Proteoglycans of human gingival epithelium and connective tissue.

Proteoglycans extracted from separated specimens of healthy human gingival epithelium and from connective tissue have been purified. The epithelial proteoglycans fractionated as a single included peak on Sepharose 4B-CL and contained heparan sulphate and dermatan sulphate glycosaminoglycans. The connective-tissue proteoglycans separated into three major populations on Sepharose 4B-CL, one of which was excluded from this gel under associative conditions (0.5 M-sodium acetate, pH 7.4). Subsequent fractionation of the excluded material under dissociative conditions (4 M-guanidinium chloride/0.05 M-sodium acetate, pH 7.4) revealed an absence of any aggregate formation of molecules within this population. The connective-tissue proteoglycans contained heparan sulphate, dermatan sulphate and chondroitin 4-sulphate, the proportions of which varied with the molecular size of the proteoglycans. Amino acid analysis of the protein cores of gingival-epithelial and connective-tissue proteoglycans revealed differences that were similar to the differences described between other types of proteoglycans such as those from skin.     

Diffusion coefficient of fluorescent phosphatidylinositol 4,5-bisphosphate in the plasma membrane of cells

Phosphatidylinositol 4,5-bisphosphate (PIP₂) controls a surprisingly large number of processes in cells. Thus, many investigators have suggested that there might be different pools of PIP₂ on the inner leaflet of the plasma membrane. If a significant fraction of PIP₂ is bound electrostatically to unstructured clusters of basic residues on membrane proteins, the PIP₂ diffusion constant, D, should be reduced. We microinjected micelles of Bodipy TMR-PIP₂ into cells, and we measured D on the inner leaflet of fibroblasts and epithelial cells by using fluorescence correlation spectroscopy. The average ± SD value from all cell types was D = 0.8 ± 0.2 μm²/s (n = 218; 25°C). This is threefold lower than the D in blebs formed on Rat1 cells, D = 2.5 ± 0.8 μm²/s (n = 26). It is also significantly lower than the D in the outer leaflet or in giant unilamellar vesicles and the diffusion coefficient for other lipids on the inner leaflet of these cell membranes. The simplest interpretation is that approximately two thirds of the PIP₂ on inner leaflet of these plasma membranes is bound reversibly.     

Terminal vascular bed of the connective tissue membrane in hypoxic hypoxia]

Morphological changes of all links of the terminal vascular bed during acute hypoxic hypoxia were studied in experiment and in postmortem material. A complex of methods was used including microdissection, injection with India ink - gelatin, clearing, silver nitrate impregnation after V. V. Kuprijanov, staining after Van Gieson and with hematoxylin-eosin, biomicroscopy and reoencephalography. Signs of desorganization of the vascular bed were revealed which manifested themselves as changes in microangioarchitectonics and diameters of vascular lumens, increased permiability of their walls with saturation of them with white and escape of its forming elements of the blood outside the limits of the vessels, as well as in destruction of the aggregate state of the blood. It considerably enlarges our knowledge of the state and changes in the vascular bed during hypoxic hypoxia.     

Extracellular cross-striated banded structures in human connective tissue.

Extracellular cross-striated banded structures have been found in the connective tissues of a variety of organs. Rarely have they been found in conditions such as: hyperplastic parathyroid, follicular adenoma of the thyroid, metastatic hemangiopericytoma in the lung, sarcoidosis of lymph node, and two biopsies of nerve as reported here. The shape and size of the structure varies, as well as its periodicity, which is usually in the range of 1000 to 15000 A. An unusual exception to this general rule is the banded structure in the follicular adenoma of the thyroid where the periodicity is 270 A. These structures are quite different from native collagen or experimentally reconstituted long-space collagen, both by staining reaction with phosphotungstic acid or uranyl acetate and lead nitrate, and in their ultrastructural morphology.     

