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Biomedical subjects

R Fleischmajer

Publications and source records attributed to R Fleischmajer.

At least 37 records · Page 2Linked to original sources
PubMed1991

Elastin-associated microfibrils (10 nm) in a three-dimensional fibroblast culture.

The purpose of this study is to present a three-dimensional dermal fibroblast model. Skin fibroblasts cultured in this system deposit large amounts of collagen and microfibrils. Fibroblasts were seeded onto a nylon filtration mesh and incubated in the presence or absence of ascorbic acid. Collagen fibril formation was found in the presence of ascorbic acid whereas microfibril formation was seen independent of ascorbic acid supplementation. Immunoelectron microscopy revealed that microfibrils were labeled with fibrillin at 67 nm periodicity. Isolated microfibrils studied by rotary shadowing had a beaded appearance consisting of beads linked to each other by a filamentous structure. The spaces between the beads ranged from 10.00-33.33 nm, suggesting that these microfibrils may have an extension-contraction mechanism. Furthermore, the size and spacing of the beads were similar to that seen in microfibrils from tissues (measured after rotary shadowing). Fibroblasts cultured in a three-dimensional mesh represent an effective in vitro model with which to study microfibril formation.

Cells, Cultured↗
PubMed1991

Rotary shadowing of collagen monomers, oligomers, and fibrils during tendon fibrillogenesis.

Collagen monomers, oligomers, and fibrillar structures were isolated from chick tendons at various stages of development and studied by rotary shadowing. Monomers of Type I collagen, solubilized in 0.15 M NaCl solutions, were mostly present as collagen, pN-collagen, and pC-collagen with few procollagen molecules. They did not form polymers, nor were they associated with a carrier. Dimers of fibrillar collagen molecules were arranged in a 4-D stagger, suggesting that this was the preferred molecular interaction for the initiation of collagen fibrillogenesis. Type XII collagen molecules were mostly free, but some were attached by their central globular domain to one end of free fibrillar collagen molecules. Tenascin and Type VI collagen were also identified. The fibril populations consisted of collagen and beaded structures. These fibrils consisted of beads (globular domains) about 23 nm in diameter, separated by a period about 27 nm in length. Beads were linked by filamentous structures. These beaded fibrils probably represent the microfibrils of elastin.

Animals↗
PubMed1991

Self reactive repertoire of tight skin mouse: immunochemical and molecular characterization of anti-topoisomerase I autoantibodies.

Tight skin (TSK) mice develop cutaneous hyperplasia accompanied by histopathological alterations of skin and collagen metabolism similar to those described in human scleroderma. Diffuse scleroderma, the most severe form of progressive systemic sclerosis, is associated with the production of autoantibodies specific for Scleroderma 70 antigen (topoisomerase I). Our studies show that there is an increase in the level of serum anti-topoisomerase I (topo I) autoantibodies in aged TSK mice. The monoclonal antibodies isolated from TSK mice bind to epitopes which interact with autoantibodies from scleroderma patients. A significant number of TSK monoclonal anti-topo I antibodies and serum immunoglobulin (Ig) from aged TSK mice bear a cross reactive idiotype (Id) recognized by a syngeneic monoclonal anti-Id antibody obtained from a 2 month-old TSK mouse. Analysis of V gene usage by monoclonal anti-topo I antibodies showed that the majority of these antibodies are encoded by VH genes derived from VHJ558 family pairing with VK genes from various families in a stochastic manner.

Animals↗
PubMed1991

Eosinophilic fasciitis associated with tryptophan ingestion. A manifestation of eosinophilia-myalgia syndrome.

Recently, the ingestion of tryptophan has been associated with eosinophilia-myalgia syndrome, which is characterized by eosinophilia, myalgias, and several less consistently reported findings. We treated 13 patients who exhibited clinical features of eosinophilic fasciitis who were taking high-dose tryptophan before the onset of clinical symptoms. Twelve patients exhibited eosinophilia, with eosinophil counts ranging from 0.13 to 0.88. The remaining patient was taking oral corticosteroids when her eosinophil count was determined. Eight patients complained of myalgias. Other symptoms included arthralgias, pruritus, cutaneous burning, weakness, fever, rashes, malaise, edema, muscle spasms, and alopecia. 5-Hydroxyindoleacetic acid levels were elevated in four of the eight urine specimens that were tested. Our findings suggest that previously diagnosed cases of eosinophilic fasciitis may represent variants of tryptophan-associated eosinophilia-myalgia syndrome. Derangements in the metabolism of tryptophan may play a role in sclerotic diseases.

