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1.
Cancer Sci ; 112(6): 2467-2480, 2021 Jun.
Article in English | MEDLINE | ID: mdl-33756060

ABSTRACT

The antibody-drug conjugate (ADC) MORAb-202, consisting of farletuzumab paired with a cathepsin B-cleavable linker and eribulin, targets folate receptor alpha (FRA), which is frequently overexpressed in various tumor types. MORAb-202 was highly cytotoxic to FRA-positive cells in vitro, with limited off-target killing of FRA-negative cells. Furthermore, MORAb-202 showed a clear in vitro bystander cytotoxic effect in coculture with FRA-positive/negative cells. In vivo antitumor efficacy studies of MORAb-202 were conducted with a single administration of MORAb-202 in triple-negative breast cancer (TNBC) patient-derived xenograft (PDx) models expressing low and high levels of FRA. MORAb-202 exhibited durable efficacy proportional to tumor FRA expression. Toxicology studies (Q3Wx2) in nonhuman primates suggested that the major observed toxicity of MORAb-202 is hematologic toxicity. Overall, these findings support the concept that MORAb-202 represents a promising investigational ADC for the treatment of TNBC patients.


Subject(s)
Antibodies, Monoclonal, Humanized/pharmacology , Antineoplastic Agents/pharmacology , Furans/chemistry , Immunoconjugates/administration & dosage , Ketones/chemistry , Triple Negative Breast Neoplasms/drug therapy , Vesicular Transport Proteins/metabolism , Animals , Antibodies, Monoclonal, Humanized/chemistry , Antineoplastic Agents/chemistry , Cell Line, Tumor , Cell Proliferation/drug effects , Cell Survival/drug effects , Female , Furans/pharmacology , Humans , Immunoconjugates/adverse effects , Immunoconjugates/chemistry , Ketones/pharmacology , Mice , Patient-Specific Modeling , Primates , Triple Negative Breast Neoplasms/metabolism , Vesicular Transport Proteins/antagonists & inhibitors , Xenograft Model Antitumor Assays
2.
Vasc Med ; 24(5): 414-421, 2019 10.
Article in English | MEDLINE | ID: mdl-31277561

ABSTRACT

Extensive atherosclerotic plaque burden in the lower extremities often leads to symptomatic peripheral artery disease (PAD) including impaired walking performance and claudication. Interleukin-1ß (IL-1ß) may play an important pro-inflammatory role in the pathogenesis of this disease. Interruption of IL-1ß signaling was hypothesized to decrease plaque progression in the leg macrovasculature and improve the mobility of patients with PAD with intermittent claudication. Thirty-eight patients (mean age 65 years; 71% male) with symptomatic PAD (confirmed by ankle-brachial index) were randomized 1:1 to receive canakinumab (150 mg subcutaneously) or placebo monthly for up to 12 months. The mean vessel wall area (by 3.0 T black-blood magnetic resonance imaging (MRI)) of the superficial femoral artery (SFA) was used to measure plaque volume. Mobility was assessed using the 6-minute walk test. Canakinumab was safe and well tolerated. Markers of systemic inflammation (interleukin-6 and high-sensitivity C-reactive protein) fell as early as 1 month after treatment. MRI (32 patients at 3 months; 21 patients at 12 months) showed no evidence of plaque progression in the SFA in either placebo-treated or canakinumab-treated patients. Although an exploratory endpoint, placebo-adjusted maximum and pain-free walking distance (58 m) improved as early as 3 months after treatment with canakinumab when compared with placebo. Although canakinumab did not alter plaque progression in the SFA, there is an early signal that it may improve maximum and pain-free walking distance in patients with symptomatic PAD. Larger studies aimed at this endpoint will be required to definitively demonstrate this. ClinicalTrials.gov Identifier: NCT01731990.


