Heart Transplantation in Systemic Sclerosis: New Impulses for Conventional Scleroderma Transplantation Regimen and Scleroderma Diagnostic Monitoring: 2 Case Reports.

BACKGROUND: Although low (but increasing) rates of lung/lung-heart transplantations of scleroderma (systemic sclerosis [SSc]) patients have been reported, exclusive heart transplantation is a rare approach for treatment of heart failure due to SSc. CASES: We report on 2 cases of SSc patients receiving a heart transplantation (HTx) due to severe and progressive right heart failure without pulmonary artery hypertension. One patient received a hepatitis C virus (HCV)-positive donor heart and recovered excellently from viral transmission after administration of a direct-acting antiviral (DAA) regimen. This is the first published case of an SSc patient who underwent HTx using an HCV-positive donor heart. The clinical course of both patients was monitored by different serum SSc biomarkers. Only xylosyltransferase activity proved to be a promising biomarker for disease stage determination and therapeutic monitoring, precisely reflecting fibrotic remodeling and successful organ recovery. CONCLUSIONS: Successful implementation of the 2 cases described here demonstrates that HTx is a safe and effective therapeutic option for defined SSc sub-patient groups despite the progressive character of the underlying disease. In the future, xylosyltransferase activity might be conducive to simplify the identification of patients with low systemic involvement but a strong indication for single heart transplantation. Finally, we demonstrate that treatment of HCV viral transmission from HCV-positive donor to organ recipient using DAA gives us new opportunities to consider HCV-positive donor organs for HTx and might reveal new possibilities to ease the lack of donor organs.

[Rabies transmission through organ transplantation]. / Übertragung von Tollwut durch Organtransplantation.

Classic rabies is a progressive and lethal infectious disease of animals, which may be transmitted to humans. Inter-human infections are extremely rare. The present case describes transmittal of rabies virus by lung transplantation from an infected donor. Histologically, a lymphocytic encephalomyelitis with neuronal cytoplasmic inclusion bodies was found. Immunohistochemically, rabies virus antigen was detected in the central, autonomous and peripheral nervous system. By means of electron microscopy, virions were demonstrated in the brain. A central task of health care in transplantations is the detection of uncommon infectious agents and the prevention of their transmittal.

Expression of brain-derived neurotrophic factor and tropomyosin-related kinase-B in a bovine jejunal nodular ganglioneuroblastoma.

This report describes the morphologic, ultrastructural, and immunophenotypic features of a nodular ganglioneuroblastoma in the jejunum of a 13-month-old Holstein-Friesian heifer. On histologic examination, the mass was composed of clusters of neuroblasts and isolated ganglionic neurons in abundant neurophilic matrix that was surrounded by scanty Schwannian stroma. On ultrastructure examination, the large ganglionic neuron-like cells had unmyelinated neurites. Most ganglionic neuron-like tumor cells expressed neurofilament, neuron-specific enolase, chromogranin A, and S-100, whereas the Schwann-cell-like stromal cells expressed S-100 and vimentin. Both brain-derived neurotrophic factor (BDNF) and tropomyosin-related kinase-B (Trk-B) were expressed in ganglionic neuron-like tumor cells, which suggested the activation or reactivation of an embryonic autocrine BDNF/Trk-B pathway that could have prolonged cell survival and promoted differentiation with neurite formation.

Evidence of recurrent atypical meningioma with rhabdoid transformation and expression of pyrogenic cytokines in a child presenting with a marked acute-phase response: case report and review of the literature.

