Quality of life after surgical reduction for severe primary lymphoedema of the limbs and genitalia.

BACKGROUND: The aim was to assess the quality of life (QoL) of patients who had surgery for primary lymphoedema. METHODS: A QoL questionnaire was administered to patients who had surgery between 1981 and 2003 (retrospective group) and between 2003 and 2006 (prospective group). RESULTS: The response rate was 70.3 per cent (109 of 155 patients): 88 patients had limb reduction (78, retrospective; ten, prospective) and 21 had genital reduction (13, retrospective; eight, prospective). Forty-nine patients (63 per cent) who had limb reduction studied retrospectively reported satisfaction with the procedure and most of these would opt for surgery again. In the prospectively studied group, nine of ten patients reported improved limbs, and seven would opt for surgery again. Nineteen of 21 patients who had genital reduction would choose to have surgery again if needed (11 of the retrospectively assessed group and all of the prospective group). Patients' perception that surgery was worthwhile was greater in both of the prospectively assessed groups (P = 0.013). CONCLUSION: Surgery for severe lymphoedema improved QoL at early assessment. This, however, may not be sustained. Genital reduction appeared to provide greater benefit than limb reduction.

Adenovirus-mediated VEGF gene therapy enhances venous thrombus recanalization and resolution.

OBJECTIVE: Rapid thrombus recanalization reduces the incidence of post-thrombotic complications. This study aimed to discover whether adenovirus-mediated transfection of the vascular endothelial growth factor gene (ad.VEGF) enhanced thrombus recanalization and resolution. METHODS AND RESULTS: In rats, thrombi were directly injected with either ad.VEGF (n=40) or ad.GFP (n=37). Thrombi in SCID mice (n=12) were injected with human macrophages transfected with ad.VEGF or ad.GFP. Thrombi were analyzed at 1 to 14 days. GFP was found mainly in the vein wall and adventitia by 3 days, but was predominantly found in cells within the body of thrombus by day 7. VEGF levels peaked at 4 days (376+/-299 pg/mg protein). Ad.VEGF treatment reduced thrombus size by >50% (47.7+/-5.1 mm(2) to 22.0+/-4.0 mm(2), P=0.0003) and increased recanalization by >3-fold (3.9+/-0.69% to 13.6+/-4.1%, P=0.024) compared with controls. Ad.VEGF treatment increased macrophage recruitment into the thrombus by more than 50% (P=0.002). Ad.VEGF-transfected macrophages reduced thrombus size by 30% compared with controls (12.3+/-0.89 mm(2) to 8.7+/-1.4 mm(2), P=0.04) and enhanced vein lumen recanalization (3.39+/-0.34% to 5.07+/-0.57%, P=0.02). CONCLUSIONS: Treatment with ad.VEGF enhanced thrombus recanalization and resolution, probably as a consequence of an increase in macrophage recruitment.

Hereditary palmoplantar keratoderma associated with primary (congenital) lymphedema.

The palmoplantar keratodermas are a heterogenous group of hereditary disorders of keratinization. They are characterized by epidermal thickening and a yellow waxy appearance of the palms and soles. Genetic studies have linked various forms of palmoplantar keratoderma to markers on chromosomes one, twelve, and seventeen, and several genes have been identified. Primary lymphedema is occasionally present at birth (congenital lymphedema or Milroy's disease), but more commonly develops at puberty (lymphedema praecox). Genetic studies have linked various autosomal dominant forms of primary lymphedema (Milroy's disease and lymphedema distichiasis), to genes on chromosomes five and sixteen respectively. We report a case of palmoplantar keratoderma in a child with congenital lymphedema. To our knowledge, this has not been previously described and may represent a new phenotype for future genetic study.

Imaging of deep vein thrombosis.

