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At least 217 records · Page 12Linked to original sources
PubMed2002

Tissue factor production not balanced by tissue factor pathway inhibitor in sepsis promotes poor prognosis.

OBJECTIVE: To determine the precise relationship among tissue factor, tissue factor pathway inhibitor (TFPI), and neutrophil elastase in sepsis, as well as to test the hypothesis that low TFPI concentrations are not sufficient to prevent tissue factor-dependent intravascular coagulation, leading to multiple organ dysfunction syndrome and death. DESIGN: Prospective, cohort study. SETTING: General intensive care unit of tertiary care emergency department. PATIENTS: Thirty-one consecutive patients with sepsis, classified as 15 survivors and 16 nonsurvivors. Ten normal, healthy volunteers served as controls. INTERVENTIONS: None. MEASUREMENTS AND MAIN RESULTS: Tissue factor antigen concentration (tissue factor), TFPI, neutrophil elastase, and global variables of coagulation and fibrinolysis were measured on the day of diagnosis of sepsis, severe sepsis, and septic shock and days on 1-4 after diagnosis. The number of systemic inflammatory response syndrome criteria that patients met and the disseminated intravascular coagulation score were determined simultaneously. The results of these measurements were compared between the survivors and the nonsurvivors. In the nonsurvivors, significantly higher concentrations of tissue factor and neutrophil elastase were found compared with the survivors and control subjects. However, the TFPI values showed no difference between the two groups. No correlation was found between the peak concentrations of tissue factor and TFPI. Disseminated intravascular coagulation scores and numbers of the SIRS criteria met by the survivors significantly decreased from day 0 to day 4, but those of the nonsurvivors did not improve during the study period. The nonsurvivors showed thrombocytopenia and higher numbers of dysfunctioning organs than did the survivors. CONCLUSIONS: We systematically elucidated the relationship between tissue factor and TFPI in patients with sepsis, severe sepsis, and septic shock. Activation of tissue factor-dependent coagulation pathway not adequately balanced by TFPI has important roles in sustaining DIC and systemic inflammatory response syndrome, and it contributes to multiple organ dysfunction syndrome and death. High concentrations of neutrophil elastase released from activated neutrophils may explain, in part, the imbalance of tissue factor and TFPI in sepsis.

Adult↗
PubMed1996

Cost and outcome of osteocutaneous free-tissue transfer versus pedicled soft-tissue reconstruction for composite mandibular defects.

Thirty-nine patients underwent reconstruction of composite mandibular defects following resection for squamous cell carcinoma. Thirty-four underwent immediate reconstruction, while 5 were reconstructed secondarily. Twenty-one received soft-tissue reconstruction only with a pectoralis major myocutaneous flap, 14 underwent osteocutaneous free-tissue transfer, and 4 received a reconstruction plate with free-tissue transfer for soft-tissue coverage. The mandibular defects in the pectoralis major myocutaneous flap group tended to be posterolateral, while free-tissue transfer defects were more severe, usually involving the anterior mandible. Length of surgery and duration of intensive care unit care were significantly longer for free-tissue transfer patients, while flap complications were more common in the pectoralis major myocutaneous flap patients. Facial appearance scores were higher for the free-tissue transfer group by both patient and physician assessment. Social function, speech, and oral function did not differ significantly. Patients reconstructed secondarily with free-tissue transfer reported significant improvement in appearance, oral continence, and social function, with little change in speech intelligibility, deglutition, or diet tolerance. The cost of the main hospitalization was significantly higher in the free-tissue transfer group than in the pectoralis major myocutaneous flap group, although when the costs of subsequent hospitalizations are included, the difference in total cost narrows. Despite more adverse defects, free-tissue transfer provided more predictable aesthetic results and expeditious return to normal social function than did pectoralis major myocutaneous flap reconstruction. The fiscal impact of these complex reconstructions is, however, significant. Cost-containment issues are presented and recommendations are made.

Aged↗
PubMed2005

Post-surgical assessment of excised tissue from patients with Buruli ulcer disease: progression of infection in macroscopically healthy tissue.

