Human fibroblasts downregulate plasminogen activator inhibitor type-1 in cultured human macrovascular and microvascular endothelial cells

We have previously reported that plasminogen activator inhibitor type-1 (PAI-1) expression in endothelial cells (ECs) can be modulated differently by smooth muscle cells depending on their origin. Human pulmonary artery smooth muscle cells (HPASMCs) strongly downregulated PAI-1 expression in ECs. Fibroblasts (FBs) are another cell type that could come in close contact with ECs. Therefore, it was the aim of this study to investigate whether FBs could also influence the fibrinolytic potential of ECs. As in the case of HPASMCs, PAI-1 antigen produced by human umbilical vein ECs (HUVECs) cocultured with human skin FBs (HSFBs) was significantly lower as compared with the sum of PAI-1 secreted by the respective cell types cultured separately. Not only HUVECs but also human skin microvascular ECs (HSMECs) responded in a dose-dependent way to serum-free conditioned media (CM) from HSFBs from one individual donor. Similar results were obtained when CM from HSFBs from four other individual donors were used. PAI-1 mRNA decreased in HUVECs incubated for 6 hours with HSFB-CM to 24% to 55% of control, depending on the preparation of HSFBs used. A significant PAI-1 downregulatory effect was only observed when CM from low-passage HSFBs (up to passage no. 5) was used, whereas no reduction in EC PAI-1 production was observed with CM obtained from HSFBs in passage no. 8. This PAI-1 downregulatory activity present in HSFB-CM was heat-labile and had a molecular mass of approximately 5 kD. When CM from HPASMCs was analyzed in the same way, an almost identical elution profile was found. In conclusion, our data showed that FBs can decrease the expression of PAI-1 in ECs. Such an effect could be operative during wound-healing and at other capillary sites where FBs could render ECs profibrinolytic, thereby facilitating processes requiring an increase in proteolytic activity such as EC migration and proliferation.     

Neoplasms of the nasal passages and paranasal sinuses in domesticated animals as reported by 13 veterinary colleges

Three hundred cases of primary neoplasms involving the nasal cavity or paranasal sinuses were found among the reports of 12,300 microscopically confirmed neoplasms. The multispecies data were compiled from abstracts of medical records by 13 colleges of veterinary medicine in the United States and Canada from 1964 to 1973. Significant numbers of neoplasms were observed in dogs, horses, and cats. Intranasal neoplasms were more frequent than those of the paranasal sinuses in dogs and cats. Only cats had a sex difference in the occurrence of nasal neoplasms, with a male predilection. The frequency of neoplasms of the nasal cavity and paranasal sinuses increased with age in all species examined. A clear relationship could not be established between nose length and of intranasal neoplasms. Of the tumors, 80% were malignant in dogs, 68% in horses, and 91% in cats. Detailed review of medical records in a subset of 49 dogs with neoplasms of the nasal passage and paranasal sinuses revealed major clinical signs of nasal and ocular discharge, facial deformity, and stertorous breathing. Median duration of signs prior to diagnosis was 3 months and 95% of the dogs had been given treatment prior to definitive diagnosis. All 49 tumors were malignant; 27 were classified histologically as carcinomas and 22 were sarcomas. Nineteen dogs were treated, using surgery alone or in combination with radiation therapy. Median survival duration was 5 months (mean 6.7 mo).     

Surgical treatment of combined valvular disease in 680 patients

Between 1982 and May 1993, we operated on 680 patients with combined valvular disease. Previous operations were including closed mitral commissurotomy in 87, and bioprosthetic valve replacement in mitral position in 15. The types of combined valve disease included mitral valve disease combined with functional tricuspid regurgitation (FTR) (245), with organic tricuspid disease (OTD) (10); mitral and aortic disease (258), combined with FTR (128), and with OTD (39). The early mortality was 4.7% in total 2.4% and 6.1% respectively in MVR or DVR plus tricuspid procedures. The main cause of early death was low cardiac output syndrome. The late mortality was 2.6% pt-yr, congestive heart failure and coagulant-related hemorrhage were the predominant causes of late death. We considered that FTR is the outcome of right ventricle decompensation, while tricuspid valve must be actively inspected intraoperatively, and must be corrected completely. OTD can be successfully repaired in most patients. Myocardial protection should be emphasized, and continuous perfusion of cold blood cardioplegia and controlled reperfusion of warm blood contained mannitol have marked effect.     