BACKGROUND: Deep vein thrombosis of the leg affects 1-2 per cent of the population with an annual incidence of 0.5-1 per 1000. It presents with non-specific symptoms and signs making clinical diagnosis difficult. Techniques to image and diagnose this condition are advancing rapidly. METHODS AND RESULTS: A literature review from 1980 to 2007 was undertaken using PubMed, The Cochrane Library, Medline and Embase. The most frequently used diagnostic test is duplex ultrasonography which is accurate above the knee and has a low cost, but is limited by inaccuracy when assessing the pelvic and distal veins and in diagnosing a new thrombosis in the post-thrombotic limb. Magnetic resonance imaging (MRI) and sonographic elasticity imaging are more recent techniques that have shown promise in overcoming these limitations. However, their availability is currently restricted because they are expensive. Computed tomography (CT) is sensitive, specific and provides good imaging of the pelvis. It has the advantage that it can be performed at the same time as CT pulmonary angiography. CONCLUSION: MRI has some specific advantages over duplex ultrasonography, but requires refinement before it can be used clinically. Venography or CT venography should be considered when duplex scanning is inadequate.

Effect of statins on proteolytic activity in the wall of abdominal aortic aneurysms.

BACKGROUND: The aim of this study was to examine the effect of statin treatment on the activity of proteases in the wall of abdominal aortic aneurysms (AAAs). METHODS: The activities of matrix metalloproteinases (MMPs) 9 and 3, cathepsins B, H, K, L and S, and the cystatin C level were measured in extracts of AAA wall taken from 82 patients undergoing AAA repair; 21 patients were receiving statin treatment before surgery. All values were standardized against soluble protein (SP) concentration in the extract, and reported as median (interquartile range) or mean(s.e.m.). RESULTS: The two groups had similar demographics. Reduced activity of MMP-9 (43 (34-56) versus 80 (62-110) pg per mg SP; P < 0.001), cathepsin H (183 (117-366) versus 321 (172-644) nmol 4-methylcoumarin-7-amide released per mg SP; P = 0.016) and cathepsin L (102 (51-372) versus 287 (112-816) micromol 7-amino-4-trifluoromethylcoumarin released per mg SP; P = 0.020) was found in the statin-treated aortas compared with AAAs from patients not taking a statin. The statin-treated group had lower MMP-3 activity, but this did not reach statistical significance (P = 0.053). Cystatin C levels were higher in statin-treated aortas than in controls (41.3(3.1) versus 28.9(2.1) ng per mg SP; P = 0.003). CONCLUSION: Statins decreased the activity of proteases that have been implicated in aneurysm disease.

Effect of collagen turnover and matrix metalloproteinase activity on healing of venous leg ulcers.

BACKGROUND: The presence of fibrous tissue in poorly healing venous leg ulcers suggests abnormal collagen metabolism. The aim was to determine whether there were differences in collagen turnover and matrix metalloproteinase (MMP) activity between ulcers that healed, those that did not heal and normal skin. METHODS: Biopsies were taken from the ulcers of 12 patients whose venous ulcers went on to heal and 15 patients whose ulcers failed to heal despite 12 months of compression bandaging. Biopsies were taken from 15 normal controls. Collagen turnover (collagen III N-terminal propeptide (PIIINP) and degraded collagen), and total MMP, MMP-1 and MMP-3 activities were measured. RESULTS: PIIINP and degraded collagen levels were higher in ulcers that healed compared with lesions that failed to heal (P = 0.005 and P < 0.001 respectively) and normal skin (P = 0.003 and P < 0.001). MMP-1 activity was also higher in healing ulcers than resistant ulcers (P < 0.001) and normal skin (P < 0.001). Significantly more total MMP activity was present in all ulcers than in normal skin (P < 0.001), but there was no difference in total MMP (and MMP-3 activity) between ulcers that healed and those that did not. CONCLUSION: Rapidly healing venous leg ulcers had increased collagen turnover and MMP-1 activity, which appeared to differentiate them from those that failed to heal within 12 months.