Subject(s)
Anti-Inflammatory Agents/therapeutic use , Antibodies, Monoclonal, Humanized/therapeutic use , Intermittent Claudication/drug therapy , Peripheral Arterial Disease/drug therapy , Aged , Anti-Inflammatory Agents/adverse effects , Antibodies, Monoclonal, Humanized/adverse effects , Biomarkers/blood , Double-Blind Method , Exercise Tolerance/drug effects , Female , Germany , Humans , Inflammation Mediators/blood , Intermittent Claudication/blood , Intermittent Claudication/diagnosis , Intermittent Claudication/physiopathology , Jordan , Male , Middle Aged , Peripheral Arterial Disease/blood , Peripheral Arterial Disease/diagnosis , Peripheral Arterial Disease/physiopathology , Proof of Concept Study , Prospective Studies , Recovery of Function , Time Factors , Treatment Outcome , United States
3.
Wounds ; 30(9): 283-289, 2018 09.
Article in English | MEDLINE | ID: mdl-30256747

ABSTRACT

OBJECTIVE: The results of the single-arm, open-label extension phase of the Grafix (cryopreserved placental membrane; CPM; Osiris Therapeutics, Inc, Columbia, MD) multicenter, blinded, randomized, controlled clinical trial for chronic diabetic foot ulcers (DFUs) is reported. MATERIALS AND METHODS: Twenty-six patients in the standard wound care (SWC) arm whose DFUs did not close in the blinded phase chose to receive weekly applications of the CPM in an open-label extension phase. RESULTS: In the extension phase, 17 (65.4%) patients closed their wounds in a median of 34 days and 3 visits. There were fewer total adverse events (AEs) (24 CPM vs. 52 SWC) and index wound-related infections (5 CPM vs. 12 SWC) during the CPM application compared with the number of AEs for the same patients during the SWC treatment in the blinded phase of the trial. CONCLUSIONS: These results corroborate the benefits of this CPM combined with SWC over SWC alone for chronic DFUs previously reported for the blinded randomized phase of the trial, which directly relate to lower health care costs.


Subject(s)
Biological Dressings , Cryopreservation , Diabetic Foot/therapy , Placenta/transplantation , Wound Healing/physiology , Aged , Diabetic Foot/complications , Female , Humans , Male , Middle Aged , Pregnancy , Treatment Outcome
4.
Oncotarget ; 6(28): 25429-40, 2015 Sep 22.
Article in English | MEDLINE | ID: mdl-26327620

ABSTRACT

Over-expression of endosialin/CD248 (herein referred to as CD248) has been associated with increased tumor microvasculature in various tissue origins which makes it an attractive anti-angiogenic target. In an effort to target CD248, we have generated a human CD248 knock-in mouse line and MORAb-004, the humanized version of the mouse anti-human CD248 antibody Fb5. Here, we report that MORAb-004 treatment significantly impacted syngeneic tumor growth and tumor metastasis in the human CD248 knock-in mice. In comparison with untreated tumors, MORAb-004 treated tumors displayed overall shortened and distorted blood vessels. Immunofluorescent staining of tumor sections revealed drastically more small and dysfunctional vessels in the treated tumors. The CD248 levels on cell surfaces of neovasculature pericytes were significantly reduced due to its internalization. This reduction of CD248 was also accompanied by reduced α-SMA expression, depolarization of pericytes and endothelium, and ultimately dysfunctional microvessels. These results suggest that MORAb-004 reduced CD248 on pericytes, impaired tumor microvasculature maturation and ultimately suppressed tumor development.