Rat model for a vascularized laryngeal allograft

A new rat model was developed to reexamine the potential for laryngeal transplantation. The final anatomic derivation evolved from two earlier developmental phases. The first model had only a single arterial anastomosis; the second had an end-to-end arterial anastomosis with an end-to-end arteriovenous shunt. The final product employed an end-to-side arterial shunt and an end-to-side arteriovenous shunt for revascularization. The allografts were sited in tandem with the intact recipient larynges and were not innervated. A total of 16 animals were studied in phase 3; 2 died and the remaining 14 had a 64% arterial patency at intervals of 1 to 14 days. Our purpose is to detail the relevant technical considerations of this new model and compare it with historical controls.     

Patient selection in outpatient parenteral antimicrobial therapy

Outcome data as well as reported anecdotal experience over the past 20 years indicate that any infection can be safely treated with parenteral antimicrobials outside the hospital setting. However, outpatient parenteral antimicrobial therapy (OPAT) is a reasonable option only when the final decision for patient selection is based on the judgment of a knowledgeable, experienced physician, and when an experienced qualified provider is available. Criteria to be considered include clinical status, patient acceptance, ability to comply with the plan of treatment, home environment, support systems, and reimbursement. Physician direction and participation in appropriate patient selection will become increasingly important as the growth of managed care increases the importance of cost-savings.     

Leukocyte Adhesion Deficiency Type II is a generalized defect of de novo GDP-fucose biosynthesis. Endothelial cell fucosylation is not required for neutrophil rolling on human nonlymphoid endothelium

Leukocyte Adhesion Deficiency Type II (LAD II) is a recently described syndrome and the two patients with this defect lack fucosylated glycoconjugates. These glycoconjugates include the selectin ligand, sialyl LewisX, and various fucosylated blood group antigens. To date, the molecular anomaly in these patients has not been identified. We localized the defect in LAD II to the de novo pathway of GDP-fucose biosynthesis, by inducing cell-surface expression of fucosylated glycoconjugates after exposure of lymphoblastoid cell lines from the LAD II patients to exogenous fucose. This defect is not restricted to hematopoietic cells, since similar findings were elicited in both human umbilical vein endothelial cells (HUVEC) and fibroblasts derived from an affected abortus. We have used these LAD II endothelial cells to examine the consequence of fucosylation of endothelial cells on the rolling of normal neutrophils in an in vitro assay. Neutrophil rolling on LPS-treated normal and LAD II HUVEC was inhibited by an E-selectin monoclonal antibody at both high and low shear rates. LAD II HUVEC lacking fucosylated glycoproteins supported leukocyte rolling to a similar degree as normal HUVEC or LAD II cells that were fucose-fed. At low shear rates, an L-selectin antibody inhibited neutrophil rolling to a similar degree whether the LAD II cells had been fucose-fed or not. These findings suggest that fucosylation of nonlymphoid endothelial cells does not play a major role in neutrophil rolling and that fucose is not a critical moiety on the L-selectin ligand(s) on endothelial cells of the systemic vasculature.     

Platelet-derived growth factor and fibronectin-stimulated migration are differentially regulated by the Rac and extracellular signal-regulated kinase pathways

Directed cell migration is essential for a variety of important biological processes ranging from development and angiogenesis to metastasis. Ras plays a pivotal role in the signaling cascade that governs chemotaxis of fibroblasts toward platelet-derived growth factor-BB (PDGF-BB). Ras activates multiple downstream pathways, which include the extracellular signal-regulated kinase (ERK), Rac, and Ral signaling cascades. We therefore investigated the role of the Rac and ERK pathways in cell migration. We showed that migration of fibroblasts toward PDGF-BB is inhibited by expression of dominant negative Asn-17 Rac1. Blocking of the ERK pathway by either expression of dominant negative Ala-218/Ala-222-mitogen-activated protein kinase kinase (A218/A222-MEK1) or by a MEK-specific inhibitor did not inhibit migration toward PDGF-BB. In contrast, migration toward soluble fibronectin was suppressed by inhibition of the ERK pathway but not by Asn-17 Rac1 expression. These results indicate that directed cell migration mediated by different receptor classes in response to different ligands differentially utilizes the Rac and ERK pathways and suggest that Rac might play a critical role in pathological processes such as angiogenesis and metastasis.