Type Of Connective Tissue Research Articles

Structure of the conus arteriosus and ventral aorta in the sea lamprey, Petromyzon marinus, and the Atlantic hagfish, Myxine glutinosa: microfibrils, a major component

Light and electron microscopic observations of the conus arteriosus (CA) and ventral aorta (VA) of the sea lamprey, Petromyzon marinus, and the Atlantic hagfish, Myxine glutinosa, reveal the presence of a unique form of fibrous extracellular matrix within their media and an unusual type of connective tissue forming the lateral subendothelial distensions found only in the lamprey CA. The extracellular matrix of the media in lamprey and hagfish CA and VA is characterized by large concentrations of tubular, elastic fibrelike microfibrils 11–17 nm in diameter. No elastic fibrelike elastin component could be found. Collagen fibrils, matrix granules, and intergranular filaments make up the remainder of the matrix. The loose connective tissue composing the lateral distensions of the larval and adult lamprey CA contains ultrastructural features similar to those of lamprey mucocartilage. It is speculated that since lampreys and hagfish are living representatives of the most primitive group of vertebrates, the microfibrils present in their major arteries may represent a primitive form of elastic fibre in which elastin has not yet developed. The functional significance of the extracellular microfibrils in the CA and VA of lamprey and hagfish and the occurrence of lateral distensions in the lamprey CA are discussed.

Quantitation of hydroxypyridinium crosslinks in collagen by high-performance liquid chromatography

An HPLC method for quantifying the 3-hydroxypyridinium crosslinks of collagen is described. It can be applied to crude hydrolysates of all types of connective tissue. Mineralized tissues can be hydrolyzed directly and analyzed without interference from the mineral ions. The hydroxylysyl (HP) and lysyl (LP) forms of hydroxypyridinium residue were resolved on a reverse-phase C18 column using a gradient of acetonitrile in water and 0.01 m n-heptafluorobutyric acid as an ion-pairing agent. The crosslinking amino acids were accurately quantified down to 2 p m (1 ng) injected, by detecting their natural fluorescence with a spectrofluorometer. Tissues in which hydroxypyridinium crosslinks were plentiful included all forms of cartilage, bone, dentin, ligament, tendon, fascia, intervertebral disc, lung, gut, cervix, aorta, and vitreous humor. Among normal tissues, LP, the minor form of the crosslink, was present in significant amounts relative to HP only in bone and dentin. Both crosslinks were essentially absent from skin, cornea, rat tail tendon, and basement membranes.

Identification of human connective tissue in transplant of human oral mucosa in nude mice.

The present study describes a method for identification of connective tissue of human oral mucosal transplants in nude mice. The method was based on the development of a murine antiserum to human fibroblasts. After absorption with murine fibroblasts the antiserum in an immunofluorescence method appeared to react specifically with human connective tissue of frozen sections, whereas the antiserum did not react with murine connective tissue. The antiserum, applied to frozen sections of human oral mucosal transplants in nude mice, could distinguish between human and murine connective tissue in the sections. The ability to distinguish between the two types of tissue was utilized to elucidate a possible relation between epithelial morphology and underlying type of connective tissue. It was found that the formation of rete ridges of transplanted human oral epithelium was dependent on the presence of subepithelial human connective tissue. The method described may be useful for the recognition of human tissue in experimental studies of human transplants to other species.

Epithelial enhancement of connective tissue differentiation in explanted somites

This paper examines the differentiation of somites from stage-16 or -17 chick embryos cultured with or without notochord in explant cultures. Histological sections of the cultures were stained with a trichrome stain to identify the different kinds of connective tissues formed. Both anterior and posterior (epithelial) somites made muscle, cartilage and loose connective tissue in explant culture. The extent of cartilage differentiation was enhanced by the presence of the notochord, confirming earlier studies. The presence of 1 mM-dibutyryl cAMP in the culture medium increased the amount of muscle found in the explants but by histological criteria did not inhibit chondrogenesis, contrary to earlier reports. The addition of quail ectoderm to the explants stimulated loose connective tissue to form directly beneath it, suggesting for the first time a role of the ectoderm in dermatome differentiation. These results suggest that the epithelial somite has the capacity to differentiate into all three connective tissue types even before it has separated into sclerotome and dermamyotome. The relative amount of different connective tissue types can be influenced by environmental factors, such as adjacent epithelia like the notochord or ectoderm.

