided a measure of local antibacterial action in vivo. Intradermal injection of higher concentrations of antibacterials, without C. ovis, produced comparable but somewhat flatter lesions, diameters of which increased with increasing concentration of drug and provided a measure of intradermal toxicity.

Animals↗

Central changes in processing of mechanoreceptive input in capsaicin-induced secondary hyperalgesia in humans.

1. Capsaicin, the algesic substance in chilli peppers, was injected intradermally in healthy human subjects. A dose of 100 micrograms given in a volume of 10 microliters caused intense pain lasting for a few minutes after injection and resulted in a narrow area of hyperalgesia to heat and a wide surrounding area of hyperalgesia to mechanical stimuli (stroking) lasting for 1-2 h. 2. Nerve compression experiments with selective block of impulse conduction in myelinated (A) but not in unmyelinated (C) fibres indicated that afferent signals in C fibres contributed to pain from capsaicin injection and to heat hyperalgesia, whereas conduction in afferent A fibres was necessary for the perception of mechanical hyperalgesia. 3. Electrical intraneural microstimulation normally eliciting non-painful tactile sensations was accompanied by pain when the sensation was projected to skin areas within the region of mechanical hyperalgesia induced by capsaicin injection. 4. The threshold for pain evoked by intraneural microstimulation was reversibly lowered and pain from suprathreshold stimulation was exaggerated during the period of mechanical hyperalgesia, regardless of lidocaine anaesthesia of the cutaneous innervation territory of the stimulated fibres. 5. The results indicate that hyperalgesia to stroking on a skin area surrounding a painful intradermal injection of capsaicin is due to reversible changes in the central processing of mechanoreceptive input from myelinated fibres which normally evoke non-painful tactile sensations.

Adult↗

The effects of bradykinin and sequence-related analogs on the response properties of cutaneous nociceptors in monkeys.

The endogenous peptide bradykinin is found in plasma and inflammatory exudates and has been implicated as a chemical mediator of inflammatory pain and hyperalgesia. Two subtypes of bradykinin receptors, B1 and B2, have been described, and antagonists for the receptor subtypes have been synthesized. The bradykinin analogs [desArg9,Leu8]BK and DArg[Hyp3,DPhe7]BK have been reported to have antagonist activity at the B1 and B2 bradykinin receptors in smooth muscle, respectively. Behavioral studies in rats indicate that the bradykinin analogs can block the algesic effects of bradykinin. We wished to determine the effects of bradykinin and the bradykinin analogs (B1 and B2 analogs, respectively) on cutaneous nociceptors in the monkey. In addition, we wished to determine the type of bradykinin receptor that mediates the sensitizing effects of bradykinin. Recordings were made from single C-fiber and A-fiber nociceptive afferents (CMHs and AMHs) that innervated hairy skin. Heat sensitivity before and after the injections was determined with a heat test sequence consisting of stimuli that ranged, in 1 degree C increments, from 41 degrees to 49 degrees C. Intradermal injections of vehicle (neutral normal saline) failed to alter the heat response of CMHs. Bradykinin (10 nmol in 10 microliters) evoked activity in 6 of 10 CMHs and sensitized all the fibers to heat stimuli. After the bradykinin injection, the mean heat threshold of the CMHs decreased from 44 +/- 0.5 degrees to 42.7 +/- 0.5 degrees C (mean +/- SEM, p less than 0.02), and the total response to the heat test sequence increased by 87% (p less than 0.002). In a related psychophysical study in human volunteers, the same dose of bradykinin resulted in a comparable (115%) increase in ratings of pain (Manning et al., 1991). Bradykinin also evoked activity in 10 of 17 AMHs and sensitized 8 AMHs to heat stimuli. Bradykinin failed to alter the threshold for activation of CMHs to mechanical stimuli as measured by application of von Frey hairs to the receptive field. In contrast to bradykinin, intradermal injection of the B1 and B2 analogs (10 nmol in 10 microliters) evoked activity in 2 of 6 and 0 of 5 CMHs, respectively. A noteworthy finding was that both analogs enhanced the response of CMHs to heat stimuli by 50% (B1 analog, 1.5 +/- 0.1; B2 analog, 1.5 +/- 0.2). The B1 (n = 10) and B2 (n = 5) analogs did not evoke activity in any of the 15 AMHs tested.(ABSTRACT TRUNCATED AT 400 WORDS)

Afferent Pathways↗

Suppressive effect of human blood coagulation factor XIII on the vascular permeability induced by anti-guinea pig endothelial cell antiserum in guinea pigs.

