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At least 991 records · Page 55Linked to original sources

PubMed2003

A wound contraction experimental model for studying keloids and wound-healing modulators.

Preventing and treating hypertrophic and keloid scars is difficult because of the lack of knowledge about their genesis. Tissue repair can be studied with biocompatible matrices and ex vivo cultures of different cell types. We used an experimental model where collagen gels populated by human fibroblasts underwent progressive contraction, allowing the study of wound healing remodeling. The fibroblast-populated lattices showed the greater contraction of the gel populated by fibroblasts from keloids versus fibroblasts from normal skin. Moreover, fibroblast growth factor (FGF) and transforming growth factor beta (TGF-beta) involved in scar formation were added to the collagen gels populated by normal skin fibroblasts. TGF-beta caused an increase in gel contraction; FGF did not. The mean percentages of contraction of the gels populated by keloid fibroblasts were very similar to the percentages of gels populated by normal skin fibroblasts with added TGF-beta. These observations confirm the existing hypothesis that TGF-beta may be involved in keloid formation.

Cells, Cultured↗

PubMed1983

The release and neosynthesis of glutamic acid are increased in experimental models of hepatic encephalopathy.

The effects of ammonium ions on the release of glutamic acid from the rat cerebral cortex were measured in vivo using cortical cups and a multiple ion detection technique. The neosynthesis of this amino acid from glucose was also studied in two experimental models of hepatic encephalopathy: (1) rats receiving large amounts of ammonium acetate (i.p.) and (2) rats with a surgically constructed portocaval anastomosis. Intraperitoneal administration of 8 mmol/kg of ammonium acetate increased the cortical release of glutamic acid from 9.1 +/- 0.8 to 19 +/- 2 (nmol X cm-2 X min-1). Moreover, 20 min after ammonium acetate administration the rate of incorporation of 13C2, originating from [13C]glucose, into glutamic acid increased by 65%. In several brain areas of rats bearing a portocaval anastomosis and fed ad libitum for 4 weeks, the content of glutamic acid slightly increased and the rate of formation of [13C2]glutamate from [13C]glucose approximately doubled. These results indicate that ammonium ions increase the release and the formation of glutamic acid in the brain. The resulting increased concentration of this amino acid in the extracellular spaces may be one of the mechanisms of ammonia toxicity in vivo.

Acetates↗

PubMed2005

Immunomodulatory effects of etanercept in an experimental model of spinal cord injury.

Etanercept is a tumor necrosis factor antagonist with anti-inflammatory effects. The aim of our study was to evaluate for the first time the therapeutic efficacy of in vivo inhibition of tumor necrosis factor-alpha (TNF-alpha) in experimental model of spinal cord trauma, which was induced by the application of vascular clips (force of 24 g) to the dura via a four-level T5-T8 laminectomy. Spinal cord injury in mice resulted in severe trauma characterized by edema, neutrophil infiltration, and cytokine production that it is followed by recruitment of other inflammatory cells, such as production of a range of inflammation mediators, tissue damage, apoptosis, and disease. Treatment of the mice with etanercept significantly reduced the degree of 1) spinal cord inflammation and tissue injury (histological score); 2) neutrophil infiltration (myeloperoxidase evaluation); 3) inducible nitric-oxide synthase, nitrotyrosine, cyclooxygenase-2, and cytokines expression (TNF-alpha and interleukin-1beta); and 4) apoptosis (terminal deoxynucleotidyl transferase dUTP nick-end labeling staining and Bax and Bcl-2 expression). In a separate set of experiment, we have also clearly demonstrated that TNF-alpha inhibitor significantly ameliorated the recovery of limb function (evaluated by motor recovery score). Taken together, our results clearly demonstrate that treatment with etanercept reduces the development of inflammation and tissue injury events associated with spinal cord trauma.

Animals↗

PubMed1999

[Serum and pulmonary angiotensin converting enzyme as a marker of acute lung injury in an experimental model of adult respiratory distress syndrome].