Adult↗
PubMed1991

Extracellular microfibrils are increased in localized and systemic scleroderma skin.

Extracellular microfibrils, about 10 nm thick with a hollow core have been found in most organs as free bundles or in association with elastic fibrils. Histochemistry of the dermis of 4 patients with localized and 6 with systemic scleroderma revealed numerous fine elastic fibrils in areas of fibrosis. Immunofluorescence and immunoelectron microscopy were performed with antibodies against fibrillin and amorphous elastin. The lower dermis revealed an increase in 10-nm microfibrils interspersed between collagen fibrils. These microfibrils stained for fibrillin but not for amorphous elastin. Fibrosis in localized and systemic scleroderma involves the deposition of collagen fibrils and microfibrils.

Extracellular Space↗
PubMed1990

Type I and type III collagen interactions during fibrillogenesis.

There is some evidence that type I and type III collagens may be present in the same fibril. In order to demonstrate this, double labeling immunofluorescence microscopy and immunoelectron microscopy were performed with antibodies directed against the collagen molecule and the aminopropeptide domains of type I and type III procollagens using embryonic (postabortion) and adult human skin. Double indirect and protein A immunoelectron microscopy were carried out with 5- and 15-nm gold particles. Skin extracts were also studied by immunoblotting. Double immunofluorescence microscopy with antibodies against type I and type III collagen molecules revealed patterns of fluorescence that were identical in both fetal and adult skins. Immunofluorescence microscopy using an antibody directed against the aminopropeptide of type III procollagen labeled the entire dermis in both embryonic and adult skins. In contrast, although the aminopropeptide of type I procollagen was present throughout embryonic dermis, it was markedly reduced in adult dermis, except for the epidermo-dermal junction. Double immunoelectron microscopy of fetal skin revealed labeling of the aminopropeptide of type I and type III procollagens on the same thin (20-30 nm) fibrils. Large type I fibrils (90-100 nm) were coated with type III collagen molecules and their corresponding aminopropeptide but not with the aminopropeptide of type I procollagen. The aminopropeptide of type I procollagen was present on thin fibrils only at the epidermo-dermal junction in adult skin. Immunoblotting of skin extracts revealed the presence of both pN-type III procollagen (collagen plus the aminopropeptide) and pN-type I procollagen in fetal skin, but only pN-type III in adult skin. This study demonstrates that type I and type III collagens coexist within the same fibril and that the aminopropeptide of type III procollagen is present at the surface of type I collagen fibrils that apparently have reached full growth.

Adult↗
PubMed1989

Alterations in dermal collagen in ultraviolet irradiated hairless mice.

Chronic exposure of the skin to sunlight results in severe dermal connective tissue damage that is characterized by the basophilic degeneration of collagen and the accumulation of an elastotic material. The aim of this study was to identify changes in collagen (the major structural protein of the skin) in ultraviolet irradiated mouse skin using immunochemical and biochemical techniques. Specific antibodies directed against the aminopropeptide of type III procollagen were used in immunofluorescence and immunoblotting studies. Immunofluorescent staining of irradiated and nonirradiated mice skin showed that the aminopropeptide of type III procollagen was distributed throughout the dermis in a pattern similar to that observed for type I collagen. Extracts of irradiated (5 and 10 weeks) and nonirradiated skins were then subjected to immunoblotting techniques. Levels of pN alpha 1, type III procollagen (measured by radioimmunoassay) were reduced in the extracts prepared from skins of mice that were irradiated for 5 and 10 weeks. Immunoelectron microscopy verified the loss of pN alpha 1 type III procollagen in irradiated skin. Collagen fibers of nonirradiated skin demonstrated normal labeling with antibody directed against the aminopropeptide of type III procollagen. In contrast, collagen fibers of 10 week irradiated skin failed to label with this antibody. The pN alpha 1 type III collagen is known to coat type I collagen fibers of normal skin. Therefore, its absence from the surface of type I collagen fibers of irradiated skin may play a role in the development of the elastotic material.

Animals↗
PubMed1989

Immunological modulation of dermal fibroblasts in scleroderma.