Mapping by monoclonal antibody detection of glycosaminoglycans in connective tissues.

Chondroitin sulphate proteoglycans are widespread connective tissue components and chemical analysis of cartilage and other proteoglycans has demonstrated molecular speciation involving the degree and position of sulphation of the carbohydrate chains. This may, in turn, affect the properties of the glycosaminoglycan (GAG), particularly with respect to self-association and interactions with other extracellular matrix components. Interactions with specific molecules from different connective tissue types, such as the collagens and their associated glycoproteins, could be favoured by particular charge organizations on the GAG molecule endowed by the sulphate groups. So far, it has not been possible to identify and map chondroitins of differing sulphation in tissues, but we have now raised three monoclonal antibodies which specifically recognize unsulphated, 4-sulphated and 6-sulphated chondroitin and dermatan sulphate. These provide novel opportunities to study the in vivo distribution of chondroitin sulphate proteoglycans. We demonstrate that chondroitin sulphates exhibit remarkable connective tissue specificity and furthermore provide evidence that some proteoglycans may predominantly carry only one type of chondroitin sulphate chain.

Connective tissue activation. XXV. Regulation of proteoglycan synthesis in human synovial cells.

In this study, virtually all sulfated glycosaminoglycan (GAG) synthesized and secreted by human synovial cells, both normal and rheumatoid, was detected in the form of proteoglycans of monomeric size. Enzyme hydrolysis studies that were performed demonstrated dermatan sulfate to be the dominant GAG in the proteoglycan, with lesser amounts of chondroitin 4/6 sulfate. Exposure to beta-xyloside, used as a false "core protein," resulted in marked enhancement of GAG chain formation, suggesting that the synthesis of the sulfated carbohydrate chain itself was not rate limiting. Proteoglycan synthesis and secretion were stimulated by several types of connective tissue activating peptides (CTAP); CTAP-III stimulation of incremental core protein and glycosaminoglycan was shown to be of a similar magnitude. Since chain synthesis was not rate limiting, it is suggested that stimulated proteoglycan formation caused by the CTAP peptides may be primarily modulated through increased formation of core protein.

Ultrastructure of mucocartilage in the larval anadromous sea lamprey, Petromyzon marinus L.

The fine structure of mucocartilage, a tissue unique to larval lampreys, was examined in Petromyzon marinus L. This tissue is surrounded by a perichondrium of vascularized, dense connective tissue composed of fibroblasts, collagen fibrils, and elastic-like microfibrils, but it is avascular itself and consists of elastic-like microfibrils, ground substance, and a few diffusely scattered fibroblasts. Fibroblasts possess rough endoplasmic reticulum, may free ribosomes, a well-developed Golgi apparatus, a tubulo-vesicular network, and a number of secondary lysosomes containing crystalline material. The appearance of the organelles suggests the involvement of the cell in the synthesis and secretion of the ground substance and microfibrils. Tubular microfibrils, 11-13 nm in diameter, comprise the major portion of the matrix, and they are similar to those described in developing mammalian elastic tissue (Ross and Bornstein, 1969). The retention of the microfibrils may represent either a primitive form of elastic fiber in this "primitive" vertebrate or reflect the larval condition of the lampreys under examination. Scattered spherical to polyhedral-shaped mitrix granules and intergranular filaments make up the remainder of the matrix. It was concluded that mucocartilage in larval lampreys is not a conventional type of vertebrate connective tissue.

