Implantation of bone marrow mononuclear cells into ischemic myocardium enhances collateral perfusion and regional function via side supply of angioblasts, angiogenic ligands, and cytokines

BACKGROUND

Bone marrow implantation (BMI) was shown to enhance angiogenesis in a rat ischemic heart model. This preclinical study using a swine model was designed to test the safety and therapeutic effectiveness of BMI.

METHODS AND RESULTS

BM-derived mononuclear cells (BM-MNCs) were injected into a zone made ischemic by coronary artery ligation. Three weeks after BMI, regional blood flow and capillary densities were significantly higher (4.6- and 2.8-fold, respectively), and cardiac function was improved. Angiography revealed that there was a marked increase (5.7-fold) in number of visible collateral vessels. Implantation of porcine coronary microvascular endothelial cells (CMECs) did not cause any significant increase in capillary densities. Labeled BM-MNCs were incorporated into approximately 31% of neocapillaries and corresponded to approximately 8.7% of macrophages but did not actively survive as myoblasts or fibroblasts. There was no bone formation by osteoblasts or malignant ventricular arrhythmia. Time-dependent changes in plasma levels for cardiac enzymes (troponin I and creatine kinase-MB) did not differ between the BMI, CMEC, and medium-alone implantation groups. BM-MNCs contained 16% of endothelial-lineage cells and expressed basic fibroblast growth factor>>vascular endothelial growth factor>angiopoietin 1 mRNAs, and their cardiac levels were significantly upregulated by BMI. Cardiac interleukin-1beta and tumor necrosis factor-alpha mRNA expression were also induced by BMI but not by CMEC implantation. BM-MNCs were actively differentiated to endothelial cells in vitro and formed network structure with human umbilical vein endothelial cells.

CONCLUSIONS

BMI may constitute a novel safety strategy for achieving optimal therapeutic angiogenesis by the natural ability of the BM cells to secrete potent angiogenic ligands and cytokines as well as to be incorporated into foci of neovascularization.

Angiotensin II type 2 receptor overexpression activates the vascular kinin system and causes vasodilation

Angiotensin II (Ang II) is a potent vasopressor peptide that interacts with 2 major receptor isoforms - AT1 and AT2. Although blood pressure is increased in AT2 knockout mice, the underlying mechanisms remain undefined because of the low levels of expression of AT2 in the vasculature. Here we overexpressed AT2 in vascular smooth muscle (VSM) cells in transgenic (TG) mice. Aortic AT1 was not affected by overexpression of AT2. Chronic infusion of Ang II into AT2-TG mice completely abolished the AT1-mediated pressor effect, which was blocked by inhibitors of bradykinin type 2 receptor (icatibant) and nitric oxide (NO) synthase (L-NAME). Aortic explants from TG mice showed greatly increased cGMP production and diminished Ang II-induced vascular constriction. Removal of endothelium or treatment with icatibant and L-NAME abolished these AT2-mediated effects. AT2 blocked the amiloride-sensitive Na(+)/H(+) exchanger, promoting intracellular acidosis in VSM cells and activating kininogenases. The resulting enhancement of aortic kinin formation in TG mice was not affected by removal of endothelium. Our results suggest that AT2 in aortic VSM cells stimulates the production of bradykinin, which stimulates the NO/cGMP system in a paracrine manner to promote vasodilation. Selective stimulation of AT2 in the presence of AT1 antagonists is predicted to have a beneficial clinical effect in controlling blood pressure.

Site-specific chemical modification with polyethylene glycol of recombinant immunotoxin anti-Tac(Fv)-PE38 (LMB-2) improves antitumor activity and reduces animal toxicity and immunogenicity

Chemical modification of proteins with polyethylene glycol (PEGylation) can increase plasma half-lives, stability, and therapeutic potency. To make a PEGylated recombinant immunotoxin with improved therapeutic properties, we prepared a mutant of anti-Tac(Fv)-PE38 (LMB-2), a recombinant immunotoxin composed of a single-chain Fv fragment of the anti-human Tac monoclonal antibody to the IL-2 receptor alpha subunit fused to a 38-kDa fragment of Pseudomonas exotoxin. For site-specific PEGylation of LMB-2, one cysteine residue was introduced into the peptide connector (ASGCGPE) between the Fv and the toxin. This mutant LMB-2 (cys1-LMB-2), which retained full cytotoxic activity, was then site-specifically conjugated with 5 or 20 kDa of polyethylene glycol-maleimide. When compared with unmodified LMB-2, both PEGylated immunotoxins showed similar cytotoxic activities in vitro but superior stability at 37 degrees C in mouse serum, a 5- to 8-fold increase in plasma half-lives in mice, and a 3- to 4-fold increase in antitumor activity. This was accompanied by a substantial decrease in animal toxicity and immunogenicity. Site-specific PEGylation of recombinant immunotoxins may increase their therapeutic potency in humans.

