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Biomedical subjects

P L Bruijnzeel

Publications and source records attributed to P L Bruijnzeel.

At least 19 recordsLinked to original sources

Beneficial effects of TCP on soman intoxication in guinea pigs: seizures, brain damage and learning behaviour.

Poisoning with the potent nerve agent soman produces a cascade of central nervous system (CNS) effects characterized by severe convulsions and eventually death. In animals that survive a soman intoxication, lesions in the amygdala, piriform cortex, hippocampus and thalamus can be observed. In order to examine the mechanisms involved in the effects of soman and to evaluate possible curative interventions, a series of behavioural, electrophysiological and neuropathological experiments were carried out in the guinea pig using the NMDA antagonist N-[1-(2-thienyl)cyclohexyl] piperidine (TCP) in conjunction with atropine and pyridostigmine. The NMDA antagonist TCP appeared to be very effective in the treatment of casualties who suffered from soman-induced seizures for 30 min: (i)Seizures were arrested within minutes after the TCP injection, confirmed by quantitative electroencephalogram (EEG), after fast Fourier analysis. Three hours after TCP the quantitative EEGs were completely normal in all frequency bands and remained normal during the entire 3-week intoxication period. The power shift to the lower (delta) frequency bands, indicative for neuropathology and found in control animals intoxicated only by soman, was not observed in the soman-TCP group. (ii)The gross neuropathology found in soman control animals within 48 h after soman was prevented in soman-TCP animals and was still absent in 3-week survivors. Instead, ultrastructural changes were observed, indicative of defense mechanisms of the cell against toxic circumstances. (iii)Twenty-four hours after soman, soman-TCP animals were able to perform in the shuttle box and Morris water maze. The beneficial effects of TCP on the performance in these tests during the 3-week intoxication period were very impressive, notwithstanding (minor) deficits in memory and learning. (iv)The increase in excitability after TCP was confirmed by an increase in the acoustic startle response. Taken together, these results confirmed the involvement of NMDA receptors in the maintenance of soman-induced seizures and the development of brain damage. They underline the current hypothesis that cholinergic mechanisms are responsible for eliciting seizure activity after soman and that, most likely, the subsequent recruitment of other excitatory neurotransmitters and loss of inhibitory control are responsible for the maintenance of seizures and the development of subsequent brain damage.

Animals↗

Scopolamine augments the efficacy of physostigmine against soman poisoning in guinea pigs.

The efficacy of the subchronically administered cholinesterase-inhibitor physostigmine (PHY) (0.025 mg/kg/h) either with or without the muscarinergic receptor antagonist scopolamine (SCO) (0.018 mg/kg/h) in counteracting soman-induced lethality and incapacitation were determined in guinea pigs. This was tested in animals that either received atropine sulphate (AS, 17.4 mg/kg i.m.) or no postintoxication therapy. Behavioral and neurophysiological readout systems were used to measure postintoxication incapacitation. Only the pretreatment with PHY alone did not offer any protection against 2x LD50 soman intoxication. Animals that received the complete treatment (PHY + SCO + AS) did not show any abberations in the performance of learned behavior. The use of AS after soman intoxication resulted in an increase of the startle response, whereas the addition of SCO to the pretreatment led to a more persistent duration of the effect in time. In case one has to rely completely on the pretreatment, the addition of SCO to PHY is life-saving. However, some postintoxication incapacitation is still present. Therefore, the pretreatment regime may perhaps further be improved by the addition of a nicotinic antagonist.

Animals↗

Therapeutic interventions in mice with chronic proliferative dermatitis (cpdm/cpdm).

