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At least 739 records · Page 41Linked to original sources
PubMed2006

Extrarenal rhabdoid tumors of soft tissue: clinicopathological and molecular genetic review and distinction from other soft-tissue sarcomas with rhabdoid features.

Malignant rhabdoid tumor (MRT) of the soft tissue is a rare and highly aggressive tumor that occurs in infancy or childhood. It predominantly involves a deep axial location such as the neck or paraspinal region. Microscopically, the tumor is composed of a diffuse proliferation of rounded or polygonal cells with eccentric nuclei, prominent nucleoli and glassy eosinophilic cytoplasm containing hyaline-like inclusion bodies, arranged in sheets and nests. These characteristic 'rhabdoid cells' are also present in certain soft-tissue sarcomas such as synovial sarcoma, extraskeletal myxoid chondrosarcoma and leiomyosarcoma. The existence of rhabdoid cells in these other sarcomas is correlated with a worse prognosis for the patients. Cytogenetic and molecular analyses have shown abnormalities in the long arm of chromosome 22 and alteration of the hSNF5/INI1 (SMARCB1) gene in renal, extrarenal and intracranial MRT. This gene alteration has been considered to be a specific molecular event in MRT, but a recent study has also demonstrated frequent alteration of this gene in proximal-type epithelioid sarcoma (ES). Both MRT of soft tissue and proximal-type ES show immunoreactivity for vimentin, cytokeratin and epithelial membrane antigen. The tumor cells of proximal-type ES are also occasionally positive for CD34 and beta-catenin, whereas MRT of soft tissue has no immunoreaction for these markers. Detailed clinicopathological and immunohistochemical evaluations are necessary to distinguish MRT of soft tissue from proximal-type ES, because these tumors demonstrated a similar morphology and the same gene alteration.

Biomarkers, Tumor↗
PubMed1999

Glucose transporter 4 (GLUT4) mRNA abundance in the adipose tissue and skeletal-muscle tissue of ovariectomized rats treated with 17 beta-estradiol or progesterone.

OBJECTIVE: To investigate the effects of 17 beta-estradiol and progesterone on the expression of glucose transporter 4 (GLUT4) in the adipose tissue and skeletal-muscle tissue of ovariectomized rats. METHODS: Female Sprague-Dawley rats (n = 63) received a daily subcutaneous injection of 10 micrograms, 50 micrograms, or 250 micrograms of 17 beta-estradiol (Group E) or of 1 mg, 5 mg or 25 mg of progesterone (Group P) for 3 days, 7 days, or 10 days (n = 3, at each dose). The expression of GLUT4 mRNA was assessed by performing ribonuclease protection assays. RESULTS: The levels of GLUT4 mRNA in adipose tissue was significantly reduced by treatment with estradiol, 50 micrograms or 250 micrograms, relative to findings in control rats (p < 0.01). No such reductions were seen regarding the progesterone treatment. The level of GLUT4 mRNA in skeletal-muscle tissue did not change, regardless of treatment. CONCLUSION: In ovariectomized rats, higher than physiologic dosages of 17 beta-estradiol can suppress the expression of GLUT4 mRNA in adipose tissue.

Adipose Tissue↗
PubMed1990

Tissue response to an experimental calcium hydroxide-based endodontic sealer: a quantitative study in subcutaneous connective tissue of the rat.

Silicone tubes containing a freshly mixed experimental Sealapex, in which titanium dioxide was removed from the original formula, were implanted in the dorsal subcutaneous connective tissue of the rat. Solid silicone rods of the same size as the tubes were also implanted and used as inert controls. The tissue reaction to both these materials was histometrically and quantitatively studied under light microscopy and by elemental electron microprobe analysis. After 7, 30 and 90 d of implantation, different grades of tissue reaction to the tested materials were recorded. A granulomatous tissue containing numerous foreign-body giant cells and macrophages with engulfed particles in their cytoplasms was initially detected in contact with the test material. In addition, many fibroblasts and newly formed vessels were also observed at these areas. The results of this study revealed that these reactions increased progressively at the 30- and 90-d observations. The electron microprobe analysis of the granulomatous tissues showed the presence of heavy components of the experimental material.

Animals↗
PubMed1989

Use of betapropiolactone to disinfect fresh tissue without impairing antigenicity: method applicable to human immunodeficiency virus (HIV) positive tissue.