Removal of estrogenic activities of bisphenol A and nonylphenol by oxidative enzymes from lignin-degrading basidiomycetes

Bisphenol A (BPA) and nonylphenol (NP) were treated with manganese peroxidase (MnP) and laccase prepared from the culture of lignin-degrading fungi. Laccase in the presence of 1-hydroxybenzotriazole (HBT), the so-called laccase-mediator system, was also applied to remove the estrogenic activity. Both chemicals disappeared in the reaction mixture within a 1-h treatment with MnP but the estrogenic activities of BPA and NP still remained 40% and 60% in the reaction mixtures after a 1-h and a 3-h treatment, respectively. Extension of the treatment time to 12 h completed the removal of estrogenic activities of BPA and NP. The laccase has less ability to remove these activities than MnP, but the laccase-HBT system was able to remove the activities in 6 h. A gel permeation chromatography (GPC) analysis revealed that main reaction products of BPA and NP may be oligomers formed by the action of enzymes. Enzymatic treatments extended to 48 h did not regenerate the estrogenic activities, suggesting that the ligninolytic enzymes are effective for the removal of the estrogenic activities of BPA and NP.

Angiotensin AT(1) and AT(2) receptors differentially regulate angiopoietin-2 and vascular endothelial growth factor expression and angiogenesis by modulating heparin binding-epidermal growth factor (EGF)-mediated EGF receptor transactivation

Angiotensin II (Ang II)-mediated signals are transmitted via heparin binding epidermal growth factor (EGF)-like growth factor (HB-EGF) release followed by transactivation of EGF receptor (EGFR). Although Ang II and HB-EGF induce angiogenesis, their link to the angiopoietin (Ang)-Tie2 system remains undefined. We tested the effects of Ang II on Ang1, Ang2, or Tie2 expression in cardiac microvascular endothelial cells expressing the Ang II receptors AT(1) and AT(2). Ang II significantly induced Ang2 mRNA accumulations without affecting Ang1 or Tie2 expression, which was inhibited by protein kinase C inhibitors and by intracellular Ca(2+) chelating agents. Ang II transactivated EGFR via AT(1), and inhibition of EGFR abolished the induction of Ang2. Ang II caused processing of pro-HB-EGF in a metalloproteinase-dependent manner to stimulate maturation and release of HB-EGF. Neutralizing anti-HB-EGF antibody blocked EGFR phosphorylation by Ang II. Ang II also upregulated vascular endothelial growth factor (VEGF) expression in an HB-EGF/EGFR-dependent manner. AT(2) inhibited AT(1)-mediated Ang2 expression and phosphorylation of EGFR. In an in vivo corneal assay, AT(1) induced angiogenesis in an HB-EGF-dependent manner and enhanced the angiogenic activity of VEGF. Although neither Ang2 nor Ang1 alone induced angiogenesis, soluble Tie2-Fc that binds to angiopoietins attenuated AT(1)-mediated angiogenesis. These findings suggested that (1) Ang II induces Ang2 and VEGF expression without affecting Ang1 or Tie2 and (2) AT(1) stimulates processing of pro-HB-EGF by metalloproteinases, and the released HB-EGF transactivates EGFR to induce angiogenesis via the combined effect of Ang2 and VEGF, whereas AT(2) attenuates them by blocking EGFR phosphorylation. Thus, Ang II is involved in the VEGF-Ang-Tie2 system via HB-EGF-mediated EGFR transactivation, and this link should be considerable in pathological conditions in which collateral blood flow is required.