Coronary intimal necrosis occurring as an early stage of atherosclerotic involvement

In a population sample in whom violent accident was the cause of death, the following prevalence of coronary intimal necrosis, occurring as an independent lesion and as an early step of atherosclerotic involvement, was revealed: 2% of children 6–10 years old, 6% of children and juveniles 11–15 years old, 14% of adolescents 16–20 years old, 32% of young adults 21–25 years old, 56% of young adults 26–30 years old, 72% of mature adults 31–35 years old and 84% of mature adults 36–40 years old. In each age subgroup, the percentage of subjects with coronary intimal necrosis was greater than the percentage of subjects with coronary atherosclerotic plaques. A centrifugal extension with age of intimal necrosis, along the coronary tree in the direction of blood flow, was observed. Histologically, the coronary intimal necrosis exhibited a mucoid form, a swelling form and a dissecting form. Indirect evidence was offered that some areas of coronary intimal necrosis formed an adequate nidus for lipid and fibrin accumulation and also induced the development of a peculiar type of subendothelial connective tissue. These successive changes led to the onset of atheromalike lesions with a prevalence of lipid deposits, or of intramural thrombi or of a fibro-hyaline cap. The onset, extent and evolution of coronary intimal necrosis was accelerated by the male sex, by some minor deviations from the basal branching anatomical pattern of the coronary arteries, by the main risk factors for coronary heart disease, as well as by some terminal diseases, such as the generalized form of sarcoidosis and the renal complications of systemic lupus erythematosus.

Evaluation of different types of autotransplanted connective tissues as potential periodontal ligament substitutes: An experimental replantation study in monkeys

The purpose of the present study was to investigate connective tissue autotransplants as potential periodontal ligament substitutes. Green Vervet monkeys ( Cercopithecus aethiops) were used. Maxillary permanent central incisors were extracted, root filled extra-orally and the periodontal ligament removed from the root surface and the socket wall. Two circular cavities were prepared mesially and distally on the root surface. Different types of connective tissue autotransplants were then placed in these cavities, whereafter the teeth were replanted. The animals were sacrificed 8 weeks after replantation and the replanted teeth were examined histometrically. The connective tissue autotransplants were then examined for their capability of preventing root resorption or inducing or forming a new periodontal ligament, including periodontal fibers and cementum, Autotransplanted cutaneous and mucosal connective tissue as well as periosteum and fascia were all found to partially prevent ankylosis by forming a fibrous barrier between the root surface and the alveolus. However, no new cementum was formed. Periodontal ligament transplants, dental follicular tissue and possibly gingival connective tissue were the only tissues capable of both preventing ankylosis and forming a hard tissue on the surface of the cavity with a morphology similar to cementum. It is concluded that cementogenesis requires a highly specialized connective tissue. In this experiment, only odontogenic tissues had this capacity.

Incorporation of labeled cortisol into different types of connective tissue

The properties of early (BFUen) and late (CFUen) erythropoietin-independent progenitors were studied in bone marrow plasma clot cultures of mice. Syngeneic serum was used as a stimulant of colony formation. It was revealed that serum from polycytemic mice did not alter the efficacy of cloning the erythroid progenitors. Varying effects produced on erythropoiesis in vivo did not significantly change the number of CFUen and BFUen, with the exception of posttransfusion polycytemia where the number of CFUen showed a statistically significant rise. Assessment of radiosensitivity and proliferative activity of the erythroid progenitors showed that for CFUen D0=206 rad and n=1.3; for BFUen D0=118 rad and n=1.4; the proportion of proliferating CFUen was 42% +/- 12.5 and that of BFUen 46% +/- 4.5. The data obtained confirm the hypothesis of the erythropoietin-independent nature of the erythroid progenitors expressed under the culture conditions used.

The practical application of 3-methylhistidine in determining the lean meat content of food products

Protein-bound 3-methylhistidine, which is present at similar concentrations in various meat species but absent from non-meat proteins, was used to estimate the lean meat content of a range of retailed meat products. The results of the application of this novel method were compared and contrasted with those using standard methods of product analysis. The presence of textured soya protein in products was determined using polyacrylamide gel electrophoresis. Formulae for the calculation of the fat-free lean meat content on the bases of (i) the 3-methylhistidine index for muscle protein and (ii) the connective tissue content, are given. The lean meat contents of products calculated on these bases were found to be of the same order as, but generally lower than, those obtained using standard methods. This was considered to be due to the presence of non-meat proteins, of added connective tissue and/or certain types of offal. These would not be included in the lean meat content, as calculated by the 3-methylhistidine index, but could be legitimately included in the meat content calculated using standard methods according to current practice. A new interpretation of ‘meat’ in terms of 3-methylhistidine content is given.