Children presenting with acute systemic illnesses that lack specific clinical or serological defining features may be diagnosed as having a chronic infection, an atypical systemic vasculitis or a connective tissue disease, but often turn out to have occult neoplasias. Cytokines have been implicated in causing many of the systemic effects in such cases. In this study, we describe the case of a 9-year-old boy presenting at an interval of 18 months with a marked acute-phase response due to a recurrent atypical meningioma with rhabdoid transformation of the tentorium cerebelli. Resection of the recurrent tumor was curative. We evaluated in detail the local and systemic production of cytokines released by the primary and the recurrent tumor. Blood and CSF samples were taken pre-, intra-, and postoperatively, and the production of IL-6, IL-1beta, and TNF-alpha was measured by enzyme-linked immunosorbent assays (ELISA). The level of IL-6 in CSF was about 150-fold increased before tumor resection, normalizing postoperatively. On the contrary, the levels of IL-1beta and TNF-alpha in CSF and of IL-6, IL-1beta, and TNF-alpha in serum were pre-, intra-, and postoperatively within normal limits. Cytokine production was also evaluated immunohistochemically, and confirmed strong IL-6 and TNF-alpha expression in the primary and the recurrent tumor, while expression of IL-1beta was lacking. The scattered MHC class II- and leukocyte common antigen (LCA)-expressing inflammatory cells, which were infiltrating exclusively the tumoral stroma, had no detectable cytokine immunoreactivity. We conclude that chronic IL-6 and TNF-alpha production by the tumor cells in this patient was responsible for the severe systemic illness with which he presented.

Adult T-cell lymphoma involving the leptomeninges associated with a spinal cord schwannoma.

Adult T-cell lymphoma (ATL-L) developing initially in the meninges is rare. An autopsy case of ATL-L with an acute onset of meningitis and generalized lymphadenopathy in association with a cervical cord schwannoma is reported here. A 78-year-old woman with sensori-motor weakness of both arms over a 1-year period, developed febrile episodes and drowsiness with neck stiffness. Lumbar puncture revealed an increased protein content (161 mg/dL) and increased cell count (463/3) consisting of 99% of lymphocytes which contained atypical lymphocytes with multilobulated nuclei ('flower cells'), which are characteristic of ATL-L. Viral titers were positive only for HTLV-I antibodies (serum X 640: CSF X 16). Biopsy of an enlarged retroperitoneal lymph node revealed malignant lymphoma of the T-cell type. Brain MRI was negative, whereas an intradural extramedullary mass was found at the C4 level. With a diagnosis of ATL-L stage IV, chemotherapy was commenced, which was effective in reducing the generalized lymphadenopathy as well as the cervical mass and restoring the CSF findings to normality. The cervical cord mass was verified to be a solitary schwannoma, and ATL-L involvement was found not only in the leptomeninges, but also within the cervical cord schwannoma.

CpG motifs of DNA vaccines induce the expression of chemokines and MHC class II molecules on myocytes.

Determining how an immune response is initiated after in vivo transfection of myocytes with plasmids encoding foreign antigens is essential to understand the mechanisms of intramuscular (i. m.) genetic immunization. Since myocytes are facultative antigen-presenting cells lacking MHC class II and co-stimulatory molecules, it was assumed that their unique role upon DNA vaccination is to synthesize and secrete the protein encoded by the plasmid. Here we describe that i. m. injection of unmethylated CpG motifs induced the expression of chemokines (monocyte chemotactic protein-1) and MHC class II molecules on myocytes. Our results indicate that immunostimulatory DNA sequences (CpG motifs) of DNA vaccines augment synthesis of chemokine by myocytes with subsequent recruitment of inflammatory cells secreting IFN-gamma, a potent cytokine that up-regulates the expression of MHC class II molecules on myocytes. A myoblast cell line triple transfected with plasmids encoding MHC class II molecules and an immunodominant CD4 T cell epitope of influenza virus presented the endogenously synthesized peptide and activated specific T cells. These findings suggest that one mechanism for the immunogenicity of DNA vaccines consists in the presentation of peptides to CD4 T cells by in vivo plasmid-transfected myocytes.

Antigen-specific downregulation of T cells by doxorubicin delivered through a recombinant MHC II--peptide chimera.