Chronic proliferative dermatitis (cpd) is a spontaneous mutation in C57BL/Ka mice (cpdm/cpdm). The dermatitis is characterized by redness, hairloss, scaling, pruritus and histologically by epithelial hyperproliferation, infiltration of eosinophils, macrophages and mast cells. Lesions similar to those in the skin occur in the esophagus and forestomach. In this paper, we describe the effect of drug treatments directed against epidermal hyperproliferation (calcipotriene and etretinate), against inflammation (corticosteroids and dapsone) and against pruritus (loratidine and capsaicin). The criteria used to objectively estimate the effect of the treatment were 1) macroscopic evaluation of the lesions (cpd score), 2) degree of epithelial hyperproliferation assessed by BrdU incorporation and epithelial thickness, and 3) microscopic evaluation of the inflammatory cells in the skin samples. Treatment of the cpdm/cpdm mice with calcipotriene (5 microg/day for 3 weeks) inhibited epidermal proliferation and the number of eosinophils. Systemic etretinate treatment (30 microg/g/day for 3 weeks) was not very effective. Topical corticosteroids (0.05 microg/day, for 3 weeks) exerted a therapeutic effect on the hyperproliferation and the number of eosinophils. Oral dapsone treatment (34 microg/g/day, for 5 weeks) reduced the BrdU incorporation in the skin and the epithelial thickness in the esophagus. The anti-histamine loratidine (orally, 1.7 microg/ g/day, for 4 weeks) reduced the severity of the lesions macroscopically, probably by suppressing the pruritus. Capsaicin (topically, 30 mM, for 5 weeks) also reduced the severity of the macroscopic observable lesions. Moreover, capsaicin reduced the dorsal and ventral epidermal thickness. The results from this and previous studies indicate that steroids (topically and systemically) and less strongly calcipotriene are the most effective treatments for the lesions observed in the cpdm/cpdm mice, since both hyperproliferation and the influx of eosinophils are reduced. Although the pathogenesis of the cpd lesions remains to be determined, our results indicate that the cpdm/cpdm mouse can be used to investigate new drugs for their possible application in chronic dermatitis.

Adrenal Cortex Hormones↗

Clinical and immunologic variables in skin of patients with atopic eczema and either positive or negative atopy patch test reactions.

BACKGROUND: Epicutaneous application of aeroallergens induces a positive atopy patch test (APT) response in about 50% of patients with atopic eczema (AE) and sensitization for these allergens. OBJECTIVE: To elucidate the mechanisms determining the outcome of the APT, the following questions were addressed. Are there differences in clinical features between patients with AE who have positive versus negative APT responses? Is a macroscopically negative APT response also histologically negative, and if so, are there differences in clinically noninvolved skin between the two groups regarding (1) the sensitivity toward an irritant, (2) the composition of cellular infiltrate, (3) the presence of aeroallergen-specific T cells, and (4) the number of IgE(+) cells? METHODS: Punch biopsy specimens from both house dust mite patch tested and the clinically noninvolved skin of patients with AE who have positive APT responses (n = 10) and negative APT responses (n = 10) and those from the normal skin of atopic individuals without AE (n = 10) and nonatopic volunteers (n = 10) were analyzed by using immunohistochemistry with mAbs against eosinophil cationic protein, IgE, the high-affinity receptor for IgE, and CD3 and CD25 mAbs. Furthermore, T-cell lines were propagated from noninvolved skin of all patient and control groups. The T-cell lines were tested for house dust mite specificity. RESULTS: Negative APT sites were immunohistochemically similar to clinically noninvolved AE skin. There were no significant differences between patients with AE who had positive and negative APT results regarding either clinical features, the composition of cellular infiltrate, or the presence of allergen-specific T cells in clinically noninvolved skin. However, differences were observed regarding the presence of IgE on epidermal CD1a(+) cells. CONCLUSION: Our results indicate that a positive APT reaction requires the presence of epidermal IgE(+) CD1a(+) cells in clinically noninvolved skin, but that also other, as yet unknown, discriminatory factors are involved.

Animals↗

Modulation of the atopy patch test reaction by topical corticosteroids and tar.

BACKGROUND: Pharmacologic studies in atopic eczema (AE) are difficult to standardize. Patients with AE differ in the stage of their skin disease (acute, subacute, chronic). OBJECTIVE: This study was designed to assess macroscopic and microscopic effects of pretreatment with topical glucocortico-steroids (GCSs) and tar on the atopy patch test (APT) reaction in patients with atopic eczema. METHODS: Nonlesional skin of the back of patients with AE (n = 6) was treated for 3 weeks at 3 different sites with triamcin-olonacetonide 0.1% in cetamacrogol ointment (GCSs), pix liquida 10% in cetamacrogol ointment (tar), and cetamacrogol ointment (vehicle), respectively. APTs were performed, and biopsy specimens were taken from all these sites (time = 0 and 24 hours) for immunohistochemical analysis. RESULTS: Treatment with both GCSs and tar was able to reduce the macroscopic outcome of the APT reaction. Furthermore, both treatment modalities had an almost equally inhibiting effect on the influx of T cells, eosinophils, and CD1(+), RFD1(+), IFN-gamma(+), and IL-4(+) cells, as well as on the percentage of vessels expressing the adhesion molecules vascular cell adhesion molecule 1 and E-selectin in response to epicutaneous aeroallergen challenge. CONCLUSION: Although both treatments significantly reduced the various cellular constituents of allergic inflammation, all cell types remained present. In addition, this study shows that the APT can be used to evaluate the effect of topical anti-inflammatory treatments on allergic inflammation in patients with AE.

