Immunohistochemical properties of motoneurons supplying the porcine trapezius muscle.

The trapezius muscle (TRAP) belongs to the scapulothoracic group of muscles, which play a crucial role in the integrity and strength of the upper limb, trunk, head, and neck movements and, thus, in maintaining balance. Combined retrograde tracing (using fluorescent tracer Fast Blue, FB) and double-labelling immunohistochemistry were applied to investigate the chemical coding of motoneurons projecting to the porcine TRAP. FB-positive (FB+) motoneurons supplying the cervical (c-TRAP) and thoracic part (th-TRAP) of the right (injected with the tracer) TRAP were located within the IX-th Rexed lamina in the ipsilateral ventral horn of the grey matter of the spinal medulla. Immunohistochemistry revealed that nearly all the neurons were cholinergic in nature [choline acetyltransferase (CHAT)- or vesicular acetylcholine transporter (VACHT)-positive]. Many retrogradelly labelled neurons displayed also immunoreactivity to calcitonin gene-related peptide (CGRP; approximately 68% of FB+ neurons). The smaller number of nerve cells (5%, 3%, 2% or 1%, respectively) stained for nitric oxide synthase (n-NOS), vasoactive intestinal polypeptide (VIP), neuropeptide Y (NPY) and substance P (SP). The retrogradely labelled neurons were closely apposed by nerve fibres expressing immunoreactivity to CHAT, VACHT, CGRP, SP, DßH, VIP, n-NOS, NPY, GAL, Leu-Enk and Met-Enk. Taking into account the clinical relevance of TRAP, the present results may be useful in designing further research aimed at the management of various dysfunctions of the muscle.

Haptoglobin as a treatment monitoring factor in feline plasmacytic gingivostomatitis.

INTRODUCTION: feline plasmacytic gingivostomatitis is an important and fairly common chronic disease. Its complex aetiology - which involves infectious agents, immunological disorders, and even genetic factors adds to the considerable difficulty of its treatment. MATERIALS AND METHODS: the study was performed on 33 cats, 26 animals diagnosed with plasmacytic gingivostomatitis (study group) and 7 clinically healthy cats (control group). The study extended over four examination periods during which clinical and X-ray examinations, morphological and biochemical blood tests, as well as haptoglobin essays were performed. RESULTS: the biochemical and haematological parameters were within normal limits. Blood serum haptoglobin measured on the first day of the treatment was above physiological levels, however its serum concentration decreased as the treatment progressed. CONCLUSIONS: in the present study, despite the bacterial inflammatory condition of periodontal pockets, after the treatment was concluded and symptoms alleviated, neither clinical examinations nor haptoglobin essays revealed deviations from values commonly accepted as normal. Fluctuations in blood serum haptoglobin levels proved to be a useful prognostic in determining the duration of necessary treatment.

Immunohistochemical characterization of the jugular (superior vagal) ganglion in the pig.

The study was carried out on three 4-month old female pigs. All the animals were deeply anesthetized and transcardially perfused with 4% buffered paraformaldehyde (pH 7.4). Left and right superior vagal ganglia (SVG) were collected and processed for immunofluorescence labeling method. The preparations were examined under a Zeiss LSM 710 confocal microscope equipped with adequate filter block. Neurons forming SVG were round or oval in shape with a round nucleus in the center. The majority of them (52%) were medium (M) (31-50 µm in diameter) while 7% and 41% were small (S) (up to 30µm in diameter) or large (L) (above 50 µm in diameter) in size, respectively. Double-labeling immunofluorescence revealed that SVG neurons stained for CGRP (approx. 57%; among them 37%, 9% and 54% were M, S and L in size, respectively), SP (14.5%; 72.4% M, 3.4% S, 24.2% L), VACHT (26%; 63% M, 24% S and 13% L), GAL (14%; 57% M, 29% S, 14% L), NPY (12%; 53% M, 12% S, 35% L), Met-Enk (5%; 40% M, 6% S and 54% L), PACAP (15%; 52% M, 24% S and 24% L), VIP (6.3%; 67% M, 8% S and 25% L), and NOS-positive (6%; 31% M and 69% L). The most abundant populations of intraganglionic nerve fibers were those which stained for CGRP or GAL, whereas only single SP-, PACAP- or Met-ENK-positive nerve terminals were observed.

Chemical Coding of Sensory Neurons Supplying the Hip Joint Capsule in the Sheep.