A method for inactivating viruses in tissues is reported that does not impair the antigenicity of the Coxsackie virus or of some common tissue antigens, a common problem with standard tissue fixation methods. Tissues can be placed briefly in Betapropiolactone before cryostat sectioning without any adverse effect on preservation or antigen expression. It is suggested that use of Betapropiolactone is applicable to tissues harbouring or exposed to the human immunodeficiency virus (HIV). As betapropiolactone has been reported to be carcinogenic in rodents any potential danger can be avoided by basic simple precautions.

Antigens, Viral↗
PubMed1999

Comprehensive MR imaging protocol for stroke management: tissue sodium concentration as a measure of tissue viability in nonhuman primate studies and in clinical studies.

PURPOSE: To investigate sodium magnetic resonance (MR) imaging for monitoring tissue viability in stroke. MATERIALS AND METHODS: A comprehensive MR imaging protocol used to measure apparent diffusion coefficient and perfusion parameters was extended to include sodium imaging. Tissue sodium concentration was estimated by using a two-compartment model. This protocol lasted less than 45 minutes. These parameters were followed over the first 6 hours in a nonhuman primate model (n = 2) of acute embolic stroke without or with thrombolytic therapy. This protocol was used in patients in whom acute (< 24 hours, n = 11) or nonacute (> or = 24 hours, n = 31) stroke was ultimately confirmed. RESULTS: The animal model showed abnormal diffusion and perfusion parameters in the lesion immediately after embolization, and these remained abnormal for over 6 hours. Tissue sodium concentration increased with time (5.7 mmol/L/h) unless halted with thrombolytic therapy. Regions with sodium concentrations over 70 mmol/L were histochemically verified as being infarcted. In patients in whom stroke older than 6 hours was clinically confirmed, sodium concentrations over 70 mmol/L were found in the appropriate brain regions. CONCLUSION: Tissue sodium concentration provides a sensitive measure of tissue viability that is complementary to the diagnostic role of diffusion and perfusion imaging for ischemic insult.

Adult↗
PubMed1992

Tissue-specific effects of physiological ANP infusion on blood-tissue albumin transport.

Blood-tissue transport of 131I-labeled bovine serum albumin (BSA) during intravenous infusion of synthetic atrial natriuretic peptide (ANP) was examined in anesthetized male Wistar rats. Plasma volumes were maintained at pre-ANP levels by infusion of 2% BSA in lactated Ringer solution (LR) to minimize compensatory responses to ANP-induced hypovolemia. 131I-BSA clearance was measured over 30 min, and 125I-BSA was injected terminally to correct for intravascular volume. Thirty-minute infusion of 20 ng.kg-1.min-1 ANP resulted in a tissue-selective increase in 131I-BSA clearance in jejunum and colon compared with controls given LR only. Smaller but significant increases in tracer clearance also were observed in fat, kidney, left ventricle, and skeletal muscle exposed to 400 ng.kg-1.min-1 ANP. The observed elevation in tracer albumin extravasation was not associated with any measurable increase in tissue extravascular water content. Furthermore, it was shown that coupling of 131I-BSA transport to filtration induced by hindlimb venous congestion was similar in control and ANP-treated rats. In a second series of experiments, plasma ANP levels were determined after 30-min ANP infusions from 0 to 180 ng.kg-1.min-1. Significant linear associations between physiological ANP levels (62-578 pg/ml) and 131I-BSA clearance were demonstrable for small intestine, colon, fat, kidney, and skeletal muscle but not for skin, heart, diaphragm, and lung. We conclude that raising plasma ANP by infusion of the synthetic peptide results in a filtration-independent, tissue-selective increase in albumin transport. Tissue uptake of albumin is a potential mechanism for extrarenal fluid shift during circulatory volume overload.

Animals↗
PubMed1998

Distribution of TmDOTP5- in rat tissues: TmDOTP5- vs. CoEDTA- as markers of extracellular tissue space.