OBJECTIVE: The current standard of treatment of Buruli ulcer disease (BUD) is surgical excision of lesions. Excision size is determined macroscopically assuming the complete removal of all infected tissue. However, dissemination of infection beyond the excision margins into apparently healthy tissue, possibly associated with recurrences, cannot be excluded in this way. To assess the central to peripheral progression of Mycobacterium ulcerans infection and the mycobacterial infiltration of excision margins, excised tissue was examined for signs of infection. METHODS: 20 BUD lesions were excised in general anaesthesia including all necrotic and subcutaneous adipose tissue down to the fascia and at an average of 40 mm into the macroscopically unaffected tissue beyond the border of the lesion. Tissue samples were subjected to PCR and histopathology. RESULTS: Although the bacillary load decreased from central to peripheral, M. ulcerans infection was detected throughout all examined tissue specimens including the peripheral segments as well as excision margins of all patients. During the post-operative hospitalization period (averaging 2 months) no local recurrences were observed. CONCLUSION: Available data suggest a correlation of surgical techniques with local recurrences. The results of this study indicate the unnoticed early progression of mycobacterial infection into macroscopically healthy tissue. Thus, the removal of all infected tissue cannot always be verified visually by the surgeon. Provided that long-term follow up of patients with positive excision margins will establish the clinical relevance of these findings, on-site laboratory assessment of excised tissue in combination with follow up may contribute to reduce recurrence rates.

Adolescent↗
PubMed2001

Detection of Mycobacterium tuberculosis group organisms in human and mouse joint tissue by reverse transcriptase PCR: prevalence in diseased synovial tissue suggests lack of specific association with rheumatoid arthritis.

Infection with mycobacterial species, including Mycobacterium tuberculosis, has long been implicated in the etiopathology of rheumatoid arthritis (RA) on the basis of clinical and pathological similarities between tuberculosis and RA. Despite evidence of immune responses to mycobacterial antigens in RA patient synovial fluid, cross-reactivity between these and host joint antigens, and the presence of M. tuberculosis protein antigen in RA synovial fluid, a definite causal association with RA has not been shown. Previous studies from our laboratory using reverse transcriptase PCR (RT-PCR) of bacterial rRNAs have shown RA synovium to be colonized by a diverse range of bacteria, most of commensal origin. However, M. tuberculosis group organism (MTG) RNA sequences were found in one RA patient tissue. Since this was considered of sufficient interest to warrant further investigation, we devised a M. tuberculosis-specific nested RT-PCR test which could be used for detection of MTG in a mixed pool of bacterial crDNAs. This test was used to investigate the distribution of MTG in RA synovial tissue and also non-RA arthritis and healthy control tissues and was also used to examine the tissue distribution of MTG in an acute and chronic model of M. tuberculosis infection in the BALB/c mouse. MTG sequences were found in a high proportion of RA patient synovial tissues but also in non-RA arthritis control tissues at lower frequency. This likely reflects trafficking of persistent M. bovis BCG to inflamed joint tissue, irrespective of cause. MTG were not found in healthy synovial tissue or the tissue of patients with undifferentiated arthritis. In both the acute and chronic models of infection in BALB/c mice, M. tuberculosis was also found to have trafficked to joint tissues, however, no signs of inflammation, arthritis, or pathology associated with M. tuberculosis infection was seen. These combined results would argue against a specific causal role of MTG in RA-like arthritis; however, their role as adjuvant in immune dysfunction in an innately susceptible host cannot be excluded.

Acute Disease↗
PubMed1999

LDL increases inactive tissue factor on vascular smooth muscle cell surfaces: hydrogen peroxide activates latent cell surface tissue factor.