Subject(s)
Angiogenesis Inhibitors/pharmacology , Antibodies, Monoclonal, Humanized/pharmacology , Antigens, CD/immunology , Antigens, Neoplasm/immunology , Carcinoma, Lewis Lung/drug therapy , Melanoma, Experimental/drug therapy , Microvessels/drug effects , Neovascularization, Pathologic , Pericytes/drug effects , Actins/metabolism , Angiogenesis Inhibitors/metabolism , Animals , Antibodies, Monoclonal, Humanized/metabolism , Antigens, CD/genetics , Antigens, CD/metabolism , Antigens, Neoplasm/genetics , Antigens, Neoplasm/metabolism , Biological Transport , Carcinoma, Lewis Lung/blood supply , Carcinoma, Lewis Lung/genetics , Carcinoma, Lewis Lung/immunology , Carcinoma, Lewis Lung/metabolism , Carcinoma, Lewis Lung/pathology , Cell Movement/drug effects , Cells, Cultured , Dose-Response Relationship, Drug , Endothelial Cells/drug effects , Endothelial Cells/immunology , Endothelial Cells/metabolism , Female , Humans , Male , Melanoma, Experimental/blood supply , Melanoma, Experimental/genetics , Melanoma, Experimental/immunology , Melanoma, Experimental/metabolism , Melanoma, Experimental/pathology , Mice, Inbred C57BL , Mice, Transgenic , Microvessels/immunology , Microvessels/metabolism , Microvessels/pathology , Neoplasm Metastasis , Pericytes/immunology , Pericytes/metabolism , Pericytes/pathology , RNA Interference , Time Factors , Transfection , Tumor Burden/drug effects
5.
Int Wound J ; 11(5): 554-60, 2014 Oct.
Article in English | MEDLINE | ID: mdl-25048468

ABSTRACT

In a randomised, controlled study, we compared the efficacy of Grafix(®) , a human viable wound matrix (hVWM) (N = 50), to standard wound care (n = 47) to heal diabetic foot ulcers (DFUs). The primary endpoint was the proportion of patients with complete wound closure by 12 weeks. Secondary endpoints included the time to wound closure, adverse events and wound closure in the crossover phase. The proportion of patients who achieved complete wound closure was significantly higher in patients who received Grafix (62%) compared with controls (21%, P = 0·0001). The median time to healing was 42 days in Grafix patients compared with 69·5 days in controls (P = 0·019). There were fewer Grafix patients with adverse events (44% versus 66%, P = 0·031) and fewer Grafix patients with wound-related infections (18% versus 36·2%, P = 0·044). Among the study subjects that healed, ulcers remained closed in 82·1% of patients (23 of 28 patients) in the Grafix group versus 70% (7 of 10 patients) in the control group (P = 0·419). Treatment with Grafix significantly improved DFU healing compared with standard wound therapy. Importantly, Grafix also reduced DFU-related complications. The results of this well-controlled study showed that Grafix is a safe and more effective therapy for treating DFUs than standard wound therapy.


Subject(s)
Diabetic Foot/therapy , Extracellular Matrix , Placenta , Skin Transplantation , Skin, Artificial , Wound Healing/physiology , Adult , Aged , Aged, 80 and over , Female , Humans , Male , Middle Aged , Pregnancy , Prospective Studies
6.
J Am Chem Soc ; 135(33): 12313-23, 2013 Aug 21.
Article in English | MEDLINE | ID: mdl-23862668

ABSTRACT

A novel clathrate phase, Ba8Au16P30, was synthesized from its elements. High-resolution powder X-ray diffraction and transmission electron microscopy were used to establish the crystal structure of the new compound. Ba8Au16P30 crystallizes in an orthorhombic superstructure of clathrate-I featuring a complete separation of gold and phosphorus atoms over different crystallographic positions, similar to the Cu-containing analogue, Ba8Cu16P30. Barium cations are trapped inside the large polyhedral cages of the gold-phosphorus tetrahedral framework. X-ray diffraction indicated that one out of 15 crystallographically independent phosphorus atoms appears to be three-coordinate. Probing the local structure and chemical bonding of phosphorus atoms with (31)P solid-state NMR spectroscopy confirmed the three-coordinate nature of one of the phosphorus atomic positions. High-resolution high-angle annular dark-field scanning transmission electron microscopy indicated that the clathrate Ba8Au16P30 is well-ordered on the atomic scale, although numerous twinning and intergrowth defects as well as antiphase boundaries were detected. The presence of such defects results in the pseudo-body-centered-cubic diffraction patterns observed in single-crystal X-ray diffraction experiments. NMR and resistivity characterization of Ba8Au16P30 indicated paramagnetic metallic properties with a room-temperature resistivity of 1.7 mΩ cm. Ba8Au16P30 exhibits a low total thermal conductivity (0.62 W m(-1) K(-1)) and an unprecedentedly low lattice thermal conductivity (0.18 W m(-1) K(-1)) at room temperature. The values of the thermal conductivity for Ba8Au16P30 are significantly lower than the typical values reported for solid crystalline compounds. We attribute such low thermal conductivity values to the presence of a large number of heavy atoms (Au) in the framework and the formation of multiple twinning interfaces and antiphase defects, which are effective scatterers of heat-carrying phonons.

