An improved noninfectious murine skin model of organized granulomatous inflammation

An improved model of granulomatous inflammation in skin was developed by second passage skin grafting of isolated, lyophilized skin granulomas, originally elicited in naive mice by inoculations of lyophilized hepatic schistosome egg granulomas. The tissue reaction is caused by a single exposure to a noninfectious, acellular granulomagenic stimulus and occurs in healthy mice free of systemic disease. The model should prove useful for isolation of granuloma initiation factor(s). Furthermore, because there is a time lag before new granuloma formation begins, a window exists for analytical dissection of the initiation process. In this study we described the responses of host cells by autoradiography, and light and electron microscopy. The activity of angiotensin-converting enzyme and proline-specific endopeptidase showed a modulation during granuloma formation. In addition we found that severe immunosuppression with high dose cyclosporine therapy did not alter granuloma formation, supporting the idea that initiation of organized granulomas is T-cell independent.     

Polyvinylchloride (PVC) particles implantation in mouse liver. A technique for experimental study of schistosome eggs-induced liver pathology.

An injection of suspended PVC particles in the caecal vein of mice induces a foreign-body portal granuloma reaction in the liver. Plastic casts of the portal system, after PVC particles implantation, show modifications in the portal bed and are compared with plastic casts obtained in mice infested by Schistosoma mansoni. This technique can be useful to study the cellular dynamics of the portal granuloma and can be a model for schistosomal eggs induced liver pathology.     

Polyvinylchloride (PVC) particles implantation in mouse liver. A technique for experimental study of schistosome eggs-induced liver pathology

Summary An injection of suspended PVC particles in the caecal vein of mice induces a foreign-body portal granuloma reaction in the liver. Plastic casts of the portal system, after PVC particles implantation, show modifications in the portal bed and are compared with plastic casts obtained in mice infested bySchistosoma mansoni. This technique can be useful to study the cellular dynamics of the portal granuloma and can be a model for schistosomal eggs induced liver pathology.This work was supported by an ATP (INSERM) 18.75.41 and a scholarship from the Société d'Hépatologie Expérimentale.     

Trichomes as models for studying plant cell differentiation

Trichomes, originating from epidermal cells, are present on nearly all terrestrial plants. They exist in diverse forms, are readily accessible, and serve as an excellent model system for analyzing the molecular mechanisms in plant cell differentiation, including cell fate choices, cell cycle control, and cell morphogenesis. In Arabidopsis, two regulatory models have been identified that function in parallel in trichome formation; the activator–inhibitor model and the activator–depletion model. Cotton fiber, a similar unicellular structure, is controlled by some functional homologues of Arabidopsis trichome-patterning genes. Multicellular trichomes, as in tobacco and tomato, may form through a distinct pathway from unicellular trichomes. Recent research has shown that cell cycle control participates in trichome formation. In this review, we summarize the molecular mechanisms involved in the formation of unicellular and multicellular trichomes, and discuss the integration of the cell cycle in its initiation and morphogenesis.     

Polyadenylate-polyuridylate enhancement of 7,12-dimethylbenz-anthracene skin carcinogenesis

Summary Double-stranded polynucleotide polyadenylate-polyuridylate (Poly AU) enhanced skin tumor formation in Swiss mice by 75% when injected prior to a single application of 7,12-dimethylbenzanthracene (DMBA). When given after the carcinogen application Poly AU did not significantly enhance tumor formation.Acknowledgment. The authors wish to thank J. Rowland for technical help.     

Polyadenylate-polyuridylate enhancement of 7,12-dimethylbenz-anthracene skin carcinogenesis.

Double-stranded polynucleotide polyadenylate-polyuridylate (Poly AU) enhanced skin tumor formation in Swiss mice by 75% when injected prior to a single application of 7,12-dimethylbenzanthracene (DMBA). When given after the carcinogen application Poly AU did not significantly enhance tumor formation.     

Bone marrow-derived mesenchymal cells and MMP13 contribute to experimental choroidal neovascularization

In this study, we evaluate the potential involvement of collagenase-3 (MMP13), a matrix metalloproteinase (MMP) family member, in the exudative form of age-related macular degeneration characterized by a neovascularisation into the choroid. RT-PCR analysis revealed that human neovascular membranes issued from patients with AMD expressed high levels of Mmp13. The contribution of MMP13 in choroidal neovascularization (CNV) formation was explored by using a murine model of laser-induced CNV and applying it to wild-type mice (WT) and Mmp13-deficient mice (Mmp13 ^?/? mice). Angiogenic and inflammatory reactions were explored by immunohistochemistry. The implication of bone marrow (BM)-derived cells was determined by BM engraftment into irradiated mice and by injecting mesenchymal stem cells (MSC) isolated from WT BM. The deficiency of Mmp13 impaired CNV formation which was fully restored by WT BM engraftment and partially rescued by several injections of WT MSC. The present study sheds light on a novel function of MMP13 during BM-dependent choroidal vascularization and provides evidence for a role for MSC in the pathogenesis of CNV.     

