Intravascular Cell Research Articles

Temporal, regional, and cell-specific changes of iNOS expression after intrastriatal microinjection of interferon gamma and bacterial lipopolysaccharide

Here we study expression of the inducible isoform of nitric oxide synthases after intrastriatal microinjection of interferon-γ and bacterial lipopolysaccharide in the rat at different time points to detect time- and localisation-dependent changes of iNOS expression. Three different areas in the striatum and the corpus callosum were evaluated. Antibodies against the glial fibrillary acidic protein and the microglia/brain macrophage epitope ED1 were used to detect colocalisation of inducible nitric oxide synthase with astrocytes or activated microglia/brain macrophages, respectively. Inducible nitric oxide synthase-positive cells occured first in intravascular and perivascular cells at 4 h. Perivascular and parenchymal inducible nitric oxide synthase expression increased up to 24 h in the striatum, whereas in the corpus callosum inducible nitric oxide synthase expression was maximal after 16 h. Inducible nitric oxide synthase was still present in perivascular cells 7 days after immunostimulation. At all time points, inducible nitric oxide synthase was predominantly detected in ED1-positive microglia/brain. Nitrotyrosine immunohistochemistry was performed to detect NO-mediated nitration of proteins at all time points. Nitrotyrosine-positive neurons and microglial cells were detected from 24 h until 7 days after immunostimulation and were absent in controls. Detailed knowledge of the changes in the time course and cellular source of inducible nitric oxide synthase expression following brain immunostimulation provide a basis for establishing treatment strategies and windows of therapeutic intervention during neuroinflammation.

Transabdominal first trimester embryofetoscopy as a potential approach to early in utero stem cell transplantation and gene therapy.

To explore the potential of embryofetoscopy for early diagnosis and for access to the fetal circulation in the first trimester of gestation. Transabdominal embryofetoscopy was performed in 14 patients scheduled for termination of pregnancy using a 1-mm semirigid fibreoptic telescope with a 18 gauge examination sheath and a single-chip digital camera. A 25 gauge needle was inserted through an additional 21 gauge side port to access the fetal circulation. Fetal head, face, abdomen, complete upper and lower limbs could be visualized in over 80% of cases. On the contrary, the fetal back and external genitalia could be examined in detail only in some cases (35.7% and 64.3%, respectively). Injection of 10-20 ml saline improved visibility in 43% of cases. Funipuncture was successful in two of three attempts. Our experience suggests that embryofetoscopy is a useful tool for early diagnosis in the first trimester of pregnancy. Funipuncture is possible thus providing the means for an early intravascular stem cell application.

Mechanical deformation induces proliferation of human colorectal carcinoma cells.

The cell biology of intravascular tumor cells is clinically important but the many important variables of this environment have proved difficult to model. We studied the effects of repetitive mechanical deformation, a phenomenon affecting all intravascular cells, on human colon cancer cell line HCT 116 in vitro. Cell proliferation, assessed by [3H]-thymidine incorporation and cell count, increased by about 30% at two days in cells subjected to deformation at 30 cycles/min as compared to controls; levels of the nuclear proliferation antigen detected by monoclonal antibody MIB-1 were also increased. Deformation increased transforming growth factor beta1 (TGF-beta1) and plasminogen activator inhibitor-1 gene expression sevenfold at two days, but mannose-6-phosphate did not affect cell proliferation, indicating that endogenous TGF-beta is not involved in the proliferative response. HCT 116 cells lack TGF-beta type II receptors, but stable transfection of TGF-beta type II receptor cDNA did not alter the cellular response to mechanical deformation, as assessed by cell proliferation, morphology, or gene expression. Mechanical deformation affects several important aspects of HCT 116 cell biology, suggesting that the intravascular environment may regulate tumor cell biology in general. Endogenous TGF-beta and TGF-beta receptor-mediated signaling are not responsible for the deformation-induced proliferative response in HCT 116.

