Relationship between long bone distortion and tibial dyschondroplasia in male turkeys

To determine whether a relationship exists between long bone distortion and tibial dyschondroplasia (TD), the hock joints of Large White commercial male turkeys were examined using low intensity x-ray imaging (hand-held lixiscope). All lame birds with long bone distortion and 96 control birds without lameness were examined at 8.3 and 12.3 wk of age for TD lesions using a lixiscope. Results indicated that the incidence of TD was less than 2% at 8.3 wk of age. The incidence increased to 21% by 12.3 wk of age. The TD lesions at 12 wk of age were considered mild covering only one-fourth of the growth plate. Chi-square analysis indicated that control turkeys without long bone distortion were just as likely to have TD lesions as were lame turkeys with long bone distortion. Under the conditions of the present experiment, TD did not appear to be a significant skeletal problem in Large White commercial male turkeys prior to 12.3 wk of age. Only 5 out of 37 (14%) toms with long bone distortion at 12.3 wk of age had TD lesions, suggesting that the valgus-varus deformity may be independent of TD.     

Matrix metalloproteinase expression in rat pancreatic islets

OBJECTIVE: To determine whether the type of prosthetic material and technique of placement influenced long-term complications after repair of incisional hernias. DESIGN: Retrospective cohort analytic study. SETTING: University-affiliated hospital. PATIENTS: Two hundred patients undergoing open repair of abdominal incisional hernias with prosthetic material between 1985 and 1994. INTERVENTIONS: Four types of prosthetic material were used and placed either as an onlay, underlay, sandwich, or finger interdigitation technique. The materials were monofilamented polypropylene mesh (Marlex, Davol Inc, Cranston, RI), double-filamented mesh (Prolene, Ethicon Inc, Somerville, NJ), expanded polytetrafluroethylene patch (Gore-Tex, WL Gore & Associates, Phoenix, Ariz) or multifilamented polyester mesh (Mersilene, Ethicon Inc). MAIN OUTCOME MEASURES: The incidence of recurrence and complications such as enterocutaneous fistula, bowel obstruction, and infection with each type of material and technique of repair were compared with univariate and multivariate analysis. RESULTS: On univariate analysis, multifilamented polyester mesh had a significantly higher mean number of complications per patient (4.7 vs 1.4-2.3; P<.002), a higher incidence of fistula formation (16% vs 0%-2%; P<.001), a greater number of infections (16% vs 0%-6%; P<.05), and more recurrent hernias (34% vs 10%-14%; P<.05) than the other materials used. The additional mean length of stay to treat complications was also significantly longer (30 vs 3-7 days; P<.001) when polyester mesh was used. The deleterious effect of polyester mesh on long-term complications was confirmed on multiple logistic regression (P=.002). The technique of placement had no influence on outcome. CONCLUSION: Polyester mesh should no longer be used for incisional hernia repair.     

Matrix metalloproteinases and metalloproteinase inhibitors in choroidal neovascular membranes

PURPOSE: Matrix metalloproteinases (MMP) are a family of extracellular matrix degrading enzymes associated with the development of neovascularization. To investigate the possible role of these enzymes in choroidal neovascularization, the mRNA expression of MMPs and tissue inhibitors of metalloproteinases (TIMPs) were analyzed in subfoveal fibrovascular membranes from patients with age-related macular degeneration (AMD). METHODS: Surgically removed subfoveal fibrovascular membranes from five eyes were analyzed for the expression of MMP and TIMP mRNA. In situ hybridization anti-sense and sense riboprobes were generated using DNA complementary to human collagenase (MMP-1), 72 kDa gelatinase (MMP-2), stromelysin (MMP-3), 92-kDa gelatinase (MMP-9), TIMP-1, TIMP-2, and TIMP-3. Vascular endothelial cells were detected using immunostaining for von Willebrand factor. RESULTS: MMP-2 and MMP-9 mRNA were detected in all specimens. Most of the membranes also expressed TIMP-1 and TIMP-3 mRNA, and two of the membranes expressed TIMP-2 mRNA. MMP-2, TIMP-1, and TIMP-2 mRNA had a similar overall distribution that was relatively uniform within the vascularized membrane stroma. MMP-2 expression appeared to be localized mainly to the vascular endothelial cells, whereas TIMP-1 and TIMP-3 were detected in other cell types such as fibroblastlike cells. MMP-9 expression was distinctly expressed by cells at the margins of the membranes and often in proximity to a thickened Bruch's membrane-like layer under the retinal pigment epithelial cells. TIMP-3 mRNA was strongly expressed within the retinal pigment epithelial cell layer and also in the stroma of one membrane. None of the membranes showed detectable MMP-1 or MMP-3 expression. CONCLUSIONS: The results support a role for MMPs in the development of choroidal neovascularization in AMD. The localization of MMP-2 and MMP-9 to the areas of new vessel formation and to the enveloping Bruch's-like membrane, respectively, suggests that MMP-2 and MMP-9 may be cooperatively involved in the progressive growth of choroidal neovascular membranes in AMD.     