The distribution of TmDOTP5- in rat tissue was compared with CoEDTA-, an anionic complex previously used as a marker of extracellular space. Heart, liver, muscle, blood, and urine were collected from rats after infusion of either complex and were quantitatively analyzed by atomic absorption spectroscopy. Although total TmDOTP5- in blood and tissue was consistently lower (0.88 +/- 0.04; n = 6) than CoEDTA- after an identical infusion protocol (presumably because of some association of the phosphonate complex with bone), a comparison of blood and tissue contents indicated that the two anionic complexes distributed into identical extracellular spaces. Relative extracellular space in the in vivo liver, as determined by TmDOTP5- and CoEDTA-, was 0.18 +/- 0.02 and 0.15 +/- 0.01, respectively. The corresponding relative extracellular space values for the in vivo heart reported by the two agents were identical (0. 11 +/- 0.02). Experiments were also performed to evaluate the washout kinetics of TmDOTP5- from anesthesized rats. In rats given a total dose of 0.16 mmol TmDOTP5-, 81% appeared in urine by 180 min, <2% was found in all remaining soft tissue, leaving approximately 18% undetected. The rate of Tm appearance in urine was fit to a standard pharmacokinetic model that included four tissue compartments: plasma, one fast equilbrating space, one slow equilibrating space, and one very slow equilibrating space (presumably bone). The best fit result suggests that the highly charged TmDOTP5- complex is cleared from plasma more rapidly than is the typical lower charged Gd-based contrast agents and that release from bone is slow compared with renal clearance.

Animals↗
PubMed1992

Tissue-specific nutritional regulation of angiotensinogen in adipose tissue.

Recent studies have found that angiotensinogen is expressed in white and brown fat pads, and adipocytes have been implicated as a primary source of angiotensinogen in several other tissues. The functional significance of this unexpected expression is unknown. To address this, we studied angiotensinogen messenger RNA (mRNA) expression and angiotensinogen secretion in adipose tissue and isolated adipocytes comparing fasted and refed rodents and those with genetic obesity with normal controls. Control 2-month-old Sprague-Dawley rats, those fasted for 3 days, or those fasted for 2 days and refed for 6 days were killed, and adipocytes were isolated from epididymal fat pads using collagenase digestion. Angiotensinogen mRNA was reduced to 14.6 +/- 2.3% of control levels under fasted conditions and increased to 228 +/- 53% of control levels after refeeding. Angiotensinogen release from adipocytes was reduced to 33% of control levels by fasting and increased to 183% by refeeding. These effects of fasting and refeeding on angiotensinogen regulation were tissue specific since liver angiotensinogen mRNA and serum angiotensinogen concentrations were unaffected. Systolic blood pressure, however, was modulated by fasting and refeeding in a manner parallel to adipocyte angiotensinogen expression. In related experiments, angiotensinogen secretion per epididymal fat pad of the ob/ob mouse model of obesity was increased an average of 3.4-fold compared with control. We conclude angiotensinogen expression in white adipocytes is regulated nutritionally in a tissue-specific manner. We propose that adipocyte angiotensinogen could play a previously unrecognized role in regulating adipose tissue blood supply and thereby fatty acid efflux from fat.(ABSTRACT TRUNCATED AT 250 WORDS)

Adipose Tissue↗
PubMed1993

Regulation of tissue-selective T-lymphocyte homing receptors during the virgin to memory/effector cell transition in human secondary lymphoid tissues.

Conventional virgin T cells efficiently and homogeneously recirculate through all secondary lymphoid tissues, but not "extralymphoid" effector sites. In contrast, memory/effector populations are composed of distinct subsets with differential, often tissue-selective, migratory capability to both secondary lymphoid tissues and effector sites. In keeping with these observations, CD45RA(high)/RO(low) virgin T cells in human peripheral blood uniformly express the peripheral lymph node (PLN) homing receptor (HR) L-selectin, and lack the skin-selective HR CLA, whereas among the CD45RA(low)/RO(high) "memory/effector" population, differential expression of these HR yields three predominant subsets: L-selectin+/CLA+, L-selectin+/CLA-, L-selectin-/CLA-. Although these subsets are of approximately equal size in the peripheral blood, the vast majority of T cells obtained from cutaneous chronic inflammatory sites display the L-selectin+/CLA+ phenotype. To investigate the mechanisms responsible for the generation of these memory/effector T-cell subsets, we developed a multiparameter flow cytometric technique that defines a common pathway of postthymic T-cell differentiation in secondary lymphoid tissues: the virgin to memory/effector transition. Our analyses indicate that these HR are differentially regulated during the virgin to memory/effector transition in a tissue-specific fashion. The great majority of memory/effector T cells produced in PLN retain high levels of L-selectin expression, and 50 to 60% upregulate CLA. In contrast, memory/effector T cells produced in appendix and tonsil are generally L-selectin(low), and CLA is upregulated on less than 10% of newly formed memory/effector T cells in appendix and on about 30 to 35% of such cells in tonsil.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMedDate not supplied

Tissue shrinkage with the holmium:yttrium aluminum garnet laser. A postoperative assessment of tissue length, stiffness, and structure.