Endothelial progenitor cells are recruited into resolving venous thrombi.

BACKGROUND: The purpose of this study was to determine whether endothelial cells of bone marrow origin are involved in thrombus recanalization. METHODS AND RESULTS: Irradiated mice were reconstituted with bone marrow from transgenic donors expressing green fluorescent protein (GFP) linked to the Tie2 promoter. Thrombi were formed in 2 groups of 6 mice. GFP-expressing cells were located and quantified in sections of the thrombi taken after 7 and 14 days. The cell markers Mac-3, F4/80, CD68 (macrophage), and vascular endothelial growth factor receptor 2 (VEGFR2; endothelial cells) were used to determine colocalization with GFP expression in tissue sections and peritoneal macrophages. The markers CD34 and VEGFR2 were used to quantify changes in circulating endothelial cells by flow cytometry of blood from 3 cohorts of wild-type animals that had either a thrombus induced (n=18), a sham operation (n=18), or no operation (n=10). The number of GFP-expressing cells was found to increase by approximately 3-fold in thrombi formed in transplanted animals between 7 and 14 days after induction (P=0.0022). No GFP-expressing cells were found lining the new vascular channels that formed at either time interval, but many of the GFP-expressing cells also expressed Mac-3, CD68, and VEGFR2. Approximately twice as many circulating CD34+/VEGFR2+ cells were found by day 3 in animals with thrombus compared with sham controls (CD45-, P=0.046 and CD45(+), P=0.016). CONCLUSIONS: Bone marrow-derived, Tie2-expressing cells were recruited into the thrombus during resolution but did not line the new vessels. Many of these cells expressed a macrophage phenotype and may represent a population of plastic stem cells that orchestrate thrombus recanalization.

Peripheral arterial embolism: prevalence, outcome, and the role of echocardiography in management.

The aims of this study were to review the prevalence and outcome of all surgically treated upper and lower limb emboli presenting to one vascular unit in the last 3 years and to compare transthoracic with transesophageal echocardiography for defining the source of the embolus. All patients who underwent surgical embolectomy for acute limb ischemia from January 2001 to June 2004 were reviewed. Transthoracic and transesophageal echocardiography were carried out on a subset of consecutive unselected patients. Forty-two patients, with a mean age of 80 years, underwent surgical embolectomy from January 2001 to June 2004 (M/F 1:1.8): 27 for lower limb ischemia and 15 for upper limb ischemia. Two thirds of these patients were found to be in atrial fibrillation at presentation (n = 28), of whom less than a third were receiving anticoagulants or antiplatelet agents (n = 8). The mean hospital stay was 15 days with 36 patients (86%) being fully anticoagulated before discharge from hospital. The 30-day mortality rate was 11% (n = 3/27) with 5 patients requiring fasciotomies (12%) and 3 patients requiring an amputation of the lower limb (11%). Postoperatively, 34 patients (81%) had transthoracic echocardiography (TTE), which demonstrated a source or potential source for thrombus in 19 (56%). Fifteen patients (36%) had transesophageal echocardiography (TEE), which changed the subsequent management in 3 patients. All patients in whom TEE altered clinical management would have required this investigation if standard clinical guidelines were followed. TEE did not identify any additional patients with cardiac embolic sources that were not detected by TTE. Arterial limb emboli are still prevalent, but limb salvage and mortality rates appear to be improving. Despite clear guidelines on anticoagulation for patients in atrial fibrillation, many are not receiving appropriate treatment. Transthoracic echocardiography is a good screening tool for detecting a potential cardiac source for peripheral embolism, with transesophageal echocardiography being reserved for specific indications.

Development of simultaneous anastomotic false aneurysms at both ends of an autologous vein graft caused by methicillin-resistent Staphylococcus aureus (MRSA).