Administration, Topical↗

Subchronic physostigmine pretreatment in marmosets: absence of side effects and effectiveness against soman poisoning with negligible postintoxication incapacitation.

Subchronic pretreatment with physostigmine (PHY) (0.0125 mg/kg/h) leading to a blood acetylcholinesterase inhibition of about 30% caused no side effects when applied to marmoset monkeys. This was evident on behavioral parameters and on EEG and cortical visual evoked response. Furthermore, this treatment regime, followed by atropine as postintoxication therapy, protected the marmosets against lethality after a 2 x LD50 dose of soman with negligible postintoxication incapacitation. These findings suggest that a symptom-free pretreatment with subchronic PHY could protect man sufficiently against severe soman intoxication.

Acetylcholine↗

Behavioral test systems in marmoset monkeys.

A number of neurobehavioral methods have been developed to test behavior in marmoset monkeys. These test systems are (1) the bungalow test, which quantifies spontaneous explorative behavior, (2) the hand-eye coordination test, which tests a learned task of coordinated motor behavior, and (3) the fear-potentiated startle response, which tests and quantifies pathological anxiety manifested by a response of fright. The test systems are extensively discussed, and the value of these test systems is exemplified by applying them to neurological disorders to register disease activity and drug efficacy.

Animals↗

Subchronic physostigmine pretreatment in guinea pigs: effective against soman and without side effects.

The behavioral and neurophysiological effects of the subchronically administered cholinesterase-inhibitor physostigmine (PHY) (0.025 mg/kg/h) either with or without the muscarinergic antagonist scopolamine (SCO) (0.018 mg/kg/h) were determined in guinea pigs. In contrast to a single injection of PHY, subchronic application by osmotic minipumps of PHY, even without SCO, caused no behavioral or neurophysiological side effects. Also, the efficacy of such a pretreatment in counteracting soman-induced lethality and apparent symptoms of intoxication were determined. After subchronically administered PHY or PHY + SCO, the treated animals were protected against a 3 x LD50 dose of soman.

Acetylcholinesterase↗

Human eosinophils constitutively express a functional interleukin-4 receptor: interleukin-4 -induced priming of chemotactic responses and induction of PI-3 kinase activity.

Similar to interleukin-3 (IL-3), IL-5, and granulocyte macrophage colony-stimulating factor (GM-CSF), IL-4 can be secreted by several cell types involved in allergic inflammatory reactions, and therefore can affect eosinophil function similarly. In this study, we investigated the presence of an IL-4 receptor (IL-4R) on human eosinophils. When two different monoclonal antibodies (mAbs) against the IL-4R alpha-chain (IL-4Ralpha) were used, fluorescent-activated cell sorter analysis revealed the presence of an IL-4Ralpha on both eosinophils of normal donors and atopic dermatitis patients. In addition, the expression of the IL-2R gamma-chain, a functional component of the IL-4R in some cell types, was demonstrated. The IL-4Ralpha appeared to be expressed constitutively, and stimulation with cytokines IL-2, IL-3, IL-5, GM-CSF, and interferon-gamma did not further increase IL-4Ralpha expression. Evidence for an IL-4Ralpha was further substantiated by mRNA analysis. Both Northern blot analysis and reverse transcriptase/polymerase chain reaction revealed the presence of mRNA for the IL-4Ralpha in eosinophils from normal individuals and AD patients. Furthermore, we demonstrated that both IL-4 and IL-13 were capable of inducing PI-3 kinase activity in human eosinophils. Because this activation could be inhibited by an IL-4Ralpha mAb, we conclude that both cytokines can activate human eosinophils through binding to a receptor complex comprising the IL-4Ralpha and-yet to be identified-associated proteins. In addition, the involvement of IL-4 in functional responses was studied. IL-4 appeared to "prime" eosinophils to respond chemotactically toward regulated on activation, normal T cells expressed and secreted, but did not affect platelet-activating factor-induced chemotaxis. Taken together, these data show the presence of a functional IL-4R on human eosinophils.