7.
Inorg Chem ; 52(12): 7061-7, 2013 Jun 17.
Article in English | MEDLINE | ID: mdl-23734787

ABSTRACT

Barium gold polyphosphide BaAu2P4 was synthesized from elements and structurally characterized by single crystal X-ray diffraction. BaAu2P4 crystallizes in a new structure type, in the orthorhombic space group Fddd (No. 70) with a = 6.517(1) Å, b = 8.867(2) Å, c = 21.844(5) Å. The crystal structure of BaAu2P4 consists of Au­P layers separated by layers of Ba atoms. Each Au­P layer is composed of infinite ∞(1)(P­) chains of unique topology linked together by almost linearly coordinated Au atoms. According to Zintl­Klemm formalism, this compound is charge balanced assuming closed shell d10 configuration for Au: Ba2+(Au+)2(P­)4. Magnetic and solid state NMR measurements together with quantum-chemical calculations reveal diamagnetic and semiconducting behavior for the investigated polyphosphide, which is as expected for the charged balanced Zintl phase. Electron localization function and crystal orbital Hamilton population analyses reveal strong P­P and Au­P bonding and almost nonbonding Au­Au interactions in BaAu2P4.

8.
Child Adolesc Ment Health ; 18(4): 218-224, 2013 Nov.
Article in English | MEDLINE | ID: mdl-32847301

ABSTRACT

BACKGROUND: We examined child and family factors associated with teacher-reported behavior problems in 79 children of substance abusers (COSAs). METHOD: Using regression models, we examined the impact of four family risk factors, cumulatively and individually, on children's behavior and explored children's engagement of adults as a protective factor. RESULTS: More than half (55%) of children had clinically elevated behavior problems. Cumulative family risks were associated with increased problems, whereas the presence of a father in the home and the child's ability to engage adults were protective. CONCLUSIONS: These findings may help explain the variation in behavioral outcomes of COSAs.

9.
Proc (Bayl Univ Med Cent) ; 25(1): 16-9, 2012 Jan.
Article in English | MEDLINE | ID: mdl-22275776

ABSTRACT

Abdominal apoplexy, or idiopathic spontaneous intraperitoneal hemorrhage, is a rare and often fatal condition resulting from a variety of disease processes affecting the arterial and venous abdominal vasculature. Preoperative and intraoperative diagnosis and treatment of abdominal apoplexy are challenging. The source of bleeding may remain elusive even after careful autopsy dissection given the absence of intravascular pressure. Despite these challenges, early diagnosis and rapid treatment remain central to a successful outcome, as nonsurgical mortality has approached 100%. Presented here are two fatal cases of abdominal apoplexy, one involving a patient with arterial dissection of the gastroduodenal artery and one involving rupture of the superior mesenteric-portal venous system with perivascular pseudoaneurysm formation.