We investigated the effect of blood coagulation factor XIII (FXIII) on enhanced permeability induced by anti-endothelial cell antiserum, that was produced by the immunization of guinea pig endothelial cells with adjuvant into rabbits repeatedly. We have found that this antiserum reacts to human and guinea pig endothelial cells but not guinea pig fibroblast cells. The permeability was enhanced by intradermal injection of 400-fold dilution of this antiserum into dorsal skin of guinea pigs. The mixture of equal volume of antiserum and FXIII was intradermally injected into dorsal skin of guinea pig after Evans blue injection, and 15 minutes later the quantity of Evans blue at the each injection site was determined. We recognized the suppressive effect of FXIII on the dye leakage. We also studied the suppressive effect on swelling induced by the antiserum. After the subcutaneous injection of the mixture of antiserum and FXIII into the back of guinea pigs, we measured the thickness of skins at the injection site after day 1, 2 and 3. As a result, FXIII significantly suppressed the swelling. We found that FXIII suppresses the acute and subacute permeability enhancement. These results suggest that FXIII plays an important role on an inflammatory site and that it may exert as an anti-inflammatory protein.

Animals↗

Inflammatory oedema induced by phospholipases A2 isolated from Crotalus durissus sp. in the rat dorsal skin: a role for mast cells and sensory C-fibers.

The ability of the phospholipases A(2) (PLA(2)s) from Crotalus durissus cascavella, Crotalus durissus collilineatus and Crotalus durissus terrificus venoms and crotapotin to increase the vascular permeability in the rat skin as well as the contribution of both mast cells and sensory C-fibers have been investigated in this study. Vascular permeability was measured as the plasma extravascular accumulation at skin sites of intravenously injected 125I-human serum albumin. Intradermal injection of crotalic PLA(2)s (0.05-0.5 microg/site) in the rat skin resulted in dose-dependent increase in plasma extravascular whereas crotapotin (1 microg/site) failed to affect this response. Co-injection of crotapotin (1 microg/site) did not modify the increased vascular permeability induced by the PLA(2)s (0.05-0.5 microg/site). Previous treatment (30 min) of the animals with cyproheptadine (2 mg/kg, i.p.) markedly reduced PLA(2) (0.5 microg/site)-induced oedema. In rats treated neonatally with capsaicin to deplete neuropeptides, the plasma extravasation induced by all PLA(2)s (0.5 microg/site) was also significantly reduced. Similarly, the tachykinin NK(1) receptor antagonist SR140333 (1nmol/site) significantly reduced the PLA(2)-induced oedema. In addition, the combination of SR140333 with cyproheptadine further reduced the increased plasma extravasation by PLA(2) from C. d. cascavella venom, but not by PLA(2) from C. d. terrificus and C. d. collilineatus venoms. Our results suggest that increase in skin vascular permeability by crotalic PLA(2)s is mediated by activation of sensory C-fibers culminating in the release of substance P, as well as by activation of mast cells which in turn release amines such as histamine and serotonin.

Animals↗

A modified technique of guinea pig testing to identify delayed hypersensitivity allergens.

A modified guinea pig testing technique was developed for the detection of weak allergens and allergenicity of materials unsuitable for testing by intradermal injection. This test involved the use of Freund's complete adjuvant to stimulate the immune system of the animal, and external application instead of intradermal injection of the test compound in the induction stage. The allergenicity of Sudan III, Brilliant Lake Red R and Sudan I was tested by this procedure. In the dose-effect study of Sudan I, the dose dependency of a positive reaction of the induction and challenge concentrations was recognized. The test was compared with three other guinea pig sensitization tests. The results obtained with this test correlated well with those obtained with the guinea pig maximization test.