Antibodies, Monoclonal↗

Efficacy of Curosurf in a rat model of acute respiratory distress syndrome.

Curosurf, a natural lung surfactant, is considered a potential candidate for improving the treatment of acute respiratory distress syndrome (ARDS). To investigate this in a rat model of early-stage ARDS, Curosurf (62.5, 125 or 250 mg x kg(-1)) was administered by intratracheal bolus at 10 or 24 h following an intratracheal lipopolysaccharide (LPS; 1.6 mg x kg(-1)) challenge. Survival, respiratory frequency (fR), lung wet weight (LWW), total protein and cell differentiation in bronchoalveolar lavage fluid (BALF) were assessed. Curosurf treatment at 10 h after LPS challenge resulted in 100% survival at both 62.5 and 125 mg x kg(-1); at a dose of 250 mg x kg(-1) administered at 10 h after LPS, 1 out of 6 animals died. At a dose of 125 mg x kg(-1) Curosurf administered at 24 h after LPS, 1 out of 6 animals died. In contrast, only 35% of animals survived when not treated with Curosurf. Curosurf treatment resulted in an improved fR and in a significantly decreased LWW, total protein and number of polymorphonuclear cells in BALF. In conclusion, Curosurf treatment improved respiratory frequency and decreased mortality, pulmonary oedema and inflammation. As the decreased mortality was observed in spontaneously breathing nonoxygenated animals, the results cannot be extrapolated to human artificially ventilated acute respiratory distress syndrome patients with the expectation of a decreased mortality. The results suggest, however, that Curosurf may be an important therapeutic measure in early-stage acute respiratory distress syndrome.

Analysis of Variance↗

New generic approach to the treatment of organophosphate poisoning: adenosine receptor mediated inhibition of ACh-release.

Current treatment of acute organophosphate (OP) poisoning includes a combined administration of a cholinesterase reactivator (oxime), a muscarinic receptor antagonist (atropine) and an anticonvulsant (diazepam). This treatment is not adequate since it does not prevent neuronal brain damage and incapacitation. Here, as in a recent review it is stated that other therapeutic approaches may improve protection. Former studies on the "direct effects" of oximes led to the conclusion that drug-induced inhibition of acetylcholine (ACh)-release shortly (1 min) after the acute OP-intoxication, could prevent and counteract convulsions and improve survival. In general, the accumulation of ACh in the synaptic cleft is considered to be responsible for the symptoms that ultimately lead to death. Therefore, prevention or suppression of this excessive accumulation of ACh could be a generic approach to antagonize OP-poisoning. Preliminary evidence for this concept has been put forward. Evaluation of drugs that would be able to prevent and counteract ACh accumulation, led to the conclusion that adenosine receptor agonists could be promising candidates. Pilot experiments demonstrated that intramuscular administration of the adenosine receptor agonists NECA (5'-N-ethylcarboxamido-adenosine) or CPA (N6-cyclopentyl adenosine) 1 min following a subcutaneous soman poisoning (1.5-2LD50) in rats, resulted in (1) prevention or postponement of chewing, salivation, convulsive activity, and respiratory distress (cholinergic symptoms), (2) improvement of survival rate (24 h), (3) a low level of extracellular brain ACh, as opposed to high levels of extracellular brain ACh in untreated animals. It is concluded that (1) adenosine agonists protect acutely soman-poisoned rats without the need of additional treatment with atropine, oxime or diazepam, (2) prevention of ACh accumulation in this way may be a new generic approach in the treatment of OP-poisoning.

Adenosine-5'-(N-ethylcarboxamide)↗

Differential effects of the T helper cell type 2-derived cytokines IL-4 and IL-5 on ligand binding to IgG and IgA receptors expressed by human eosinophils.