Angiotensin II type 2 receptor is upregulated in human heart with interstitial fibrosis, and cardiac fibroblasts are the major cell type for its expression

The expression pattern of angiotensin (Ang) II type 2 receptor (AT2-R) in the remodeling process of human left ventricles (LVs) remains poorly defined. We analyzed its expression at protein, mRNA, and cellular levels using autopsy, biopsy, or operation LV samples from patients with failing hearts caused by acute (AMI) or old (OMI) myocardial infarction and idiopathic dilated cardiomyopathy (DCM) and also examined functional biochemical responses of failing hearts to Ang II. In autopsy samples from the nonfailing heart group, the ratio of AT1-R and AT2-R was 59% and 41%, respectively. The expression of AT2-R was markedly increased in DCM hearts at protein (3.5-fold) and mRNA (3.1-fold) levels compared with AMI or OMI. AT1-R protein and mRNA levels in AMI hearts showed 1.5- and 2.1-fold increases, respectively, whereas in OMI and DCM hearts, AT1-R expression was significantly downregulated. AT1-R-mediated response in inositol phosphate production was significantly attenuated in LV homogenate from failing hearts compared with nonfailing hearts. AT2-R sites were highly localized in the interstitial region in either nonfailing or failing heart, whereas AT1-R was evenly distributed over myocardium at lower densities. Mitogen-activated protein kinase (MAPK) activation by Ang II was significantly decreased in fibroblast compartment from the failing hearts, and pretreatment with AT2-R antagonist caused an additional significant increase in Ang II-induced MAPK activity (36%). Cardiac hypertrophy suggested by atrial and brain natriuretic peptide levels was comparably increased in OMI and DCM, whereas accumulation of matrix proteins such as collagen type 1 and fibronectin was much more prominent in DCM than in OMI. These findings demonstrate that (1) AT2-R expression is upregulated in failing hearts, and fibroblasts present in the interstitial regions are the major cell type responsible for its expression, (2) AT2-R present in the fibroblasts exerts an inhibitory effect on Ang II-induced mitogen signals, and (3) AT1-R in atrial and LV tissues was downregulated during chronic heart failure, and AT1-R-mediated functional biochemical responsiveness was decreased in the failing hearts. Thus, the expression level of AT2-R is likely determined by the extent of interstitial fibrosis associated with heart failure, and the expression and function of AT1-R and AT2-R are differentially regulated in failing human hearts.

Angiotensin II type 1 receptor-induced extracellular signal-regulated protein kinase activation is mediated by Ca2+/calmodulin-dependent transactivation of epidermal growth factor receptor

The signaling cascade elicited by angiotensin II (Ang II) resembles that characteristic of growth factor stimulation, and recent evidence suggests that G protein-coupled receptors transactivate growth factor receptors to transmit mitogenic effects. In the present study, we report the involvement of epidermal growth factor receptor (EGF-R) in Ang II-induced extracellular signal-regulated kinase (ERK) activation, c-fos gene expression, and DNA synthesis in cardiac fibroblasts. Ang II induced a rapid tyrosine phosphorylation of EGF-R in association with phosphorylation of Shc protein and ERK activation. Specific inhibition of EGF-R function by either a dominant-negative EGF-R mutant or selective tyrphostin AG1478 completely abolished Ang II-induced ERK activation. Induction of c-fos gene expression and DNA synthesis were also abolished by the inhibition of EGF-R function. Calmodulin or tyrosine kinase inhibitors, but not protein kinase C (PKC) inhibitors or downregulation of PKC, completely abolished transactivation of EGF-R by Ang II or the Ca2+ ionophore A23187. Epidermal growth factor (EGF) activity in concentrated supernatant from Ang II-treated cells was not detected, and saturation of culture media with anti-EGF antibody did not affect the Ang II-induced transactivation of EGF-R. Conditioned media in which cells were incubated with Ang II could not induce phosphorylation of EGF-R on recipient cells. Platelet-derived growth factor-beta receptor was not phosphorylated on Ang II stimulation, and Ang II-induced c-jun gene expression was not affected by tyrphostin AG1478. Our results demonstrated that in cardiac fibroblasts Ang II-induced ERK activation and its mitogenic signals are dominantly mediated by EGF-R transactivated in a Ca2+/calmodulin-dependent manner and suggested that the effects of Ang II on cardiac fibroblasts should be interpreted in association with the signaling pathways regulating cellular proliferation and/or differentiation by growth factors.

Positively charged liposome functions as an efficient immunoadjuvant in inducing cell-mediated immune response to soluble proteins

In order to design an optimized liposome immunoadjuvant for inducing cell-mediated immune response against soluble proteinaceous antigens, we investigated the effect of liposomal surface charge on the immunoadjuvant action. Positively charged liposomes containing soluble antigens functioned as a more potent inducer of antigen-specific cytotoxic T lymphocyte responses and delayed type hypersensitivity response than negatively charged and neutral liposomes containing the same concentrations of antigens. To clarify the reason of the differential immune response, we examined the delivery of soluble proteins by the liposomes into the cytoplasm of macrophages, using fragment A of diphtheria toxin (DTA) as a marker. We found that positively charged liposomes encapsulating DTA are cytotoxic to macrophages, while empty positively charged liposomes, DTA in negatively charged and neutral liposomes are not. Consistent with this, only macrophages pulsed with OVA in positively charged liposomes could significantly stimulate OVA-specific, class I MHC-restricted T cell hybridoma. These results suggest that the positively charged liposomes can deliver proteinaceous antigens efficiently into the cytoplasm of the macrophages/antigen-presenting cells, where the antigens are processed to be presented by class I MHC molecules to induce the cell-mediated immune response. Possible development of the safe and effective vaccine is discussed.