Cutaneous wound healing: recruiting developmental pathways for regeneration

Following a skin injury, the damaged tissue is repaired through the coordinated biological actions that constitute the cutaneous healing response. In mammals, repaired skin is not identical to intact uninjured skin, however, and this disparity may be caused by differences in the mechanisms that regulate postnatal cutaneous wound repair compared to embryonic skin development. Improving our understanding of the molecular pathways that are involved in these processes is essential to generate new therapies for wound healing complications. Here we focus on the roles of several key developmental signaling pathways (Wnt/β-catenin, TGF-β, Hedgehog, Notch) in mammalian cutaneous wound repair, and compare this to their function in skin development. We discuss the varying responses to cutaneous injury across the taxa, ranging from complete regeneration to scar tissue formation. Finally, we outline how research into the role of developmental pathways during skin repair has contributed to current wound therapies, and holds potential for the development of more effective treatments.     

Serum proteins of mice with splenomegaly.

Our earlier serum electrophoretic study in 'lethargic' mutant mice showed that the quantity of protein in 1 band is inversely related to the size of the spleen. In this study, we demonstrate that this protein band almost entirely disappears in mice with splenomegaly following spontaneous skin infection. The results suggest that this serum protein may play a role in regulating growth of lymphoid tissue.     

Über die Entwicklung des Fremdkörpergranuloms in verschiedenen Organsystemen

Summary The weight has been measured of the granuloma produced after implantation of the same foreign body in the kidneys, the testes, the liver and the subcutaneous tissue of male rats. It was found that granulomae in the testes and liver are nearly twice as heavy as in the kidney or in the subcutaneous tissue. Enhancement or inhibition of this reaction by treating the animals with cortexone shows organ-dependent effects on granuloma formation.     

Neogenesis of functional hair follicles in adult mouse skin selectively induced by tumour-promoting phorbol esters

Summary Neogenesis of functional hair follicles in the tail skin of adult mice can quantitatively be demonstrated after long-term treatment with tumour-promoting phorbol esters. The ability to induce the formation of new hair follicles correlates with the hyperplasiogenic and tumour-promoting capacity of the phorbol esters. Hyperplasiogenic but nonpromoting phorbol esters do not lead to the formation of new hair follicles.Acknowledgment. I am grateful to Dr K. Goerttler and Dr F. Marks for helpful advice and discussions.     

Different roles of the human Orc6 protein in the replication initiation process

In eukaryotes, binding of the six-subunit origin recognition complex (ORC) to DNA provides an interactive platform for the sequential assembly of pre-replicative complexes. This process licenses replication origins competent for the subsequent initiation step. Here, we analyze the contribution of human Orc6, the smallest subunit of ORC, to DNA binding and pre-replicative complex formation. We show that Orc6 not only interacts with Orc1–Orc5 but also with the initiation factor Cdc6. Biochemical and imaging experiments reveal that this interaction is required for licensing DNA replication competent. Furthermore, we demonstrate that Orc6 contributes to the interaction of ORC with the chaperone protein HMGA1a (high mobility group protein A1a). Binding of human ORC to replication origins is not specified at the level of DNA sequence and the functional organization of origins is poorly understood. We have identified HMGA1a as one factor that might direct ORC to AT-rich heterochromatic regions. The systematic analysis of the interaction between ORC and HMGA1a revealed that Orc6 interacts with the acidic C-terminus of HMGA1a and also with its AT-hooks. Both domains support autonomous replication if targeted to DNA templates. As such, Orc6 functions at different stages of the replication initiation process. Orc6 can interact with ORC chaperone proteins such as HMGA1a to facilitate chromatin binding of ORC and is also an essential factor for pre-RC formation.     

Neogenesis of functional hair follicles in adult mouse skin selectively induced by tumour-promoting phorbol esters

Neogenesis of functional hair follicles in the tail skin of adult mice can quantitatively be demonstrated after long-term treatment with tumour-promoting phorbol esters. The ability to induce the formation of new hair follicles correlates with the hyperplasiogenic and tumour-promoting capacity of the phorbol esters. Hyperplasiogenic but nonpromoting phorbol esters do not lead to the formation of new hair follicles.     