Immunohistochemical properties of nerve fibres supplying the joint capsule were previously described in many mammalian species, but the localization of sensory neurons supplying this structure was studied only in laboratory animals, the rat and rabbit. However, there is no comprehensive data on the chemical coding of sensory neurons projecting to the hip joint capsule (HJC). The aim of this study was to establish immunohistochemical properties of sensory neurons supplying HJC in the sheep. The study was carried out on 10 sheep, weighing about 30-40 kg. The animals were injected with a retrograde neural tracer Fast Blue (FB) into HJC. Sections of the spinal ganglia (SpG) with FB-positive (FB+) neurons were stained using antibodies against calcitonin gene-related peptide (CGRP) substance P (SP), pituitary adenylate cyclase-activating peptide (PACAP), nitric oxide synthase (n-NOS), neuropeptide Y (NPY), vasoactive intestinal polypeptide (VIP), Leu-5-enkephalin (Leu-Enk), galanin (GAL) and vesicular acetylcholine transporter (VACHT). The vast majority of FB+ neurons supplying HJC was found in the ganglia from the 5th lumbar to the 2nd sacral. Immunohistochemistry revealed that most of these neurons were immunoreactive to CGRP or SP (80.7 ± 8.0% or 56.4 ± 4.8%, respectively) and many of them stained for PACAP or GAL (52.9 ± 2.9% or 50.6 ± 19.7%, respectively). Other populations of FB+ neurons were those immunoreactive to n-NOS (37.8 ± 9.7%), NPY (34.6 ± 6.7%), VIP (28.7 ± 4.8%), Leu-Enk (27.1 ± 14.6) and VACHT (16.7 ± 9.6).

The influence of resiniferatoxin on the chemical coding of caudal mesenteric ganglion neurons supplying the urinary bladder in the pig.

Resiniferatoxin (RTX) is used as experimental drug therapy for a range of neurogenic urinary bladder disorders. The present study investigated the chemical coding of caudal mesenteric ganglion (CaMG) neurons supplying the porcine urinary bladder after intravesical RTX instillation. The CaMG neurons were visualized with retrograde tracer Fast Blue (FB) and their chemical profile was disclosed with double-labelling immunohistochemistry using antibodies against tyrosine hydroxylase (TH), neuropeptide Y (NPY), vasoactive intestinal polypeptide (VIP), somatostatin (SOM), calbindin (CB), galanin (GAL) and neuronal nitric oxide synthase (nNOS). It was found that in both the control (n = 6) and RTX-treated pigs (n = 6), the vast majority (92.3 ± 2.7% and 93.1 ± 1.3%, respectively) of FB-positive (FB+) nerve cells were TH+. Intravesical instillation of RTX caused a decrease in the number of FB+ / TH + neurons immunopositive to NPY (91.0 ± 2.2% in control animals vs. 58.8 ± 5.0% in RTX-treated pigs) or VIP (1.7 ± 0.5% vs. 0%) and an increase in the number of FB+ / TH+ neurons immunoreactive to SOM (3.4 ± 1.5% vs. 20.6 ± 4.3%), CB (1.8 ±0.7% vs. 13.4 ± 2.3%), GAL (1.5 ± 0.6% vs. 7.5 ± 1.0%) or nNOS (0% vs. 10.9 ± 3.4%). The present results suggest that therapeutic effects of RTX on the mammalian urinary bladder can be partly mediated by CaMG neurons.

Activating PI3Kδ mutations in a cohort of 669 patients with primary immunodeficiency.

The gene PIK3CD codes for the catalytic subunit of phosphoinositide 3-kinase δ (PI3Kδ), and is expressed solely in leucocytes. Activating mutations of PIK3CD have been described to cause an autosomal dominant immunodeficiency that shares clinical features with common variable immunodeficiency (CVID). We screened a cohort of 669 molecularly undefined primary immunodeficiency patients for five reported mutations (four gain-of-function mutations in PIK3CD and a loss of function mutation in PIK3R1) using pyrosequencing. PIK3CD mutations were identified in three siblings diagnosed with CVID and two sporadic cases with a combined immunodeficiency (CID). The PIK3R1 mutation was not identified in the cohort. Our patients with activated PI3Kδ syndrome (APDS) showed a range of clinical and immunological findings, even within a single family, but shared a reduction in naive T cells. PIK3CD gain of function mutations are more likely to occur in patients with defective B and T cell responses and should be screened for in CVID and CID, but are less likely in patients with a pure B cell/hypogammaglobulinaemia phenotype.