Extraprostatic localization of prostatic acid phosphatase and prostate-specific antigen: distribution in cloacogenic glandular epithelium and sex-dependent expression in human anal gland

Immunoreactivities of prostatic acid phosphatase (PACP) and prostate-specific antigen (PSA) were demonstrated in normal anal glands of males (11 of 25) and urethral glands of both sexes (six of six), by indirect immunoperoxidase staining. These prostatic antigens were colocalized in nonmucous epithelial cells. In the anal gland, PACP and PSA were distributed exclusively in acinus-forming, tall columnar cells, while columnar cells with brush borders, goblet cells, and transitional cells in the duct were negative. The anal glands from 20 females were devoid of such acinar structures and were negative for the antigens. Normal urinary bladder mucosa (n = 17) lacked immunoreactivity. A few endocrine-type cells, which showed PACP immunoreactivity but no PSA staining, were identified in normal rectal mucosa (n = 17) and were found rarely in the anal gland. The results of the present study suggest (1) that the development of acinar cells in the anal gland is an androgen-dependent phenomenon, and (2) that the ability to express PACP and PSA is a feature common to cloacogenic glandular epithelium.

Apoptotic cells in the human endometrium and placental villi: pitfalls in applying the TUNEL method

Apoptotic cells were histochemically demonstrated by the TdT-mediated biotinylated dUTP nick end-labeling (TUNEL) method in formalin-fixed and paraffin-embedded sections of the human endometrium and placental villi. In 53 endometrial biopsy specimens, labeled nuclei were identified in 16 samples showing a desquamating change, associated with menstruation, functional bleeding or adenocarcinoma. Cells in the normal proliferative and secretory phases were unlabeled. The labeled nuclei in the gland and stroma corresponded well to the so-called apoptotic bodies. Placental tissues at various stages of gestation were obtained by spontaneous abortion, intrauterine fetal death or normal delivery. Syncytiotrophoblastic cells in an early gestational stage (7-12 weeks) and in the term placenta were focally labeled, and the labeled cells possessed pyknotic nuclei and densely eosinophilic cytoplasm. In the early gestational chorionic villi with marked hydropic degeneration or in hydatidiform mole, the stromal cells were frequently labeled. Villous cells in coagulation necrosis (infarction) also revealed strong signals. The apoptotic bodies were not recognizable histologically in these labeled villi. The placenta at the 20th to 33rd week of gestation lacked labeling. From a technical point of view, it should be noted that cells in the foci showing ischemia or coagulation necrosis were labeled positively.

Angiotensin II-induced transactivation of epidermal growth factor receptor regulates fibronectin and transforming growth factor-beta synthesis via transcriptional and posttranscriptional mechanisms

The signaling cascade elicited by angiotensin II (Ang II) resembles that characteristic of a growth factor, and recent evidence indicates transactivation of epidermal growth factor receptor (EGF-R) by G protein-coupled receptors. Here, we report the involvement of EGF-R in Ang II-induced synthesis of fibronectin and transforming growth factor-beta (TGF-beta) in cardiac fibroblasts. Ang II stimulated fibronectin mRNA levels dose dependently, with a maximal increase (approximately 5-fold) observed after 12 hours of incubation. Fibronectin synthesis induced by Ang II or calcium ionophore was completely abolished by tyrosine kinase inhibitors and intracellular Ca2+ chelating agents. Ang II-induced fibronectin mRNA was not affected by protein kinase C inhibitors or protein kinase C depletion, whereas specific inhibition of EGF-R function by a dominant negative EGF-R mutant and tyrphostin AG1478 abolished induction of fibronectin mRNA. We isolated the rat fibronectin gene, including the 5'-flanking region, and found that the activator protein-1 (AP-1) binding site present in the promoter region was responsible for the Ang II responsiveness of this gene. A gel retardation assay revealed the binding of nuclear protein to the AP-1 site, which was supershifted with anti-c-fos and anti-c-jun but not anti-activating transcription factor (ATF)-2 antibodies. Conditioned medium from Ang II-treated cells contained TGF-beta bioactivity, and addition of neutralizing TGF-beta antibody modestly (46%) inhibited induction of fibronectin. Ang II-induced synthesis of TGF-beta was also abolished by inhibition of EGF-R function. The effect of TGF-beta was exerted by stabilizing fibronectin mRNA without affecting the promoter activity and required de novo protein synthesis. We concluded that Ang II-induced expression of fibronectin and TGF-beta is mediated by downstream signaling of EGF-R transactivated by Ca2+-dependent tyrosine kinase and that Ang II-induced fibronectin mRNA expression is regulated by 2 different mechanisms, which are transcriptional control by binding of the c-fos/c-jun complex to the AP-1 site and posttranscriptional control by mRNA stabilization due to autocrine or paracrine effects of TGF-beta. Thus, this study suggests that the action of Ang II on extracellular matrix formation should be interpreted in association with the EGF-R signaling cascade.