BACKGROUND: Tissue factor, which is required for the initiation of the extrinsic coagulation cascade, is known to be upregulated in cells within atherosclerotic lesions, including smooth muscle cells. Tissue factor expression on the smooth muscle cell surface could be of pathological significance as a contributor to plaque growth, thrombus formation, and the acute coronary syndrome after plaque rupture. METHODS AND RESULTS: In this study, we show that LDL increased tissue factor mRNA and cell surface protein in smooth muscle cells without a marked increase in surface tissue factor activity. Hydrogen peroxide activated tissue factor on the cell surface but did not increase tissue factor mRNA or cell surface protein. Sequentially added LDL and hydrogen peroxide increased mRNA, cell surface protein, and activity; surface activity was greater than that observed with hydrogen peroxide alone. The action of hydrogen peroxide did not involve a regulatory mechanism associated with the cytoplasmic tail of tissue factor because a truncated tissue factor lacking the cytoplasmic tail was activated by hydrogen peroxide. CONCLUSIONS: These results suggest a novel 2-step pathway for increased tissue factor activity on smooth muscle cell surfaces in which lipoproteins regulate synthesis of a latent tissue factor and oxidants activate the protein complex.

Animals↗
PubMed1996

Intravenous somatic gene transfer with antisense tissue factor restores blood flow by reducing tumor necrosis factor-induced tissue factor expression and fibrin deposition in mouse meth-A sarcoma.

Fibrin is deposited on the endothelial cell surface in the vasculature of murine methylcholanthrene A-induced sarcomas after injection of tumor necrosis factor (TNF). Capillary endothelial cells of the tumor vascular bed become positive for tissue factor after TNF injection, based on immunocytochemistry and in situ hybridization. Intravascular clot formation was not dependent on tissue factor derived from tumor cells, since in vessels of tumors not expressing tissue factor, TNF also induced fibrin/fibrinogen deposition. However, the time course of fibrin/fibrinogen deposition after TNF differed in tumors expressing no, little, or greater amounts of tissue factor. Fibrin/fibrinogen deposition was more rapid in tumors in which the neoplastic cells expressed tissue factor than in tumors not expressing tissue factor. In the tumors not expressing tissue factor, activation of coagulation was dependent on TNF-induced synthesis of tissue factor by host cells, i.e., endothelium or monocytes/macrophages. Intravenous somatic gene transfer with tissue factor cDNA in the antisense orientation (but not sense or vector alone) reduced intravascular fibrin/fibrinogen deposition and restored blood flow to the tumor, showing that de novo tissue factor expression is central in TNF-induced activation of the coagulation mechanism.

Animals↗
PubMed2003

Comparison of conventional sonography, real-time compound sonography, tissue harmonic sonography, and tissue harmonic compound sonography of abdominal and pelvic lesions.

OBJECTIVE: The purpose of this study was to compare conventional sonography, real-time spatial compound sonography, tissue harmonic sonography, and tissue harmonic sonography merged with compound sonography for overall image quality, lesion conspicuity, and elimination of artifacts. SUBJECTS AND METHODS. In this study, 150 lesions in 122 randomly selected patients with various abdominal and pelvic lesions were evaluated. For each lesion, sonograms were obtained with four techniques: conventional sonography, real-time spatial compound sonography, tissue harmonic sonography, and tissue harmonic compound sonography. All images were reviewed and graded independently by two observers for overall image quality, lesion conspicuity, and elimination of artifacts. RESULTS: Statistical analysis showed that for overall image quality, lesion conspicuity, and elimination of artifacts, tissue harmonic compound sonography was significantly superior to all of the other techniques; real-time spatial compound sonography was better than tissue harmonic sonography; and conventional sonography was the least valuable of all (p < 0.001). When data were analyzed separately according to lesion types, tissue harmonic compound sonography was significantly superior for revealing stone diseases, liver cysts, gallbladder polyps, and uterine myomas. For the remainder of lesion groups, spatial compounding was superior to tissue harmonic sonography for all aspects of evaluation, and conventional sonography was the least valuable (p < 0.05). CONCLUSION: In abdominal and pelvic scanning, tissue harmonic compound sonography provides the best overall image quality, best lesion conspicuity, and least artifacts of all the evaluated imaging modes. Spatial compound sonography is better than tissue harmonic sonography for the evaluation of lesions in general, despite some differences among lesion groups.

Adolescent↗
PubMed1993

[Study on the enzymatic properties of N-acetyl-beta, D-glucosaminidase A (NAG A) from the tissue of renal cell carcinomas: comparison of the enzymatic properties with those of normal renal tissues, with special regard to sugar-chain structures].

