Biomedical subjects

Y Abe

Publications and source records attributed to Y Abe.

At least 253 records · Page 14Linked to original sources

PubMed1999

Expression of E-cadherin in bone and soft tissue sarcomas: a possible role in epithelial differentiation.

The cadherin-mediated cell-cell adhesion system is now known to play a critical role in both the morphogenesis of cancer cells and suppression of their invasion. However, the pattern of expression of E-cadherin, the major cadherin of epithelial cells in bone and soft tissue sarcomas, remains unclear. This prompted us to study E-cadherin expression in a variety of bone and soft tissue sarcomas. Using the monoclonal antibody HECD-1, raised against the extracellular domain of E-cadherin, we observed immunoreactivity in 1 pleomorphic rhabdomyosarcoma, 2 of 5 diffuse mesotheliomas, 4 of 5 clear cell sarcomas, 1 of 5 epithelioid sarcomas, and 10 synovial sarcomas. Other types of bone and soft tissue sarcoma (4 osteosarcomas, 4 chondrosarcomas, 3 primitive neuroectodermal tumors, 1 fibrosarcoma, 4 malignant fibrous histiocytomas, 5 liposarcomas, 4 leiomyosarcomas, 6 alveolar and 5 embryonal rhabdomyosarcomas, 4 angiosarcomas, 4 malignant peripheral nerve sheath tumors, 2 extraskeletal myxoid chondrosarcomas, 2 extraskeletal osteosarcomas, and 3 alveolar soft part sarcomas) were completely negative for E-cadherin. Our findings indicate that E-cadherin is expressed in certain kinds of soft tissue sarcomas, especially those with epithelioid features, suggesting that E-cadherin plays a role in the constitution of their architecture.

Bone Neoplasms↗

PubMed1999

Bioactive ceramics prepared by sintering and crystallization of calcium phosphate invert glasses.

Novel glass-ceramics were synthesized via sintering and crystallization by heating powder compacts of SiO2-free calcium phosphate invert glasses of 60CaO x 30P2O5 x 7Na2O x 3TiO2 or 60CaO x 30P2O5 x 7Na2O x 3MgO at 800-850 degrees C in air. The glass-ceramics were relatively dense materials consisting of crystalline phases such as beta-Ca3(PO4)2 and beta-Ca2P2O7 with glassy phases. The compacts were densified by the viscous flow of the glassy phases while heating. By soaking in simulated body fluid at 37 degrees C, a calcium phosphate phase was formed newly on the surface of the glass-ceramic derived from 60CaO x 30P2O5 x 7Na2O x 3TiO2 glass, while the phase was not formed on that derived from 60CaO x 30P2O5 x 7Na2O x 3MgO glass: the former was implied to show bioactivity. Composition of the glassy phase as the matrix varies with the additives such as TiO2 and MgO, and the chemical properties of the phase influence the bioactivity of the glass-ceramics. The glass-ceramic derived from 60CaO x 30P2O5 x 7Na2O x 3TiO2 glass has relatively high fracture toughness of K(IC) approximately 2 MPa m(0.5) and bending strength of 100-120 MPa.

Calcium Compounds↗

PubMed1999

Discovery of orally active nonpeptide bradykinin B2 receptor antagonists.

Orally active nonpeptide bradykinin (BK) B2 receptor antagonists have been discovered by using directed random screening and chemical modification. These compounds displaced [3H]BK binding to B2 receptors in guinea-pig ileum membranes, rat uterus membranes and human lung fibroblasts with nanomolar IC50s. They did not inhibit different specific radio-ligand bindings to other receptor sites including B2 receptors. In isolated guinea-pig ileum preparations, these compounds had no agonistic effect on smooth muscle contraction at 10(-6) M, and caused parallel rightward shifts of the concentration-response curves to BK on contraction with higher p A2 values. They also blocked human B2 receptor-mediated phosphatidylinositol hydrolysis without agonistic effect. In vivo, the oral administrations of these antagonists potently inhibited BK-induced bronchoconstriction in guinea-pigs. They also reduced carrageenin-induced paw edema and caerulein-induced pancreatitis in rats. Moreover, these compounds alleviated kaolin-induced pain in mice by oral administration. These results show that our compounds are potent, selective, and orally active BK B2 receptor antagonists and that they may have therapeutic potential against inflammatory diseases and pain.

Administration, Oral↗

PubMed1999

Nonpeptide mimic of bradykinin with long-acting properties.