Response of different types of connective tissue to hormones

A comparative study was made of the lysosomal glycosidases of the eye tissues (sclera and cornea) and also of bone tissue and cartilage from rabbits. Intraperitoneal injection of thyrocalcitonin (TCT), deoxycorticosterone (DOC), hydrocortisone (HC), and somatotropic hormone (STH) were shown to modify the activity of β-galactosidase, β-glucosidase, and hyaluronidase and the functional state of the lysosomal membranes in the tissues. HC and STH stabilize, whereas DOC and large doses of TCT labilize the lysosomal membranes. After injection of HC and STH the absolute activity of the enzymes in the tissue homogenates falls, whereas DOC has the opposite action.

Extraction and purification of proteoglycans from various types of connective tissue

A new procedure for the isolation of proteoglycans has been described. Tissues are extracted with 4 M guanidinium chloride. the extracting solven is then exchanged for 7 M urea and the extract is chromatographed on a DEAE-cellulose column previously equilibrated with 7 M urea. Non-proteoglycan proteins were eluted with urea in weak salt solutions. Subsequently proteoglycans were eluted with strong salt solutions. By the procedure proteoglycans from tissues containing only small amounts of proteoglycans can be obtained virtually free from collagen in a form suitable for further fractionation.

Arterial mesenchyme and arteriosclerosis. Some aspects of the organization and interaction of connective tissue proteoglycans.

Arterial mesenchyme, because of its micro-architecture and the variety of macromolecules it contains, is more complex than other types of connective tissue. In addition to collagen and elastin, it contains several glycosaminoglycans, including hyaluronic acid, dermatan sulphate, chondroitin-4-sulphate, chondroitin-6-sulphate and heparan sulphate, as well as glycoproteins that have yet to be fully characterized. These constituents are not distributed evenly through the arterial wall, but are localized in particular regions as shown by histological methods (reviewed by Muir, 1965). Presumably, therefore, each has a specific function related to the biomechanical and biochemical properties of the tissue.

Enhancement of axonal regeneration in the brain of the rat by corticotrophin and triiodothyronine

Rats with simple incised wounds of the telencephalon were treated for either 7 or 50 days with either sunthetic corticotrophin (ACTH) or triiodothyronine (T3). Control animals received no treatment. Regenerating axons, which entered and sometimes crossed the lesions, were detected histologically in rats treated with both hormones. The effects of both ACTH and T3 were mediated during the first 7 days after placement of the lesion. We suggest that ACTH, in suitable dosage, acts by allowing the formation of a suitable type of loose connective tissue in the lesion, while T3 increases the rate of synthesis of axoplasmic structural protein.

EFFECTS OF DRY AND MOIST HEAT ON SELECTED HISTOLOGICAL CHARACTERISTICS OF BEEF SEMIMEMBRANOSUS MUSCLE

ABSTRACT— Samples of raw and heat‐treated beef semimembranosus muscle were examined histologically to determine how deep‐fat frying, oven roasting, oven braising and pressure braising to 70°C affected histological characteristics of the muscle. A panel of three persons used an ocular micrometer to measure muscle fiber width, observed color and type of connective tissue and distribution of fat and estimated quantity of connective tissue of 475 histological sections. Differences among heat treatments in muscle fiber width and relative proportion of straight and wavy connective tissue were not significant. However, there was a significantly (P<0.05) larger quantity of granular tissue in deep‐fat fried, pressure braised, and oven braised samples than in oven roasted samples. Intact fat cell walls were observed in both raw and heated samples.

Eustachian tube of several mammalian species.