Matrix metalloproteinase and matrix metalloproteinase inhibitor expression in endometrial stromal cells during progestin-initiated decidualization and menstruation-related progestin withdrawal

Estradiol (E) primes human endometrial stromal cells (HESCs) for the decidualizing effects of progesterone in vivo and in vitro. Matrix metalloproteinase (MMP) expression was evaluated in confluent HESCs incubated in control medium, and in medium supplemented with either E, or the synthetic progestin medroxyprogesterone acetate (P), or E + P. Measurements with a specific ELISA indicated that basal pro-MMP-1 output was unaffected by E, whereas E + P, which induces the expression of several decidualization-related markers, produced a time-dependent inhibition in HESC-secreted levels of pro-MMP-1. Consistent with progestin inhibition of MMP-1 protein expression in the HESCs, P but not E, reduced steady state levels of MMP-1 messenger RNA (mRNA) as determined by Northern analysis. By contrast, mRNA levels for MMP-2 and the MMP inhibitor TIMP-1 were not altered by either P or E. Steroid withdrawal studies indicated that after MMP-1 expression was suppressed by incubation of the HESCs with E + P, 4 days of exposure to the antiprogestin RU 486 (mifepristone) significantly up-regulated MMP-1 levels in the conditioned medium by severalfold compared with cultures maintained in E + P. The change to steroid-free control medium required a more prolonged period of withdrawal to attain up regulatory effects that were comparable with those evoked by RU 486. The ELISA measurements were validated by immunoblot analysis with a specific MMP-1 antibody, which showed corresponding changes in a band at the expected mobility of about 50 kDa. Moreover, Northern analysis revealed parallel changes in MMP-1 mRNA levels, whereas neither MMP-2 nor TIMP-1 mRNA levels were modulated by adding or withdrawing steroids. The contrast between regulated MMP-1 expression and constitutive MMP-2 expression observed in the cultured HESCs is consistent with the demonstrated presence on the MMP-1 promoter of regulatory elements such as AP-1 and PEA-3 that are absent from the MMP-2 promoter. Extrapolation of these in vitro changes in HESCs to in vivo endometrial events suggests that: 1) inhibition of MMP-1 expression by E and progesterone would stabilize the perivascular endometrial ECM to prevent local hemorrhage during endovascular invasion by the implanting trophoblast; 2) enhanced expression of MMP-1 evoked by steroid withdrawal would mediate endometrial ECM degradation leading to sloughing of the functional layer during menstruation.     

Immunohistochemical study of a chondroitin-6-sulfate in growth plates of broiler chickens with high and low genetic predispositions to tibial dyschondroplasia

The distribution of a chondroitin-6-sulfate (C6S) epitope, which is a biochemical marker of chondrocyte hypertrophy, was studied in the growth plates of two lines of 3-week-old broiler chickens with low and high genetic predispositions to tibial dyschondroplasia (TD). Ultrathin sections of growth plates from both groups were subjected to immunolocalization with monoclonal antibody 3-B-3(-), the epitope of which is increased on proteoglycans made by hypertrophic chondrocytes. Bound antibody was localized with colloidal gold-labeled protein A for observation with an electron microscope. The 3-B-3(-) epitope was localized in pericellular and interterritorial matrix of growth plates of both lines. In the low-TD-incidence birds, the concentration of 3-B-3(-) bound to C6S progressively increased from the proliferative zone to the hypertrophic zone. However, in the high-TD-incidence line, the epitope expression remained at a low level in all zones. The increase of the 3-B-3(-) epitope produced by maturing growth-plate chondrocytes is indicative of changes in the glycosaminoglycan chains of proteoglycans that may be important in the process of matrical calcification. Thus, failure of chondrocytes of the high-TD-incidence line to produce this change in post-translational modification of their proteoglycans could be important in the pathological process.     