The effect of laser energy on the length, stiffness, and structure of connective tissue was examined in a rabbit patellar tendon model. A holmium:yttrium-aluminum-garnet laser was used to deliver a calculated dose of laser energy (300 J/cm2) to one randomly selected patellar tendon in each of 13 adult New Zealand White rabbits. The contralateral patellar tendon was used as a control. Radiopaque markers were placed in the patella and tibial tuberosity to allow for patellar tendon length measurements (via standard lateral radiographs) before and after laser application and at 4 and 8 weeks. Limbs were not immobilized during the postoperative period. The tendons were harvested at 0 weeks (N = 7) and 8 weeks (N = 6) and evaluated for tensile, stiffness, cross-sectional area, histologic changes, and electron microscopic appearance. The results demonstrated significant tendon shrinkage (6.6% +/- 1.4%) after application of the calculated laser energy dose. However, tendon length had increased significantly beyond the immediate postlaser length at 4 weeks and beyond its original length by 8 weeks. At 8 weeks, the lased tendons were significantly less stiff with significantly greater cross-sectional areas than contralateral controls. There was generalized fibroblastic response throughout the entire lased tendon characterized by a marked increase in cellularity. There was also a change from the normal bimodal pattern of large- and small-diameter collagen fibers to a unimodal pattern with predominantly small-diameter fibers in the lased tendons. The tissue alterations seen in this study suggest that the biologic response of connective tissue to laser energy causes a further compromise in tissue integrity, beyond that attributed to the initial physical effects of the laser. These alterations must be taken into consideration when determining postoperative rehabilitation of laser-modified tissues.

Adult↗
PubMed2004

Tissue-specific autoregulation of the LXRalpha gene facilitates induction of apoE in mouse adipose tissue.

The functions of the liver X receptors (LXRs) are not well documented in adipose tissue. We demonstrate here that expression of the LXRalpha gene is highly induced in vivo and in vitro in mouse and human adipocytes in the presence of the synthetic LXR agonist T0901317. This autoregulation is caused by an identified LXR-responsive element motif in the mouse LXRalpha promoter, which is conserved in the human LXRalpha promoter. Using different LXR-deficient mice, we demonstrate that the basal expression level of LXRalpha is increased in LXRbeta(-/-) mice, whereas the basal expression level of LXRbeta is unchanged in LXRalpha(-/-) mice. The two LXRs can compensate for each other in mediating ligand-activated regulation of LXR target genes involved in lipid homeostasis in adipose tissue. Sterol regulatory element binding protein-1 (SREBP-1), ATP binding cassette transporter A1 (ABCA1), ABCG1, as well as apolipoprotein E (apoE) are induced in vivo by T0901317 in wild-type, LXRalpha(-/-) or LXRbeta(-/-) mice but not in LXRalpha(-/-)beta(-/-) mice. Although SREBP-1 and ABCG1 are induced in liver, muscle, and adipose tissue, the apoE, glucose transporter-4 (GLUT4), and LXRalpha genes are specifically induced only in adipose tissue. We suggest that an important aspect of LXRalpha autoregulation in adipose tissue may be to increase the level of LXRalpha over a threshold level necessary to induce the expression of certain target genes.

3T3-L1 Cells↗
PubMed1990

Comparison of the effects of fibrinogen and fibrin products and isolated peptide chains on the fibrin-mediated stimulation of plasminogen activation by tissue-type plasminogen activator, and on the fibrin-dependent enhancement of the amidolytic activity of one-chain tissue-type plasminogen activator.