Scleroderma can be considered as a model to study the mechanism of fibrosis. Lymphocytes and monocytes/macrophages are recruited during the inflammatory process associated with this disorder. These activated blood cells release a series of factors--lymphokines and monokines--which in turn recruit more fibroblasts, possibly stimulate their proliferation, and regulate their synthesis of collagen and glycosaminoglycans. These factors represent both positive and negative modulators for these processes. It may be the absence of an inhibitory factor(s) and/or presence of other stimulator(s) which allow the fibroblast to synthesize collagen in an uncontrolled manner, leading to the increased accumulation of this protein in the dermis. Although there is an increase in collagen accumulation in vitro, the ratio of type I/type III collagen remains unaltered. It has been suggested that an increase in T-helper cells could explain the production of collagen stimulatory lymphokines. Collagen production may also be regulated by a feedback mechanism involving the amino and carboxyl propeptides of procollagen. In scleroderma this mechanism may be altered by the lymphokine/monokine factor(s) which affect collagen synthesis. Fibrosis probably is not the primary event in scleroderma but represents the final or terminal stage of the disease. Future research on the interactions which take place between the cells of the immune system and fibroblasts may clarify the mechanism of fibrosis in scleroderma and other disorders.

Cell Division↗
PubMed1988

Clinical, pathologic, and immunopathologic manifestations of the toxic oil syndrome. Analysis of fourteen cases.

The clinical, pathologic, and immunopathologic findings of 14 patients with the toxic oil syndrome are presented. The toxic oil syndrome occurred in Madrid, Spain, as a consequence of ingestion of an industrial oil sold as olive oil. The syndrome occurred in two phases. In the acute phase patients developed an interstitial pneumonitis, fever, and exanthem, and some died of respiratory insufficiency. Of those who survived, some developed a chronic phase with a neuromyopathic and scleroderma-like illness that had many features of a collagen vascular disease. Histologic examination of lung in the acute phase showed an endovasculitis and features of adult respiratory distress syndrome. In the chronic phase the skin showed various degrees of sclerodermoid changes and vessel injury. Immunofluorescence with antiprocollagen and antifibronectin antibodies revealed abundant perivascular fluorescence suggestive of vascular injury. Electron microscopy corroborated this by the presence of endothelial swelling and basal lamina reduplication. Similar findings have been described in systemic sclerosis, and this provides an important model for study of connective tissue disease, including scleroderma.

Adolescent↗
PubMed1988

Identification of collagen fibrils in scleroderma skin.

Skin from early and late stages of scleroderma has been shown to contain large amounts of thin (30-40 nm diameter) collagen fibrils that may be present in bundles or intermingled with large diameter fibrils (90-120 nm). The nature of these fibrils is unknown. Skin biopsies were obtained from involved areas of nine patients with progressive systemic sclerosis (PSS), one case of generalized morphea, one case of morphea, and six normal controls. Intact skin was analyzed by immunoelectron microscopy (IEM), while extracts were subjected to sodium dodecyl polyacrylamide gel electrophoresis (SDS-PAGE), Western immunoblotting, radioimmunoassay (RIA), and enzyme-linked immunosorbent assay (ELISA). Fine fibrils 20-40 nm in diameter in the mid to lower dermis of scleroderma skin were labeled with antibodies directed against the aminopropeptide (AP) of type III procollagen. Antibodies directed against the AP of type I procollagen labelled fine fibrils in the lower dermis. Larger fibrils (80-120 nm) did not label. pN alpha 1 (III) was found to be present in both normal and scleroderma skin. Extracts of scleroderma skin contained 2.5 times the amount of pN (III) collagen and 3.0 times the amount of fibronectin as did extracts of normal skin. The data indicate that the increase in thin fibrils in scleroderma skin is most likely due to an increase in type III collagen, which retains the AP at its surface.

Adult↗
PubMed1988

Procollagen intermediates during tendon fibrillogenesis.

The purpose of this study was to correlate ultrastructural features of tendon collagen fibrils at various stages of development with the presence of procollagen, pN-collagen, pC-collagen, and the free amino propeptides and carboxyl propeptide of type I procollagen. Tendons from 10-, 14-, and 18-day chicken embryos reveal small, well-defined intercellular compartments containing collagen fibrils with diameters showing a unimodal distribution. At 21 days (hatching) and 9 days (post hatching) and at 5 weeks (post hatching), the compartments are larger, less well-defined, and there is multimodal distribution of tendon fibril diameters. Procollagen and the intermediates pN-collagen and pC-collagen are present in tendons up to 18 days. Thereafter there is a marked reduction in procollagen, whereas the intermediates persist throughout all stages of development. Similarly, free amino propeptides and carboxyl propeptides of type I procollagen were found at all stages. The amino propeptide of type III procollagen was restricted to the peritendineum until 7 weeks post hatching. At that time, a network of fibrils containing the amino propeptide of type III procollagen was seen delineating well-circumscribed compartments of collagen fibrils throughout the entire tendon. This study supports the notion that pN- and pC-collagen have an extracellular role and participate in collagen fibrillogenesis.