Caudal mesenteric ganglion in the sheep - macroanatomical and immunohistochemical study.

The caudal mesenteric ganglion (CaMG) is a prevetrebral ganglion which provides innervation to a number of organs in the abdominal and pelvic cavity. The morphology of CaMG and the chemical coding of neurones in this ganglion have been described in humans and many animal species, but data on this topic in the sheep are entirely lacking. This prompted us to undertake a study to determine the localization and morphology of sheep CaMG as well as immunohistochemical properties of its neurons. The study was carried out on 8 adult sheep, weighing from 40 to 60 kg each. The sheep were deeply anaesthetised and transcardially perfused with 4% paraformaldehyde. CaMG-s were exposed and their location was determined. Macroanatomical observations have revealed that the ovine CaMG is located at the level of last two lumbar (L5 or L6) and the first sacral (S1) vertebrae. The ganglion represents an unpaired structure composed of several, sequentially arranged aggregates of neurons. Immunohistochemical investigations revealed that nearly all (99.5%) the neurons were DßH-IR and were richly supplied by VACHT-IR nerve terminals forming "basket-like" structures around the perikarya. VACHT-IR neurones were not determined. Many neurons (55%) contained immunoreactivity to NPY, some of them (10%) stained for Met-ENK and solitary nerve cells were GAL-positive. CGRP-IR nerve fibres were numerous and a large number of them simultaneously expressed immunoreactivity to SP. Single, weakly stained neurones were SP-IR and only very few nerve cells weakly stained for VIP.

MRI assessment of early response to certolizumab pegol in rheumatoid arthritis: a randomised, double-blind, placebo-controlled phase IIIb study applying MRI at weeks 0, 1, 2, 4, 8 and 16.

OBJECTIVES: To identify the first time point of an MRI-verified response to certolizumab pegol (CZP) therapy in patients with rheumatoid arthritis (RA). METHODS: Forty-one patients with active RA despite disease-modifying antirheumatic drug therapy were randomised 2:1 to CZP (CZP loading dose 400 mg every 2 weeks at weeks 0-4; CZP 200 mg every 2 weeks at weeks 6-16) or placebo→CZP (placebo at weeks 0-2; CZP loading dose at weeks 2-6; CZP 200 mg every 2 weeks at weeks 8-16). Contrast-enhanced MRI of one hand and wrist was acquired at baseline (week 0) and weeks 1, 2, 4, 8 and 16. All six time points were read simultaneously, blinded to time, using the Outcome Measures in Rheumatology Clinical Trials RA MRI scoring system. Primary outcome was change in synovitis score in the CZP group; secondary outcomes were change in bone oedema (osteitis) and erosion scores and clinical outcome measures. RESULTS: Forty patients were treated (27 CZP, 13 placebo→CZP), and 36 (24 CZP, 12 placebo→CZP) completed week 16. In the CZP group, there were significant reductions from baseline synovitis (Hodges-Lehmann estimate of median change, -1.5, p=0.049) and osteitis scores (-2.5, p=0.031) at week 16. Numerical, but statistically insignificant, MRI inflammation reductions were observed at weeks 1-2 in the CZP group. No significant change was seen in bone erosion score. Improvements across all clinical outcomes were seen in the CZP group. CONCLUSIONS: CZP reduced MRI synovitis and osteitis scores at week 16, despite small sample size and the technical challenge of reading six time points simultaneously. This study provides essential information on optimal MRI timing for subsequent trials. TRIAL REGISTRATION NUMBER: ClinicalTrials.gov, NCT01235598.

SLC28A3 genotype and gemcitabine rate of infusion affect dFdCTP metabolite disposition in patients with solid tumours.