Allergens↗

Poly-L-lactic acid.

Poly-L-lactic acid, a synthetic biodegradable polymer, is available as an injectable intradermal implant for use in the correction and restoration of the signs of facial lipoatrophy in patients with HIV infection. In a 96-week noncomparative study in HIV-infected patients with severe facial lipoatrophy, 41% of patients treated with intradermal poly-L-lactic acid injections had a total cutaneous thickness of >10 mm at the nasogenian fold at week 24. Poly-L-lactic acid was injected into multiple sites of each cheek at baseline and at weeks 2, 4, and 6. Significant (p < 0.001) increases from baseline in total cutaneous thickness were reported at all evaluation time points up to 96 weeks after the start of treatment. In a randomized, nonblind study, significant (p < 0.001) increases from baseline in dermal thickness were observed at week 24 in HIV-infected patients with facial lipoatrophy who received immediate or deferred (by 12 weeks) treatment with poly-L-lactic acid, administered by injection into multiple intradermal sites every 2 weeks (three injection sessions in total). Improvements in depression and anxiety scores, patient visual analog scale assessments, and photographic assessments were also reported in patients treated with poly-L-lactic acid in the immediate versus deferred treatment trial. Poly-L-lactic acid was generally well tolerated. No serious adverse events were reported.

Adipose Tissue↗

Evaluation of artecoll polymethylmethacrylate implant for soft-tissue augmentation: biocompatibility and chemical characterization.

Artecoll polymethylmethacrylate implant (Artecoll) is a combination of polymethylmethacrylate beads suspended in 3.5% atelocollagen and has been designed for use in soft-tissue augmentation applications. The biocompatibility and immunogenicity of Artecoll were evaluated to assess the safety of this product for use in the dermis. To characterize the collagen component, chemical analysis was performed including trypsin sensitivity, differential scanning calorimetry, and pepsin content. Particle size analysis was also performed on the polymethylmethacrylate beads. The ability of this material to elicit an immunologic response was measured in a sensitized and nonsensitized guinea pig intradermal model. In these studies, 24 guinea pigs were injected intradermally with either Artecoll or Zyderm, a bovine collagen product for soft-tissue augmentation. Six sites were evaluated for each material at 3, 7, and 28 days after injection. In the sensitized model, 60 guinea pigs were divided into five groups, and each group received a sensitizing dose (in conjunction with Freund's adjuvant) of Zyderm, Artecoll, or a nonsensitizing dose of the same materials. The fifth group served as a nontreatment control. After the animals were sensitized, they were challenged with intradermal injections of various antigens to evaluate delayed type hypersensitivity reactions. Chemical characterization indicated polymethylmethacrylate beads of varying sizes, including many less than 35 microns, and a vehicle of extensively denatured and impure collagen. In vivo evaluations indicated that Artecoll elicited an immune response in guinea pigs, including delayed type hypersensitivity and antibody reactions. Histological assessment demonstrated particle phagocytosis and transepidermal elimination. Following immunization with Artecoll, guinea pigs were also found to be sensitized to pepsin, an impurity found in the collagen carrier. The biocompatibility of this material was compared with that of bovine dermal collagen (Zyderm collagen implant), which is widely used and accepted as biocompatible. The results of this evaluation indicate that Artecoll polymethylmethacrylate implant has the potential to elicit an immune response in humans, and polymethylmethacrylate beads are susceptible to phagocytosis and elimination.

Adjuvants, Immunologic↗

A comparison of the effects of captopril and enalapril on skin responses to intradermal bradykinin and skin blood flow in the human forearm.