OBJECTIVE: To know if the determination of the angiotensin converting enzyme in serum (SACE) and lung (LACE) may be useful as a marker of acute lung injury (ALI) in the adult respiratory distress syndrome (ARDS). METHOD: By reproducing in a experimental model of ALI with oleic acid in dogs which simulate the early stage of ARDS, we have correlated the pathologic and analytical changes observed with the results of the determinations of SACE and LACE. RESULTS: We have found sequential pulmonary lesions (congestion, edema, hemorrhage polynuclear infiltration and thrombosis) and biological alteration (hypoxemia, pulmonary hypertension, early leukopenia and final leukocytosis, thrombopenia and hypofibrinogenemia) that reproduce the typical changes of ARDS, together with the decrease of SACE--slow and progressive--and LACE--abrupt in the onset and maintained during the experiment--. CONCLUSIONS: The LACE is a good marker of the beginning of the lesion because its decrease coincides with the first pathological changes (congestion) and with the hypoxemia, pulmonary hypertension and leukopenia, maintained without changes, during the whole experiment. On the other hand, the SACE corresponds as an inespecifical reactant, marker of acute inflammation and loss of pulmonary endothelium, because its progressive decrease evolutioned with the pathological lesions and the analytical changes. In conclusion, the sequential determination of SACE has a prognostic and evolutive value in comparison with the LACE, which has a diagnostic value from the beginning of the experiment of ALI and maintained throughout.

Animals↗

PubMed1991

Cardiac function after hepatic ischemia-anoxia and reperfusion injury: a new experimental model.

BACKGROUND AND METHODS: During liver transplantation, reperfusion of the donor liver and in the clinical setting, end-stage liver disease, have occasionally resulted in profound cardiovascular disturbances. The etiology of hepatic injury-induced myocardial dysfunction is still unclear. In this study, the aims were to develop an experimental model that would facilitate the study of the effects of hepatic failure on myocardial function and to determine whether hepatic ischemia or anoxia and reperfusion injury of similar duration would result in the same degree of hepatic failure. Seventy male Sprague-Dawley rats were used as organ donors. Three simultaneous liver-heart perfusions (corresponding to three groups) were established using a modified Krebs-Henseleit buffer with 2% bovine albumin, membrane oxygenation, and a peristaltic pump. Group 1 (n = 10) and group 2 (n = 15) experiments consisted of liver-heart perfusions after 90 mins of normothermic hepatic ischemia or 90 mins of hepatic anoxia, respectively, followed by reoxygenation and 60 mins of reperfusion. Group 3 (n = 8) experiments consisted of sham liver-heart perfusions studied over the same experimental time period (60 mins). Myocardial function variables, liver function tests, arterial blood gases, and electrolytes were measured at baseline and at 3-, 10-, 30-, and 60-min intervals during reperfusion in all experiments. RESULTS: Ischemia or anoxia-induced hepatic failure resulted in a similar degree of hepatic dysfunction. Both forms of acute hepatic failure caused significant increases in liver function tests, a reduction in heart rate (p less than .05), coronary flow (p less than .05), and an increase in calculated coronary vascular resistance (p less than .05). There were no changes in buffer pH, CO2, or ionized calcium that could explain the coronary vasoconstriction. CONCLUSIONS: Hepatic dysfunction induced by ischemia or anoxia of similar duration results in a similar hepatic metabolic profile during reperfusion and can cause direct myocardial dysfunction of the isolated perfused rat heart.

Animals↗

PubMed1991

The effects of vasopressin infusion on hepatic haemodynamics in an experimental model of liver metastases.

Vasoactive drugs have a variety of effects upon splanchnic and hepatic haemodynamics which may alter tumour blood flow and potentiate the delivery of a chemotherapeutic drug to hepatic tumour. We have investigated the effects of vasopressin infusion on hepatic tumour blood flow in an experimental model of liver tumour. Hepatic tumour was induced by the intraportal inoculation of HSN sarcoma cells. Hepatic and splanchnic blood flow was determined using a dual reference microsphere technique before and after an intravenous infusion of vasopressin at a dose of 0.1 mU kg-1 min-1 for 10 min. There was a significant increase in systemic arterial blood pressure associated with a rise in portal venous inflow (P less than 0.01, Wilcoxen Signed rank Test) and a significant fall in hepatic arterial flow (P less than 0.05). The tumour: liver blood flow ratio was significantly increased by vasopressin infusion (P less than 0.02). Vasopressin infusion decreases hepatic arterial flow and increases tumour blood flow which may potentiate the delivery of a regionally delivered chemotherapeutic drug to hepatic tumour.