As the number of drugs with potential therapeutic use for T-cell-mediated diseases increases, there is a need to find methods of delivering such drugs to T cells. The major histocompatibility complex (MHC)--peptide complexes are the only antigen-specific ligands for the T-cell receptor (TCR) expressed on T cells, and they may be an appropriate drug delivery system. We engineered a soluble bivalent MHC class II-peptide chimera on the immunoglobulin scaffold (I-E(d)alpha beta/Fc gamma 2a/HA110-120, DEF) that binds stably and specifically to CD4 T cells recognizing the HA110-120 peptide. Doxorubicin, a powerful antimitogenic anthracycline, was enzymatically assembled on the galactose residues of a DEF chimera. The DEF-gal-Dox construct preserved both the binding capacity to hemagglutinin (HA)-specific T cells, and the drug toxicity. Brief exposure of HA-specific T cells to DEF-gal-Dox construct in vitro was followed by drug internalization in the lysosomes, translocation to the nucleus, and apoptosis. Administration of DEF-gal-Dox to mice expressing the TCR-HA transgene reduced the frequency of TCR-HA T cells in the spleen and thymus by 27% and 42%, and inhibited HA proliferative capacity by 40% and 60%, respectively. It has not been demonstrated previously that pharmacologically active drugs able to modulate T-cell functions can be delivered to T cells in an antigen-specific manner by soluble, bivalent MHC II-peptide chimeras.

Sporadic unilateral vestibular schwannoma with islets of meningioma: case report.

OBJECTIVE AND IMPORTANCE: Vestibular schwannomas with meningioma islets have been rarely reported in the literature; they have been observed only among patients with neurofibromatosis Type II. We present a case of a sporadic mixed tumor in a patient without neurofibromatosis Type II that was not suspected before surgery. CLINICAL PRESENTATION: A 59-year-old female patient presented with clinical signs of progressive loss of hearing. Her family history did not include evidence of neurological diseases. Magnetic resonance imaging scans revealed a typical unilateral vestibular schwannoma. INTERVENTION: The tumor presented with invasion of the surrounding arachnoid membrane, as well as Cranial Nerves VII and VIII. Preservation of the facial nerve with complete removal of the tumor was not possible. Therefore, Cranial Nerve VII reconstruction was performed. CONCLUSION: The concomitant occurrence of schwannomas and meningiomas infiltrating the arachnoid membrane might be related to poor clinical outcomes for patients with neurofibromatosis Type II, with respect to preservation of facial and acoustic nerves. Among sporadic schwannomas, this phenomenon is extremely rare.

Dendritic cells at a DNA vaccination site express the encoded influenza nucleoprotein and prime MHC class I-restricted cytolytic lymphocytes upon adoptive transfer.

Intradermal inoculation of plasmids expressing antigens that contain MHC class I-restricted epitopes leads to the induction of specific CD8(+) cytotoxic T lymphocytes (CTL). The role of in situ transfected antigen-presenting cells (APC) in the priming of specific CTL subsequent to intradermal DNA immunization was investigated using a plasmid (NPV1) expressing the nucleoprotein (NP) of influenza virus that contains a nuclear targeting signal and a dominant class I/K(d)-restricted epitope. Inoculation of NPV1 leads to in situ transfection of MHC class II(+) and class II(-) cells, as revealed by the nuclear localization of NP. Between 2 and 3% of MHC class II(+) and class II(-) cells with the ability to migrate out of the epidermis expressed NP. Upon adoptive transfer into naive recipients, class II(+) migratory cells recovered from the area inoculated with NP-expressing plasmid were significantly superior regarding the ability to prime virus-specific CTL as compared to MHC class II(-) cells. Together, these results are consistent with the role of local dendritic cells loaded with antigen in the priming of CTL by intradermal DNA immunization.

Disruption of intracerebral progression of C6 rat glioblastoma by in vivo treatment with anti-CD44 monoclonal antibody.