Matrix metalloproteinase expression during experimental autoimmune encephalomyelitis and effects of a combined matrix metalloproteinase and tumour necrosis factor-alpha inhibitor

Diaspirin crosslinked hemoglobin (DCLHb Baxter Healthcare Corp., Round Lake, IL, USA), a hemoglobin-based blood substitute has been found to be an effective resuscitative agent following hemorrhage in animals. The present study was undertaken to determine the effect of DCLHb on microvascular perfusion in the brain and kidney following hemorrhage in anaesthetized, male Sprague Dawley rats using laser Doppler flowmetry. Hemorrhage was induced by withdrawal of arterial blood at a rate of 0.5 to 1.0 ml/min until blood pressure of 35-40 mmHg was achieved. This was maintained for up to 30 min. The arterial blood pH, pO2, pCO2 and total hemoglobin (THb) were monitored. Hemorrhage significantly decreased pH, pCO2 and THb and increased pO. Hemorrhage significantly decreased (26%) brain blood perfusion due to a decrease (17%) in the concentration of moving red blood cells (CMBC). In the kidney there was a greater decrease (65%) in blood perfusion due to a significant decrease in both CMBC (28%) and red blood cell velocity (49%). Resuscitation with vehicle (Ringer's lactate, 4 ml/kg, i.v.) did not produce any improvement in cerebral and renal blood perfusion. Resuscitation with DCLHb (400 mg/kg, i.v.) improved perfusion in the brain (112%) due to an increase in the CMBC (69%) and the velocity of red blood cells (33%). Similarly, in the kidney, DCLHb increased perfusion (178%) by increasing CMBC (55%) and red blood cell velocity (89%) of hemorrhaged rats. The increase in renal blood perfusion was more marked (p < 0.001) than the changes in cerebral blood perfusion following resuscitation with DCLHb in hemorrhaged rats. It is concluded that DCLHb can significantly increase cerebral and renal blood perfusion of hemorrhaged rats and this effect may contribute to its efficacy as a resuscitative solution.     

Matrix metalloproteinase expression in Macaca mulatta endometrium: evidence for zone-specific regulatory tissue gradients

Matrix metalloproteinases (MMPs) are highly expressed in the human endometrium during menstruation, and these enzymes participate in the cyclic destruction and regeneration characteristic of the primate endometrium. To examine hormonal regulation of MMPs in vivo, we evaluated MMP expression and localization in the endometrium of ovariectomized rhesus macaques under various hormonal conditions. Although all MMPs were up-regulated by progesterone (P4) withdrawal, their expression declined spontaneously after menstruation in the absence of P4. Of 7 MMPs examined, only matrilysin and stromelysin-3 were suppressed any further when P4 levels were experimentally re-elevated. MMP expression was confined to the upper functionalis zone during menstruation, but after menstrual breakdown was complete, matrilysin and the tissue inhibitor of MMPs, TIMP-1, shifted expression from the functionalis to the basalis zone in the absence of both estradiol and P4. The spiral arteries in the functionalis, but not the basalis, were intense foci of MMP and TIMP-1 expression. Menstruation and MMP expression after P4 withdrawal were similar in both the presence and absence of estradiol. In sum, endometrial MMPs in vivo are strongly up-regulated by P4 withdrawal, but zone-specific tissue gradients greatly influence the pattern and degree of MMP expression.     