BACKGROUND: Gemcitabine is used for the treatment of several solid tumours and exhibits high inter-individual pharmacokinetic variability. In this study, we explore possible predictive covariates on drug and metabolite disposition. METHODS: Forty patients were enrolled. Gemcitabine and dFdU concentrations in the plasma and dFdCTP concentrations in peripheral blood mononuclear cell were measured to 72 h post infusion, and pharmacokinetic parameters were estimated by nonlinear mixed-effects modelling. Patient-specific covariates were tested in model development. RESULTS: The pharmacokinetics of gemcitabine was best described by a two-compartment model with body surface area, age and NT5C2 genotype as significant covariates. The pharmacokinetics of dFdU and dFdCTP were adequately described by three-compartment models. Creatinine clearance and cytidine deaminase genotype were significant covariates for dFdU pharmacokinetics. Rate of infusion of <25 mg m(-2) min(-1) and the presence of homozygous major allele for SLC28A3 (CC genotype) were each associated with an almost two-fold increase in the formation clearance of dFdCTP. CONCLUSION: Prolonged dFdCTP systemic exposures (≥72 h) were commonly observed. Infusion rate <25 mg m(-2) min(-1) and carriers for SLC28A3 variant were each associated with about two-fold higher dFdCTP formation clearance. The impacts of these covariates on treatment-related toxicity in more selected patient populations (that is, first-line treatment, single disease state and so on) are not yet clear.

Sources of sensory innervation of the hip joint capsule in the rabbit - a retrograde tracing study.

The aim of the study was to investigate the sensory innervation of the hip joint capsule in the rabbit. Individual animals were injected with retrograde fluorescent tracer Fast Blue (FB) into the lateral aspect of the left hip joint capsule (group LAT, n = 5) or into the medial aspect of the hip joint capsule (group MED, n = 5), respectively. FB-positive (FB+) neurons were found within ipsilateral lumbar (L) and sacral (S) dorsal root ganglia (DRG) from L7 to S2 (group LAT) and from L6 to S4 (group MED). They were round or oval in shape with a diameter of 20-90 µm. The neurons were evenly distributed throughout the ganglia. The average number of FB+ neurons was 16 ± 2.8 and 27.6 ± 3.5 in rabbits from LAT and MED, respectively. The largest average number of FB+ neurons in animals of group LAT was found within the S1 DRG (8 ± 1.7), while S2 ganglion contained the smallest number of the neurons (3.6 ± 1). In the L7 DRG, the average number of FB+ neurons was 6.2 ± 1.6. In rabbits of MED group, the largest number of FB+ neurons was found within the S1 DRG (13.4 ± 4), while the smallest one was found within the S3 ganglion (1.4 ± 0.4). In L6, L7, S2 and S4 ganglia, the number of retrogradely labelled neurons amounted to 1.6 ± 0.5, 4 ± 1.5, 4.4 ± 1.5 and 2.8 ± 1.7, respectively. The data obtained can be very useful for further investigations regarding the efficacy of denervation in the therapy of hip joint disorders in rabbits.

Immunohistochemical characterization of neurons in the vestibular ganglion (Scarpa's ganglion) of the pig.

The study was carried out on three 4-month old female pigs. All the animals were deeply anesthetized and transcardially perfused with 4% buffered paraformaldehyde (pH 7.4). Vestibular ganglia (VG) were collected and processed for double-labelling immunofluorescence method. The preparations were examined under the Zeiss LSM 710 confocal microscope equipped with adequate filter blocks. Neurons forming VG were round or oval in shape with a round nucleus in the center. The majority of them (58%) were medium (M) (31-50 microm in diameter) while 28 % and 14% were small (S) (up to 30 microm in diameter) or large (L) (above 50 microm in diameter) in size, respectively. Double-labeling immunofluorescence revealed that VG neurons stained for CGRP (approx. 81%; among them 70.5%, 26.2% and 3.3% were M, S and L in size, respectively), VACHT (57%; 63% M, 24% S, 13% L), Met-Enk (25%; 60% M, 12% S, 28% L), VIP (20%; 88% M, 6% S, L), NPY (15%; 67% M, 20% S, 13% L), GAL (15%; 74% M, 21% S, 5% L), SP (12%; 69% M, 25% S, 6% L) and NOS-positive (12%; 50% S, 50% M). The most abundant populations of intraganglionic nerve fibers were those which stained for CGRP or Met-Enk, whereas only single SP- or NOS-positive nerve terminals were observed.

Immunohistochemical properties of motoneurons supplying the trapezius muscle in the rat.