OBJECT: Glioblastoma multiforme (GBM) invasiveness is a complex process that involves recognition and attachment of GBM cells to particular extracellular matrix (ECM) molecules before migrating into proteolytically modified matrix and inducing angiogenesis. The CD44 molecule, which is a transmembrane adhesion molecule found on a wide variety of cells including GBM, has been suggested as the principal mediator of migration and invasion. The aim of the present study was to demonstrate whether an antibody specific to the standard form of CD44 (CD44s, 85-90 kD) might prevent invasion and thus disrupt progression of C6 GBM in vivo. METHODS: Immunostaining demonstrated homogeneous expression of CD44s on the surface of C6 GBM cells and tumors. Flow cytometric analysis demonstrated binding saturation of anti-CD44s monoclonal antibody (mAb) to the receptor at 1 microg/5 x 10(5) cells. Blocking of CD44s in vitro resulted in a dose-dependent progressive (up to 94+/-2.7%; mean +/- standard deviation [SD]) detachment of C6 cells from ECM-coated culture. Blocking of CD44s in vivo resulted in significantly reduced C6 brain tumors (3.6+/-0.4% [SD])--measured as the quotient: tumor surface (mm2)/brain surface (mm2) x 100--compared with untreated (19.9+/-0.9%) or sham-treated (19.2+/-1.1 to 19.3+/-2.5% [SD]) rats. Disruption of C6 GBM progression correlated with an improved food intake; treated rats were significantly less cachectic (166.6+/-16.4 g [SD]) than those that were untreated (83+/-2.7 g [SD]) or sham-treated (83.4+/-1.1 to 83+/-2.2 g [SD]) rats. CONCLUSIONS: The authors conclude that CD44s-targeted treatment with specific mAb may represent an effective means for preventing progression of highly invasive GBMs.

Multimedia-based courseware in the Virtual Learning Center at the Hannover Medical School.

The commercial use of the World Wide Web causes an extensive change in information technology. Web browser are becoming the universal front-end for all kinds of client-server applications. The possibilities of telematics offer a base for multimedia applications, for instance telelearning. Learning is not limited by geography and does not cause pressure of time by the user. The development of such multimedia information and communication systems demands cooperative working teams of authors, who are able to master several areas of medical knowledge as well as the presentation of these using different multimedia facilities. A very important part of graphic design in the context of multimedia applications is the creation and interactive use of images (still, moving). The growth and the complexity of medical knowledge as well as the need for continuous, fast, and economically feasible maintenance impose requirements on the media used for medical education and training. Web-based courseware in the Virtual Learning Center at the Hannover Medical School is an innovative education resource for medical students and professionals.

Cerebral vasculitis in chronic mucocutaneous candidiasis: autopsy case report.

An autopsy case of chronic mucocutaneous candidiasis (CMCC) is reported here, in which cerebral vasculitis developed in the final stage. A 32-year-old man who had suffered from superficial candidial infection since his childhood was diagnosed as having CMCC. During the past 7 years the patient had developed various associated disorders including insulin-dependent diabetes mellitus (IDDM), common variable immunodeficiency (CVID), candidial esophagitis, multiple digestive tract ulcers and pyothorax. In 1998, at the age of 32, he developed convulsions that were accompanied by impairment of consciousness, and which were temporarily treated with steroid pulsed-medication. Epileptic status associated with widespread cerebral infarctions occurred subsequently, however, and the patient died of sepsis 2 months later. At autopsy, multiple cerebral infarctions and arterial thrombosis were evident. These were histologically proven to be primary vasculitis which was confined solely to the brain, and this was verified by general pathological examination. Thus, some as yet unknown cerebrovascular factors might be involved in the onset of an autoimmune-related vasculitis in patients with a longstanding immunodeficiency state such as CMCC.

CD44s-targeted treatment with monoclonal antibody blocks intracerebral invasion and growth of 9L gliosarcoma.