Animals↗

PubMed1984

Prolonged bile duct obstruction: a new experimental model for cirrhosis in the rat.

Hepatic morphological abnormalities were examined in rats whose bile ducts had been either cannulated and then obstructed or irreversibly ligated for 5, 10, 15 and 28 days or longer. Throughout the experiment most of the morphological changes observed in the cannulated group were comparable to those in the ligated group. Portal inflammation and marginal bile duct proliferation were noted with the same frequency in both groups. Biliary obstruction for 15 days or more led to cirrhosis. After 28 days obstruction, five out of six cannulated rats and four out of six ligated animals respectively developed cirrhosis. The development of cirrhosis was progressive and associated with ascites. It is concluded that in the rat the morphological sequelae of long term cholestasis induced by either cannulation and obstruction or ligation of bile ducts are similar and are accompanied by cirrhosis. The advantages of this experimental model for the study of human cirrhosis are discussed.

Animals↗

PubMedDate not supplied

Tubulovasostomy in the rat. A new experimental model.

Tubular patency is the primary concern in the evaluation of procedures for epididymovasostomy. The epididymal lumen easily becomes occluded or obstructed, with the resulting recurrence of azoospermia. Recently, two-layer direct anastomosis has been advocated. The aim of the present study was to present an experimental model of tubulovasostomy in the rat. Microsurgery was performed in 18 rats (16-40 X magnification). Suture material used was 11/0 Vycryl or nylon for the internal layer of the anastomosis and 10/0 Ethilon for the external layer. After 6 and 12 weeks, semen samples were obtained by electroejaculation and evaluated for sperm count and motility.

Animals↗

PubMed2006

Experimental model of tooth movement by orthodontic force in mice and its application to tumor necrosis factor receptor-deficient mice.

Orthodontic tooth movement is achieved by mechanical loading; however, the biological mechanism involved in this process is not clearly understood owing to the lack of a suitable experimental model. In the present study, we established an orthodontic tooth movement model in mice using a Ni-Ti closed coil spring that was inserted between the upper incisors and the upper first molar. Histological examination demonstrated that the orthodontic force moved the first upper molar mesially without necrosis of the periodontium during tooth movement. The number of TRAP-positive osteoclasts on the pressure side significantly increased in a time-dependent manner. Quantitative real time-based reverse transcription-polymerase chain reaction analysis demonstrated increased levels of mRNA for cathepsin K. Immunohistochemical staining revealed the expression of tumor necrosis factor-alpha (TNFalpha) in periodontium on the pressure side of the first molar during orthodontic tooth movement. When this tooth movement system was applied to TNF type 1 receptor-deficient mice and TNF type 2 receptor-deficient mice, tooth movement observed in TNF type 2 receptor-deficient mice was smaller than that in the wild-type mice and TNF type 1 receptor-deficient mice. The number of TRAP-positive osteoclasts on the pressure side was significantly small in TNF type 2 receptor-deficient mice compared with that in TNF type 1 receptor-deficient mice on day 6 after application of the appliance. The present study indicates that TNFalpha signaling plays some important roles in orthodontic tooth movement.

Acid Phosphatase↗

PubMed1998

Expression of cytokeratin 20 in developing rat liver and in experimental models of ductular and oval cell proliferation.

BACKGROUND/AIMS: Recently, a novel type of cytokeratin (CK) has been added to the classical catalog of CKs as CK20. The aim of the present study was to examine the immunoreactivity for CK20 in normal and developing rat liver and in experimental models of bile ductular and oval cell proliferation. METHODS: Eighty-five Fischer rats, subdivided into five groups, were utilized in this study: fetal rats, ranging from day 10 to day 21 of gestation; newborn-neonatal rats, from 2 h to 10 days of age; bile duct ligated (BDL) rats; alpha-naphthyl-isothiocyanate (ANIT)-treated rats; and rats fed a choline-deficient diet containing N-2 Fluorenylacetamide (CD-AAF rats). Frozen sections from each liver were stained with the CK20 specific monoclonal antibody IT-Ks20.10. RESULTS: The present study shows that CK20 is a "bile duct type" CK. In the fetal rat, CK20 appears late during intrahepatic bile duct development, at day 20 of gestation. A marked increase in CK20 expression occurs after birth, suggesting that intrahepatic bile duct maturation continues after birth and that CK20 may be considered as a "maturation" marker of the biliary tree. In BDL rats and in ANIT-treated animals, immunoreactivity of bile ductules for CK20 was strikingly heterogeneous. A variable number of proliferating biliary cells were weakly positive or negative for CK20 and their number increased with the duration of the obstruction or ANIT treatment. In CD-AAF-treated rats, we found a uniform staining of proliferating oval cells for CK20. This finding is in contrast with the observation in BDL and in ANIT groups, and suggests the existence of different mechanisms regulating the proliferation and differentiation of biliary cells under those conditions. CONCLUSIONS: In rat liver, CK20 may be added to the list of "bile duct type" cytokeratins. During development, CK20 expression may be related to the maturation stage of the biliary tree. Typical ductular proliferation induced by BDL or ANIT feeding clearly differs from the oval cell proliferation in the CD-AAF model in terms of immunoreactivity for CK20.