Selection of broiler chickens for a high and low incidence of tibial dyschondroplasia with observations on spondylolisthesis and twisted legs (perosis)

Radiography was used to select normal birds and affected with tibial dyschondroplasia from a commercial stock of broiler chickens. Birds were selected for three generations and mated like to like in an attempt to establish low and high incidence strains. Incidence of tibial dyschondroplasia in the low incidence strain was reduced to negligible levels while it was increased in the high incidence strain. Incidence of the defect in the high incidence strain could be influenced by diet. Observations during the selection program on the incidence of spondylolisthesis and twisted legs in birds younger than eight weeks of age indicated that these other skeletal defects were unrelated to tibial dyschondroplasia.     

Matrix metalloproteinase activity in equine synovial fluid: influence of age, osteoarthritis, and osteochondrosis

OBJECTIVE: To investigate the influence of age, osteoarthritis (OA), and osteochondrosis (OC) on the matrix metalloproteinase (MMP) activity in the synovial fluid (SF) of equine joints. METHODS: SF was collected from normal and osteoarthritic metacarpophalangeal joints (normal: 14 adult, 28 juvenile; OA: 22 adult). And from normal and osteochondrotic tarsocrural joints (5 months: 11 normal, 8 OC; 11 months: 7 normal, 6 OC). Subsequently, overall MMP activity was measured. RESULTS: The level of active MMPs was almost twofold higher in SF from juvenile horses (age up to 11 months) than in SF from mature animals (4-30 years; p < 0.001). In juvenile horses MMP activity was higher in 5 month old foals than in 11 month old foals (p < 0.01). In adult horses MMP activity was independent of age. In OA joints the activity was nearly twice as high as in normal joints (p < 0.001). In OC joints MMP activity was not significantly different from normal, age matched, control joints. CONCLUSIONS: MMP activity in SF from normal adult joints is not related to age. In juvenile joints MMP activity is significantly higher than activity in joints from adult animals. It is hypothesised that the gradual decrease in MMP activity with increasing age reflects the declining metabolic activity resulting from ceasing growth and the accompanying decrease in cartilage remodelling. The increased MMP activity in osteoarthritis joints most likely reflects matrix destruction. In osteochondrosis MMP mediated matrix degradation appears not to be different from normal joints.     

Matrix metalloproteinase (MMP)-9 type IV collagenase/gelatinase implicated in the pathogenesis of Sj?gren''s syndrome

Integrin-ligand binding generates many intracellular signals, including signals to initiate focal contact formation and to regulate cellular decisions concerning growth and differentiation. Oligomerization of the beta subunit cytoplasmic domain appears to be required for many of these events. In order to study these processes, we have generated a novel chimeric protein, consisting of the chicken integrin beta 1 cytoplasmic domain connected to the central rod domain of a neuronal intermediate filament, alpha-internexin. This chimeric protein, when expressed transiently in 293T cells, oligomerizes in a beta cytoplasmic domain-dependent manner. This oligomerization requires the membrane proximal amino acids LLMII of the beta 1 cytoplasmic domain, as demonstrated by deletion analysis. Therefore, the integrin beta cytoplasmic domain in this system contains an oligomerization function, which may provide some insight as to the function of intact integrins in vivo.     

Matrix metalloproteinase stromelysin-1 triggers a cascade of molecular alterations that leads to stable epithelial-to-mesenchymal conversion and a premalignant phenotype in mammary epithelial cells

Matrix metalloproteinases (MMPs) regulate ductal morphogenesis, apoptosis, and neoplastic progression in mammary epithelial cells. To elucidate the direct effects of MMPs on mammary epithelium, we generated functionally normal cells expressing an inducible autoactivating stromelysin-1 (SL-1) transgene. Induction of SL-1 expression resulted in cleavage of E-cadherin, and triggered progressive phenotypic conversion characterized by disappearance of E-cadherin and catenins from cell-cell contacts, downregulation of cytokeratins, upregulation of vimentin, induction of keratinocyte growth factor expression and activation, and upregulation of endogenous MMPs. Cells expressing SL-1 were unable to undergo lactogenic differentiation and became invasive. Once initiated, this phenotypic conversion was essentially stable, and progressed even in the absence of continued SL-1 expression. These observations demonstrate that inappropriate expression of SL-1 initiates a cascade of events that may represent a coordinated program leading to loss of the differentiated epithelial phenotype and gain of some characteristics of tumor cells. Our data provide novel insights into how MMPs function in development and neoplastic conversion.     