Combined retrograde tracing (using fluorescent tracer Fast blue) and double-labelling immunofluorescence were used to study the distribution and immunohistochemical characteristics of neurons projecting to the trapezius muscle in mature male rats (n = 9). As revealed by retrograde tracing, Fast blue-positive (FB+) neurons were located within the ambiguous nucleus and accessory nucleus of the grey matter of the spinal cord. Immunohistochemistry revealed that nearly all the neurons were cholinergic in nature [choline acetyltransferase (ChAT)-positive]. Retrogradely labelled neurons displayed also immunoreactivities to calcitonin gene-related peptide (CGRP; approximately 60% of FB+ neurons), nitric oxide synthase (NOS; 50%), substance P (SP; 35%), Leu5-Enkephalin (LEnk; 10%) and vasoactive intestinal polypeptide (VIP; 5%). The analysis of double-stained tissue sections revealed that all CGRP-, VIP- and LEnk-immunoreactive FB+ perikarya were simultaneously ChAT-positive. The vast majority of the neurons expressing SP- or NOS-immunoreactivity were also cholinergic in nature; however, solitary somata were ChAT-negative. FB+ perikarya were surrounded by numerous varicose nerve fibres (often forming basket-like structures) immunoreactive to LEnk or SP. They were also associated with some CGRP-, NOS- and neuropeptide Y-positive nerve terminals.

Interleukin 2 in cancer therapy.

Cancer immunotherapy with interleukin-2 (IL-2) has demonstrated long term disease control in metastatic renal cell carcinoma and malignant melanoma. With introduction of novel kinase inhibitors, immunomodulatory molecules, cytokines, and vaccines for treatment of cancer there is an increased interest in combining these therapeutic strategies with IL-2. Here we discuss toxicity and established activity of IL-2 in the management of advanced malignancies, and speculate on future use of this cytokine for treatment of cancer.

Blood outgrowth endothelial cell-based systemic delivery of antiangiogenic gene therapy for solid tumors.

Endothelial cells and endothelial cell precursors encoding a therapeutic gene have induced antitumor responses in preclinical models. Culture of peripheral blood provides a rich supply of autologous, highly proliferative endothelial cells, also referred to as blood outgrowth endothelial cells (BOECs). The aim of this study was to evaluate a novel antiangiogenic strategy using BOECs expressing fms-like tyrosine kinase-1 (sFlt1) and/or angiostatin-endostatin (AE) fusion protein. Conditioned medium from BOECs expressing sFlt1 or AE suppressed in vitro growth of pulmonary vein endothelial cells by 70% compared with conditioned medium from non-transduced BOEC controls. Reverse transcriptase-PCR analysis indicated that systemically administered BOECs proliferated in tumor tissue relative to other organs in C3(1)SV40 TAG transgenic (C3TAG) mice with spontaneous mammary tumors. Tumor volume was reduced by half in C3TAG mice and in mice bearing established lung or pancreatic tumors in response to the treatment with sFlt1-BOECs, AE-BOECs or their combination. Studies of tumor vascular density confirmed that angiogenic inhibition contributed to slowed tumor growth. In an orthotopic model of glioma, the median survival of mice treated with sFlt1-BOECs was double that of mice receiving no BOEC treatment (P=0.0130). These results indicate that further research is warranted to develop BOECs for clinical application.

Immunohistochemical characterization of neurones in the hypoglossal nucleus of the pig.

In this study, the presence of several neurotransmitters and transmitter synthesizing enzymes was studied in hypoglossal nucleus (HN) of the juvenile (4 months old) female pigs (n = 3). Double-labeling immunofluorescence revealed neurones expressing cholinacetyltranspherase (ChAT), calcitonin gene-related peptide (CGRP), nitric oxide synthase (NOS), and somatostatin (SOM). Nerve fibers within HN were ChAT, CGRP, NOS, SOM, substance P (SP), Leu-5-enkephalin (Leu-5-Enk), ss-dopamine hydroxylase (DssH), neuropeptide Y (NPY) positive. Virtually all the perikarya contained ChAT, whereas CGRP was present in 47% of the neurones. Nerve cell bodies containing NOS or SOM were only occasionally observed. Immunoreactive nerve fibers were found in a close vicinity of the perikarya, often forming baskets around nerve cell bodies. The results obtained were compared with similar data obtained in other species. The presence of immunoreactive structures, origin of the nerve fibers, and functional significance of the findings are discussed.

Design and modification of EGF4KDEL 7Mut, a novel bispecific ligand-directed toxin, with decreased immunogenicity and potent anti-mesothelioma activity.