1. The effects of captopril and enalapril on skin responses to intradermal injections of bradykinin and skin blood flow in the forearm were investigated in this randomised, double-blind, placebo-controlled, cross-over study. 2. Intradermal injections of 0, 1, 2.5 and 5 micrograms of bradykinin in 0.9% sodium chloride were made into the forearm of twelve healthy volunteers before and at 2, 6 and 24 h after single oral doses of 25 mg captopril, 10 mg enalapril or placebo. Forearm skin blood flow was measured by the technique of laser Doppler flowmetry (LDF) before the injections were made and the skin responses evaluated at 15 min after injections of bradykinin by measurement of cutaneous blood flow outside the induced weal, erythema area and weal volume. 3. The bradykinin-induced cutaneous responses measured by LDF, erythema area and weal volume increased with incremental bradykinin dose. Compared with placebo, captopril significantly augmented the cutaneous vasodilator effects of bradykinin, measured by LDF and erythema area, at 2 h and the weal responses at 2 and 6 h. Enalapril enhanced the vasodilator responses to bradykinin at 2 and 6 h and the weal responses at 2, 6 and 24 h. Neither captopril nor enalapril significantly affected forearm skin blood flow. 4. This study showed that captopril and enalapril potentiated the effects of intradermal bradykinin both with respect to blood flow changes and weal formation in keeping with effective kininase II inhibition and the time course of these changes are consistent with enalapril being a longer acting drug than captopril. Captopril and enalapril exerted no influence on forearm skin blood flow measured by LDF.

Adult↗

111In-oxine and 99mTc-HMPAO labelling of antigen-loaded dendritic cells: in vivo imaging and influence on motility and actin content.

In cancer vaccination trials, antigen-loaded dendritic cells (DCs) are usually injected intradermally and are expected to rapidly move to a regional lymph node where antigen presentation should occur. In this study we investigated the influence of indium-111 oxine (111In) and technetium-99m hexamethylpropylene amine oxime (99mTc-HMPAO) labelling on the motility and actin content of antigen-loaded DCs in parallel with in vivo migration in humans. Human autologous monocyte-derived DCs loaded with a tumour antigen were labelled with 111In (0.11, 0.37 or 0.74 MBq/10(7) DCs) or 99mTc-HMPAO (18.5 or 185 MBq/10(7) DCs). 111In labelling was much more stable than 99mTc-HMPAO labelling. Quantitative videomicroscopy showed that the mean distance of displacement of DCs increased in accordance with the 111In activity used for labelling. Monomeric (G) and filamentous (F) actin content of DCs evaluated by quantitative immunofluorescence demonstrated that the ratio of filamentous to globular actin content in labelled DCs increased significantly in accordance with the activity used for labelling with both tracers. Twelve patients enrolled in a phase I/II vaccination trial received injections of 10(7) antigen-loaded DCs labelled with either 0.74 MBq of 111In (group A, n=6/12) or 18.5 MBq of 99mTc-HMPAO (group B, n=6/12) in the proximal part of the legs, one intradermally on one side, one subcutaneously on the opposite side. In three of the six patients of each group, antigen-loaded DCs were incubated with monophosphoryl lipid A (MPL) just before the labelling, in order to initiate the maturation process (subgroup MPL+). Only one MPL+ patient of group A exhibited faint focal uptake in the inguinal region on the late images. Group B presented a more complex pattern of radioactivity distribution (early bladder activity without brain uptake) indicating that 99mTc-HMPAO is not a suitable radiopharmaceutical for labelling of loaded DCs. The activity cleared from DCs as a labelled molecule different from the lipophilic 99mTc-HMPAO. Only one of the six patients had nodular inguinal uptake on the intradermally injected side (DCs not incubated with MPL). In conclusion, the present study did not demonstrate migration of loaded labelled DCs from intradermal or subcutaneous sites of injection to regional lymph nodes. This provides an indication that a large proportion of antigen-loaded DCs, as used in current human trials for cancer therapy, may not reach regional lymph nodes.

Actins↗

Development of an acute cutaneous swine model for Loxosceles envenomation.

