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PubMed2002

Cells of the connective tissue differentiate and migrate into pollen sacs.

In angiosperms, archesporial cells in the anther primordium undergo meiosis to form haploid pollen, the sole occupants of anther sacs. Anther sacs are held together by a matrix of parenchyma cells, the connective tissue. Cells of the connective tissue are not known to differentiate. We report the differentiation of parenchyma cells in the connective tissue of two Gordonia species into pollen-like structures (described as pseudopollen), which migrate into the anther sacs before dehiscence. Pollen and pseudopollen were distinguishable by morphology and staining. Pollen were tricolpate to spherical while pseudopollen were less rigid and transparent with a ribbed surface. Both types were different in size, shape, staining and surface architecture. The ratio of the number of pseudopollen to pollen was 1:3. During ontogeny in the connective tissue, neither cell division nor tetrad formation was observed and hence pseudopollen were presumed to be diploid. Only normal pollen germinated on a germination medium. Fixed preparations in time seemed to indicate that pseudopollen migrate from the connective tissue into the anther sac.

Asteraceae↗

PubMed1989

Association of fibronectin with the microfibrils of connective tissue.

The association of fibronectin with the microfibrils of connective tissue was examined in the zonular fibers of the mouse eye by immunohistochemical methods at the light and electron microscopic level. Mouse eyes fixed in formaldehyde were embedded either in paraffin for immunostaining by the peroxidase-antiperoxidase (PAP) method or in Lowicryl for immunolabeling by antirabbit globulin antibodies bound to 5 or 15 nm gold particles. Ultrastructural studies were also carried out after glutaraldehyde perfusion. Both the PAP and immunogold procedures demonstrated the association of fibronectin with microfibrils. After immunolabeling with 5 nm gold particles, examination at high magnification localized fibronectin to fine filaments that appeared to be attached to the surface of microfibrils. The filaments extended outward singly or formed loose aggregates. Their diameter ranged from 1.2 to 3 nm, with a mean of 1.5 nm. Because of their similarity to the fibronectin molecules previously described after rotary shadowing, the filaments were likely to be fibronectin molecules themselves. Since fibronectin is known to have high affinity for the amyloid P component, a model is presented in which fibronectin filaments are bound to the amyloid P component making up the tubular core of microfibrils in mice. Evidence is presented that fibronectin filaments may link microfibrils to one another and thus insure the continuity and strength of zonular fibers. More generally, it is likely that connective-tissue microfibrils, whether or not inserted into elastic fibers, are bonded through fibronectin to surrounding cells, collagen fibrils, or proteoglycans, and thus insure cohesion among connective tissue elements.

Actin Cytoskeleton↗

PubMed1981

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 extraorally 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.

Animals↗

PubMed1998

Air oesophagogram: a frequent, but not a specific sign of oesophageal involvement in connective tissue diseases.

OBJECTIVE: This study investigates the role of the air oesophagogram in conventional chest X-rays for the diagnosis of oesophageal dysmotility in patients with connective tissue diseases. METHODS: Fifty-one patients with connective tissue diseases were studied by oesophageal manometry and lateral and posterior-anterior chest X-rays. The presence or absence of oesophageal air on chest X-rays were evaluated separately in the upper, middle and distal segment of the oesophagus. Forty-seven chest X-rays of patients without connective tissue diseases, who had undergone manometry for the evaluation of oesophagus-related symptoms and who had normal oesophageal function, were analysed as a control. RESULTS: A total of 23/51 patients with connective tissue diseases showed oesophageal dysfunction in manometry; 16/51 patients (31%) had air in two or more oesophageal segments on the lateral chest X-ray. There was a significant association of manometrically proven oesophageal dysmotility and air in two or three oesophageal segments (P < 0.05; sensitivity 48%, specificity 82%). However, the prevalence of an air oesophagogram showed no significant difference between patients with connective tissue diseases and the control group (10/47; 21%). CONCLUSION: The radiological sign of an air oesophagogram is neither sensitive nor specific enough to omit oesophageal motility studies in patients with connective tissue diseases.

Air↗

PubMed1983

Overlapping connective tissue diseases in children.