Glioma invasiveness is a complex process involving recognition and attachment of tumor cells to particular extracellular matrix (ECM) molecules prior to migrating into proteolytically modified matrix and inducing angiogenesis. CD44 is a group of transmembrane adhesion molecules found on a wide variety of cells including gliomas that has been suggested as the principal mediator of migration/invasion. The aim of the present study was to demonstrate whether antibody specific for the standard form of CD44 (CD44s, 85-90 kDa) might prevent invasion, thus blocking growth of the 9L gliosarcoma in vivo. High expression of CD44s on the surface of 9L cells and brain tumors was demonstrated by immunochemistry. Fluorescence-activated cell sorting (FACS) demonstrated binding saturation of anti-CD44s monoclonal antibody (mAb) to the receptor at 1 microg/5 x 10(5) cells. Blocking of CD44s in vitro resulted in a dose-dependent progressive, up to 95%+/-2.5% detachment of 9L cells from ECM-coated culture surfaces. Blocking of CD44s in vivo resulted in significantly reduced 9L brain tumors (2.5%+/-0.4%)--measured as the quotient: tumor surface (mm2)/brain surface (mm2) x 100--as compared to untreated (16.1%+/-2.2%) or sham-treated rats (16%+/-3.7% to 16.1%+/-3%). We conclude that CD44s-targeted treatment with specific mAb may be an effective means for preventing glioma progression.

Characterization of mutated protein encoded by partially duplicated fibrillin-1 gene in tight skin (TSK) mice.

Fibrillin-1 (Fbn-1) is a ubiquitous protein present in the extracellular matrix of various organs and it is a major component of microfibrils embedded in the core of elastic fibers. In humans, mutations or deletions of the Fbn-1 gene are associated with several genetic diseases. In addition, several microsatellite alleles near Fbn-1 gene were found associated with diffuse scleroderma. In TSK/+ mice, which develop a scleroderma-like syndrome, the Fbn-1 gene exhibits an inframe duplication of exons 17-40. In this study, we report that the synthesis and secretion of wild-type Fbn-1 in TSK/+ is higher than that of the mutated Fbn-1 protein excluding the possibility that TSK genetic defect is due to a loss of the wild allele. We also demonstrate for the first time that TGF-beta, which plays a crucial role in skin fibrosis, binds to both wild-type and mutated Fbn-1. The amount of bound TGF-beta was higher in mutated than wild-type Fbn-1 and appears related to the number of TGF-beta binding motifs.

Expression of granulocyte colony-stimulating factor in recurrent glial tumors is inversely correlated with tumor progression.

We have previously reported that in vivo-expression of granulocyte colony-stimulating factor (G-CSF) is a characteristic feature of reactive and neoplastic astrocytes. The aim of the present study was to analyze the expression of G-CSF protein in primary and recurrent astroglial, oligodendroglial and mixed glial-differentiated tumors. G-CSF expression was present in all GFAP-positive tumors excepting glioblastomas. G-CSF expression was significantly reduced in recurrent tumors more dedifferentiated than their primary counterparts. G-CSF expression was absent in all GFAP-negative tumors such as oligodendrogliomas. Our results demonstrate that G-CSF is a highly sensitive differentiation marker of neoplastic astrocytes, which is lost during tumor progression.

Doxorubicin-induced cell death in highly invasive human gliomas.