矩阵对角化中可逆矩阵的研究

通过对矩阵的对角化研究,找出了在对角化过程中所取的可逆阵之间的内在联系,并分别从矩阵以及线性变换两个角度给出了可逆阵之间的关系.如果n阶方阵A可对角化,则存在可逆阵P,使P-1AP为对角阵.若取可逆阵Q,Q-1AQ也为对角阵,那么适当调整Q的列向量的次序后,调整后的P,Q的列向量之间存在线性关系,且列向量之间的线 性变换的矩阵为准对角矩阵,该准对角矩阵的每个块矩阵的阶数等于A的某个特征值的重数,并举例说明了这一结论.     

Proximal intra-articular tibial fracture in skiers

56 cases of proximal intraarticular tibia fractures over a 4-year period are reviewed. In every case the patients described a preceding valgus-compression trauma of their knee. Clinically we always found a hemarthrosis combined with a tenderness on pressure at the fractured condyle. Roentgenograms should be performed in 4 projections, eventually followed by conventional tomograms or computed tomography. Frequency of the several fracture types is demonstrated following the classification of the AO working group for osteosynthesis. The Eminentia intercondylaris was concerned in 13 cases as avulsion fracture of the anterior cruciate ligament (ACL) with a double peak distribution in the under 20-years- and over 40-years-age group. In the remaining cases we observed split- and/or compression fractures of the lateral tibial plateau of the 40 to 60 year old skier, in 20% communitive fractures. In 85% of the ACL-avulsion fractures we applied a cast brace as a conservative measure, whereas 75% of the tibia plateau fractures were treated operatively by mean of open reconstruction of the articular surface and internal fixation based on the AO-principles as well as bone graft buttressing in two third of the cases.     

DNA sequence organisation in avian genomes

By means of renaturation kinetics of DNA of the three avian species Cairina domestica, Gallus domesticus and Columba livia domestica the following major DNA repetition classes were observed: a very fast reannealing fraction comprising about 15% of the DNA, a fast or intermediate reannealing fraction that makes up 10%, and a slow reannealing fraction of about 70%, which apparently renatures with single copy properties. --Comparing the reassociation behaviour of short (0.3 kb) and long (greater than 2 kb) DNA fragments of duck and chicken it becomes apparent that only 12% (duck) and 28% (chicken) of the single copy DNA are interspersed with repetitive elements on 2 to 3 kb long fragments. The lengths of the repetitive sequences were estimated by optical hyperchromicity measurements, by agarose A-50 chromatography of S1 nuclease resistant duplexes and by electron microscopic measurements of the S1 nuclease resistant duplexes. It was found that in the case of the chicken DNA the single copy sequences alternating with middle repetitive ones are at least 2.3 kb long; the interspersed moderate repeats have a length average of at least 1.5 kb. The sequence length of the moderate repeats in duck DNA is smaller. The results show that the duck and the chicken genomes do not follow the short period interspersion pattern of genome organisation, characteristic of the eucaryotic organisms studied so far.     

Membrane type-1 matrix metalloproteinase in human ocular tissues

PURPOSE: Membrane type-1 matrix metalloproteinase (MT1-MMP) (MMP-14) (EC 3.4.24.xx) is involved in the activation of progelatinase A (MMP-2) (EC 3.4.24.24). MMP-2 is present at least in the interphotoreceptor matrix and vitreous. The purpose of this study was to determine the distribution of MT1-MMP, and MMP-2, in human ocular tissues. METHODS: The distribution of MT1-MMP and MMP-2 was investigated in vitreous and in membrane extracts from eye tissues obtained from postmortem human eyebank eyes. Western blot analysis was performed using mouse monoclonal anti-MT1-MMP and anti-MMP-2 antibodies. RESULTS: MT1-MMP was found in sclera, cornea, lens, choroid, retinal pigment epithelium (RPE) and retina. MMP-2 was found in sclera, cornea, choroid, vitreous, RPE and retina but was absent from lens. CONCLUSION: We provide the first evidence for the presence and distribution of membrane-type-1 matrix metalloproteinase in human ocular tissues. MT1-MMP may be responsible for the activation of progelatinase A in many ocular extracellular matrices in a manner similar to that exhibited in other systems.