Of 18 children with different connective tissue diseases four were found to have overlaps. Two presented features of SLE and PSS or SLE and PM and 2 had features of SLE, PSS and JRA. In two of them antiribonucleoprotein antibodies were detected by radical immunodiffusion. But these antibodies were also detected in a few children suffering from a single connective tissue disease. On the other hand, the six children with anti-RNP were not characterized by a particular clinical picture or a better prognosis; when compared to adults, no significant difference could be observed except that the Raynaud phenomenon, sausage fingers and myositis seemed less frequent in childhood. It may be concluded that combinations of connective tissue disease can occur in children but anti-RNP does not appear as a good biological marker.

Adolescent↗

PubMed2005

Expression of connective tissue growth factor is a prognostic marker for patients with intrahepatic cholangiocarcinoma.

BACKGROUND AND AIMS: Connective tissue growth factor is a member of the 'CCN' protein family. Consistent with its profibrotic properties, it is over-expressed in several human epithelial malignancies. PATIENTS AND METHODS: We have retrospectively evaluated by immunohistochemistry the presence of connective tissue growth factor in archival tissues from 55 resected intrahepatic cholangiocarcinomas and compared its expression to the main pathological parameters, disease free and overall survival. RESULTS: Tumours were scored as high and low/absent expressers (> or =50%, 0-50% cells, respectively). Thirty-three of 55 cholangiocarcinomas (60%) were high and 22 (40%) low expressers. No significant correlation was found between connective tissue growth factor and tumour grade, tumour location, vascular and perineural invasion. Eighteen of 22 (82%) low/absent expressers and 12/33 (36%) high expressers had recurrence of disease (P=0.001). Low/absent expressers showed a poor disease free and overall survival compared with the higher expressers (P<0.001). Vascular invasion was related to tumour recurrence (P=0.025) and to decreased disease free survival (P<0.05). During proportional hazard regression analysis, only connective tissue growth factor was found to influence disease free survival (P=0.01). CONCLUSIONS: Expression of connective tissue growth factor is an independent prognostic indicator of both tumour recurrence and overall survival for intrahepatic cholangiocarcinoma patients regardless of tumour location, tumour grade, vascular and perineural invasion.

Adult↗

PubMed1976

Defects in the biochemistry of collagen in diseases of connective tissue.

The collagens are the major structural glycoproteins of connective tissues. A unique primary structure and a multiplicity of post-translational modification reactions are required for normal fibrillogenesis. The post-translational modifications include hydroxylation of prolyl and lysyl residues, glycosylation, folding of the molecule into triple-helical conformation, proteolytic conversion of precursor procollagen to collagen, and oxidative deamination of certain lysyl and hydroxylysyl residues. Any defect in the normal mechanisms responsible for the synthesis and secretion of collagen molecules or the deposition of these molecules into extracellular fibers could result in abnormal fibrillogenesis; such defects could result in a connective tissue disease. Recently, defects in the regulation of the types of collagen synthesized and in the enzymes involved in the post-translational modifications have been found in heritable diseases of connective tissue. Thus far, the primary heritable disorders of collagen metabolism in man include lysyl hydroxylase deficiency in Ehlers-Danlos syndrome type VI, p-collagen peptidase deficency in Ehlers-Danlos syndrome type VII, decreased synthesis of type III collagen in Ehlers-Danlos syndrome type IV, lysyl oxidase deficency in S-linked cutis laxa and Ehlers-Danlos syndrome type V, and decreased synthesis of type I collagen in osteogenesis imperfecta.

Aortic Diseases↗

PubMed1994

Connective tissue forces from mandibular advancement.

PURPOSE: To quantify the connective tissue forces generated during surgical lengthening of the mandible. PATIENTS AND METHODS: Sixty-three patients who had mandibular advancements by sagittal ramus osteotomy were used in this study. Prior to sectioning the rami, the overjet was recorded. After sectioning the rami, a spring-gauge was attached to the mandibular orthodontic wire and pulled anteriorly to determine how much force was necessary to bring the mandibular incisors into a Class I relationship with the maxillary incisors. Aggressive stripping of the perimandibular periosteum and connective tissues on the distal segment was then performed. The amount of force was again recorded. RESULTS: The mean preoperative overjet in the 63 patients was 6 mm (range, 3 to 11 mm). The mean amount of force required to advance the mandible prior to stripping the tissues was 1,498 g compared with a mean of 787 g after stripping (P < .001). There were statistically significant correlations between the preoperative overjet and the prestripping and poststripping force levels (P < .001). There was also a significant relationship between prestripping and poststripping values (P < .001). CONCLUSION: The results of this study indicate that orthopedic forces are generated by the perimandibular connective tissues following advancement by the mandible. The effect of these forces on the temporomandibular joint should be evaluated in future studies.