10.
J Biomed Mater Res A ; 93(1): 235-42, 2010 Apr.
Article in English | MEDLINE | ID: mdl-19557790

ABSTRACT

The susceptibility of meniscus allografts to enzymatic degradation may be reduced through tissue stabilization. We have previously reported on an epoxide-based crosslinker, triglycidyl amine (TGA), which can be used alone or with a bisphosphonate (MABP) to stabilize heterograft heart valves and reduce their pathologic calcification. Our objective was to evaluate the effects of TGA and TGA-MABP pretreatment on an orthopedic allograft involving meniscus crosslinking, degradation, calcification, and compressive properties. Ovine menisci treated with TGA or TGA-MABP for up to seven days and glutaraldehyde crosslinked controls were examined in vitro for degree of crosslinking, resistance to degradation by collagenase, and material property changes. Likewise treated menisci were implanted in rats for eight weeks and examined for calcium content and biomechanical changes. TGA treatment for three days significantly reduced collagen loss by 88% and increased thermal denaturation temperatures (Ts) above 80 degrees C versus Ts of 70 degrees C or less for non-crosslinked meniscus. In vitro, TGA and TGA-MABP significantly increased aggregate modulus by 19% and 32% compared to native controls, respectively. TGA decreased permeability by 53% while TGA-MABP increased it by 303%. In vivo, TGA significantly reduced explant calcification by 42% compared to glutaraldehyde, and including MABP reduced it by 90%. Analyses revealed that TGA and TGA-MABP stabilized menisci had significantly lower modulus and permeability values than glutaraldehyde controls by at least 28% and 86%, respectively. It is concluded that TGA crosslinking of meniscus increases resistance to both collagenase degradation and pathologic calcification, while demonstrating comparable or improved biomechanical properties versus glutaraldehyde controls.


Subject(s)
Epoxy Compounds/pharmacology , Menisci, Tibial/drug effects , Menisci, Tibial/physiology , Animals , Biomechanical Phenomena/drug effects , Cross-Linking Reagents/pharmacology , Elastic Modulus/drug effects , Glutaral/pharmacology , Permeability/drug effects , Rats , Rats, Sprague-Dawley , Sheep
11.
Am J Pathol ; 175(3): 988-97, 2009 Sep.
Article in English | MEDLINE | ID: mdl-19679875

ABSTRACT

Serotonin (5HT) receptor signaling and 5HT-related agents, such as the anorexogen fenfluramine (Fen), have been associated with heart valve disease. We investigated the hypothesis that Fen may disrupt mitral valve interstitial cell (MVIC) homeostasis through its effects on mitogenesis and extracellular matrix biosynthesis. Normal and myxomatous mitral valves, both human and canine, were harvested, and primary MVIC cultures were established. 5HT caused increased phosphorylation of extracellular signal-related kinase in MVIC; Fen alone did not. However, Fen combined with 5HT increased the level of MVIC extracellular signal-related kinase, when compared with 5HT alone. In addition, MVIC mitogenesis per (3)H-thymidine ((3)HTdR) demonstrated a 5HT dose-dependent increase, with no effect of Fen alone. In contrast, Fen combined with 5HT inhibited the MVIC (3)HTdR response when compared with 5HT alone. Furthermore, fluoxetine, a 5HT transporter inhibitor, while having no effect alone, suppressed Fen-5HT (3)HTdR inhibition when administered with Fen plus 5HT. Finally, MVIC incorporations of (3)H-proline and (3)H-glucosamine, measures of extracellular matrix collagen and glycosaminoglycan respectively, were increased with 5HT alone; however, Fen did not affect MVIC glycosaminoglycan or collagen either alone or in combination with 5HT. Taken together, the ratios of (3)H-proline or (3)H-glycosaminoglycan to (3)HTdR in MVIC, normalized to 5HT alone, demonstrated a significant imbalance of extracellular matrix production versus proliferation in MVIC cultures with Fen plus 5HT exposure. This imbalance may explain in part the pathophysiology of Fen-related mitral valve disease.


Subject(s)
Fenfluramine/pharmacology , Mitral Valve/drug effects , Selective Serotonin Reuptake Inhibitors/pharmacology , Serotonin/pharmacology , Adult , Aged , Aged, 80 and over , Animals , Cell Proliferation/drug effects , Cells, Cultured , Dogs , Dose-Response Relationship, Drug , Drug Antagonism , Extracellular Matrix Proteins/biosynthesis , Female , Heart Valve Diseases , Humans , Male , Middle Aged , Mitral Valve/pathology , Receptors, Serotonin/metabolism , Young Adult
12.
Genesis ; 45(8): 518-22, 2007 Aug.
Article in English | MEDLINE | ID: mdl-17661401