Animals↗
PubMed1987

Amino and carboxyl propeptides in bone collagen fibrils during embryogenesis.

Collagen fibrillogenesis was studied in tibiae of chick embryos, 9, 11, and 14 days old. Specimens were incubated with antibodies against the amino and the carboxyl propeptides of type-I collagen and subjected to ferritin-labelling immuno-electron microscopy. The amino propeptide was found in thin fibrils, 20-40 nm in diameter, distributed at 60-nm periodicity. The carboxyl propeptide antibody labelled a wide spectrum of fibrils, although the majority were in the range of 40-100 nm, distinctly larger than those labelled with the amino propeptide antibody. The presence of pN (amino propeptide plus collagen) and pC (carboxyl propeptide plus collagen) collagen was also demonstrated by Western blotting in all specimens. This study suggests that the sequence of propeptide removal may regulate collagen fibril diameter.

Animals↗
PubMed1987

The carboxylpropeptide of type I procollagen in skin fibrillogenesis.

Previous studies suggested that the aminopropeptide of type I procollagen may initiate fibril formation. The purpose of this investigation was to study the location of the carboxylpropeptide of type I procollagen during collagen fibrillogenesis. Chick embryonic and posthatching skin specimens were studied by immunofluorescence and immunoelectron microscopy and by immunoblotting with antibodies against the amino and carboxylpropeptide of type I procollagen. The carboxylpropeptide was demonstrated at the surface of collagen fibrils, 20-40 nm in diameter (10-day embryos) and in fibrils, 40-65 nm (21-day embryos). In addition, the carboxylpropeptide was found at the cell surface and free in the ground substance. The aminopropeptide was only seen in fibrils, 20-30 nm in diameter, as previously reported. Ratios of pN-collagen/pC-collagen increased from 16 days embryonic to 3 and 9 days postembryonic skins. This study suggests that both pN-collagen (aminopropeptide plus collagen) and pC-collagen (carboxylpropeptide plus collagen) participate in fibrillogenesis.

Animals↗
PubMed1986

Glycosaminoglycans of skin and urine in pseudoxanthoma elasticum: evidence for chondroitin 6-sulfate alteration.

Abnormally elevated hyaluronic acid and dermatan sulfate were isolated from lesional skin of a patient with severe pseudoxanthoma elasticum. These glycosaminoglycans (estimated as uronic acid) surpassed the normal controls by 33.6 and 4.8 magnitudes, respectively. Urine chondroitin 6-sulfate of the same patient moved faster by electrophoresis on cellulose acetate than its counterpart isolated from urine of another four patients or from the normal controls. Hyaluronic acid and chondroitin 6-sulfate exceeded their counterparts in normal urine by 2- to 10- and 4- to 18-folds, respectively. These increments correlated with the pseudoxanthoma elasticum severity in three of the five patients studied. The data showed: the first conclusive evidence that dermatan sulfate increased in lesional skin of a patient, with severe pseudoxanthoma elasticum, who also had considerably augmented HA, alteration of the same patient's urine chondroitin 6-sulfate, and diversified urine glycosaminoglycans in pseudoxanthoma elasticum.

Adult↗
PubMed1986

Eosinophilic pustular folliculitis.

We present the case of an American adult patient with eosinophilic pustular folliculitis. The majority of previously reported patients have been Japanese. Eosinophilic pustular folliculitis is a rare condition characterized by recurrent, peripherally expanding, sterile papulopustules and plaques. Hair-bearing areas such as the face, chest, back, and extensor surfaces of the upper arms are usually involved, although palms and soles can be affected as well. Histologic examination shows subcorneal and intrafollicular abscesses and spongiosis of the outer root sheath. The eosinophil is a prominent infiltrating cell, although mononuclear cells and neutrophils may also be seen. There is often a dense perivascular infiltrate of eosinophils in the dermis. Our patient was unusual in that he did not respond to multiple therapeutic regimens.

Adult↗