From the archives of the AFIP: pulmonary vasculature: hypertension and infarction.

Pulmonary hypertension is the hemodynamic consequence of vascular changes within the precapillary (arterial) or postcapillary (venous) pulmonary circulation. These changes may be idiopathic, as in primary pulmonary hypertension or pulmonary veno-occlusive disease, but more commonly they represent a secondary response to alterations in pulmonary blood flow. The pulmonary and systemic bronchial circulations form broad anastomoses that largely prevent infarction except in settings of markedly elevated pulmonary venous pressure, underlying malignancy, or excessive embolic burden. Causes of precapillary pulmonary hypertension include long-standing cardiac left-to-right shunt, chronic thromboembolic disease, and widespread pulmonary embolism arising from intravascular malignant cells, parasites, or foreign materials. The classic radiologic features of precapillary pulmonary hypertension are central arterial enlargement, sharply pruned peripheral vascularity, and right-sided heart hypertrophy and chamber dilatation. Postcapillary pulmonary hypertension may develop secondary to focal venous constriction or to compromised pulmonary venous drainage due to left atrial neoplasia, mitral stenosis, or left ventricular failure. Radiologic manifestations of postcapillary pulmonary hypertension include prominent septal lines, small pleural effusions, and occasionally air-space opacities. In addition, radiologic evaluation of postcapillary pulmonary hypertension may demonstrate evidence of pulmonary arterial hypertension, secondary to the retrograde transmission of elevated pulmonary venous pressure across the capillary bed.

Interactions between cancer cells and the endothelium in metastasis.

The haematogenous phase of cancer metastasis facilitates the transport of metastatic cells within the blood and incorporates a sequence of interactions between circulating intravascular cancer cells and the endothelium of blood vessels at the sites of tumour cell arrest. Initial interactions involve mechanical contact and transient adhesion, mediated by endothelial selectins and their ligands on the neoplastic cells. This contact initiates a sequence of activation pathways that involves cytokines, growth factors, bioactive lipids, and reactive oxygen species produced by either the cancer cell or the endothelium. These molecules elicit expression of integrin adhesion molecules in cancer cells and the endothelium, matrix metalloproteinases, and chemotactic factors that promote the attachment of tumour cells to the vessel wall and/or transvascular penetration. Induction of endothelial free radicals can be cytotoxic to cancer cells. Collectively, the sum of these interactions constitutes an interdependent relationship, the outcome of which determines the fate of the metastatic process.

Role of the endothelial glycocalyx in dromotropic, inotropic, and arrythmogenic effects of coronary flow.

Coronary flow regulates cardiac functions, and it has been suggested that endothelial membrane glycosylated proteins are the primary shear stress mechanosensors. Our hypothesis was that if these proteins are the sensors for flow, then intracoronary perfusion of lectins or specific antibodies should differentially depress coronary flow-enhanced responses of different parenchymal cell types such as auricular-ventricular (A-V) nodal cells (dromotropic effect), contractile myocytes (inotropic effect), and junctional Purkinje-muscle cells (spontaneous ventricular rhythm). The coronary flow stimulatory effects on A-V delay and spontaneous ventricular rhythm were selectively depressed by six of eight lectins. None of the lectins depressed the coronary flow inotropic effect. Antibodies against endothelial surface proteins, alpha(v)beta(5)-integrin and sialyl-Lewis(b) glycan, depressed the dromotropic but not the inotropic effects of coronary flow, whereas the vascular cell adhesion molecule 1 antibody had no effect on the dromotropic, but enhanced the inotropic, effect. The fact that lectins and antibodies differentially depressed regional coronary flow effects suggests that there is a chemical distinctiveness in their intravascular endothelial cell surfaces. However, nonselective cross-linking of endothelial glycocalyx proteins with 2,000-kDa dextran-aldehyde or vitronectin indistinctively depressed the dromotropic and inotropic effects of coronary flow. These results indicate that coronary flow-induced stress acts on specific structures located in the capillary intravascular membrane glycocalyx.