Kinins, members of a family of peptides released from kininogens by the action of kallikreins, have been implicated in a variety of biological activities including vasodilation, increased vascular permeability, contraction of smooth muscle cells and activation of sensory neurons. However, investigation of the physiological actions of kinins have been greatly hampered because its effects are curtailed by rapid proteolytic degradation. We examined the pharmacological characteristics of the first nonpeptide bradykinin receptor agonist 8-[2,6-dichloro-3-[N-[(E)-4-(N-methylcarbamoyl)cinnamidoacetyl+ ++]-N-methylamino]benzyloxy]-2-methyl-4-(2-pyridylmethoxy)quinolin e (FR190997). FR190997, whose structure is quite different from the natural peptide ligand, but is similar to the nonpeptide antagonists FR165649, FR167344 and FR173657, potently and selectively interacts with the human B2 receptor and markedly stimulates inositol phosphate formation in transfected Chinese hamster ovary (CHO) cells. FR190997 induces concentration-dependent contraction of isolated guinea pig ileum. In vivo, FR190997 mimics the biological action of bradykinin and induces hypotensive responses in rats with prolonged duration, presumably as a consequence of its resistance to proteolytic degradation. Therefore, FR190997 is a highly potent and subtype-selective nonpeptide agonist which displays high intrinsic activity at the bradykinin B2 receptor. This compound represents a powerful tool for further investigation of the physiology and pathophysiology of bradykinin receptors.

Animals↗

PubMed1999

Dynamic viscoelastic properties of antimicrobial tissue conditioners containing silver-zeolite.

OBJECTIVES: The purpose of this study was to determine the effects of including the antimicrobial silver-zeolite (SZ) on the dynamic viscoelastic properties of various tissue conditioners. METHODS: The dynamic viscoelastic properties of five commercially available tissue conditioners: Visco-gel (VG), GC Soft-Liner (SL), FITT (FT), SR-Ivoseal (IV) and Shofu Tissue Conditioner (TC) containing SZ were evaluated after 1 and 28 days of water- and artificial saliva immersions with the use of complex modulus and loss tangent parameters. Values for these two parameters for each tissue conditioner were statistically analyzed by one- and two-way ANOVA and Bonferroni's test. RESULTS: Complex modulus and loss tangent values of TC were not significantly different among specimens containing 0, 2, 5 and 10 wt.%-SZ, respectively. In FT and TC containing 2 wt.%-SZ, these values were not significantly different between 1 and 28 days in both water- and saliva immersions. CONCLUSION: The results suggest that incorporating SZ does not affect TC's inherent dynamic viscoelastic properties, while the other tissue conditioners investigated may be found to have changed viscoelastic properties as a consequence of the inclusion of SZ.

Acrylic Resins↗

PubMed1999

Macrophage inflammatory protein 1alpha enhances in a different manner adhesion of hematopoietic progenitor cells from bone marrow, cord blood, and mobilized peripheral blood.

Regulatory mechanisms governing adhesion of hematopoietic progenitor cells to the stromal nische are poorly understood. Growth factors such as stem cell factor (SCF), granulocyte-macrophage colony-stimulating factor, and thrombopoietin were reported to upregulate the adhesion of hematopoietic progenitors to immobilized fibronectin through activation of integrin alpha4beta1 and alpha5beta1. Macrophage inflammatory protein (MIP)-1alpha is a C-C chemokine that suppresses colony formation by stem/progenitor cells in vitro. We asked if MIP-1alpha would modulate the adhesive phenotype of colony-forming cells (CFCs) obtained from healthy donor bone marrow (BM), cord blood (CB), and mobilized peripheral blood (mPB) CD34+ cells, in comparison with SCF, using immobilized fibronectin. SCF significantly increased the level of adhesion of CFCs from BM, CB, and mPB. On the other hand, MIP-1alpha significantly increased the level of adhesion of CFCs from BM and CB, but less so from mPB. The effects of MIP-1alpha were inhibited by blocking antibodies to integrin alpha4, alpha5, or beta1, and polymerization plus rearrangement of F-actin were observed in affected cells by labeling with rhodamine-conjugated phalloidine. These data indicate that the effect of MIP-1alpha on the adhesive phenotype of CFCs is mediated by modulation of the organization of integrin. The amount of MIP-1alpha receptor on mPB was less than for BM or CB, which may explain the distinct characteristics in the adhesive response induced by MIP-1alpha. We suggest that hematopoietic progenitor cells from different sources may be heterogeneous with respect to maturation, integrin affinity, MIP-1alpha receptor expression, and regulation of MIP-1alpha signaling. Our data indicate that MIP-1alpha may affect migration, homing, and mobilization of hematopoietic progenitors by modulating the adhesive phenotype of these cells.

Actins↗

PubMed1999

Primary structure and function of superoxide dismutase from the ascidian Halocynthia roretzi.

A protein with a molecular weight of 17K, immunoreactive with the S-1B2 antibody, has been isolated from hemocytes of Halocynthia roretzi. Its amino acid sequence has been determined by sequential Edman degradation analysis of peptide fragments derived from proteolytic fragmentation. The 17K protein is a single chain protein consisting of 151 amino acids with an acylated N-terminal serine. A comparison of the amino acid sequence of H. roretzi 17K protein with those of other proteins reveals that the 17K protein is Cu,Zn-SOD. The protein was found to have a KCN-inhibited SOD activity. Cu,Zn-SOD has been purified from H. roretzi plasma. The molecular weight is 17K and the activity is inhibited with KCN and diethyldithiocarbamate. It has been demonstrated that it can enhance phagocytosis by H. roretzi hemocytes. Thus, plasma Cu,Zn-SOD plays a role in H. roretzi as a defense molecule.

Amino Acid Sequence↗

PubMed1999

Topical treatment of nasal polyps with a beclomethasone dipropionate powder preparation.