Methicillin-resistant Staphylococcus aureus (MRSA) infection is a well recognised problem, especially in vascular surgical patients with synthetic bypass grafts. This is to our knowledge the first report in the literature of the development of anastomotic false aneurysms at both ends of an autologous vein graft, as a result of MRSA infection within the vascular wall.

Failure of thrombus to resolve in urokinase-type plasminogen activator gene-knockout mice: rescue by normal bone marrow-derived cells.

BACKGROUND: Monocytes may have an important role in the resolution of venous thrombosis. Increased expression of tissue-type plasminogen activator (tPA) and urokinase-type plasminogen activator (uPA) is associated with an ingress of monocytes into the thrombus. This study was designed to evaluate the importance of these activators in thrombus resolution. METHODS AND RESULTS: Inferior caval vein thrombosis was induced in cohorts of adult wild-type, uPA gene-knockout (uPA-/-), and tPA gene-knockout (tPA-/-) mice in a flow model. Thrombi were harvested from wild-type and uPA-/- mice (n=60 per group) between 1 and 60 days. Thrombi were also obtained from groups of wild-type and tPA-/- mice (n=24 per group) between 1 and 28 days. Thrombus size and macrophage content were measured by computer-assisted image analysis. Thrombus resolution was significantly impaired in the uPA-/- mice compared with wild-type controls (P<0.0001) but was unaffected in tPA-/- mice. Monocyte content in wild-type mice was highest at 14 days after thrombus induction and was approximately 4 times greater than in uPA-/- mice (P=0.0043). Thrombus size in uPA-/- mice transplanted with wild-type marrow (0.29+/-0.06 mm2) was significantly smaller than in uPA-/- mice given uPA-/- bone marrow (3.9+/-1.1 mm2) (P=0.0022). Donor bone marrow-derived cells expressing LacZ were present in the thrombus after transplantation. CONCLUSIONS: The resolution of experimental venous thrombus is dependent on uPA but is unaffected by the absence of tPA. Absence of uPA is also associated with delayed monocyte recruitment into the thrombus. Transplanting wild-type bone marrow restores thrombus resolution in uPA-/- animals, suggesting an important role for bone marrow-derived cells in this process.

Analysis of the phenotypic abnormalities in lymphoedema-distichiasis syndrome in 74 patients with FOXC2 mutations or linkage to 16q24.

INTRODUCTION: Lymphoedema-distichiasis syndrome (LD) (OMIM 153400) is a rare, primary lymphoedema of pubertal onset, associated with distichiasis. Causative mutations have now been described in FOXC2, a forkhead transcription factor gene. Numerous clinical associations have been reported with this condition, including congenital heart disease, ptosis, varicose veins, cleft palate, and spinal extradural cysts. SUBJECTS: We report clinical findings in 74 affected subjects from 18 families and six isolated cases. All of them were shown to have mutations in FOXC2 with the exception of one family who had two affected subjects with lymphoedema and distichiasis and linkage consistent with the 16q24 locus. RESULTS: The presence of lymphoedema was highly penetrant. Males had an earlier onset of lymphoedema and a significantly increased risk of complications. Lymphatic imaging confirmed the earlier suggestion that LD is associated with a normal or increased number of lymphatic vessels rather than the hypoplasia or aplasia seen in other forms of primary lymphoedema. Distichiasis was 94.2% penetrant, but not always symptomatic. Associated findings included ptosis (31%), congenital heart disease (6.8%), and cleft palate (4%). Other than distichiasis, the most commonly occurring anomaly was varicose veins of early onset (49%). This has not been previously reported and suggests a possible developmental role for FOXC2 in both venous and lymphatic systems. This is the first gene that has been implicated in the aetiology of varicose veins. CONCLUSION: Unlike previous publications, the thorough clinical characterisation of our patients permits more accurate prediction of various phenotypic abnormalities likely to manifest in subjects with FOXC2 mutations.

The effects of 10 years of recombinant human growth hormone (GH) in adult GH-deficient patients.