The histological structure of the eustachian tube of the opossum, mole, bat, man, cat, horse, sheep, rat, and rabbit was compared at the (1) pharyngeal opening, (2) midportion of the tube, and (3) entrance of the tube into the tympanic cavity. The tubes were compared to man and characterized in terms of (1) the type of epithelium, (2) type and distribution of glands, (3) distribution of the lymphoid area, (4) type of connective tissue or cartilage or both, and (5) the absence or presence of a diverticulum. Special emphasis was placed upon the histological details of the human tubal cartilage.

Early Morphological Changes Produced by Anti-inflammatory Steroids on Tissue Culture Fibroblasts

The fibroblast, a widely distributed cell of mesenchymal origin, is the most abundant cell type of loose connective tissue (1). Although these cells participate in many functions, their name refers to their ability to elaborate connective tissue fibers. The fibroblast's major activity is exhibited in the formation of new connective tissue components during growth, regeneration and repair (2). These cells have been shown, by Dougherty et al., to play a major part during the development of inflammatory reactions (3-5). Fibroblasts are extremely sensitive target cells to anti-inflammatory steroids (6-8). The growth inhibitory effects of anti-inflammatory steroids on conective tissue cells in vitro (6-10) and in vivo (11, 12) is a well-known phenomenon. The following is a description of the early morphological changes occurring in tissue culture fibroblasts, in the presence of the most potent naturally occurring steroid, Cortisol, and the most potent topical synthetic anti-inflammatory steroid, fluocinolone acetonide (13-15).

The organization of the connective tissue of Discocelides langi, (Turbellaria, polycladida)

The organization of the connective tissue of the polyclad turbellarian Discocelides langi has been studied using light microscopical, histochemical and electron microscopical techniques. Filamentous components are found in the subepidermal membrane and in the body, especially around muscle cells. The subepidermal membrane is complex, consisting of an outer limiting component and the membrane proper. The membrane proper is composed of filamentous lamellae. The filaments, probably belonging to the collagen family of proteins, form an orthogonally arranged grid system. Large amounts of ground substance are found in the interior of the body. Histochemical observations indicate that it probably consists of both neutral and acid polysaccharides in combination with protein components. On electron micrographs it presents itself as a finely granular to fibrillar net-like material of low density. A frequently occurring component is a prominent system of membranous strands, composed of polysaccharide-protein materials. They are in continuity with and similar to cellular mucous coats or glycocalyx components. The inherent difficulties in identification of connective tissue cells are discussed. In the peripheral parts of the animal, cells which are closely apposed, and reminiscent of planarian fixed parenchyma cells are found. In the interior parts cells similar to these are present but are embedded in ground substance. The cells often are large and branched and contain a cytoplasm with few organelles and of very low density on electron micrographs. Another type is strongly basophilic due to a high content of RNA. The fine structural morphology is very varied but is always characterized by the presence of a great number of ribosomes, either free or membranebound. This type possibly represents the formative cells responsible for synthesis of protein filaments and ground substance. The connective tissue system found is discussed in relation to other types of turbellarian connective tissue. Also the functional implications are commented on.

Histo-Immunological Detection of Collagen Fractions

SummaryThe soluble and insoluble fractions of collagen from chicken leg tendon were used as antigens to induce corresponding antibodies in adult rabbits and guinea pigs. Antibodies were checked immuno-sero-logically and the globulins or its gamma fraction labeled with fluorescein isothiocyanate and purified with Sephadex. Adequately controlled Coons' technique was used in order to detect the presence of the antigen in different types of connective tissue of adult chickens. It was observed: 1) as previously demonstrated, there was cross reaction between the neutral-soluble and the citrate-soluble fractions, whereas a direct reaction occurred with the insoluble collagen fraction, 2) the fluorescent antibodies against these different fractions reacted similarly with the collagen fibers and bundles but not with reticulin and elastic fibers, mucopolysaccharides, basement membranes, nor with matrix of cartilage and bone, 3) intensity of fluorescence was higher with the fibers of dense connective tissue as compa...