Intact fibrin monomer, the early fibrin degradation product (X-fragment), late fibrinogen degradation products (fragments D and E), fibrinogen cyanogen bromide fragment FCB-2, and isolated peptide chains of fibrinogen and fibrin were investigated for their ability to replace fibrin in the stimulation of one-chain tissue-type plasminogen activator. They were also investigated for their ability to stimulate plasminogen activation by one-chain tissue-type plasminogen activator, which occurs via ternary complex formation. The stimulatory effect of the different fibrin/ogen products decreased in the order: fibrin X-fragment greater than fibrin monomer greater than CNBr-fragment FCB-2 greater than fibrin alpha-chain. Fibrin beta/gamma-chains and fibrinogen peptide chains were found to be weak stimulators. Fibrinogen fragments D and E have almost no effect. The amidolytic activity of one-chain tissue-type plasminogen activator was stimulated by intact fibrin monomer and somewhat more strongly by fibrin X-fragment. This stimulation by fibrin monomer, which occurred via an increase in the kcat value, was competitively inhibited by isolated fibrin alpha-chain (Ki = 0.12 mumol/l). The results show that the fibrin-mediated stimulation of plasminogen activation occurs when both one-chain tissue-type plasminogen activator and plasminogen are bound to fibrin, and that this process is essentially independent of the conformation of the fibrin molecule. In comparison, the fibrin-dependent stimulation of the amidolytic activity of one-chain tissue-type plasminogen activator is a more complex process, which depends on the correct conformation of the fibrin molecule.

Amino Acid Sequence↗
PubMed1998

A partial cDNA sequence of the ovine insulin receptor gene: evidence for alternative splicing of an exon 11 region and for tissue-specific regulation of receptor isoform expression in sheep muscle, adipose tissue and liver.

Insulin is as integral and important to the management of metabolism in ruminants as it is in non-ruminants. The suggestion of a lowered ruminant sensitivity and/or responsivity to insulin may relate more to the insulin receptor than to the hormone itself. We screened an ovine cDNA library using degenerate primers and polymerase chain reaction (PCR) to detect and sequence a cDNA portion corresponding to exons 10, 11 and 12 of the human insulin receptor gene in which a 36 base pair (bp) segment (exon 11) is alternatively spliced to produce two distinct receptor isoforms differing in functional characteristics including binding affinity for insulin. The ovine cDNA segment (nucleotides 671 to 770) displayed 84, 84, and 78% nucleotide homology to equivalent segments from the human, rhesus monkey and rat respectively. Reverse transcription PCR (RT-PCR) of selected tissues (liver, m. longissimus dorsi, m. rectus capitis and omental, perirenal and subcutaneous fats) taken at slaughter from three male, pure Dutch Texel lambs (experiment 1) and five male Texel-Greyface crossbred lambs (experiment 2) revealed two mRNA products in each tissue (including spleen; experiment 2 only) corresponding to cDNAs of molecular sizes 161 and 197 bp -- a difference of 36 bp. Sequence alignment showed the 36 bp segment to be homologous to the alternatively spliced exon 11 region of the human insulin receptor gene and to be highly conserved with that from other species. The abundance of the exon 11(+) isoform in the purebred Texel genotype was significantly higher in liver than in perirenal fat and rectus capitis and longissimus dorsi skeletal muscles (P<0.05) and higher also than in subcutaneous and omental fats (P<0.01). There was, however, no difference in the abundance of the exon 11(+) isoform between the individual muscle and fat depots in this sheep genotype. The abundance of the exon 11(+) isoform in the crossbred Texel genotype was significantly higher in liver (P<0. 05) than in the muscles (rectus capitis, P<0.05; longissimus dorsi, P<0.001), all three fats (P<0.001) and spleen (P<0.001). In the crossbred genotype, the abundance of the exon 11(+) isoform was higher in skeletal muscle than in all three fat depots (P<0.001), in which the isoform abundance was similar. Altered ratios of expression of the two products of this alternative splicing event could determine tissue sensitivity and/or responsivity to insulin and provide a mechanism for the management of nutrient partitioning and nutrient utilisation between tissues which is fundamental to the growth of tissues and manipulation of carcass characteristics in meat-producing animals.

Adipose Tissue↗
PubMed2005

Evaluation of the safety and efficacy of periodontal applications of a living tissue-engineered human fibroblast-derived dermal substitute. II. Comparison to the subepithelial connective tissue graft: a randomized controlled feasibility study.