The enzymatic properties of N-acetyl-beta,D-glucosaminidase A (NAG A) partially purified from the tissues of seven cases of human renal cell carcinomas were studied individually and compared with those of normal renal tissues. In the carcinoma tissues, the Km value of the enzyme toward a synthetic glucosaminide substrate was 0.180 +/- 0.07 mM, the optimal pH of the enzyme ranged from pH 4.7 to 4.9 and the enzyme showed fairly stable for metal ions. These enzyme characteristics were similar to those of the normal tissues. On the contrary, the sugar-chain structures of the enzyme from the carcinoma tissues studied by lectin affinity chromatographies, were statistically different from those of the normal tissues. Namely, both complex type of sugar-chains as well as hybrid type sugar-chains without fucose linkage to the innermost N-acetylglucosamine (GlcNAc) were significantly increased in the enzyme from the carcinoma tissues, while high mannose type sugar-chains and hybrid type sugar-chains with fucose linkage to the innermost GlcNAc were significantly decreased in the carcinoma tissues compared to the normal tissues. These results indicate that the processing of sugar-chains of the enzyme has possibly changed in the carcinoma tissues.

Acetylglucosaminidase↗
PubMed1999

Increased level of exon 12 alternatively spliced BRCA2 transcripts in tumor breast tissue compared with normal tissue.

The breast cancer susceptibility gene BRCA2 is expressed in a wide range of tissues as an 11-kb mRNA transcript encoding a 3418-amino acid protein, which is involved in the response to DNA damage. To obtain a better molecular characterization of BRCA2 expression in breast tissue, we analyzed full-length BRCA2 mRNA by means of reverse transcriptase-PCR with a panel of primer pairs encompassing the entire cDNA sequence. We report the identification of an exon 12 alternatively spliced BRCA2 transcript (delta12-BRCA2) in normal human breast tissue, in a wide variety of other normal human tissues, and in several mouse tissues. The deletion observed in this transcript (96 bp) preserves the open reading frame, and translation of the transcript would result in a BRCA2 isoform lacking 32 amino acids between codons 2280 and 2311. The analysis of matched normal and primary tumor breast tissues from 12 patients showed that the expression level of the delta12-BRCA2 transcript was higher in 4 of 12 (33%) tumor tissues compared with their normal breast tissues. Overproduction of the delta12-BRCA2 variant was associated with steroid receptor-negative tumors (P = 0.0005). These data suggest that the mechanisms generating the BRCA2 mRNA variant exist in normal breast tissue and may be dysregulated in steroid receptor-negative breast tumor tissues.

Alternative Splicing↗
PubMedDate not supplied

Reduced nonspecific steroidal esterase activity in human malignant tumor tissue from liver, colon and breast when compared to peritumoral and normal tissue levels.

The levels of a nonspecific steroidal esterase estimated as alpha naphthyl acetate esterase (ANAE) activity were measured in apparently normal (peritumoral) tissue of liver, colon and breast cancer patients, in malignant tumor tissue from the same patients and in normal colon tissue from healthy individuals who never had colon cancer. Cancer tissue from all three organs showed 35-79% reduced levels of ANAE activity when compared to peritumoral tissue of the same organ (p < 0.03). When ANAE activity of normal colon tissue from healthy individuals who never had colon cancer was compared with peritumoral colon tissue from colon cancer patients, which were combined with colonic biopsies from cancer-free patients previously operated on for colon cancer, a 50% reduced ANAE activity was observed in these tissues compared to the normal (p < 0.005). A highly significant reduction of enzyme activity was also found when malignant colon tissue from the cancer patients was compared to normal colon tissue from healthy individuals who never had colon cancer.

Adenocarcinoma↗
PubMed1996

Local deep tissue penetration of compounds after dermal application: structure-tissue penetration relationships.