Glioblastoma is the most invasive form of primary brain tumors, and is often refractory to chemotherapy. Herein, we provide evidence that two highly invasive human glioma cell lines U-87 MG and U-373 MG, entered apoptosis after 48 hours following 24 h growth arrest induced by Doxorubicin (10 micrograms/2 x 10(5) cells/ml). Apoptosis depended solely on the level of intracellular drug accumulation, and it was not related to a functional p53 tumor suppressor factor. The multidrug resistance gene 1 (mdr-1) encoded P-glycoprotein (P-gp) was weakly expressed in these cells upon exposure to Doxorubicin, and exerted no influence on the extent of cellular drug efflux. Drug efflux occurred only in U-373 MG glioma cells subsequent to physical damage of the membrane upon exposure to Doxorubicin. Pretreatment of tumor cells with 10 micrograms/ml Doxorubicin precluded tumor formation on the chorioallantoic membrane (CAM) of embryonated hen eggs. Single-dose application of 0.4 microgram Doxorubicin on CAM/U-87 MG and CAM/U-373 MG tumor transplants inhibited tumor invasion in CAM tissue by 40 to 50%. These data suggest that highly invasive glioblastomas can be driven to apoptosis following growth arrest induced by Doxorubicin, providing that intracellular drug accumulation suffices cytotoxic levels.

Antineoplastic efficacy of doxorubicin enzymatically assembled on galactose residues of a monoclonal antibody specific for the carcinoembryonic antigen.

We have developed a novel procedure to couple enzymatically the antineoplastic agent doxorubicin (Dox) on the galactose residues of a monoclonal antibody specific for the tumor-associated carcinoembryonic antigen. The synthesis of the immunoconjugate consists of covalent attachment of the NH2 terminus of Dox to oxidized galactose residues of desialylated monoclonal antibody, followed by concurrent stabilization of Schiff bases by mild reduction with pyridine borane. The immunoconjugate preserved both antibody specificity and drug cytotoxicity. At equimolar concentrations, the immunoconjugate was 8 times more cytotoxic against two carcinoembryonic antigen-expressing carcinoma cell lines, LoVo and SW-480, than Dox alone. The intracellular drug accumulation was 8-8.5 times higher than that obtained with free Dox, and >50% of the drug delivered by the conjugate was retained for 24 h in the tumor cells. Only 4 days after treatment with a single dose of immunoconjugate carrying 2.5 ng of Dox, LoVo and SW-480 tumor transplants on the chorioallantoic membrane of embryonated hen eggs showed reduced tumor-induced angiogenesis and tumor progression by half, with no detectable damage to surrounding tissues. In contrast, the same amount of free drug induced insignificant changes in tumor progression and tumor-induced angiogenesis. Enzymatically mediated, glycosidic coupling of antineoplastic agents to antibodies specific for tumor-associated antigens may represent a novel platform for the development of more efficient anticancer agents with reduced side effects.

The interactive use of networking multimedia--innovative education resource for professionals and patients.

The combination of new and rapidly developing interactive multimedia computers and applications with electronic networks will require a restructuring of our traditional approach to strategic planning and organizational structure. Worldwide telecommunication networks (using satellites, cable) are now facilitating the global pooling of healthcare information and medical knowledge independent of location. The development of multimedia information and communication systems demands cooperative working teams of authors, who are able to master several areas of medical knowledge as well as the presentation of these in different multimedia forms. The assemblage of telematics and services offers a base for multimedia applications, for example teleteaching, telelearning, telepublishing, teleconsulting, teleconferencing, telemedicine etc. The expansion of the internet will also lead to the formation of interdisciplinary "Global Education Networks". The theory and practice of education are undergoing dramatic changes. Lifelong learning and adaptation of medical practice to new knowledge and new techniques will be even more important in the future.

[Basic fibroblast growth factor (b-FGF) in the perimatrix of cholesteatoma]. / "Basic fibroblast growth factor" (b-FGF) in der Perimatrix des Cholesteatoms.