Intravascular origin of metastasis from the proliferation of endothelium-attached tumor cells: a new model for metastasis.

Metastasis is a frequent complication of cancer, yet the process through which circulating tumor cells form distant colonies is poorly understood. We have been able to observe the steps in early hematogenous metastasis by epifluorescence microscopy of tumor cells expressing green fluorescent protein in subpleural microvessels in intact, perfused mouse and rat lungs. Metastatic tumor cells attached to the endothelia of pulmonary pre-capillary arterioles and capillaries. Extravasation of tumor cells was rare, and it seemed that the transmigrated cells were cleared quickly by the lung, leaving only the endothelium-attached cells as the seeds of secondary tumors. Early colonies were entirely within the blood vessels. Although most models of metastasis include an extravasation step early in the process, here we show that in the lung, metastasis is initiated by attachment of tumor cells to the vascular endothelium and that hematogenous metastasis originates from the proliferation of attached intravascular tumor cells rather than from extravasated ones. Intravascular metastasis formation would make early colonies especially vulnerable to intravascular drugs, and this possibility has potential for the prevention of tumor cell attachment to the endothelium.

Intravascular tumour in intra-oral pleomorphic adenomas: a diagnostic and therapeutic dilemma.

Intravascular tumour has been described very rarely in pleomorphic adenomas. The aim of this study was to establish the frequency of intravascular tumour in pleomorphic adenomas arising in minor salivary glands and to determine the biological significance of this phenomenon. Representative sections of 67 widely excised pleomorphic adenomas were examined for the presence of intravascular tumour. Sixty-two cases were derived from the palate while the remaining five were from the cheeks and lips. In instances where intravascular tumour was identified, multiple serial sections were assessed and immunohistochemical stains were performed. None of these cases showed cytological evidence of malignancy. Solid cords of intravascular tumour were present in six palatal tumours (8.9%) and consisted of plasmacytoid myoepithelial cells permeating muscular walled blood vessels and capillaries both within the tumour and capsule. Immunoperoxidase staining confirmed that the intravascular cells were phenotypically identical to those of the tumour being S100- and smooth muscle actin (SMA) positive. There is some evidence that this phenomenon represents true vascular invasion although artefactual spillage cannot be excluded. Although the biological significance of intravascular tumour in pleomorphic adenomas of minor salivary glands remains unknown, the occurrence of metastatic disease has not been demonstrated nor have aggressive behaviour or recurrences.

Vitronectin receptors are expressed by macaque trophoblast cells and play a role in migration and adhesion to endothelium

The objective of this work was to develop an in vitro system that would extend the usefulness of the macaque as a model for studying trophoblast invasion and spiral artery modification. We sought to determine whether trophoblast cells isolated from early gestation macaque placentas expressed vitronectin receptors and tested the idea that these receptors play a role in trophoblast migration and adhesion. Cytotrophoblast cells were isolated from 40–100 day macaque placentas, cultured, and characterized by immunofluorescence microscopy and flow cytometry. The cells expressed αV, β3, and β1 integrins on their surfaces. Immunohistochemical analysis of early gestation placentas and decidua basalis confirmed that intravascular trophoblast cells express αVβ3/β5. Using migration chambers we found that the trophoblast cells migrated towards vitronectin but not towards bovine serum albumin. This specific migration was blocked by preincubating the trophoblast cells with anti-vitronectin receptor (αVβ3/β5) antibodies. In other experiments, macaque trophoblast cells adhered to myometrial endothelial cells in a time-dependent manner and adhesion was significantly blocked by antibodies against αVβ3/β5 integrin. The results suggest that vitronectin receptors expressed by macaque trophoblast cells play a role in the migratory activity of these cells and may also be important in mediating attachment to endothelium.