The long term effects of GH replacement in adult GH-deficient (GHD) patients have not yet been clarified. We studied 21 GHD adults who originally took part in a randomized, double blind, placebo-controlled trial of GH treatment in 1987. After completion of that trial, 10 patients received continuous GH replacement for the subsequent 10 yr, whereas 11 did not. A group of 11 age- and sex-matched normal controls were also studied in 1987 and 1997. Lean body mass, as assessed by total body potassium measurement and computed tomography scanning of the dominant thigh, increased in the GH-treated group (P < 0.01 for both) only (P < 0.05 between groups for total body potassium). Low density lipoprotein cholesterol decreased in the GH-treated group (P < 0.05) only. Carotid intima media thickness was significantly greater (P < 0.05) in the untreated group than in the GH-treated group. Assessment of psychological well-being using the Nottingham Health Profile revealed improvement in overall score, energy levels, and emotional reaction in the GH-treated group compared with those in the untreated group (P < 0.02). In conclusion, GH treatment for 10 yr in GHD adults resulted in increased lean body and muscle mass, a less atherogenic lipid profile, reduced carotid intima media thickness, and improved psychological well-being.

Induced expression of adipophilin mRNA in human macrophages stimulated with oxidized low-density lipoprotein and in atherosclerotic lesions.

Oxidized low-density lipoprotein (OxLDL) plays a critical role in foam cell formation and atherosclerogenesis. A cDNA encoding adipophilin was identified in cultured human macrophages stimulated with OxLDL using mRNA differential display. Adipophilin is a 50 kDa protein known to be a specific marker for adipocyte cell differentiation and lipid accumulation in a variety of cells. The time-dependent induction of adipophilin mRNA in macrophages was specific to OxLDL but not native LDL, and not to various cytokines and serum. In human atherosclerotic lesions, adipophilin mRNA expression was localized in a subset of lipid-rich macrophages. These data suggest that adipophilin-expressing macrophages may represent foam cells and this gene expression is likely to be associated with the lipid accumulation in foam cells of the atherosclerotic lesions.

Recruitment of labelled monocytes by experimental venous thrombi.

OBJECTIVE: Infusing monocytes that have been stimulated to produce fibrinolytic activators and factors that regulate cell proliferation, migration and maturation, might enhance venous thrombus resolution. The aim of this study was to determine the time course of infused monocyte recruitment into venous thrombus in an appropriate model of this disease. DESIGN AND METHODS: Thrombus was induced in the inferior vena cava of male Wistar rats using reduced flow (80-90% stenosis). The vessel wall was examined at 1hr by scanning electron microscopy. Resolving thrombi with surrounding vena cava were obtained at 1, 7, 14 and 21 days after induction (n = 8). Sections, taken at 0.5 mm intervals (10-15 sections per thrombus), were stained using haematoxylin, Martius Scarlet Blue and antibodies against monocytes, platelets and fibrin. Sections from human venous thrombi (n = 4) were similarly stained. The area occupied by monocytes (in relative pixel units, RPU) was determined using computer aided image analysis. Peripheral rat blood monocytes were extracted, fluorescently labelled and injected intravenously into 7 rats prior to thrombus induction, Vena cava with thrombus was harvested 1 h, 2, 3, 4, 7, 14 and 25 days after induction and their fluorescence measured. The fluorescent content of the caval wall and thrombus was analysed in greater detail at 2 and 25 days after thrombus induction (n = 4 at each time interval). RESULTS: Experimental thrombi were structurally similar to human thrombus and resolved within 14-21 days. Scanning electron microscopy showed minimal endothelial damage at 1 h with signs of early thrombus formation (platelet, red cell leukocyte and fibrin deposition). Neutrophils were the predominant leukocyte in the thrombus at 1 day, with monocytes making up only 0.3% (0.04% sem) of the area of the thrombus. There was a steady increase in thrombus monocyte content and by 21 days the percentage area of thrombus covered by monocytes had increased by over 35 fold to 11.5% (2.3% sem) (p <0.001). Initially, monocytes appeared around the edge of the thrombus and became more evenly distributed through the thrombus as resolution progressed. Labelled monocytes could be found in the circulation up to 1 week after infusion. The fluorescent content (RPU) of the thrombus increased over 25 days (mean RPU At 2 days 0.012, sem 0.005; mean RPU at 25 days 1.062, sem 0.252, p = 0.008). The number of labelled monocytes in the vessel wall peaked at 2 days and decreased thereafter. CONCLUSION: The structure of thrombi produced by this model was comparable to that of human venous thrombi. Endogenous and injected monocytes migrated into the thrombus during natural resolution, possibly via the vein wall. Monocyte targeting could therefore be used to develop novel treatments for venous thrombosis, with the aim of reducing post-thrombotic complications.