Topically applied compounds can penetrate directly into deeper underlying tissues. In this report, an attempt has been made to establish structure-deep tissue penetration relationships for a variety of solutes with diverse physicochemical properties. Stepwise multiple linear regression analysis was performed with the concentration in the immediately overlying tissue, the solute molecular size and the octanol/water partition coefficient as independent variables. During the initial period of direct penetration, the concentration of any solute in a given tissue was dependent on the concentration in the preceding tissue. The presence of molecular weight and lipophilicity terms as independent variables improved the regressions for some tissues. The solute concentration in the deeper tissues of sacrificed animals was higher for the smaller solutes. Due to the dominance of solute clearance by blood perfusing the tissues, the dependence of solute concentrations in anesthetized animal tissues on size was less than observed for sacrificed animals. The predictions from these regression analyses yielded predictions similar to those based on a physiological pharmacokinetic model. However, only about 50% of the data was explained by both models. Based on the preliminary qualitative and quantitative analysis, deep tissue penetration of solutes after application, as aqueous solutions, to the epidermis is greater for smaller solutes with adequate lipophilicity.

Administration, Cutaneous↗
PubMed1999

In vivo analysis of microcirculation following closed soft-tissue injury.

Major loss of tissue is an almost invariable consequence of severe closed soft-tissue injury. Clinically, the extent of soft-tissue trauma determines the outcome of complex injuries and significantly influences bone healing. With use of a new animal model, this study quantitatively analyzed microcirculation, i.e., nutritive perfusion and leukocyte-endothelial cell interaction, in skeletal muscle after standardized closed soft-tissue injury. By means of a computer-assisted controlled-impact technique, a severe standardized closed soft-tissue injury was induced in the left hindlimb of 28 rats. The rats were assigned to four experimental groups (n = 7 per group) that differed by time of analysis (1.5, 24, 72, and 120 hours after injury); rats that were not injured served as controls (n = 7). Intramuscular pressure was measured, and microcirculation in the rat extensor digitorum longus muscle was analyzed by in vivo fluorescence microscopy, which allowed assessment of microvascular diameters, functional capillary density, number of rolling and adherent leukocytes in venules, and microvascular permeability. Edema weight gain was quantified by the ratio of wet to dry weight of the extensor digitorum longus muscle. Microvascular perfusion of the skeletal muscle was characterized by a significant reduction in functional capillary density, which was paralleled by an increase in capillary diameter throughout the 120 hours of observation when compared with the controls. Trauma-induced inflammatory response was reflected by a markedly increased rolling and adherence of leukocytes, primarily restricted to the endothelium of postcapillary venules; this was accompanied by increased microvascular permeability, indicative of a substantial loss of endothelial integrity. The microcirculation surrounding the core of the damaged tissue area resembled that of ischemia-reperfusion injury in skeletal muscle, i.e., heterogeneous capillary perfusion, pronounced microvascular leakage, and adherence of leukocytes. Enhanced vascular leakage and leukocyte adherence (24-72 hours after injury) coincided with the maximum intramuscular pressure (which was not indicative of compartment syndrome) and edema formation. These results demonstrate that initial changes, leading to ultimate tissue death, after closed soft-tissue injury are caused on the microcirculatory level. This standardized model provides further insight into microvascular pathophysiology and cellular interactions following closed soft-tissue injury. Thus, it is an adequate tool for testing novel therapeutic interventions.

Animals↗
PubMed1983

High-energy diets produce different effects on fatty acid synthesis in brown adipose tissue, white adipose tissue and liver in the rat.

The influence of feeding rats a high-energy diet for 7 days on fatty acid synthesis in brown adipose tissue, white adipose tissue and liver of the rat was investigated. The incorporation of 3H2O and [U-14C]glucose into fatty acid was measured in vivo. The rats fed the high-energy diets had higher rates of fatty acid synthesis in white adipose tissue than the controls fed on chow, while fatty acid synthesis in brown adipose tissue and liver was either decreased or unchanged relative to that of controls fed on chow. After an oral load of [U-14C]glucose the incorporation of radioactivity into tissue fatty acid was several-fold higher in brown adipose tissue than in white adipose tissue in rats fed on chow. In rats fed the high-energy diets, incorporation of radioactivity into fatty acid in brown adipose tissue was decreased while that into white adipose tissue was either increased (Wistar rats) or unchanged (Lister rats).

Adipose Tissue↗
PubMed1990

Lipogenesis in genetically diabetic (db/db) mice: developmental changes in brown adipose tissue, white adipose tissue and the liver.