Bone Resorption↗

PubMed1979

Biochemistry of the elastic fibers in normal connective tissues and its alterations in diseases.

The elastic fibers present in various connective tissues of the body are responsible for physiologic elasticity of the organs. These fibers consist of 2 distinct components, elastin and the elastic fiber microfibrils. Controlled synthesis and balanced interaction of these 2 components are essential for normal fibrillogenesis. The intracellular biosynthesis of elastin by connective tissue cells, such as smooth muscle cells, involves assembly of the polypeptide chains on the membrane-bound ribosomes, hydroxylation of some prolyl residues to hydroxyproline, and secretion of the polypeptides packaged in Golgi vacuoles. In the extracellular space the elastin molecules assemble into fiber structures which are stabilized by the synthesis of complex covalent cross-links, desmosines. Recently, aberrations in the structure or metabolism of elastin have been detected in a variety of heritable and acquired diseases affecting skin and other connective tissues. These conditions include pseudoxanthoma elasticum, cutis laxa, and elastosis perforans serpiginosa, as well as arteriosclerosis and other degenerative changes of the vascular connective tissues.

Amino Acids↗

PubMed2006

Effects of periodontal cell grafts and enamel matrix proteins on the implant-connective tissue interface: a pilot study in the minipig.

We have developed an experimental model to help identify and characterize factors necessary for periodontal connective tissue attachment formation on dental implants. In this pilot study, we report the effect of autogenous periodontal cell grafts, with and without the a pplication of enamel matrix derivative (EMD), on the implant-connective tissue interface. Periodontal ligament (PDL) and gingival connective tissue (GCT) cultures were established from an adult minipig. Implants were placed in osteotomies prepared with exaggerated countersinks that served as recipient sites for autogenous cell grafts in bilateral edentulated posterior mandibular sextants. In addition, 1 side received an application of EMD before placement of the autogenous cell grafts. A bioabsorbable membrane covering the coronal portion of the implants was placed before closure. After 8 weeks, quantitative histomorphometric and qualitative light microscopic analyses revealed that the implants that received gelatin vehicle alone were surrounded by bone, whereas the implants that received GCT cell grafts were mostly surrounded by fibrous connective tissue. In contrast, implants that received PDL cells without the application of EMD demonstrated good bone contact, but strands of epithelium were observed in the implant-connective tissue interface. Implants that received PDL cells and EMD also had good bone contact but without evidence of epithelium. A cementum-like interface was not observed in any of the groups. Results of this pilot study suggest that EMD and the type of cell populations present in the implant wound-healing environment may alter the implant-connective tissue interface.

Animals↗

PubMed1992

The role of connective tissue in inhibiting epithelial downgrowth on titanium-coated percutaneous implants.

Ideally, the surface of epithelium-penetrating implants should impede apical epithelial migration. Previous studies have shown that micromachined grooved surfaces can produce connective-tissue ingrowth, which inhibits epithelial downgrowth on percutaneous implants [Chehroudi et al., J. Biomed. Mater. Res., 24, 9, (1990)]. However, in those studies, connective tissue and epithelium interacted with the same surface so that the effects of the surfaces on each population could not be determined separately. The objectives of this study were (a) to examine cell behavior on implants in which connective tissue contacted surfaces of various topographies and epithelium encountered only a smooth surface, and (b) to compare one-stage and two-stage surgical techniques. Implants had a base component (BC) which was either smooth or had a surface with 19-micron- or 30-micron-deep grooves or 120-micron-deep tapered pits, and a skin-penetrating component (SPC) which was smooth. In the two-stage technique, the BC was implanted subcutaneously for 8 weeks, which permitted the healing of the peri-implant connective tissue. In the second stage the SPC was connected to the BC. For one-stage implants, BC & SPC were connected and implanted percutaneously. Implants (BC & SPC) were removed 1, 2, or 3 weeks after percutaneous implantation and histological sections were measured for recession, connective tissue and epithelial attachment as well as capsule thickness. Light microscopy indicated that both grooved and tapered pitted surfaces encouraged connective tissue ingrowth. On the grooved surfaces, the orientation of fibroblasts changed from an oblique to a more complex pattern which included cells having round nuclei within the grooves, as well as cells oriented oblique or perpendicular to the grooves. In the tapered pits a hammock-like arrangement of fibroblasts was observed. In some cases, foci of mineralization and formation of bonelike tissue were found on the grooved and pitted surfaces. The apical migration of the epithelium was significantly (p less than 0.05) inhibited by those micromachined surfaces which produced connective tissue ingrowth to the BC. This study found that placing the implants in two stages improved the performance of percutaneous devices, and that a further improvement was achieved if the implant had a surface promoting connective tissue ingrowth.