1-Naphthylisothiocyanate↗

PubMed1984

The problem of evaluating in situ pinning of slipped capital femoral epiphysis: an experimental model and a review of 63 consecutive cases.

Over a 3-year follow-up period, 63 hips (in 49 patients) that were pinned as treatment for slipped capital femoral epiphysis were examined and evaluated. A 36.8% incidence of unsuspected pin penetration was discovered. Four types of experimental models representing different degrees of severity of slipped capital femoral epiphysis were designed and manufactured in the bioengineering laboratory. In situ pinning was performed on each model. An extensive series of controlled test films on the models indicated the difficulty of accurately determining the true position of the pins with conventional roentgenographic views. Subsequent fluoroscopic analysis revealed a verifiable correlation between the limited visualization of conventional X-ray analysis following the pinning of a slipped capital femoral epiphysis and unrecognized pin penetration.

Bone Nails↗

PubMed2005

Toward a novel experimental model of infection to study American cutaneous leishmaniasis caused by Leishmania braziliensis.

Leishmania spp. cause a broad spectrum of diseases collectively known as leishmaniasis. Leishmania braziliensis is the main etiological agent of American cutaneous leishmaniasis (ACL) and mucocutaneous leishmaniasis. In the present study, we have developed an experimental model of infection that closely resembles ACL caused by L. braziliensis. In order to do so, BALB/c mice were infected in the ear dermis with 10(5) parasites and distinct aspects of the infection were evaluated. Following inoculation, parasite expansion in the ear dermis was accompanied by the development of an ulcerated dermal lesion which healed spontaneously, as seen by the presence of a scar. Histological analysis of infected ears showed the presence of a mixed inflammatory infiltrate consisting of both mononuclear and polymorphonuclear cells. In draining lymph nodes, parasite replication was detected throughout the infection. In vitro restimulation of draining lymph node cells followed by intracellular staining showed an up-regulation in the production of gamma interferon (IFN-gamma) and in the frequency of IFN-gamma-secreting CD4(+) and CD8(+) T cells. Reverse transcription-PCR of ears and draining lymph node cells showed the expression of CC chemokines. The dermal model of infection with L. braziliensis herein is able to reproduce aspects of the natural infection, such as the presence of an ulcerated lesion, parasite dissemination to lymphoid areas, and the development of a Th1-type immune response. These results indicate that this model shall be useful to address questions related to the concomitant immunity to reinfection and parasite persistence leading to mucocutaneous leishmaniasis.

Animals↗

PubMed2002

Experimental models to study cholangiocyte biology.

Cholangiocytes-the epithelial cells which line the bile ducts-are increasingly recognized as important transporting epithelia actively involved in the absorption and secretion of water, ions, and solutes. This recognition is due in part to the recent development of new experimental models. New biologic concepts have emerged including the identification and topography of receptors and flux proteins on the apical and/or basolateral membrane which are involved in the molecular mechanisms of ductal bile secretion. Individually isolated and/or perfused bile duct units from livers of rats and mice serve as new,physiologically relevant in vitro models to study cholangiocyte transport. Biliary tree dimensions and novel insights into anatomic remodeling of proliferating bile ducts have emerged from three-dimensional reconstruction using CT scanning and sophisticated software. Moreover, new pathologic concepts have arisen regarding the interaction of cholangiocytes with pathogens such as Cryptosporidium parvum. These concepts and associated methodologies may provide the framework to develop new therapies for the cholangiopathies, a group of important hepatobiliary diseases in which cholangiocytes are the target cell.