STUDY OBJECTIVE: To develop an acute cutaneous swine model for Loxosceles envenomation which could be used to objectively compare various treatment modalities. PARTICIPANTS: Nine weanling, mixed-breed domestic piglets. INTERVENTIONS: Piglets were injected intradermal in the hindlimb with Loxosceles deserta venom in increasing doses and concentrations until consistently large lesions were obtained. A minimum of 3 injections/venom preparation were carried out, with no more than 2 injections/animal. Repeat injections in the same animal were separated by 8 d. MEASUREMENTS AND MAIN RESULTS: All lesions were measured daily for erythema and necrosis for 7 consecutive days. Data are reported as individual and mean maximal values. The piglets receiving 0.1, 0.2 or 0.3 ml of 5 microliters venom/ml saline developed small inconsistent lesions, with the largest necrotic lesion 5 mm. Those injected with 0.3 ml of venom diluted 15 microliters/ml saline developed small necrotic lesions (mean 4 mm, maximal 10 mm). All piglets injected with 25 microliters of venom diluted to 0.3 ml developed large necrotic lesions (mean 33 mm) with substantial erythema (mean 177 mm). CONCLUSION: Intradermal injection of 0.1 ml of 25 microliters purified Loxosceles deserta venom diluted to 0.3 ml with sterile saline produced large necrotic lesions in piglets. This model may be used to study Loxosceles envenomation and treatment.

Animals↗

Kinetic expression of endothelial adhesion molecules and relationship to leukocyte recruitment in two cutaneous models of inflammation.

BACKGROUND: Adhesive interactions between circulating leukocytes and endothelium is requisite for subsequent leukocyte extravasation at inflammatory sites. These adhesive events are mediated by a repertoire of proteins and carbohydrate moieties on both leukocyte and endothelial membranes. Understanding the kinetic expression of these adhesion molecules during an inflammatory cascade in vivo is important for the design and testing of rational therapeutic approaches directed at the blockade of adhesion molecule function in inflammatory disease. EXPERIMENTAL DESIGN: Two cutaneous inflammatory models were examined using healthy rhesus monkeys. Acute cutaneous injury was studied during a 72-hour period by intradermal injection of endotoxin (lipopolysaccharide) and subsequent biopsy. These tissues were then compared with those obtained from a cutaneous delayed-type hypersensitivity reaction (DHR), elicited by intradermal injections of mammalian tuberculin in sensitized animals and followed for up to 11 days. Expression of E-selectin, P-selectin, VCAM-1, and ICAM-1 was assessed using immunohistochemistry and compared with leukocyte localization and immunohistochemical expression of interleukin (IL) 1, IL-8 and tumor necrosis factor-alpha (TNF-alpha). Finally, relevant adhesion ligands on leukocytes were assessed using flow cytometry. RESULTS: The lipopolysaccharide model was characterized by early (0.5 hours) and sustained (up to 72 hours) expression of E-selectin on the superficial dermal vasculature, with maximal expression by 8 hours. The expression of VCAM-1 was either not detected or minimal. Neutrophil localization, as detected by elastase immunoreactivity, paralleled E-selectin expression with a 4- to 12-hour lag phase, being maximal by 24 hours. In contrast, DHR was characterized by the dual asynchronous expression of both E-selectin and VCAM-1. Localization of CD2+ lymphocytes, representing the predominant cell type recruited, kinetically followed the expression of E-selectin and VCAM-1, being maximal in number at approximately 48 hours after peak expression of both of these endothelial proteins. Neutrophil recruitment in lipopolysaccharide-induced injury was associated with immunohistochemical localization of TNF-alpha, IL-1, and IL-8, whereas only TNF-alpha was consistently detected in DHR. During DHR, blood lymphocyte expression of L-selectin, VLA-4 (CD49d; alpha chain), and lymphocyte function-associated antigen 1 (both CD11a (alpha chain) and CD18 (beta chain)) did not change. CONCLUSIONS: The results from this study demonstrate that cutaneous inflammatory infiltrates of varying cellular compositions are associated temporally and spatially with unique patterns of endothelial adhesion molecule and cytokine expression.