Positively charged liposome functions as an efficient immunoadjuvant in inducing immune responses to soluble proteins

To design an optimum liposome immunoadjuvant for soluble protein antigens, we investigated the relationship between liposomal surface charge and adjuvant action. Positively charged multilamellar vesicles (MLV) were taken up efficiently by macrophages, while negatively charged and neutral MLVs were hardly picked up. Consistent with this, positively charged MLVs containing soluble chicken egg albumin (OVA) functioned as a more potent inducer of antigen-specific cytotoxic T lymphocyte (CTL) responses and antibody production than negatively charged and neutral MLVs containing the same concentrations of antigens. These results indicate that the positive charge on the surface of liposomes represents an important factor for enhancing their immunoadjuvancy in the induction of antigen-specific immune responses.

Tumor necrosis factor alpha production by peripheral blood mononuclear cells of patients with chronic liver disease

We investigated the production of tumor necrosis factor alpha by peripheral blood mononuclear cells of patients with chronic liver disease and its association with hepatitis activity. Tumor necrosis factor alpha production was measured with an enzyme-linked immunosorbent assay. Tumor necrosis factor alpha production by peripheral blood mononuclear cells stimulated with recombinant gamma-interferon of patients with chronic active hepatitis (5.8 +/- 4.0 units per ml, p less than 0.05) and patients with cirrhosis (4.1 +/- 2.1 units per ml, p less than 0.05) was significantly increased when compared with controls (2.5 +/- 1.6 units per ml). Tumor necrosis factor alpha production by peripheral blood mononuclear cells stimulated with a combination of recombinant gamma-interferon and recombinant interleukin 2 of patients with chronic persistent hepatitis (5.8 +/- 3.8 units per ml, p less than 0.05), patients with chronic active hepatitis (8.9 +/- 3.0 units per ml, p less than 0.001) and patients with cirrhosis (6.7 +/- 3.2 units per ml, p less than 0.05) was significantly increased in comparison with controls (3.3 +/- 1.8 units per ml). Tumor necrosis factor alpha production of patients with chronic active hepatitis was significantly higher than that of patients with chronic persistent hepatitis (p less than 0.05). There was a significant correlation (r = 0.5699, p less than 0.005) between tumor necrosis factor alpha production and histologic activity index in patients with chronic persistent hepatitis or chronic active hepatitis. These findings show that tumor necrosis factor alpha production is increased in chronic liver disease and that the increased tumor necrosis factor alpha production is related to hepatitis activity.

Interactive binding to the two principal ligand binding sites of human serum albumin: effect of the neutral-to-base transition