Changes in the levels of soluble adhesion molecules and coagulation factors in patients with deep vein thrombosis.

Current biochemical markers of thrombosis, such as d-dimer, are of little value in demonstrating the presence of thrombus postoperatively, as their levels are elevated by surgery. Thrombosis involves adhesive interactions between the endothelium, platelets and leukocytes. The aim of the study was to determine which of a panel of haemostatic and adhesion factors are altered by the presence of thrombus, but not by surgery. These factors were measured in 20 patients with established spontaneous DVTs, 13 patients having hip replacement surgery and 28 control patients. Circulating levels of P-selectin, VCAM-1 and tissue factor were found to be increased when thrombus was present (p <0.018, p <0.0001, p <0.0028 respectively), but were not altered by surgery. The significance of these circulating factors in venous thrombosis remains to be established, but it is conceivable that they are the product of increased leukocyte trafficking and activity. Assay of VCAM-1, in particular, may be of use in the early detection of venous thrombi in postoperative patients.

The response of the vessel wall to thrombosis: the in vivo study of venous thrombolysis.

The vessel wall is the site of synthesis and regulation of the fibrinolytic system, and this delicate process is overwhelmed by occlusive thrombosis in veins. The endothelium may or may not survive thrombus formation, but has strong powers of regeneration, and is subsequently vital to the process of recanalizing the vessel. The endogenous fibrinolytic response to venous thrombosis is not well delineated but appears to involve both the newly formed endothelium within and beneath the organizing thrombus, together with an increase in tissue plasminogen activator synthesis or storage in distant uninvolved veins. The further use of thrombus models in which the endothelium is not definitely damaged should enable greater understanding of its role. Immunocytochemistry and in situ hybridization may be helpful in defining some of the unanswered questions.

The relative importance of incompetent communicating veins in the production of varicose veins and venous ulcers.

To investigate the possible anatomic and hemodynamic reasons for the variability in response to surgery for venous insufficiency (a 50% ulcer recurrence rate following ligation of incompetent perforating veins), we performed phlebography and venous pressure measurements in 109 legs of 77 patients and in 30 healthy volunteers. Patients were divided into five groups: saphenofemoral incompetence alone (group 1), saphenopopliteal incompetence (group 2), incompetent lower leg communicating veins alone (group 3), calf communicating veins and saphenous incompetence (group 4), and postthrombotic limbs (group 5). Patients in groups 1 through 4 had phlebographically normal deep veins. As compared to the normal controls (68%), preoperative pressure measurements revealed a significantly smaller pressure fall during exercise (deltaVPex) in all groups, which was the least marked in groups 3 (26%) and 5 (17%). These latter two groups failed to increase their pressure fall with thigh tourniquet. deltaVPex 3 months after operation demonstrated normalization in groups 1, 2, and 4 (52%, 57% and 59% respectively). Groups 3 and 5 improved little following surgical ligation. Whenever saphenous vein incompetence coexists with lower leg communicating vein incompetence, the former appears to be the dominant cause of the pressure abnormalities. Based on venous pressure measurements and phlebography, patients with normal deep veins and who increase their deltaVPex with a thigh tourniquet should respond favourably to orthodox surgical ligation of the saphenofemoral or saphenopopliteal junction. By contrast, if no change in deltaVPex is noted in patients with incompetent perforating veins and the deep veins look abnormal on the phlebogram, then ligation of the incompetent communicating veins would appear to be associated with a high recurrence rate.