Developmental changes in lipogenesis have been examined in interscapular brown adipose tissue (BAT), epididymal white adipose tissue and the liver of genetically diabetic (db/db) mice and their normal siblings. Lipogenesis was measured in vivo with 3H2O, from weaning (21 days of age) until 20 weeks of age. Hyperinsulinaemia was evident in db/db mice at all ages. Low rates of lipogenesis were observed at weaning in tissues of both groups of mice, but the rate rose rapidly in the first few days post-weaning. In normal mice, peak lipogenesis was obtained in each tissue at 4-5 weeks of age, and there were no major changes (on a whole-tissue basis) thereafter. A different developmental pattern was apparent in db/db mice. The rate of lipogenesis in BAT rose sharply after weaning, reaching a peak at 26 days of age (several times higher than normal mice), and then falling rapidly such that by 45 days of age it was lower than in normal mice; at age 20 weeks lipogenesis in BAT of the diabetic animals was negligible. In white adipose tissue of the db/db mutants lipogenesis (per tissue) reached a maximum at 5 weeks of age, and fell substantially between 10 and 20 weeks of age. Hepatic lipogenesis in the db/db mice rose progressively from weaning until 8 weeks of age, and then decreased. Except at weaning, hepatic lipogenesis (per tissue) was much greater in db/db mice than in normal mice, and the liver was a more important site of lipogenesis in diabetic mice than in normals, accounting for up to 60% of the whole-body total. In contrast, BAT accounted for a considerably smaller proportion of whole-body lipogenesis in db/db mice than in normal mice. It is concluded that there are major developmental differences in lipogenesis between tissues of db/db mice, and between diabetic and normal animals. The data suggest that there is an early and preferential development of insulin resistance in BAT of the db/db mutant.

Adipose Tissue↗
PubMed2005

Optimal molecular profiling of tissue and tissue components: defining the best processing and microdissection methods for biomedical applications.

Isolation of well-preserved pure cell populations is a prerequisite for sound studies of the molecular basis of any tissue-based biological phenomenon. This article reviews current methods for obtaining anatomically specific signals from molecules isolated from tissues, a basic requirement for productive linking of phenotype and genotype. The quality of samples isolated from tissue and used for molecular analysis is often glossed over or omitted from publications, making interpretation and replication of data difficult or impossible. Fortunately, recently developed techniques allow life scientists to better document and control the quality of samples used for a given assay, creating a foundation for improvement in this area. Tissue processing for molecular studies usually involves some or all of the following steps: tissue collection, gross dissection/identification, fixation, processing/embedding, storage/archiving, sectioning, staining, microdissection/annotation, and pure analyte labeling/identification and quantification. We provide a detailed comparison of some current tissue microdissection technologies, and provide detailed example protocols for tissue component handling upstream and downstream from microdissection. We also discuss some of the physical and chemical issues related to optimal tissue processing, and include methods specific to cytology specimens. We encourage each laboratory to use these as a starting point for optimization of their overall process of moving from collected tissue to high quality, appropriately anatomically tagged scientific results. In optimized protocols is a source of inefficiency in current life science research. Improvement in this area will significantly increase life science quality and productivity. The article is divided into introduction, materials, protocols, and notes sections. Because many protocols are covered in each of these sections, information relating to a single protocol is not contiguous. To get the greatest benefit from this article, readers are advised to read through the entire article first, identify protocols appropriate to their laboratory for each step in their workflow, and then reread entries in each section pertaining to each of these single protocols.

Biomarkers↗
PubMed2001

Influence of species, environmental factors, and tissue cellularity on calcification of porcine aortic wall tissue.