Increased numbers of eosinophilic granulocytes that exhibit an activated phenotype are found in bronchial tissue and bronchial alveolar lavage fluid of patients with allergic asthma. Little is known about the processes that lead to activation of eosinophils in vivo, but Igs might be important stimulants. In the present study we investigated the capacity of human eosinophils to interact with beads coated with human serum IgG or IgA. Binding of IgG/IgA-coated beads to eosinophils from normal donors appeared to be dependent on priming with Th2-derived cytokines. Priming with granulocyte-macrophage CSF, IL-4, or IL-5 is required for eosinophils to form rosettes with IgA-beads. IL-4 priming resulted in a fast and transient effect on binding of IgA-beads, whereas the effect of IL-5 priming was slower and longer lasting. The expression of Fc alphaR (CD89) was low compared with that on neutrophils, and experiments with the blocking mAb My43 (CD89) showed no inhibition of rosette formation between eosinophils and IgA-coated beads. However, polymeric myeloma IgA effectively inhibited the rosette formation of IgA-coated beads to eosinophils. Binding of IgG-beads could only be primed with granulocyte-macrophage CSF and IL-5, not with IL-4. These data are concurrent with the hypothesis that Th2-derived cytokines spatially produced at the side of an allergic inflammatory response can direct eosinophils to a rather restricted primed phenotype by IL-4 or to a more generalized primed phenotype by IL-5.

Antibodies, Monoclonal↗

Pharmacological effects of oximes: how relevant are they?

The increased international concern about the threat of military and terroristic use of nerve agents, prompted us to critically consider the expected value of the currently available oxime treatment of nerve agent poisoning. Although oximes have been designed to reactivate the inhibited acetylcholinesterase (AChE), clinical experience has indicated that they are not always very effective as reactivators and at this very moment none of them can be regarded as a broad-spectrum antidote. In spite of this drawback, oximes are worth further investigating, since recent data derived from soman or tabun lethally intoxicated non-human primates suggest that the oxime HI-6 may exert a pharmacological effect that is not related to reactivation of inhibited AChE, but still leads to survival. This pharmacological effect causes recovery of neuronal transmission in the respiratory centres of the brain and recovery of neuromuscular transmission in the diaphragm. These findings have stimulated research to reveal the pharmacological basis of these effects in order to find drugs which could be more effective and less toxic than the available oximes. Since cholinergic drugs were able to exert this effect, a new concept for further treatment is suggested: maintenance of neuronal transmission in spite of continued AChE-inhibition by pharmacological manipulation of the cholinergic receptor. This should renew interest in the diverse pharmacological effects of oximes to reach a more effective treatment in the future.

Animals↗

Evaluation of the atopy patch test and the cutaneous late-phase reaction as relevant models for the study of allergic inflammation in patients with atopic eczema.

OBJECTIVE: The study was designed to evaluate the atopy patch test (APT) and the late-phase reaction (LPR) after intracutaneous allergen injection as models for the study of allergic inflammation in atopic eczema. METHODS: Immunocytochemistry was used to analyze skin biopsy specimens from sites of APTs and LPRs at 2 and 24 hours and to compare these with lesional and nonlesional skin of patients with atopic eczema. RESULTS: A lack of neutrophil infiltration in specimens from both the APT and lesional skin sites was observed, whereas neutrophils were abundantly present in the specimens from LPR sites. With double-staining techniques it was demonstrated that the few neutrophils present in specimens from APT sites and in lesional skin were mostly located in intravascular areas, whereas in the LPR specimens they were located predominantly in extravascular areas. Eosinophils infiltrated at an earlier time point in the LPR as compared with the APT. Furthermore, there was a decrease of intact mast cells in the LPR site compared with the APT sites and lesional skin. No significant difference in T-cell number was observed between the two tests. Upregulation of E-selectin expression on endothelial cells occurred at an earlier time point in the LPR as compared with the APT. CONCLUSION: There are important differences in cellular infiltrate between the APT and the LPR. The close macroscopic and microscopic similarities between the specimens from APT sites and lesional skin of patients with atopic eczema support the argument that the APT is a more valid in vivo model with which to study allergic inflammation in atopic eczema than the LPR.

Adult↗

Pathogenesis of skin lesions in mice with chronic proliferative dermatitis (cpdm/cpdm).