The relationship between the two principal ligand binding sites, sites I and II, on human serum albumin (HSA) was quantitatively and qualitatively examined by equilibrium dialysis and fluorescence spectroscopy. Among the three subsite markers to site I, only the binding of dansyl-L-asparagine (DNSA), which is a subsite Ib marker (K. Yamasaki et al., Biochim. Biophys. Acta 1295 (1996) 147), was inhibited by the simultaneous binding of a site II ligand, such as ibuprofen and diazepam. This indicates that, in contrast to subsite Ib, subsites Ia and Ic do not strongly interact with site II. The thermodynamic characteristics for the coupling reaction between DNSA and ibuprofen and between DNSA and diazepam, which gave positive coupling free energies and negative values for both coupling enthalpy and entropy, indicated that the reaction process was entropically driven. Increase of pH from 6.5 to 8.2 caused an increase in coupling constant and entropy for the mutual antagonism between DNSA and the site II ligands on binding to HSA. The site II ligand-induced red-shift of lambda(max) and solvent accessibility of DNSA in subsite Ib were decreased when the albumin molecule was isomerized from the neutral (N) to the base (B) conformation in the physiological pH region. Based on these findings, we conclude that a 'competitive' like strong allosteric regulation exists for the binding of these two ligands to the N conformer, whereas for the B conformer this interaction can be classified as nearly 'independent'. Since the distance between Trp-214, which resides within the site I subdomain, and Tyr-411, which is involved in site II, is increased by 6 A during the N-B transition (N.G. Hagag et al., Fed. Proc. 41 (1982) 1189), we propose a mechanism for the pH-dependent antagonistic binding between subsite Ib and site II, which involves the transmission of ligand-induced allosteric effects from one site to another site, modified by changes in the spatial relationship of sites I and II caused by the N-B transition.

Morphological features and associated anomalies of schizencephaly in the clinical population: detailed analysis of MR images

Although they are well documented in autopsy series, the macroscopic features and associated anomalies of schizencephalies have not been described in detail in a large clinical population. To assess the macroscopic findings of schizencephaly and the prevalence of associated findings, we conducted a retrospective MR analysis of a group of patients with schizencephaly. The MR studies of 35 patients with schizencephaly were retrospectively reviewed. The images were examined for the location and size of the schizencephalic cleft, the presence and location of associated polymicrogyria, and the presence, location, and severity of other brain anomalies. A total of 54 schizencephalic clefts were seen in the 35 patients. These clefts were unilateral in 18 (51%) patients and bilateral in 17 (49%) patients; three clefts were identified in two patients. Nine clefts (17%) had fused lips and 45 had separated-lip clefts (83%). Polymicrogyria was present inside 23 clefts (43%), while subependymal heterotopias were present at the cleft orifice in 27 clefts (50%). Polymicrogyria was identified outside the cleft, both adjacent to and remote from the cleft, in 23 patients (66%). Abnormal cerebral white-matter signal intensity was present in seven patients (20%), while white-matter volume diminution was noted in all patients. Ventricular diverticula with mass effect, roofing membranes, remnant floors, and cord-like remnants were present in 12, 1, 11, and 3 patients, respectively. Our results show that the spectrum of macroscopic findings in schizencephaly includes fused-lip and separated-lip clefts, polymicrogyric and non-polymicrogyric cleft linings, cyst-like diverticula and membranous structures, and subependymal heterotopia at the cleft. Concomitant anomalies are polymicrogyria outside the cleft, white-matter diminution, septal and optic pathway anomalies, callosal anomalies and hippocampal anomalies. Unilateral and bilateral clefts occur in a nearly equal frequency in the clinical population, in contrast to the high incidence of bilateral schizencephaly reported in the pathological literature.

Possible efficacy of lamivudine treatment to prevent hepatitis B virus reactivation due to rituximab therapy in a patient with non-Hodgkin's lymphoma

We used regimens containing rituximab in the treatment of five hepatitis B virus surface antibody (HBsAb)-positive patients with non-Hodgkin's lymphoma (NHL). Serum levels of HBsAb were obtained and analyzed in four of these patients. Two patients were HBs antigen (HBsAg) positive. One of these HBsAg-positive patients was treated with lamivudine because the patient developed fulminant hepatitis from hepatitis B virus (HBV) infection prior to chemotherapy. However, none of the other patients were administered lamivudine. An HBsAg-positive patient who did not receive lamivudine treatment later developed fulminant hepatitis. Another HBsAg-positive patient receiving lamivudine prophylaxis did not develop severe hepatitis arising from HBV. In the three patients not receiving lamivudine treatment, serum HBsAb titers decreased soon after the administration of rituximab. These results suggest that rituximab reduced the antibody titer for HBV, thus inducing an immunological environment leading to easy reactivation of HBV. Lamivudine prophylaxis was effective, at least when rituximab was given to an HBsAg-positive patient with non-Hodgkin's lymphoma.