Valve tissue calcification has complex host, implant, and mechanical determinants. We studied the influence of species (rat v sheep), environmental factors (presence v absence of blood contact and arterial stress), and tissue cellularity (normal v acellularized tissue) on porcine aortic wall mineralization. Porcine aortic wall samples underwent standard glutaraldehyde-fixation or combined enzyme-detergent acellularization. Samples were implanted subcutaneously in rats (n = 8) and in juvenile sheep (n = 8). Furthermore, in juvenile sheep, similar samples were implanted into the jugular vein (blood contact) and into the carotid artery (blood contact and arterial stress). After 8 and 12 weeks, tissue was explanted and evaluated by X-ray, light- and electron-microscopy, and calcium content measurement (atomic absorption spectrometry). On the Von Kossa staining, auto-fluorescence of elastic fibers was used to identify the relation between calcific deposits and elastin. Subcutaneously implanted, glutaraldehyde-fixed tissue calcified severely in rat, but much less in sheep (calcium content: 56.2 +/- 13.6 v 9.9 +/- 9.0 microg/mg, respectively; P <.001). In sheep, the presence of blood contact (venous implants) increased wall calcification significantly (36.9 +/- 15.8; P <.001), but hemodynamic stress (arterial implants) had no additional mineralizing effect on the aortic wall (P >.05 v venous implants). Calcification of glutaraldehyde-fixed tissue occurred predominantly at the level of cells and cellular remnants, as confirmed by electron- and fluorescence-microscopy, locating calcific deposits in between elastic fibers. Acellularized tissue calcified significantly less, but an inflammatory response towards the tissue led to fragmentation, lysis, and subsequent calcification of elastic fibers. Results from subcutaneous implantations show large inconsistencies in calcification between the species. In sheep, blood contact increases aortic wall calcification significantly, while arterial stress has no additional effect. The sheep-jugular implantation model can be used as a simplified model for further study of aortic wall calcification and new antimineralization treatments. Calcification of glutaraldehyde-fixed aortic wall tissue is initiated at the level of cellular remnants, with little or no contribution from elastic fibers. Acellularization can avoid this cell-mediated calcification, but an additional treatment (glutaraldehyde, cryopreservation, photo-fixation,.) will be necessary to avoid the inflammation leading to elastolysis and consequent calcification of elastic fibers.

Animals↗
PubMed2002

Connective tissue and bacterial deposits on rubber dam sheet and ePTFE barrier membranes in guided periodontal tissue regeneration.

The aim of this study was to compare the connective tissue and bacterial deposits on rubber dam sheets and expanded polytetrafluoroethylene membranes used as barrier membranes in guided tissue regeneration for periodontal treatment. Twenty patients having intrabony defects and/or furcation defects were surgically treated by guided tissue regeneration employing either rubber dam sheets (10 patients) or expanded polytetrafluoroethylene membranes (10 patients) as barrier membranes. Four to six weeks after the first operation, membranes were retrieved from the lesion sites and processed for scanning electron microscopy. The lesion-facing surfaces of membranes were examined for the presence of connective tissue and bacterial deposits. The differences between the numbers of fields and the distributions of connective tissue and bacteria on both types of membranes were analysed by the Chi-square test at the level of 0.05 significance. The results showed a lot of fibroblasts with their secreted extracellular matrices, known as components of the connective tissue on rubber dam sheets and expanded polytetrafluoroethylene membranes. There was no significant difference in the total number of connective tissue on both types of membranes (P = 0.456). Many bacterial forms including cocci, bacilli, filaments and spirochetes with the interbacterial matrices were identified. The total number of bacteria on rubber dam sheets was statistically less than that on expanded polytetrafluoroethylene membranes (P < 0.001). The comparable number of connective tissue on both types of membranes suggests that the healing process under both types of membranes was also comparable. Therefore, the rubber dam sheet might be used as a barrier membrane in guided tissue regeneration.

Alveolar Bone Loss↗
PubMed2004

[Application of hard tissue slicing in research of bone tissue engineering].

OBJECTIVE: To improve the method of hard tissue slicing for research of bone tissue engineering. METHODS: The method of hard tissue slicing especially the key technique-slice mounting had been studied and improved. RESULTS: The experiments showed that our research improved techniques in hard tissue slicing not only in keeping the characteristics of hard tissue slicing, easily stain with HE, Masson, immunohistochemistry, and distinguishing the differences among tissues easily, but also in overcoming the shortcoming of issue shedding easy to happen in the general hard tissue slicing. CONCLUSION: The improved techniques in hard tissue slicing is a more useful hard tissue slicing techniques.

Animals↗