Primary large cell carcinoma of the submandibular gland

A rare case of primary large cell carcinoma of the submandibular gland is reported. A 53-year-old man presented with a tumor in the left submandibular region extending to the supraclavicular fossa. After unsuccessful radiochemotherapy at another hospital, he was referred to our department for combined therapy of radiation, hyperthermia, and intraarterial anticancer drug infusion. Although the local tumor decreased in size after therapy, the patient died of respiratory insufficiency due to rapid progression of pulmonary metastases. Autopsy showed that tumor cells in both the submandibular gland and the lung were compatible with undifferentiated large cell carcinoma without tubular formation or laminar structure. The submandibular tumor was considered to be the primary site because cicatricial tissue surrounding the lesion suggested that had formed over a long period. The pulmonary lesions were considered to be metastases because necrosis and intravascular carcinoma cell embolism were noted. The above findings led to the final diagnosis of primary large cell carcinoma of the submandibular gland with pulmonary metastases. This condition has rarely been reported in the literature.

Microcirculatory Stasis Induced by Hemorheological Disorders: Further Evidence

Reinvestigate the microcirculatory alterations immediately responsible for blood rheological disorders and blood stases, which are related to red blood cell (RBC) aggregation in capillaries. Blood rheological disorders were produced by significantly intensified intravascular red blood cell aggregation in the intestinal mesentery of Wistar rats and in the cerebral cortex of Chinchilla rabbits, either systemically (by intravascular administration of high molecular-weight dextran) or locally (by increase of high-molecular compounds in blood plasma inside individual or groups of capillaries). Under conditions where the microvascular lumina were not decreased and the arteriolovenular pressure gradients got even higher, the significantly enhanced intravascular RBC aggregation resulted in the slowing down of blood flow in the microvessels to a full stop. A significant increase in microvascular RBC aggregation results in local hemorheological disorders, which is, in all probability, related to derangement of the blood-flow structuring in microvessels.

Disseminated intravascular meconium in a newborn with meconium peritonitis

A 3-day-old premature infant with meconium peritonitis, periventricular leukomalacia, and pulmonary hypertension died with respiratory insufficiency. An autopsy disclosed intravascular squamous cells in the lungs, brain, liver, pancreas, and kidneys. Numerous pulmonary capillaries and arterioles were occluded by squamous cells, accounting for pulmonary hypertension. Brain parenchyma surrounding occluded cerebral vessels showed infarct and gliosis. A mediastinal lymph node filled with squamous cells alluded to the mechanism by which these cells from the peritoneal cavity likely entered the bloodstream—namely, via diaphragmatic pores connecting with lymphatics. Thus, disseminated intravascular meconium rarely may complicate meconium peritonitis and have devastating consequences.

Macrophage tropism of rabbit hemorrhagic disease virus is associated with vascular pathology

To delineate the interactions between rabbit hemorrhagic disease virus (RHDV) and host cells, organ and cellular targets of infection were identified in vivo. Viral specific antigens were detected by immunohistochemistry in liver, lung, spleen and lymph nodes cells. Also, intravascular infected cells were detected in most organs including kidneys, myocardium, thymus and central nervous system. To further characterize infected target cells, viral proteins and cell-specific surface antigens were identified simultaneously in double labeling experiments. Numerous lymphoid organ macrophages, from the splenic red pulp, circulating monocytes, alveolar macrophages and Kupffer cells were double labeled, demonstrating that cells of the mononuclear phagocyte lineage are major hosts for RHDV. Double labeling for other specific cell markers were negative. The distribution of viral antigens in these tissues coincided with those areas where cells presented morphology of apoptosis. Association of intravascular monocyte infection and apoptosis, could represent a possible mechanism to develop disseminated intravascular coagulation.