Animals↗

PubMed1997

Effect of cytomegalovirus on an experimental model of chronic renal allograft rejection under triple-drug treatment in the rat.

BACKGROUND: Cytomegalovirus (CMV) infection is thought to be a risk factor of chronic rejection. In clinical studies and animal models, mainly concerning graft vasculopathy, CMV has been demonstrated to enhance allograft arteriosclerosis. In this study we have investigated the effect of CMV on the early inflammatory response and graft histology in an experimental model of renal transplantation in a rat strain combination that develops chronic rejection under triple-drug immunosuppression. METHODS: Renal transplantations were performed in a rat strain combination of DA-->BN receiving triple-drug treatment (2 mg/kg methylprednisolone, 2 mg/kg azathioprine, 5 mg/kg cyclosporine daily subcutaneously). One group of immunosuppressed animals was infected with rat CMV, the Maastricht strain (10(5) plaque-forming units intraperitoneally), and the other group was left uninfected. As a positive control for alloresponse, one group of recipients received neither immunosuppression nor virus. Syngenic transplantations with triple-drug treatment and CMV were used as negative controls. The grafts were monitored by frequent ultrasound-guided fine-needle aspiration biopsies, and the intragraft inflammation was quantified in detail by the increment method and expressed in corrected increment units (CIU). Graft histology was performed in parallel. RESULTS: Nonimmunosuppressed animals developed acute rejection with a high peak of inflammation (7.9+/-3.2 CIU), a typical blast response, and lymphocytosis followed by infiltration of macrophages and necrosis within 7 days. Triple drug-treated animals had a short, mild inflammatory response (3.3+/-1.4 CIU at the peak) in the graft 3-5 days after transplantation but ended up with histological changes characteristic of chronic rejection with vasculopathy and fibrosis 40-60 days later. Triple drug-treated animals with CMV demonstrated a significantly stronger inflammation (4.5+/-1.8 CIU, P<0.01) than those without, and lymphoid activation continued longer and was followed by infiltration of macrophages in the graft. CMV infection of the graft was demonstrated by viral culture and antigen detection. In histology, chronic rejection with intimal thickening of arteries and arterioles and medial necrosis of large arteries was seen at 14 days, ending up with remarkable graft fibrosis within 20 days after transplantation. CONCLUSION: CMV prolonged and increased graft inflammation and accelerated chronic rejection of renal allografts under triple-drug treatment.

Animals↗

PubMed2004

Stress increases susceptibility to oxidative/nitrosative mucosal damage in an experimental model of colitis in rats.

Inflammatory bowel diseases (IBDs) are multifactorial processes. Clinical and animal studies indicate that emotional stress may contribute to the onset and progress of these diseases. On the other hand, enhanced free radical production in mucosal cells has been also implicated in the pathogenesis of IBD. Using an experimental model of colitis induced by intrarectal instillation of 2,4,6-trinitrobenzene sulfonic acid (TNBS) plus ethanol (vehicle), we sought to determine whether prior exposure to immobilization stress modifies the susceptibility to oxidative damage in colonic mucosa. Several groups of Wistar rats were used: control (C) and stressed (by immobilization of 6 hr every day during 10 days; S) groups and rats receiving a colitis-inducing dose of TNBS on day 5 (30 mg; TNBS30) and a noninflammatory dose of TNBS on day 5 (5 mg; TNBS5) with or without stress (prior exposure, days 0-5, and after, days 5-10). At the 10th day, colonic tissue was dissected and processed for biochemical studies. TNBS30 led to body weight loss, macroscopic colonic ulceration, and inflammation (determined by histological parameters and myeloperoxidase [MPO] activity) and to an increase in inducible nitric oxide synthase (NOS-2) activity and expression. TNBS5-instilled animals' body weight and biochemical inflammatory parameters were not significantly different from those in control animals. Interestingly, while stress did not modify body weight, macroscopic aspect of the mucosa, or NOS activity in animals receiving TNBS30, immobilization increased body weight loss, MPO levels, and malondialdehyde (MDA; an indicator of lipid peroxidation) levels after TNBS5. On the other hand, stress increased NOS-2 activity and immunohistochemical expression after instillation of TNBS5. Moreover, constitutive, Ca2+ -dependent NOS activity decreased in stressed animals instilled with TNBS5 compared with nonstressed animals receiving TNBS5 (-28.5 +/- 6.6%; P < 0.05). These findings indicate that previous exposure to stressful stimuli is a factor in susceptibility to oxidative damage in experimental colitis and support a possible protective effect of treatment of stress before and during the development of inflammation in the colon.