ABSTRACT

The use of Cre-loxP technology for the purpose of cell type-specific gene ablation has revolutionized developmental biology and biomedicine. Several transgenic mouse lines have been developed for the analysis of gene function in the gastrointestinal tract, but in all of these the expression of Cre is limited to the epithelial cell layer. No Cre- expressing transgenic mouse lines ("Cre lines") exist for the deletion of loxP-flanked genes specifically in gut mesoderm. To address this deficiency, we have derived a bacterial artificial chromosome based transgenic mouse line in which the Cre gene is controlled by the Foxl1 promoter and enhancer elements. X-Gal staining of Foxl1-Cre; Rosa26R bi-transgenic lines confirm that Foxl1-Cre results in recombination specifically in the gastrointestinal mesenchyme. The Foxl1-Cre line will facilitate the dissection of mesenchymal to epithelial signaling that is known to play a major role in the patterning and function of the gastrointestinal tract.


Subject(s)
Chromosomes, Artificial, Bacterial , Forkhead Transcription Factors/genetics , Gastrointestinal Tract/metabolism , Gene Deletion , Integrases/genetics , Mesoderm/metabolism , Animals , Cell Survival , Embryo, Mammalian/cytology , Embryo, Mammalian/metabolism , Female , Gastrointestinal Tract/cytology , Male , Mesoderm/cytology , Mice , Mice, Knockout , Mice, Transgenic
13.
J Biomed Mater Res A ; 82(4): 1004-11, 2007 Sep 15.
Article in English | MEDLINE | ID: mdl-17370325

ABSTRACT

Polyurethane cardiovascular implants are subject to oxidation initiated surface degradation, which is mediated by monocyte-derived macrophages (MDM); this often leads to surface cracking and device failure. The present studies examined the hypothesis that covalently attaching antioxidant, di-tert-butylphenol (DBP), to the urethane nitrogens of a polyether polyurethane (PU) via bromo-alkylation reactions could prevent this problem. PU was configured with two dosages of DBP, 0.14 mM DBP/g PU of DBP (PU-DBP) and a more highly modified (HM) 0.40 mM DBP/g PU (PU-DBP-HM). THP-1 cells, a human MDM cell line, stimulated with phorbol ester and seeded on PU, PU-DBP, and PU-DBP-HM films were assessed for reactive oxygen species (ROS) production via a fluorescent based dihydrorhodamine-123 assay. Results from these studies showed a significant dose-dependent reduction of ROS levels for THP-1 cells seeded on PU-DBP versus unmodified PU. PU, PU-DBP, or PU-DBP-HM films were implanted into subdermal pouches of Sprague-Dawley rats. Films were explanted after 10 weeks and assessed for oxidative degradation via light and scanning electron microscopy (SEM) and Fourier transformation infrared spectroscopy (FTIR). Light microscopy showed extensive surface cracking, which was confirmed via SEM, on unmodified PU surfaces that was absent in both PU-DBP and PU-DBP-HM explanted films. FTIR analysis showed reduction in oxidation-induced ether crosslinking that was directly related to DBP dosages. It is concluded that modifying PU with the covalent attachment of an antioxidant confers biodegradation resistance in vivo in a dose dependent manner; this effect is likely due to quenching of the ROS generated by the adherent macrophages.


Subject(s)
Biocompatible Materials/chemistry , Phenols/chemistry , Polyurethanes/chemistry , Animals , Cell Line , Drug Stability , Humans , Macrophages/metabolism , Magnetic Resonance Spectroscopy , Materials Testing , Microscopy, Electron, Scanning , Prostheses and Implants , Rats , Rats, Sprague-Dawley , Reactive Oxygen Species/metabolism , Spectroscopy, Fourier Transform Infrared
14.
Biomaterials ; 28(4): 690-9, 2007 Feb.
Article in English | MEDLINE | ID: mdl-17027944