Intravascular Large Cell Lymphoma: Clinicopathological, Immuno-Histochemical and Molecular Genetic Studies

Intravascular large cell lymphoma (IVLL) is a rare neoplasm characterized by a proliferation of lymphoma cells within the blood vessels. Its cell origin and clinicopathological characteristics have not been well understood. The study uses 5 male and 4 female patients who were diagnosed as having IVLL from 1978 to 1996. We examined cell lineage and adhesion molecules using immunohistochemical staining and performed a molecular analysis by using poly-merase chain reaction (PCR) on the IgH gene, on T-cell receptor chain genes, and the Epstein-Barr virus (EBV) and in situ hybridization on EBV. The immunohistochemical and PCR results disclosed 8 cases of B- cell and one of T-cell lymphoma. Three of four cases whose frozen specimens were available expressed CD5. PCR showed EBV in 7 of 9 cases, although EBV was found by in situ hybridization in only 3 cases. Lymphoma cells express CDlla and CD49d (VLA-4), while endothelial cells expressed CD54 (CDlla ligand) and CD106 (CD49d ligand). Such interaction of these adhesion molecules might contribute to the intravascular proliferation of lymphoma cells. Furthermore, the CD5 expression of lymphoma cells suggests that IVLL most likely originates from a unique subtype of B cells, although their normal counterpart remains uncertain.

Murine hepatic microvascular adhesion molecule expression is inducible and has a zonal distribution.

The structural and functional heterogeneity of hepatocytes and non-parenchymal cells across the liver lobule or acinus has been well documented. The geographic distribution and potential for induced expression of adhesion molecules on murine hepatic microvascular cells has not been reported, although these molecules are able to influence the metastatic outcome of intravascular cancer cells. We have postulated that the expression of adhesion molecules on these cells is susceptible to regulation by environmental factors and that these molecules have a zonal distribution across the acinus. To test this hypothesis, we injected C57BL/6 mice with bacterial lipopolysaccharide, 1 microg/g body weight, i.p. At various time points (0-48 h) after stimulation, liver tissue sections were prepared for immunohistochemistry. Confocal microscopy was used to detect the expression of vascular cell adhesion molecule-1 (VCAM-1), E-selectin, intercellular adhesion molecule-1 (ICAM-1) and alpha v integrin. The expression patterns were quantitatively measured by histomorphometry. Under basal conditions, ICAM-1 was weakly expressed in terminal portal veins while minimal VCAM-1 and no E-selectin were detected. Following stimulation with lipopolysaccharide, VCAM-1 and E-selectin were expressed on the endothelium of terminal portal veins and on sinusoidal lining cells with significantly stronger expression in the periportal zone than midzone. VCAM-1 expression peaked at 4 h and decreased gradually by 48 h. E-selectin peaked at 2 h and disappeared by 12 h after stimulation. ICAM-1 expression showed a much stronger and more uniform expression across the acinus with the peak reached by 4 h and sustained for longer than 48 h after lipopolysaccharide administration. The alpha v integrin was not detected under basal conditions or after lipopolysaccharide stimulation. Expression of all these adhesion molecules (ICAM-1, VCAM-1, E-selectin and alpha v integrin) was induced by growth of B16F1 melanoma cells in the peritoneal cavity of the mouse. These results support the hypotheses that expression of microvascular adhesion molecules in the mouse liver is susceptible to regulation by environmental stimuli and has a zonal heterogeneity across the acinus.