Doppler examination vs clinical and phlebographic detection of the location of incompetent perforating veins: a prospective study.

Accuracy in excess of 80% has been claimed both for ultrasound and for phlebographic localization of incompetent perforating veins (ICPVs). To test these claims, a blind prospective study was carried out to compare three methods of simultaneous ICPV detection with operative findings. ICPV localization on the medial side of 39 legs was made by clinical examination, ultrasound, and ascending phlebography, each by a different observer. The ICPVs were confirmed at operation. All three methods were comparable in their accuracy in predicting the anatomical site of ICPVs. Phlebography produced fewer (seven) and ultrasound more (49) false-positive results than clinical examination did. There was no specific advantage of ultrasound over clinical examination. The advantages of phlebography, (1) fewer unnecessary explorations and (2) assessment of the status of the deep venous sytem, must be weighed against its cost and morbidity.

High and constant plasma levels of tissue plasminogen activator and PEG-hirudin can be achieved by subcutaneous delivery.

Intramural thrombosis is a consistent finding in the arteries of patients who die following coronary angioplasty. This thrombosis is thought to have a role in restenosis, which is a common complication of coronary angioplasty. It has been hypothesised that antithrombotics such as hirudin or tissue-type plasminogen activator (tPA), may be therapeutically useful following angioplasty. This report describes the bioavailability of both agents following subcutaneous (sc) injection in cholesterol-fed rabbits. Intravenously delivered tPA has a half-life of 3-5 minutes. The half-life of intravenously administered hirudin is less than one hour in many species. In order to prolong the duration of action recombinant hirudin was conjugated to polyethylene glycol (PEG). Polyethylene glycol conjugated recombinant hirudin (PEG-rH) (0.7 mg/kg) antigen and activity were measurable after just 1 hr, reaching a maximum (663 and 884 ng/ml respectively) at 12 hours. Significant levels were present in rabbit plasma 24 hours after injection. Subcutaneously delivered recombinant (r-tPA) (1 mg/kg) was present in significant amounts 1 hr after injection, reaching a maximum (92 IU/ml) at 2 hours. Levels of tPA at 9 hours were approximately 80x normal circulating levels. High and constant levels of functional activity of both PEG-rH and r-tPA in rabbit plasma are achieved by subcutaneous delivery.

Tissue plasminogen activators in breast cancer.

Increased levels of tissue fibrinolytic activity have been detected in some malignant tumours and they have been implicated in metastatic spread. We have investigated tissue plasminogen activator (tPA) and urokinase (UK) in 26 breast carcinomas and 13 benign breast biopsies. Tissue extracts were analysed for overall fibrinolytic activity on fibrin plates and by fibrin-overlay zymography after electrophoresis on SDS-PAG. Supernatants of the extracts were analysed by an antigenic immunoassay (ELISA) and a functional bioimmunoassay (BIA) using polyclonal antibodies. Total ELISA and BIA results correlated (P less than 0.001) and all the tissues contained similar tPA levels. Malignant extracts contained significantly increased UK compared with benign extracts (1.60 +/- 0.37 iu, 0.36 +/- 0.16 iu; P less than 0.002). Zymography showed no high molecular weight inhibitor complexes and UK was almost exclusively confined to the malignant tissues (P much less than 0.02). The results suggest that malignant transformation of breast tissue is associated with the significantly increased production of UK. This may be responsible for the characteristics of malignancy or it may be a growth factor.