An immunohistochemical and clinicopathological study of gastrointestinal stromal tumors

Immunohistochemical and clinicopathological features of 58 gastrointestinal stromal tumors (GIST) were studied. One occurred in the esophagus, 41 in the stomach, nine in the small intestine, and seven in the large intestine. By using indirect immunoperoxidase staining for Cajal cell markers (c-kit protein and CD34), smooth muscle markers (alpha-smooth muscle actin, desmin, heavy caldesmon and calponin) and Schwann cell markers (S-100 protein and Leu 7), GIST were classified into five groups, such as Cajal cell type (n = 9), myogenic type (n = 5), Schwann cell type (n = 2), mixed cell type (n = 40) and undifferentiated type (n = 2). c-kit Protein (42/58; 72%) and CD34 (45/58; 78%) were commonly and diffusely expressed in GIST. Novel smooth muscle markers, caldesmon (29/58; 50%) and calponin (18/58; 31%), were useful in detecting myogenic characters of GIST. S-100 protein was expressed in 16 (28%) tumors, two of which were also reactive with Leu 7 (CD57). Three small bowel tumors with skeinoid fibers expressed the Cajal cell markers, and were categorizable in GIST. Clinicopathological analyses using aggressive (n = 21) and non-aggressive (n = 21) GIST indicated that the malignant potential was correlated with the intestinal location, large tumor size, high cellularity, necrosis, solid (non-interlacing bundled) pattern of growth, negativity of c-kit protein and/or CD34, high mitotic count, and high MIB-1 labeling.

Correlation of brightening with cumulative enzyme activity related to lignin biodegradation during biobleaching of kraft pulp by white rot fungi in the solid-state fermentation system

Biobleaching of hardwood unbleached kraft pulp (UKP) by Phanerochaete chrysosporium and Trametes versicolor was studied in the solid-state fermentation system with different culture media. In this fermentation system with low-nitrogen and high-carbon culture medium, pulp brightness increased by 15 and 30 points after 5 days of treatment with T. versicolor and P. chrysosporium, respectively, and the pulp kappa number decreased with increasing brightness. A comparison of manganese peroxidase (MnP), lignin peroxidase (LiP), and laccase activities assayed by using fungus-treated pulp and the filtrate after homogenizing the fungus-treated pulp in buffer solution indicated that enzymes secreted from fungi were adsorbed onto the UKP and that assays of these enzyme activities should be carried out with the treated pulp. Time course studies of brightness increase and MnP activity during treatment with P. chrysosporium suggested that it was difficult to correlate them on the basis of data obtained on a certain day of incubation, because the MnP activity fluctuated dramatically during the treatment time. When brightness increase and cumulative MnP, LiP, and laccase activities were determined, a linear relationship between brightness increase and cumulative MnP activity was found in the solid-state fermentation system with both P. chrysosporium and T. versicolor. This result suggests that MnP is involved in brightening of UKP by white rot fungi.

Down syndrome cell adhesion molecule DSCAM mediates homophilic intercellular adhesion

Down Syndrome (DS) caused by trisomy 21 is the most common birth defect associated with mental retardation. Recently, a novel gene named, DSCAM, has been identified in the DS critical region. DSCAM is predicted to be a transmembrane protein with a very high structural and sequence homology to Ig superfamily of cell adhesion molecules and is expressed in the developing nervous system with the highest level in fetal brain. Diverse glycoproteins of cell surfaces and extracellular matrices operationally termed as 'adhesion molecule' are important in the specification of cell interactions during development, maintenance and regeneration of the nervous system. To understand the cellular function of DSCAM protein, we transfected human DSCAM cDNA into mouse fibroblast L cells and analysed its expression. On Western blot analysis, antibodies raised against recombinant DSCAM-Ig3 recognized a 198 kDa protein band in the membrane fraction of DSCAM transfected L cells. Stable transformants expressing DSCAM showed uniform surface expression. DSCAM-expressing transfectants exhibited enhanced adhesive properties, aggregating with faster kinetics and forming aggregates in a homophilic manner. Divalent cations are not required for this cell aggregation. These results demonstrate that DSCAM is a cell adhesion molecule that can mediate cation-independent homophilic binding activity between DSCAM expressing cells.

Hydrocarbon Deposition Attenuates Osteoblast Activity on Titanium

Although the reported percentage of bone-implant contact is far lower than 100%, the cause of such low levels of bone formation has rarely been investigated. This study tested the negative biological effect of hydrocarbon deposition onto titanium surfaces, which has been reported to be inevitable. Osteogenic MC3T3-E1 cells were cultured on titanium disks on which the carbon concentration was experimentally regulated to achieve carbon/titanium (C/Ti) ratios of 0.3, 0.7, and 1.0. Initial cellular activities such as cell attachment and cell spreading were concentration-dependently suppressed by the amount of carbon on the titanium surface. The osteoblastic functions of alkaline phosphatase activity and calcium mineralization were also reduced by more than 40% on the C/Ti (1.0) surface. These results indicate that osteoblast activity is influenced by the degree of hydrocarbon contamination on titanium implants and suggest that hydrocarbon decomposition before implant placement may increase the biocompatibility of titanium.