Animals↗

PubMed1989

[The microtexture of amnion and chorion connective tissue].

On microscopical, stereo-scan and TEM observations the microtexture of the connective tissue of amnion and chorion have been analysed. The "compact layer" of the amnion-connective tissue consists of single collagen fibrils, which are arranged felt-like in parallel layers. In the "fibroblast layer" the fibrils are mostly arranged in bundles, forming a network. Single fibrils and bundles of fibrils in both layers are arranged surface parallel. The superficial layer of the chorion's connective tissue is predominated by wave-like bundles of fibrils in parallel and latticed arrangements, which are consolidated by transversely and diagonally running fibres. In the inferior layer the fibres leave their formation, run diagonally in the direction of the trophoblast and interweave with each other to a mat of fibrils at the border to the trophoblast. The tensile strength of the amnion connective tissue is due to the felt-like fibril texture of the "compact-layer" and the special arrangement of surface-parallel collagen fibres and fibrils.

Amnion↗

PubMed1999

[Connective tissue diseases in the hospital outpatient service in Lomé (Togo)].

PURPOSE: There have been few studies of connective tissue diseases in Africa. METHODS: A retrospective study was conducted in order to describe the various connective tissue diseases and their semiological profile in patients attending the dermatology and rheumatology units at Lomé hospital. RESULTS: Clinical examinations showed that eighty-four (0.2%) out of the 34,169 patients were suffering from connective tissue diseases. Diseases that were encountered were the following: scleroderma (18 cases), systemic lupus erythematosus (four cases), discoid lupus erythematosus (15 cases), rheumatoid arthritis (29 cases), polymyositis and dermatomyositis (16 cases), juvenile rheumatoid arthritis (one case), giant cell arteritis (one case). Raynaud's syndrome was present in six out of the 18 patients suffering from scleroderma. Nephrotic syndrome was observed in a patient suffering from systemic lupus erythematosus. A septicemia caused this patient's death. Two patients suffering from polymyositis had cancer. No etiology was found in the 14 other patients. Hip involvement was present in two patients suffering from rheumatoid arthritis. Patients with rheumatoid arthritis had no systemic involvement (nodulitis, vasculitis). CONCLUSION: Our results are in agreement with those of previous studies on connective tissue diseases in Africa. However, further studies are required to better understand the epidemiological and semiological profiles of connective tissue diseases in Africa.

Adolescent↗

PubMed2000

Effect of in vitro testing over extended periods on the low-load mechanical behaviour of dense connective tissues.

Many biomechanical studies are performed on dense connective tissues in the laboratory over a substantial time period; however, the effect of the in vitro testing environment on the cyclic load-relaxation behaviour of these structures is not well established. This study evaluated the effect of long duration of testing on ligament viscoelastic behaviour, using the rabbit femur-medial collateral ligament-tibia complex as a model. Dissected rabbit knee joints were mounted on a materials testing machine, and isolated ligament complexes were cycled at a frequency of one cycle/min to a fixed displacement of 0.7 mm for an 18-hour period. After an initial period of exponential load relaxation, the cyclic peak loads slowly decreased over the 18-hour period. The average decrease in the cyclic peak load between 0.5 and 18.0 hours was 0.26% (of the original peak load) per hour (r2 = 0.934), or a total of 8.6+/-4.6% over this period (p < 0.0001). Thus, low-load testing of dense connective tissues in the laboratory over extended periods significantly alters their biomechanical behaviour, and these changes should be considered in long-term laboratory-based studies of dense connective tissues.

Animals↗

PubMed1982

Connective tissue composition of the equine sarcoid.

The connective tissue composition and organisation of the "equine sarcoid" was compared with that of normal adult equine skin to determine whether the cells which produce their respective connective tissue matrices show similar biosynthetic characteristics. No major qualitative difference could be found between the collagen compositions of skin and sarcoid material, although the organisation into fibres of Type III collagen in the sarcoid was markedly greater than that of skin.

Animals↗

PubMed2004

Proliferative activities of epithelial and connective tissue cells in the rat periodontal regeneration using argyrophilic nucleolar organizer regions staining.