Polarization of immunity induced by direct injection of naked sequence-stabilized mRNA vaccines

In the context of developing a safe genetic vaccination strategy we tested and studied globin-stabilized mRNA-based vaccination in mice. This vaccination strategy has the advantages of genetic vaccination (easy production, adaptability to any disease and inexpensive storage when lyophilized), but not the drawbacks of DNA vaccination (long-term uncontrolled expression of a transgene, possibility of integration into the host genome and possible induction of anti-DNA antibodies). We report here that injection of naked -globin untranslated region (UTR)-stabilized mRNA coding for -galactosidase is followed by detectable translation in vivo. In addition, we show that such a vaccination strategy primes a T helper 2 (Th2) type of response which can be enhanced and shifted to a Th1-type immune response by application of recombinant granulocyte/macrophage colony-stimulating factor 1 day after mRNA injection. Our data demonstrate that the administration of globin UTR-stabilized mRNA is a versatile vaccination strategy that can be manipulated to fit the requirement of antiviral, antibacterial or antitumor immunity.Received 14 June 2004; received after revision 19 July 2004; accepted 9 August 2004     

Expulsion of the placenta from the uterus is the principal initiator for collagen degradation in mouse uterus

In unilaterally pregnant mice, collagen degradation in the non-pregnant uterine horn was not initiated by removal of the fetus only but by removal of both the fetus and placenta. The results indicate that expulsion of the placenta from the uterus is a principal factor in the initiation of the process of collagen degradation simultaneously in the whole uterus.     

小鼠皮肤局部缺血模型的建立

目的研究建立稳定的昆明小鼠皮肤局部缺血模型。方法取40只雌性昆明小鼠，随机分为A／B两组，每组20只。分别在小鼠背部建立深达皮下筋膜层的u型皮瓣。A组为3．3×1．5cm皮瓣组．B组为2．5×1．5CITI皮瓣组。皮瓣游离缘垫以医用橡胶，缝合切口，造成皮肤缺血模型，术后观察皮瓣发绀水肿及坏死情况，并用散斑全景实时血流成像仪（MoorFLH）检测皮瓣血流。结果肉眼观察，3．3×1．5cm皮瓣组在术后第2天，50％小鼠皮瓣末端坏死，坏死面积达皮瓣面积的（37．20±4．83）％。术后第3天100％小鼠皮瓣末端坏死。并随时间的延长，坏死面积逐渐扩大。2．5×1．5皮瓣组在术后第1天皮瓣出现发绀，水肿，发绀水肿面积占（77．46±4．51）％，术后第3，第5天发绀水肿区面积逐渐减小，至术后第7天，发绀、水肿完全消退。散斑全景实时血流成像仪（MoorFLPI）检测皮肤血流显示，术后第1天皮瓣显著性缺血（P〈0．05），术后第7天血流基本恢复到术前水平。结论成功建立了昆明小鼠皮肤局部缺血模型，为进一步研究组织微血管再生的机理和策略提供简单而稳定的动物模型。     

A new approach to analysis of human sweating

In human skin transplanted to the back of 3 strains of immuno-deficient mice the functin of the eccrine sweat glands of the human transplant was tested by topical intradermal application of pilocarine, adrenaline and atropine+pilocarpine. Sweat responses were observed in pre-selected fields of observation by means of video macroscope. The iodine strarch reaction served as an indicator for the appearance of seat sport and permitted the evaluation of areas wetted by sweat in the field of observation. Among 9 animals tested, the hybrids between the CB-17-scid mouse and the BALB/cA-nu mouse (BALB/cA-nu,scid) seemed to exhibit the most consistent seweating response to local pharmacological stimulation. According to histological examination, eccrine sweat glands were preserved in human skin trasplanted into the back skin of the BALB/cA-nu,scid mouse strain. the heterologous, human skin graft provides a novel model permitting, independent of the normal sweat gland innervation, the analysis of moecular receptors of sweat gland cells by which the actions of natural transmitters and pharmacological agents are transduced.     

Preferential excretion of glycated albumin in C57BL-Ks-J mice: effects of diabetes.

Urinary excretion of glycated albumin was quantitated in genetically hyperglycemic mice (C57BL-Ks-J, db/db mice), a model for non-insulin-dependent diabetes mellitus, and compared with their non-diabetic littermates. The data indicated a preferential excretion of glycated albumin in non-diabetic mice. This phenomenon of 'editing' of glycated albumin is decreased significantly in diabetic mice. Quantitative measurements of overall excretion of glycated albumin suggested that the loss of editing in diabetic mice is due to the dilution of glycated albumin by the unmodified albumin which is excreted in large amounts in diabetic mice. Therefore, the loss of editing observed in this model resembled the one we characterized in insulin-dependent diabetic humans and a streptozotocin-diabetic rat model.