Correction of the PNH Defect by GPI-Anchored Protein Transfer

Hemolytic anemia is a major feature of paroxysmal nocturnal hemoglobinuria (PNH). Intravascular red blood cell (RBC) destruction is caused by increased sensitivity of the abnormal erythrocyte to complement-mediated lysis, due to the GPI absence of a membrane-bound glycosylphosphatidylinositol (GPI)-linked protein, which functions as an inhibitor of reactive lysis (CD59). Both in vivo and in vitro models have suggested the feasibility of cell-to-cell transfer of GPI proteins, and patients with hemolysis could potentially benefit from transfer of CD59 to their deficient erythrocytes. We studied the ability of RBC components prepared from outdated packed RBC collections, as well as high-density lipoprotein (HDL) preparations, rich in CD55 and CD59, to promote protein transfer, as assessed by flow cytometry, immunoblotting, and susceptibility to complement-mediated lysis. By flow cytometry, CD55 and CD59 were present on RBC-derived microvesicles that stained with an antiglycophorin antibody Ab; in addition, soluble CD59 and CD55 were detected by immunoblot in soluble fractions eluated from RBC units stored for more than 35 days, but not in fresh blood. Both commercial HDL preparations and those prepared in our laboratory contained CD55 and CD59, as assayed by immunoblot. When RBC that were deficient (GPI)-anchored protein, obtained from five patients, with PNH were incubated with HDL preparations for 2 to 4 hours, there was significant transfer of both proteins to the cell surface, as demonstrated by flow cytometry. Washed RBC microvesicles, prepared by ultrasonification, also mediated transfer of GPI-linked proteins to deficient RBC. Pretreatment of microvesicles, RBC eluate preparations, and HDL with phosphatidylinositol-specific, phospholipase C, abrogated protein transfer to deficient cells, indicating that increased cell-associated CD55 and CD59 levels were related to insertion of the intact GPI moiety, rather than to simple adhesion. PNH RBC that were exposed to HDL, RBC eluate preparations, or microvesicles demonstrated decreased in vitro complement-mediated hemolysis in the Ham test. Transfer of GPI-linked proteins from soluble preparations containing CD55 and CD59 to PNH erythrocytes is feasible and may have clinical utility.

Correction of the PNH Defect by GPI-Anchored Protein Transfer

AbstractHemolytic anemia is a major feature of paroxysmal nocturnal hemoglobinuria (PNH). Intravascular red blood cell (RBC) destruction is caused by increased sensitivity of the abnormal erythrocyte to complement-mediated lysis, due to the GPI absence of a membrane-bound glycosylphosphatidylinositol (GPI)-linked protein, which functions as an inhibitor of reactive lysis (CD59). Both in vivo and in vitro models have suggested the feasibility of cell-to-cell transfer of GPI proteins, and patients with hemolysis could potentially benefit from transfer of CD59 to their deficient erythrocytes. We studied the ability of RBC components prepared from outdated packed RBC collections, as well as high-density lipoprotein (HDL) preparations, rich in CD55 and CD59, to promote protein transfer, as assessed by flow cytometry, immunoblotting, and susceptibility to complement-mediated lysis. By flow cytometry, CD55 and CD59 were present on RBC-derived microvesicles that stained with an antiglycophorin antibody Ab; in addition, soluble CD59 and CD55 were detected by immunoblot in soluble fractions eluated from RBC units stored for more than 35 days, but not in fresh blood. Both commercial HDL preparations and those prepared in our laboratory contained CD55 and CD59, as assayed by immunoblot. When RBC that were deficient (GPI)-anchored protein, obtained from five patients, with PNH were incubated with HDL preparations for 2 to 4 hours, there was significant transfer of both proteins to the cell surface, as demonstrated by flow cytometry. Washed RBC microvesicles, prepared by ultrasonification, also mediated transfer of GPI-linked proteins to deficient RBC. Pretreatment of microvesicles, RBC eluate preparations, and HDL with phosphatidylinositol-specific, phospholipase C, abrogated protein transfer to deficient cells, indicating that increased cell-associated CD55 and CD59 levels were related to insertion of the intact GPI moiety, rather than to simple adhesion. PNH RBC that were exposed to HDL, RBC eluate preparations, or microvesicles demonstrated decreased in vitro complement-mediated hemolysis in the Ham test. Transfer of GPI-linked proteins from soluble preparations containing CD55 and CD59 to PNH erythrocytes is feasible and may have clinical utility.

Delivery of colloidal particles and red blood cells to tissue through microvessel ruptures created by targeted microbubble destruction with ultrasound.