Animals↗

A skin test for pseudorabies virus infection in swine.

Heat-inactivated pseudorabies virus caused cutaneous delayed-type hypersensitive reactions when injected intradermally on the dorsolateral aspect of the thorax and tips of the ears of pigs previously exposed to the homologous virus. The reaction induced by subcutaneous injection in the lower eyelid was more easily administered and evaluated. Nonexposed control pigs did not react to the antigen and exposed and control pigs did not react when injected with a cell control antigen prepared in a similar manner. A positive response was detectable as early as seven days after exposure, reached near maximal levels by 28 days, and remained at similar levels for at least 90 days.

Animals↗

Sympathectomy does not abolish bradykinin-induced cutaneous hyperalgesia in man.

Bradykinin is an endogenous peptide that is thought to be a chemical mediator of the hyperalgesia following inflammation. In rat, bradykinin has been postulated to cause hyperalgesia to mechanical stimuli by releasing prostaglandin from sympathetic post-ganglionic terminals. The aim of this study was to determine whether bradykinin-induced cutaneous hyperalgesia in humans requires post-ganglionic sympathetic terminals. In humans, intradermal injection of bradykinin produces dramatic hyperalgesia to heat but not mechanical stimuli. Therefore, we measured the magnitude and duration of pain and hyperalgesia to heat stimuli following intradermal injection of bradykinin into the leg of a woman before and 6 months after an ipsilateral, surgical, lumbar sympathectomy. The pain and hyperalgesia to heat following bradykinin was found to be unaffected by the sympathectomy. These results suggest that the algesic effects of cutaneous bradykinin in human are independent of the sympathetic nervous system.

Adolescent↗

Epidemiological survey of histoplasmine and paracoccidioidine skin reactivity in an agricultural area in Bolívar state, Venezuela.

Paracoccidiodomycosis and histoplasmosis are endemic diseases in the south of Venezuela, representing a public health problem. Prevalence of Paracoccidiodes brasiliensis and Histoplasma capsulatum infections were estimated in Monte Ralo, a rural community area of Bolivar state using paracoccidiodine and histoplasmine skin tests. Paracoccidiodine was intradermically injected to 173 persons and readings were made at 24 and 48 h afterwards to 167 persons (97.85%). Reaction was positive in 8.5% (n = 14) at 24 h post-injection and 13.2% (n = 20) at 48 h. Farmers showed the higher percentage of positivity at 24 and 48 h. One hundred-seventy five persons were intradermically injected with histoplasmine but 167 and 157 of them attended for reading of the dermal reaction at 24 and 48 h post-injection respectively. Tests were positive in 25.7% (n = 43) at 24 h and 42.7% (n = 67) at 48 h. Further studies are needed in surrounding places to delimit the endemic area of these mycosis in the Bolivar state. However, epidemiological vigilance of PCM and H should be considered by local health authorities.

Adolescent↗

Specific inhibition of wheal-and-erythema responses with univalent haptens and univalent antibody fragments.

Wheal-and-erythema responses were studied in normal human volunteers and in a single human subject who is sensitive to the 2,4-dinitrophenyl group. In the normal subjects, reactive skin sites were established by intradermal injection of purified rabbit antibody specific for the 2,4-dinitrophenyl group. In both the active and passively sensitized subjects, wheal-and-erythema was elicited by intradermal injection of a 2,4-dinitrophenyl protein, but not by injection of the same conjugate mixed with certain low molecular weight 2,4-dinitrophenyl haptens or with univalent fragments split by papain from anti-2,4-dinitrophenyl antibody. The latter fragments, unlike intact, bivalent, antibody, do not sensitize normal human skin sites. From these and other observations it is concluded that the wheal-and-erythema response in human skin requires mutually multivalent antigen and antibody. This requirement suggests that multimolecular complexes, containing at least 2 antigen and 2 antibody molecules, are essential in the pathogenesis of this allergic response.

Animals↗