ABSTRACT

Heart valve replacements fabricated from glutaraldehyde (Glut)-crosslinked heterograft materials, porcine aortic valves or bovine pericardium, have been widely used in cardiac surgery to treat heart valve disease. However, these bioprosthetic heart valves often fail in long-term clinical implants due to pathologic calcification of the bioprosthetic leaflets, and for stentless porcine aortic valve bioprostheses, bioprosthetic aortic wall calcification also typically occurs. Previous use of the epoxide-based crosslinker, triglycidyl amine (TGA), on cardiac bioprosthetic valve materials demonstrated superior biocompatibility, mechanics, and calcification resistance for porcine aortic valve cusps (but not porcine aortic wall) and bovine pericardium, vs. Glut-prepared controls. However, TGA preparation did not completely prevent long-term calcification of cusps or pericardium. Herein we report further mechanistic investigations of an added therapeutic component to this system, 2-mercaptoethylidene-1,1-bisphosphonic acid (MABP), a custom synthesized thiol bisphosphonate, which has previously been shown in a preliminary report to prevent bioprosthetic heterograft biomaterial calcification when used in combination with initial TGA crosslinking for 7 days. In the present studies, we have further investigated the effectiveness of MABP in experiments that examined: (1) The use of MABP after optimal TGA crosslinking, in order to avoid any competitive interference of MABP-reactions with TGA during crosslinking; (2) Furthermore, recognizing the importance of alkaline phosphatase (ALP) in the formation of dystrophic calcific nodules, we have investigated the hypothesis that the mechanism by which MABP primarily functions is through the reduction of ALP activity. Results from cell-free model systems, cell culture studies, and rat subcutaneous implants, show that materials functionalized with MABP after TGA crosslinking have reduced ALP activity, and in vivo have no significant calcification in long-term implant studies. It is concluded that bioprosthetic heart valves prepared in this fashion are compelling alternatives for Glut-prepared bioprostheses.


Subject(s)
Aortic Valve/transplantation , Bioprosthesis , Calcification, Physiologic/physiology , Diphosphonates , Epoxy Compounds , Heart Valve Prosthesis , Alkaline Phosphatase/metabolism , Animals , Cells, Cultured , Cross-Linking Reagents/chemistry , Diphosphonates/chemistry , Epoxy Compounds/chemistry , Liver , Male , Models, Biological , Rats , Sheep , Solubility , Substrate Specificity , Swine , Time Factors
15.
Nature ; 435(7044): 944-7, 2005 Jun 16.
Article in English | MEDLINE | ID: mdl-15959514

ABSTRACT

The specification of the vertebrate liver is thought to occur in a two-step process, beginning with the establishment of competence within the foregut endoderm for responding to organ-specific signals, followed by the induction of liver-specific genes. On the basis of expression and in vitro studies, it has been proposed that the Foxa transcription factors establish competence by opening compacted chromatin structures within liver-specific target genes. Here we show that Foxa1 and Foxa2 (forkhead box proteins A1 and A2) are required in concert for hepatic specification in mouse. In embryos deficient for both genes in the foregut endoderm, no liver bud is evident and expression of the hepatoblast marker alpha-fetoprotein (Afp) is lost. Furthermore, Foxa1/Foxa2-deficient endoderm cultured in the presence of exogenous fibroblast growth factor 2 (FGF2) fails to initiate expression of the liver markers albumin and transthyretin. Thus, Foxa1 and Foxa2 are required for the establishment of competence within the foregut endoderm and the onset of hepatogenesis.


Subject(s)
DNA-Binding Proteins/metabolism , Liver/embryology , Liver/metabolism , Nuclear Proteins/metabolism , Transcription Factors/metabolism , Animals , DNA-Binding Proteins/deficiency , DNA-Binding Proteins/genetics , Fibroblast Growth Factor 2/pharmacology , Gene Deletion , Gene Expression Regulation, Developmental/drug effects , Hepatocyte Nuclear Factor 3-alpha , Hepatocyte Nuclear Factor 3-beta , Hepatocyte Nuclear Factor 3-gamma , Liver/drug effects , Mice , Nuclear Proteins/deficiency , Nuclear Proteins/genetics , RNA, Messenger/genetics , RNA, Messenger/metabolism , Transcription Factors/deficiency , Transcription Factors/genetics
16.
J Clin Invest ; 115(4): 1006-15, 2005 Apr.
Article in English | MEDLINE | ID: mdl-15761495