UNLABELLED: The growth of a cholesteatoma requires angioneogenesis in the connective tissue of the perimatrix. Angioneogenesis is also needed for wound healing as a host response to tissue injury. Normal wound repair is conducted through a wide number of growth factors. Basic fibroblast growth factor (b-FGF) plays a pivotal role in wound repair. This cytokine exerts its effects through stimulation of a wide range of target cells. B-FGF is chemotactic and mitogenic for fibroblasts, endothelial cells and keratinocytes. In addition, b-FGF can stimulate the production of collagenase and plasminogen activators to enhance fibroblast proliferation and angioneogenesis. Its necessity for normal wound repair has been confirmed by several workers. METHOD: In order to demonstrate angioneogenesis in the cholesteatoma perimatrix the distribution of b-FGF as the pivotal cytokine of the process was investigated in the perimatrix of 18 cholesteatoma specimens. RESULTS: B-FGF could be observed in 12 of 18 specimens (66%) in close approximation to histological signs of inflammation and wound healing. Areas with b-FGF also exhibited proliferation of the covering squamous epithelium. Cholesteatoma matrix tissue without inflammation or any sign of wound healing did not express b-FGF (6 of 18). CONCLUSION: Histological changes and distribution pattern of b-FGF in the perimatrix of cholesteatoma in the present study indicate that the perimatrix cells and substances of the wound healing cascade may play an important role in cholesteatoma development, angiogenesis and growth.

Dietary L-arginine decreases myointimal cell proliferation and vascular monocyte accumulation in cholesterol-fed rabbits.

L-arginine, the precursor of endogenous nitric oxide (NO), has been shown to enhance endothelial function and to reduce the progression of atherosclerosis in cholesterol-fed rabbits. In the present study, we investigated whether myointimal cell proliferation is enhanced in hypercholesterolaemic rabbit aorta and whether chronic treatment of the rabbits with L-arginine or with the NO synthase inhibitor L-NAME influences this proliferative response and vascular monocyte accumulation. Rabbits were fed 1% cholesterol or normal rabbit chow for 12 weeks. Subgroups of cholesterol-fed rabbits were treated with oral L-arginine (2.25%) or L-NAME (3 mg/dl) in drinking water. Myointimal cell proliferation was quantified in aortic segments by immunohistochemical detection of bromodeoxyuridine (BrdU) incorporation into nuclear DNA; vascular monocyte accumulation was assessed by immunohistochemistry using a monoclonal anti-macrophage/monocyte antibody (RAM-11). Plasma levels of L-arginine and the endogenous NO synthase inhibitor, ADMA, were quantified by high-performance liquid chromatography (HPLC). Cholesterol feeding increased the aortic intima/media (I/M) ratio, which was not measurable in the control group, to 1.9 +/- 0.3. This was paralleled by enhanced cell proliferation (cholesterol, 2.4 +/- 0.2%; P < 0.05; control, 0.02 +/- 0.001% BrdU-positive cells per 72 h) and vascular monocyte accumulation. Double immunostaining for BrdU and alpha-actin showed that about two thirds of the proliferating cells were smooth muscle cells. ADMA levels increased from 0.8 +/- 0.1 micromol/l to 2.2 +/- 0.2 micromol/l in cholesterol-fed rabbits, but were unchanged by L-arginine or L-NAME treatment. Myointimal proliferation and intima/media ratios were correlated with ADMA plasma levels. Dietary L-arginine reduced monocyte accumulation by 85 +/- 2% (P < 0.05 vs cholesterol), myointimal cell proliferation (1.8 +/- 0.3% per 72 h; P < 0.05) and intimal thickening (I/M ratio: 0.7 +/- 0.2), whereas the inhibitor of NO synthase, L-NAME, further increased cell proliferation to 3.1 +/- 0.4% per 72 h (P < 0.05). No significant difference was observed in vascular monocyte infiltration between the cholesterol and L-NAME groups. We conclude that cell proliferation and vascular monocyte accumulation are enhanced in hypercholesterolaemic rabbit aorta. These atherogenic effects can be attenuated by dietary L-arginine. Decreased NO formation might underlie the enhanced monocyte accumulation and cell proliferation in hypercholesterolaemic rabbit aorta. The observed inhibition of cell proliferation adds to our understanding of the antiatherosclerotic effects of L-arginine in vivo.