BACKGROUND: The subepithelial connective tissue graft, traditionally harvested from the patient's palate, is commonly used for root coverage in periodontal recession defects. This study evaluates the safety and effectiveness of a living human fibroblast-derived dermal substitute (HF-DDS) compared to a connective tissue graft (CTG) for root coverage in these situations. METHODS: Thirteen patients were selected for this study. Each patient had Miller Class I or II bilateral facial recession defects > or =3 mm on two non-adjacent teeth. The test tooth received an HF-DDS graft, while a CTG was placed on the control site. The 10 test surgeries were performed by one operator and three pilot surgeries were performed by another surgeon. Eight of the HF-DDS sites received a single thickness of material; five received a double thickness. Clinical measurements were taken at baseline; 1 week; and 1, 3, and 6 months following surgery. Parameters measured were plaque index, recession depth, clinical attachment levels, recession width, probing depth, and width of keratinized tissue. All clinical readings were taken by a masked, calibrated examiner. RESULTS: There were no statistically significant differences between the test and control groups. The amount of root coverage was slightly greater for the control group than for the test group, but statistically the difference was insignificant. The width of the recession defect measured at the cemento-enamel junction (CEJ) for the test group was slightly smaller than that of the control group at the conclusion of the study. The amount of keratinized tissue was the same in both groups at 6 months. The probing depth was slightly greater in the control group as was the gain in clinical attachment, but neither was statistically significant. The amount of root coverage obtained when one layer of HF-DDS was used compared to the amount of coverage obtained when two layers were used approached statistical significance, but the small sample size may have been responsible for the difference. CONCLUSION: Within the limits of this study, the human fibroblast-derived dermal substitute may offer potential as a substitute to the connective tissue graft for covering areas of facial Miller Class I or Class II gingival recession in humans.

Adult↗
PubMed2007

Matrix metalloproteinases, tissue inhibitor of matrix metalloproteinase-1, and laminin-5 gamma2 chain immunolocalization in gingival tissue of endotoxin-induced periodontitis in rats: effects of low-dose doxycycline and alendronate.

BACKGROUND: Matrix metalloproteinases (MMPs) play important roles in tissue destruction mechanisms of periodontitis. MMP-8 and -13 are the major collagenases that act in extracellular matrix degradation in periodontal tissues. MMP-14 is a membrane-type MMP, and laminin (Ln)-5 is a basal membrane component. The aim of the present study was to evaluate the effects of doxycycline and alendronate on gingival tissue expression of MMP-8, -13, and -14; tissue inhibitors of MMP (TIMP)-1; and Ln-5 gamma2 chain in experimental periodontitis induced by Escherichia coli endotoxin (LPS) in rats. METHODS: Experimental periodontitis was induced by repeated injection of LPS. Forty-four adult male Sprague-Dawley rats were divided into five study groups: saline control, LPS, LPS + doxycycline, LPS + alendronate, and LPS + doxycycline + alendronate. Doxycycline and alendronate were given as a single agent or as combination therapy during the 7 days of the experimental study period. On day 7, the rats were sacrificed, and the gingival tissues were analyzed immunohistochemically for expression of MMP-8, -13, and -14, Ln-5 gamma2 chain, and TIMP-1. Alveolar bone loss was evaluated morphometrically under a stereomicroscope. Data were tested statistically by Kruskal-Wallis and Mann-Whitney tests and Spearman correlation analysis. RESULTS: Alveolar bone loss was significantly higher in the LPS, doxycycline, alendronate, and combination groups than in the saline control group (all P <0.01). MMP-8 expression was significantly higher in the LPS group than in the saline control group (P = 0.001). Individual administration of doxycycline or alendronate significantly decreased the expression of MMP-8 compared to LPS (P = 0.01). Combined drug administration reduced MMP-14 significantly compared to doxycycline (P = 0.004). No significant differences in Ln-5 gamma2 chain expression were found between the study groups (P >0.05). MMP-14 significantly correlated with the Ln-5 gamma2 chain in the LPS + alendronate group (P = 0.04) and with the amount of alveolar bone loss in the LPS + doxycycline + alendronate group (P = 0.03). CONCLUSIONS: Our findings suggest that alendronate and/or doxycycline may inhibit MMP-8 expression significantly; particularly, their combined administration may provide beneficial effects in periodontal treatment. Moreover, individual administration of alendronate and doxycycline results in significant increases in TIMP-1 expression in gingiva. However, these effects of combined low-dose doxycycline and alendronate on MMPs and TIMP should be verified by clinical human trials before these agents are used in dental practice.