Change in elastin structure in human aortic connective tissue diseases

Summary Biochemical pathogenesis of the aortic connective tissue diseases (such as, Marfan's syndrome, dissecting aneurysm or aortic aneurysm) was examined by estimating glycoprotein, collagen and elastin contents in the aorta and the intramolecular cross-linking component (isodesmosine) and the intermolecular cross-linking components (cystine, histidinoalanine) in comparison with the control samples obtained from subjects with aortic regurgitation. The elastin content in the aorta and isodesmosine content obtained from the extract of the aortic sample found to be decreased. Ratio of cysteine residues (Cys/Cys-Cys) in the elastin fraction in disease increased. Content of histidinoalanine was found to be decreased. It may be suggested that elastin is maintained in its native nature and shape by intra- and inter-molecular cross-linking bridges, and they are readily denatured by various disease conditions. After elastin was solubilized by elastase, immunoreactive elastin content in those aortic diseases was found to be increased in the human connective tissue. Serum elastase and elastase-like activities tend to increase more than those in the control. These findings may suggest that the change in the structure of elastin would make more susceptible to elastase and other proteolytic enzymes. The reasonable hypothesis may be that molecular defect of fibillin or other constitutional structural glycoproteins produce deficient and functionally incompetent elastin associated microfibrils, and the defect of microfibrils cause to insufficient intra- and inter-molecular cross-links in elastin.     

Modulation of connective tissue metabolism by partially purified human interleukin 1

We have investigated the relationship between the monokine interleukin 1 (IL-1) and the connective tissue-stimulating activities produced by monocytes such as mononuclear cell factor (MCF). Using almost exclusively human tissue we have monitored a wide range of MCF-like activities through the partial purification of IL-1 by gel filtration and isoelectric focusing. Activities measured include stimulation of chondrocytes to produce prostaglandins, plasminogen activator and proteoglycanase, enhancement of synovial cell proliferation, and stimulation of cartilage resorption, in addition to IL-1 (lymphocyte activating factor) activity. The activities described show the same molecular heterogeneity; the active material has similar potencies in the different systems, and removal of IL-1 activity by pretreatment with phenylglyoxal also results in loss of the connective tissue-stimulating activities. These results show that the factors responsible for this wide range of activities are very closely related to IL-1 and give further evidence in support of the possible involvement of IL-1 in the processes of joint destruction occurring in chronic inflammatory conditions such as rheumatoid arthritis.     

Utrastructural interrelationships of collagen fibrillar components in human connective tissue]

The data on structural interconnections between collagenous fibres in the human dermis and periosteum were obtained by means of raster electron microscopy. Collagenous fibres were demonstrated to be connected with each other by means of fine connective fibres situating mainly transversaly towards the main collagenous fibres. Comparing the data obtained with those from the literature, a suggestion was made on the existence, in the connective tissue, of a special connective system composing of peculiar fibrillar structures which maintains dynamic equilibrium in arrangement of collagenous fibres, muscles, vessels, etc. The system of the connective fibres demonstrates a common compositional principle for all the structures mentioned above, but in every case having its peculiarities.     

The development of the connective tissue in the human orbit.

The development of the mesenchymal structures of the human orbit was studied using 10 mu or 60 mu serial sections of orbits of foetuses of 35 to 320 mm stages (C.R. length; 2-9 months). The ontogenesis of the orbital walls, the eye muscles, the blood vessels and the connective tissue was compared. This comparison revealed that the eye muscles and their fasciae together with the adventitial layers of the larger blood vessels and nerves develop first, closely linked in time to the progress of ossification and growth of most of the orbital bones. Only the (endochondral) ossification of the ethmoid starts much later. The orbital connective tissue septa development commences later, i.e. from the third month onwards, concurrently with the development of special mesenchymal condensations, a particular capillary system and adipose tissue. About five months later the adult configuration is attained.     

A rapid connective tissue stain for glycol methacrylate embedded tissue

No reliable connective tissue stains for GMA sections were available until recently. However, the use of toluidine blue in combination with basic fuchsin appeared to be a rapid and reliable connective tissue stain for glycol methacrylate (GMA) embedded tissue.     

Host-supplied connective tissue as a guide for proliferating tumor cells in human tumor xenografts

The morphologic alterations of 7 human tumors of different origin and various histologic types, heterotransplanted to athymic nude mice, were investigated in the present study. Constant patterns of histologic and ultrastructural changes were observed in all 7 tumors. Following the initial dying of most inoculated tumor cells, host-supplied inflammatory cells invaded the xenografts and phagocytosed necrotic tumor cells. Fibroblasts which vivaciously produced collagenous material invaded the xenografts and built up solid strands of connective tissue which tightly contacted surviving tumor cells. These stands were used as guide-rails for ingrowing blood vessels. Immediately after their immigration, the first mitoses of tumor cells occurred in close proximity to capillary-conducting strands of connective tissue resulting in a revival of tumor cell proliferation near to the fibrous cords and a spreading of newly formed tumor cells along the strands of connective tissue. These results point to the host-supplied connective tissue as playing an important role for tumor proliferation and local tumor expansion.