Animals↗

PubMed1989

[New experimental models in microbial ecology].

Peculiar features of dysbiosis development in persons under extreme conditions were studied. It was shown that a number of extreme factors participated in formation of dysbiotic disorders in intestinal microflora. Of paramount importance was the neuro-emotional stress. Lability of bifido- and lactoflora was considered as the starting mechanism in dysbacteriosis under the extreme conditions. In the experimental models with rats SPF and Primates during flights of biosatellites of the Kosmos series the role of indigenous++ microflora in maintaining the microecological homeostasis, as well as the need for development of artificial and controlled intestinal microflora promising in prophylaxis of dysbacteriosis under extreme conditions was shown. The theoretical and experimentally grounded necessity of maintaining constant intestine microbiocenosis was confirmed by the practice of using the system of measures for recovery, stabilization and optimization of microflora in persons under extreme conditions.

Animals↗

PubMed2004

Use of Scots pine seedling roots as an experimental model to investigate gene expression during interaction with the conifer pathogen Heterobasidion annosum (P-type).

The root-rot fungus Heterobasidion annosum is a major pathogen of woody trees in temperate regions of the world. In this study, seedling root of Scots pine was used as an experimental model to investigate gene expression in conifer trees during challenge with H. annosum. Initial cellular and histochemical studies have established the systems and indicated the key sequence of events during the infection process. Also, to correlate histochemical observations with the time-dependent pattern of events in host gene expression, a transcriptome profiling of a selected set of host genes from a pine-root subtraction cDNA library was conducted. Differential screening of the subset of genes arrayed on nylon membrane with cDNA probes made from seedling roots infected for 1, 3, 7 and 15 days revealed a number of up-regulated genes [disease-resistance gene analog, antimicrobial peptide (AMP) gene homolog etc.] following inoculation. The results also showed strong expression of genes involved in cell defense and protein synthesis at the early stages of the infection (3-7 days) with a decline at late stages of infection (15 days). The decline in expression of key defense genes at late stages of infection correlated well with the period of vascular colonization and subsequent loss of root turgor. Northern analyses with two of the major induced genes (AMP homolog and disease-resistance gene analog) indicated a several-fold increase in host gene expression following infection. In addition, a particular single gene (thaumatin-like protein) was consistently expressed throughout the four sampling periods of the experiment. BlastX analyses revealed that the Scots-pine thaumatin-like gene shared 51-77% sequence homology with other thaumatin-like proteins in GenBank. The importance of these results in tree defense and use of conifer seedling root in host-parasite interaction in forest trees is discussed.

Amino Acid Sequence↗

PubMed1983

The effects of antithrombin III, heparin and a novel heparinoid infusions on the bleeding tendency using an experimental model in the rat.

The effects of selective increase of plasma AT-III concentration (to 2 U/ml and 8 U/ml) in the presence or absence of low dose commercial heparin and a novel natural heparinoid (Org 10172) on APTT, clotting factors and bleeding were investigated in an experimental model in rats. Slight increases in the APTT were observed with: a. Org 10172, b. both AT-III doses and c. combinations hereoff. However, synergism was observed in the prolongations of the APTT when the AT-III concentrate (70 U/kg and 500 U/kg) was combined with both heparin dosages. AT-III concentrates (70 U/kg and 500 U/kg) or Org 10172 (2,5 mg/kg) separately or in combination showed no effect on bleeding. Heparin (0, 125 and 0,25 mg/kg i.v.) also showed no effect on bleeding neither if they were combined with the lower dose AT-III. However, heparin (both dosages) combined with 500 U/kg of AT-III concentrates significant increased blood loss. These observations suggest that infusion of AT-III concentrate additionally to low dose heparin therapy did not increase bleeding in the rat model used provided that extreme high AT-III plasma levels (8 U/ml) were avoided. The novel natural heparinoid Org 10172 alone or combined with either AT-III dosage induced no increased bleeding.

Animals↗