Alendronate↗
PubMed2000

MR imaging differentiation of soft-tissue hemangiomas from malignant soft-tissue masses.

OBJECTIVE: The purpose of this study was to determine whether MR imaging features can reliably distinguish hemangiomas from malignant soft-tissue masses. MATERIALS AND METHODS: We retrospectively reviewed MR imaging studies of 22 patients with soft-tissue hemangiomas and 22 patients with malignant soft-tissue masses. Images were reviewed and agreement reached by a consensus interpretation of two observers and by an independent observer. Masses were evaluated for signal intensity on T1- and T2-weighted images, for enhancement with gadolinium administration, and for morphology (lobulation, septation, central low-intensity dots). Lesion T2 signal and lesion enhancement with gadolinium administration were also objectively measured using regions of interest and comparison with skeletal muscle. RESULTS: Signal intensity on T1-weighted imaging of hemangiomas and malignant soft-tissue masses was similar. Subjective analysis showed greater T2 signal and gadolinium enhancement in hemangiomas; however, the differences were not statistically significant on objective analysis. Lobulation, septation, and central low-signal-intensity dots were all more common in hemangiomas, with statistical significance achieved; the combination of all three findings was specific for hemangioma. CONCLUSION: Although no single MR imaging feature was diagnostic in this study, analysis of lesion morphology, signal intensity, and enhancement with gadolinium allowed MR imaging differentiation of hemangiomas from malignant soft-tissue masses.

Adolescent↗
PubMed1985

Determination of the tissue-to-blood partition coefficient for 131iodo-antipyrine in human subcutaneous adipose tissue.

131Iodo-antipyrine (131I-AP) is commonly used for blood flow measurements in adipose tissue. These estimations have been based on the assumption of the tissue-to-blood partition coefficient being 1 ml g-1. No exact determination of the tissue-to-blood partition coefficient for 131I-AP in adipose tissue has been carried out. In the present study a partition coefficient of 1.12 +/- 0.06 (mean +/- S.D.) for 131I-AP in adipose tissue has been determined based on the partition coefficient for 131I-AP between lipid-saline (1.24 ml g-1), red blood cells-plasma (0.64 ml g-1), protein-saline (0.19 ml g-1) and plasma-saline (0.84 ml ml-1).

Adipose Tissue↗
PubMed1995

Fibrillin-1 and fibrillin-2 show temporal and tissue-specific regulation of expression in developing elastic tissues.

The recent characterization of multiple fibrillin genes raises the question of whether each of the fibrillin proteins is a component of elastic fiber microfibrils and whether their expression during development of elastic tissues is consistent with a function associated with elastogenesis. To address these possibilities, the expression of fibrillin-1 and fibrillin-2 was compared with expression of MAGP and tropoelastin in two elastogenic tissues that undergo different developmental programs. For both fibrillins, the greatest increase in expression occurred during the last half of fetal development when elastin production is highest. In fetal bovine nuchal ligament, mRNA levels for fibrillin-1 and fibrillin-2 increased approximately threefold during this period, whereas tropoelastin increased 20-fold. Although the relative increase in expression of both fibrillins was equivalent, the basal level of fibrillin-1 expression was greater than fibrillin-2. In developing bovine aorta, fibrillin mRNA levels again paralleled tropoelastin expression although, compared to ligament, elastin synthesis began at an earlier fetal age in this tissue. Furthermore, the relative increase in aortic fibrillin-2 expression was greater than that for fibrillin-1 and the ratio of fibrillin-2 to fibrillin-1 was higher than in the ligament. In contrast to the fibrillins, MAGP expression in nuchal ligament and aorta remained at a constant high level throughout the fetal period. Indirect immunofluorescent staining and immunoelectron microscopy localized both fibrillins as well as MAGP to elastic fiber microfibrils in these developing tissues. The coordinate upregulation of fibrillin-1 and fibrillin-2 expression with the onset of tropoelastin production is consistent with a role in elastic fiber assembly. Our findings also suggest temporal and tissue-specific regulation for the fibrillins during development.

Age Factors↗