BACKGROUND: Potency, immunogenicity, and toxicity are three problems that limit the use of targeted toxins in solid tumour therapy. METHODS: To address potency, we used genetic engineering to develop a novel bispecific ligand-directed toxin (BLT) called EGF4KDEL, a novel recombinant anti-mesothelioma agent created by linking human epidermal growth factor (EGF) and interleukin-4 (IL-4) to truncated pseudomonas exotoxin (PE38) on the same single-chain molecule. Immunogenicity was reduced by mutating seven immunodominant B-cell epitopes on the PE38 molecule to create a new agent, EGF4KDEL 7Mut. RESULTS: In vitro, bispecific EGF4KDEL showed superior anti-mesothelioma activity compared with its monospecific counterparts. Toxicity in mice was diminished by having both ligands on the same molecule, allowing administration of a 10-fold greater dose of BLT than a mixture of monomeric IL4KDEL and EGFKDEL. EGF4KDEL 7Mut, retained all of its functional activity and induced about 87% fewer anti-toxin antibodies than mice given the parental, non-mutated form. In vivo, intraperitoneal (IP) injection of the BLT showed significant (P<0.01) and impressive effects against two aggressive, malignant IP mesothelioma models when treatment was begun 14-16 days post tumour innoculation. CONCLUSION: These data show that EGF4KDEL 7Mut is a promising new anti-mesothelioma agent that was developed to specifically address the obstacles facing clinical utility of targeted toxins.

Phase I study of bortezomib and cetuximab in patients with solid tumours expressing epidermal growth factor receptor.

Bortezomib inhibits nuclear factor-kappaB (NF-kappaB). Cetuximab is a chimeric mouse-human antibody targeted against epidermal growth factor receptor (EGFR). We hypothesised that concomitant blockade of NF-kappaB and EGFR signalling would overcome EGFR-mediated resistance to single-agent bortezomib and induce apoptosis through two molecular pathways. The aim of this phase I trial was to establish the maximum tolerated dose (MTD) for bortezomib plus cetuximab in patients with EGFR-expressing epithelial tumours. The 21-day treatment cycle consisted of bortezomib administered on days 1 and 8 through dose escalation (1.3-2 mg m(-2)). Cetuximab was delivered at a dose of 250 mg m(-2) on days 1, 8 and 15 (400 mg m(-2) day 1 cycle 1). A total of 37 patients were enroled and given a total 91 cycles. No grade > or =3 haematological toxicity was noted. Non-hematological grade > or =3 toxicities included fatigue (22% of patients), dyspnoea (16%) and infection (11%). The MTD was not reached at the highest tested bortezomib dose (2.0 mg m(-2)). Efficacy outcomes included disease progression in 21 patients (56.7%) and stable disease (SD) at 6 weeks in 16 patients (43.3%). Five of the six patients with SD at 12 weeks were diagnosed with cancers of the lungs or head and neck. This combination therapy was moderately effective in extensively pretreated patients with non-small cell lung or head and neck cancers and warrants further investigation.

Morphological examination of the proximal ganglion of the vagus nerve in the pig.

This is the first report dealing with the localisation and morphology of the proximal (jugular) ganglion in the pig. Six 3-months-old pigs of both sexes were used in this study. Tissues were stained with three histological methods: Klüver-Barer counterstained with Cresyl violet, Haematoxylin-eosin and Mayer's haematoxylin. The localisation and morphological features of the ganglion and ganglionic neurones were described and discussed.

Systemic inhibition of tumour angiogenesis by endothelial cell-based gene therapy.

Angiogenesis and post-natal vasculogenesis are two processes involved in the formation of new vessels, and both are essential for tumour growth and metastases. We isolated endothelial cells from human blood mononuclear cells by selective culture. These blood outgrowth cells expressed endothelial cell markers and responded correctly to functional assays. To evaluate the potential of blood outgrowth endothelial cells (BOECs) to construct functional vessels in vivo, NOD-SCID mice were implanted with Lewis lung carcinoma cells subcutaneously (s.c.). Blood outgrowth endothelial cells were then injected through the tail vein. Initial distribution of these cells occurred throughout the lung, liver, spleen, and tumour vessels, but they were only found in the spleen, liver, and tumour tissue 48 h after injection. By day 24, they were mainly found in the tumour vasculature. Tumour vessel counts were also increased in mice receiving BOEC injections as compared to saline injections. We engineered BOECs to deliver an angiogenic inhibitor directly to tumour endothelium by transducing them with the gene for human endostatin. These cells maintained an endothelial phenotype and decreased tumour vascularisation and tumour volume in mice. We conclude that BOECs have the potential for tumour-specific delivery of cancer gene therapy.