Chronic proliferative dermatitis is a spontaneous mutation in C57BL/Ka mice (cpdm/cpdm), showing alopecia, epithelial hyperproliferation, infiltration by eosinophils and macrophages, and vascular dilatation. To further elucidate its pathogenesis, organs of 1-, 2-, 3-, 4-, 5-, and 6-week-old cpdm/cpdm mice were examined. At 4 weeks, the epidermal thickness was increased, whereas already at 3 weeks, the bromodeoxyuridine incorporation was increased in the basal keratinocytes. However, already at the age of 1 week, skin, lungs, and lymph nodes were infiltrated by eosinophils although no macroscopic lesions were present. Compared with control animals, 6-week-old cpdm/cpdm mice had decreased serum IgE levels and increased numbers of mast cells. From the age of 1 week these mast cells became increasingly IgE positive. In contrast, the mast cells of the control animals remained IgE negative. Mast cells of control and cpdm/cpdm mice were interleukin-4 and tumor necrosis factor-alpha positive. A likely explanation for the tissue infiltration of eosinophils could be the release of interleukin-4 and tumor necrosis factor-alpha from activated mast cells. Tumor necrosis factor-alpha may lead to the expression of E-selectin on endothelial cells, facilitating interleukin-4-mediated eosinophil transendothelial migration. Although various pathogenetic aspects of the cpdm/cpdm mouse need further elucidation, this model can be a tool to study eosinophil infiltration, leukocyte-endothelial cell interactions, and mast cell proliferation. Furthermore, the cpdm/cpdm mouse can be used to study chronic inflammatory skin disease because of the severe epidermal proliferation.

Animals↗

Evaluation of variables influencing the outcome of the atopy patch test.

BACKGROUND: The number of positive atopy patch test (APT) results in patients with atopic eczema (AE) varies in different studies, probably because of different test techniques. Variables that may influence the outcome of the APT were evaluated. METHODS: APTs were performed in 84 patients with AE, 30 control patients with atopic disease, and 85 healthy volunteers, with house dust mite and grass pollen allergens in concentrations of 100, 1000, 10,000, and 100,000 allergenic units/ml. The influence of 0, 10, or 20 tape strippings was investigated. The tests were performed on the back and/or the antecubital fossa and evaluated after 20 minutes and 24, 48, and 72 hours. In all patients the total and specific serum IgE levels were measured. RESULTS: The maximal number of positive APT results were obtained under the following conditions: an allergen concentration equal to 10,000 allergenic units/ml, 10 tape strippings and readings at 24 and 48 hours. Positive APT results were observed in five of 30 control patients with atopic disease and in none of 85 healthy volunteers. Statistically significantly higher total and allergen-specific serum IgE levels were found in the group of patients with AE with positive APT results. CONCLUSIONS: We recommend the previously described conditions to get an optimal method for APT. The correlation between the APT and the total and specific serum IgE suggests an important role for IgE in the reaction mechanism behind the APT.

Adult↗

Maintenance of donor phenotype after full-thickness skin transplantation from mice with chronic proliferative dermatitis (cpdm/cpdm) to C57BL/Ka and nude mice and vice versa.

Chronic proliferative dermatitis is a spontaneous mutation in C57BL/Ka mice (cpdm/cpdm) and is characterized by epithelial hyperproliferation, infiltration by eosinophils and macrophages, and vascular dilatation. To elucidate whether these pathologic features are the result of a local (skin) process or a consequence of a systemic disorder, transplantations were performed of full-thickness grafts of affected skin from cpdm/cpdm mice and normal skin from control (C57BL/Ka) mice on the back of cpdm/cpdm, C57BL/Ka and athymic nude mice. After 3 months, the grafts maintained the histologic phenotype of the donor animal. Intercellular adhesion molecule-1 continued to be expressed by basal keratinocytes of the cpdm/cpdm grafts after transplantation. In contrast, the basal keratinocytes of the C57BL/Ka grafts onto cpdm/cpdm mice remained negative for intercellular adhesion molecule-1 3 months after transplantation. An increased number of proliferating keratinocytes was present in the cpdm/cpdm skin-graft transplanted to nudes or to C57BL/Ka mice based on short-term bromodeoxyuridine labeling. The bromodeoxyuridine incorporation in the keratinocytes of the control C57BL/Ka skin grafts transplanted to cpdm/cpdm, nude, or C57BL/Ka mice was the same as in the keratinocytes of normal C57BL/Ka mice. This study demonstrates that the pathologic features found in the cpdm/cpdm mice are the result of a disorder in the epidermis or dermis and not due to a systemic defect.

Animals↗