ABSTRACT

Mutations in the gene encoding hepatocyte nuclear factor-4alpha (HNF-4alpha) result in maturity-onset diabetes of the young (MODY). To determine the contribution of HNF-4alpha to the maintenance of glucose homeostasis by the beta cell in vivo, we derived a conditional knockout of HNF-4alpha using the Cre-loxP system. Surprisingly, deletion of HNF-4alpha in beta cells resulted in hyperinsulinemia in fasted and fed mice but paradoxically also in impaired glucose tolerance. Islet perifusion and calcium-imaging studies showed abnormal responses of the mutant beta cells to stimulation by glucose and sulfonylureas. These phenotypes can be explained in part by a 60% reduction in expression of the potassium channel subunit Kir6.2. We demonstrate using cotransfection assays that the Kir6.2 gene is a transcriptional target of HNF-4alpha. Our data provide genetic evidence that HNF-4alpha is required in the pancreatic beta cell for regulation of the pathway of insulin secretion dependent on the ATP-dependent potassium channel.


Subject(s)
DNA-Binding Proteins/genetics , DNA-Binding Proteins/metabolism , Gene Expression Regulation , Insulin/metabolism , Phosphoproteins/genetics , Phosphoproteins/metabolism , Transcription Factors/genetics , Transcription Factors/metabolism , Animals , Calcium/metabolism , Diabetes Mellitus, Type 2/genetics , Diabetes Mellitus, Type 2/metabolism , Female , Glucose/metabolism , Glucose Tolerance Test , Glyburide/pharmacology , Hepatocyte Nuclear Factor 4 , Hyperinsulinism , Hypoglycemic Agents/pharmacology , Islets of Langerhans/cytology , Islets of Langerhans/drug effects , Islets of Langerhans/physiology , Mice , Mice, Knockout , Potassium Channels, Inwardly Rectifying/genetics , Potassium Channels, Inwardly Rectifying/metabolism , Promoter Regions, Genetic , Protein Subunits/genetics , Protein Subunits/metabolism
17.
J Biol Chem ; 279(40): 41936-41, 2004 Oct 01.
Article in English | MEDLINE | ID: mdl-15252040

ABSTRACT

Foxa1 is a member of the winged helix family of transcription factors and is expressed in the collecting ducts of the kidney. We investigated its potential contribution to renal physiology in Foxa1-deficient mice on a defined genetic background. Foxa1(-/-) mice are dehydrated and exhibit electrolyte imbalance as evidenced by elevated hematocrit and plasma urea levels, hypernatremia, and hyperkalemia. This phenotype is the consequence of decreased urine osmolality secondary to renal vasopressin resistance. Mutations of the human genes encoding the vasopressin 2 receptor and aquaporin 2 cause nephrogenic diabetes insipidus; however, expression of these genes is maintained or increased, respectively, in Foxa1(-/-) mice. Likewise, expression of the genes encoding the Na-K-2Cl cotransporter (NKCC2), the potassium channel ROMK, the chloride channel CLCNKB, barttin (BSND), and the calcium-sensing receptor (CASR), each of which is important in sodium reabsorption in the loop of Henle, is maintained or even increased in Foxa1-deficient mice. Thus, we have shown that Foxa1(-/-) mice represent a new model of nephrogenic diabetes insipidus with unique molecular etiology, and we have identified the first transcription factor whose mutation leads to a defect in renal water homeostasis in vivo.


Subject(s)
DNA-Binding Proteins/deficiency , Diabetes Insipidus, Nephrogenic/etiology , Nuclear Proteins/deficiency , Transcription Factors/deficiency , Animals , Aquaporins/analysis , DNA-Binding Proteins/physiology , Diabetes Insipidus, Nephrogenic/genetics , Diabetes Insipidus, Nephrogenic/metabolism , Disease Models, Animal , Hepatocyte Nuclear Factor 3-alpha , Homeostasis/genetics , Ion Channels/genetics , Kidney/metabolism , Kidney/pathology , Mice , Mice, Knockout , Mutation , Nuclear Proteins/physiology , Phenotype , RNA, Messenger/analysis , Transcription Factors/physiology , Water-Electrolyte Balance/genetics
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