BACKGROUND AND OBJECTIVE: It is still an open question why long junctional epithelium can proliferate and occupies the root surface following periodontal surgery or experimentally produced periodontitis, and why the epithelium repopulated once on the root surface is replaced by the connective tissue. The aim of this study is to investigate the proliferative activity of the newly formed regenerative connective tissue and long junctional epithelium during wound healing by staining argyrophilic proteins of the nucleolar organizer regions (AgNORs). METHODS: Regenerative connective tissue and long junctional epithelium were experimentally created by insertion of a rubber piece between maxillary molars of rats for 1 week. After removal of the rubber, AgNORs parameters including nuclear area (NA), AgNORs area (AA), AgNORs percentage nuclear area (APNA), AgNORs number (AN) and nuclear number (NN) in regenerative connective tissue and long junctional epithelium were measured and analyzed statistically. RESULTS: APNA in long junctional epithelium after 1 and 4 weeks was over two times greater than that in the regenerative connective tissue. AA in long junctional epithelium was significantly higher than in regenerative connective tissue at 1 and at 4 weeks post-treatment. AN was higher in the central portion than at the root surface except at 20 weeks. APNA and AA decreased remarkably in long junctional epithelium at 12 weeks post-treatment (approximately half at 4 weeks), whereas in regenerative connective tissue, they did not change distinctly. CONCLUSIONS: These results imply that long junctional epithelium cannot supply sufficient epithelial cells because of their significantly low rates of proliferation, consequently long junctional epithelium becomes shorter after 12 weeks, whereas the proliferative activity of regenerative connective tissue maintains the same level of proliferation, and ultimately long junctional epithelium is replaced by regenerative connective tissue.

Animals↗

PubMed1990

A possible receptor-binding function for the N-terminus of connective tissue activating peptide III.

Connective tissue activating peptide III (CTAP-III) is an 85-residue peptide which has been purified from platelets and shown to possess mitogenic activity toward a variety of fibroblastic cell lines. beta-Thromboglobulin (beta TG) is an 81-residue peptide which is derived from CTAP-III by cleavage of the N-terminal tetrapeptide Asn-Leu-Ala-Lys which results in the loss of mitogenic activity. The near-UV CD spectra for the two proteins indicated that the conformations as well as the electronic environments of the two disulfide bonds, and also of the single aromatic tyrosine residue, were similar in CTAP-III and beta TG. However, differences in the far-UV CD spectra of these proteins indicated a substantial decrease in alpha-helical content for beta TG (29%) as compared to CTAP-III (38%). Structure prediction analysis also suggested that the longer N-terminal segment of CTAP-III may form an alpha-helix. The N-terminal region of beta TG, which lacks this tetrapeptide, was predicted to be in an unordered, or possibly a turn, conformation. This predicted structural difference appears to be due to the high helix-forming potential of the N-terminal tetrapeptide Asn-Leu-Ala-Lys in CTAP-III. These results suggest a possible structural role for the N-terminal region of CTAP-III in the expression of the biologic activities of this protein. On the basis of these studies, a reasonable hypothesis to account for the difference in mitogenic activity between beta TG and CTAP-III is that the N-terminal region must be helical for receptor binding to occur.

Amino Acid Sequence↗

PubMed1992

Pulmonary function in childhood connective tissue diseases.

The term connective tissue diseases (CTD) defines a group of illnesses characterized by the presence of immune abnormalities and by widespread inflammation involving various organs and tissues including the lung. These diseases are not frequent in the paediatric age group. Very few data on pulmonary function are available in paediatric CTD. We investigated possible early lung function abnormalities and any likely relationship with clinical activity of the disease in a group of 81 paediatric CTD patients, without clinical or radiological evidence of pulmonary involvement. Measurement of lung volumes and diffusion lung capacity were performed. A sample of 65 subjects, defined as normal on the basis of history and clinical examination, and matched by age and height with the group of patients, was chosen as control group. CTD patients did not show significant deviations from the control distribution with respect to functional residual capacity (FRC) and maximal expiratory flow at 75% of the forced vital capacity (MEF75) values. On the contrary, both vital capacity (VC) and diffusing capacity of the lungs for carbon monoxide (DLCO) were quite impaired in most CTD during the active phase of the disease. Our results show a functional lung impairment in most children with clinically active CTD, even in absence of abnormalities on chest X-ray pictures.

Adolescent↗