Role of calcium-sensitive tyrosine kinase Pyk2/CAKbeta/RAFTK in angiotensin II induced Ras/ERK signaling

In cardiac fibroblasts, angiotensin II (Ang II) induced a rapid increase in extracellular signal regulated kinase (ERK) activity in a pertussis toxin insensitive manner. This ERK activation was abolished by the Gq-associated phospholipase C inhibitor U73122 but was insensitive to protein kinase C (PKC) inhibitors or PKC downregulation by phorbol ester. Intracellular Ca2+ chelation by BAPTA-AM or TMB-8 abolished Ang II induced ERK activation, whereas treatment with EGTA or nifedipine did not affect it. Ca2+ ionophore A23187 also induced a rapid increase in ERK activity to an extent similar to that of Ang II stimulation. Calmodulin inhibitors (W7 and calmidazolium) and tyrosine kinase inhibitors (genistein and ST638) completely blocked ERK activation by Ang II and A23187. Both Ang II and A23187 caused a rapid increase in the binding of GTP to p21(Ras), which was nearly abolished by genistein and calmidazolium. Transfection with the dominant negative mutant of Ras and the Ras inhibitor manumycin completely inhibited Ang II induced ERK activation. It was also found for the first time that cardiac fibroblasts abundantly expressed Ca2+-sensitive tyrosine kinase Pyk2/CAKbeta/RAFTK and that Ang II markedly induced its activation in a Ca2+/calmodulin-sensitive manner. Overexpression of the dominant negative mutant of Pyk2 significantly attenuated Ang II or A23187-induced ERK activities (36% and 38% inhibition compared with that in mock-transfected cells, respectively) and ERK tyrosine phosphorylation levels, as well as an increase in the binding of GTP to p21(Ras). These findings demonstrate that in cardiac fibroblasts, Ang II induced Ras/ERK activation is dominantly regulated by Gq-coupled Ca2+/calmodulin signaling and that Pyk2 plays an important role in the signal transmission for efficient activation of the Ang II induced Ras/ERK pathway.

neu oncogene protein and epidermal growth factor receptor are independently expressed in benign and malignant breast tissues

The neu oncogene protein, p185, and epidermal growth factor receptor (EGFR) were localized immunohistochemically in benign and malignant human breast tissues using monoclonal antibodies. Both benign and malignant epithelial cells were positive for these oncogene proteins in acetone-postfixed frozen sections. Stromal cells were negative for p185, but occasionally positive for EGFR. Myoepithelial cells were consistently positive for EGFR, and p185 was localized predominantly in duct-lining cells, where the basolateral plasma membrane was the normal expression site of both substances. Paraformaldehyde-prefixed frozen sections were less sensitive for antigen demonstration. Based on the intensity of immunoreactivity, 11 of 37 acetone-postfixed breast carcinomas (30%) were judged neu overexpressors, while none of 24 benign tissues overexpressed neu. Epidermal growth factor receptor was demonstrated in 18 of 36 acetone-postfixed cancer tissues (50%) and was overexpressed in three (8%). At the cellular level, heterogenous expression of p185 and EGFR was occasionally observed in both benign and malignant tissues, and a single case of cancer overexpressing both neu and EGFR showed reciprocal patterns of staining, indicating their independent expression. In some carcinomas, EGFR was localized only in stromal cells. Our findings confirmed mutually independent expression of the two closely related protooncogenes in benign and malignant breast tissues.

Localized accumulation of Russell body-containing plasma cells in gastric mucosa with Helicobacter pylori infection: 'Russell body gastritis'

One of the gastric biopsy specimens taken from a 53-year-old male showed localized accumulation of plasma cells containing Russell bodies, in association with infection of Helicobacter pylori (H. pylori). An endoscopic study demonstrated multiple ulcer scars in the antrum. Immunohistochemically, H. pylori infection was identified both on the surface of the foveolar epithelial cells and in the cytoplasm of macrophages in the lamina propria mucosae. Plasma cells filled with 'Russell bodies', so-called 'Motts cells', were immunoreactive for CD45, CD79a and IgG. This seems to be a previously unrecognized tissue reaction in gastric mucosa associated with H. pylori infection, which we have called 'Russell body gastritis'.