We have previously shown that the application of ultrasound to thin-shelled microbubbles flowing through small microvessels (<7 microm in diameter) produces vessel wall ruptures in vivo. Because many intravascular drug- and gene-delivery vehicles are limited by the endothelial barrier, we hypothesized that this phenomenon could be used to deliver drug-bearing vehicles to tissue. An exteriorized rat spinotrapezius muscle preparation was used. Intravascular fluorescent red blood cells and polymer microspheres (PM) (205 and 503 nm in diameter) were delivered to the interstitium of rat skeletal muscle through microvessel ruptures created by insonifying microbubbles in vivo. On intravital microscopy, mean dispersion areas per rupture for red blood cells, 503-nm PM, and 205-nm PM were 14.5x10(3) microm2, 24. 2x10(3) microm2, and 27.2x10(3) microm2, respectively. PM dispersion areas were significantly larger than the mean dispersion area for red blood cells (P<0.05). Microvessel ruptures caused by insonification of microbubbles in vivo may provide a minimally invasive means for delivering colloidal particles and engineered red blood cells across the endothelial lining of a targeted tissue region.

Expression of matrix metalloproteinases and tissue inhibitors of metalloproteinases in HTLV-I-associated myelopathy.

Matrix metalloproteinases (MMPs) have been reported to be involved in inflammatory disorders of the central nervous system (CNS). However, little is known about the role of MMPs in the pathogenesis of HTLV-I-associated myelopathy (HAM)/Tropical spastic paraparesis (TSP). To address this issue, we examined the tissue expression and localization of MMPs and their inhibitors, tissue inhibitors of metalloproteinases (TIMPs) in the spinal cord lesions of HAM/TSP using immunohistochemistry. In addition, the blood and cerebrospinal fluid (CSF) levels of MMPs and TIMPs of the patients with HAM/TSP were determined using sandwich enzyme immunoassays (SIA) and gelatin zymography. Immunohistochemical studies revealed that collagen IV and decorin immunoreactivity on the basement membrane of CNS parenchymal vessels was partially disrupted where inflammatory mononuclear cells infiltrated in active-chronic lesions of HAM/TSP. In these lesions, MMP-2 (gelatinase A) was immunostained mainly on the surface of foamy macrophages and lymphocytes, whereas MMP-9 (gelatinase B) expression was positive in the intravascular and perivascular mononuclear cells but not on foamy macrophages. In contrast, inactive chronic lesions of the spinal cords of the HAM/TSP contained fewer MMP-2-positive or MMP-9-positive mononuclear cells than active-chronic lesions. Many parenchymal vessels had thickened vascular walls which showed increased immunoreactivity to decorin. SIA revealed that production levels of MMP-2 and MMP-9 in both blood and CSF were higher in the patients with HAM/TSP than those in non-inflammatory other neurological disease controls (ONDs). Using zymography, proMMP-9 was detected more frequently in the CSF of patients with HAM/TSP than those in ONDs. Taken together, our data indicate that MMP-2 and MMP-9 may play an important role in the blood-brain barrier breakdown and tissue remodeling in the CNS of HAM/TSP.

Intravascular large cell lymphoma: A patient with asymptomatic purpuric patches and a chronic clinical course

Intravascular large cell lymphoma (malignant angioendotheliomatosis) is a rare, multifocal, intravascular neoplasm of lymphoid cells that preferentially involves the vasculature of the skin and central nervous system. We describe a 54-year-old man with asymptomatic purpuric patches on the lower extremities for 10 years duration and a more recent lesion on the right arm. A biopsy specimen showed intravascular collections of tumor cells with irregular nuclear contours and prominent nucleoli. These cells were leukocyte common antigen (CD45), CD20, and CDW75 positive, but CD3, CD43, CD45RO, and cytokeratin negative. Polymerase chain reaction analysis of the skin for immunoglobulin heavy chain gene rearrangement detected a clonal population of B cells, supporting the diagnosis of a B-cell lymphoma. Peripheral blood showed no abnormal circulating cells. This case of malignant angioendotheliomatosis is unusual for its prolonged clinical course and presence of purpuric patches. (J Am Acad Dermatol 1998;39:318-21.)