The clinical efficacy of a topical preparation consisting of beclomethasone dipropionate (BDP) powder and a mucous membrane adhesive agent (hydroxypropylcellulose, HPC) for nasal polyps was examined. For 1 week, in 31 patients with bilateral nasal polyposis, the clinical efficacy of the topical BDP-HPC powder treatment was examined. The effect of this treatment on the histology of the nasal polyps was also investigated. The controls were six patients with bilateral nasal polyposis, who underwent identical surgery without prior use of the topical steroid therapy. Polyp shrinkage and improvement of some nasal symptoms (rhinorrhea, ease of noseblowing, and nasal blockage) were observed with the topical treatment. Significant clinical improvement (P < 0.05) was seen in the group treated with topical BDP HPC powder compared with the untreated control group. Histological examination of the excised nasal polyps in both groups demonstrated no clear differences attributable to BDP HPC powder. The topical treatment of nasal polyps with BDP HPC powder is a useful conservative therapy.

Administration, Topical↗

PubMed1999

Preimplantation diagnosis by fluorescence in situ hybridization using 13-, 16-, 18-, 21-, 22-, X-, and Y-chromosome probes.

PURPOSE: Our purpose was to select the proper chromosomes for preimplantation diagnosis based on aneuploidy distribution in abortuses and to carry out a feasibility study of preimplantation diagnosis for embryos using multiple-probe fluorescence in situ hybridization (FISH) on the selected chromosomes of biopsied blastomeres. METHODS: After determining the frequency distribution of aneuploidy found in abortuses, seven chromosomes were selected for FISH probes. Blastomeres were obtained from 33 abnormal or excess embryos. The chromosome complements of both the biopsied blastomeres and the remaining sibling blastomeres in each embryo were determined by FISH and compared to evaluate their preimplantation diagnostic potential. RESULTS: Chromosomes (16, 22, X, Y) and (13, 18, 21) were selected on the basis of the high aneuploid prevalence in abortuses for the former group and the presence of trisomy in the newborn for the latter. Thirty-six (72%) of 50 blastomeres gave signals to permit a diagnosis. Diagnoses made from biopsied blastomeres were consistent with the diagnoses made from the remaining sibling blastomeres in 18 embryos. In only 2 of 20 cases did the biopsied blastomere diagnosis and the embryo diagnosis not match. CONCLUSIONS: If FISH of biopsied blastomere was successful, a preimplantation diagnosis could be made with 10% error. When a combination of chromosome-13, -16, -18, -21, -22, -X, and -Y probes was used, up to 65% of the embryos destined to be aborted could be detected.

Abortion, Spontaneous↗

PubMed1999

Thrombospondin 2 expression is correlated with inhibition of angiogenesis and metastasis of colon cancer.

Two subtypes of thrombospondin (TSP-1 and TSP-2) have inhibitory roles in angiogenesis in vitro, although the biological significance of these TSP isoforms has not been determined in vivo. We examined TSP-1 and TSP-2 gene expression by reverse transcription polymerase chain reaction (RT-PCR) analysis in 61 colon cancers. Thirty-eight of these 61 colon cancers were positive for TSP-2 expression and showed hepatic metastasis at a significantly lower incidence than those without TSP-2 expression (P = 0.02). TSP-2 expression was significantly associated with M0 stage in these colon cancers (P = 0.03), whereas TSP-1 expression showed no apparent correlation with these factors. The colon cancer patients with TSP-2 expression showed a significantly low frequency of liver metastasis correlated with the cell-associated isoform of vascular endothelial growth factor (VEGF-189) (P = 0.0006). Vascularity was estimated by CD34 staining, and TSP-2(-)/VEGF-189(+) colon cancers showed significantly increased vessel counts and density in the stroma (P < 0.0001). TSP-2(-)/VEGF-189(+) colon cancer patients also showed significantly poorer prognosis compared with those with TSP-2(+)/VEGF-189(-) (P = 0.0014). These results suggest that colon cancer metastasis is critically determined by angiogenesis resulting from the balance between the angioinhibitory factor TSP-2 and angiogenic factor VEGF-189.

Analysis of Variance↗

PubMed1999

The effect of Helicobacter pylori eradication therapy on gastric antral myoelectrical activity and gastric emptying in patients with non-ulcer dyspepsia.

BACKGROUND: Dysmotility of the gastroduodenal region and delayed gastric emptying have been considered to play roles in non-ulcer dyspepsia (NUD). Helicobacter pylori-induced inflammation of the gastric mucosa may affect gastric motility. AIM: To evaluate the effects of H. pylori eradication therapy on gastrointestinal motility and symptoms in NUD patients. METHODS: : Forty-six NUD patients were examined for gastric emptying, antral myoelectrical activity, H. pylori infection, and symptom scores. In H. pylori-positive NUD patients, gastric emptying, antral myoelectrical activity, and symptom scores were also analysed 2 months after cure of H. pylori infection. RESULTS: Sixty-seven per cent of NUD patients were H. pylori-positive. Both abnormal gastric emptying and antral myoelectrical activity were observed in NUD patients. H. pylori-positive NUD patients were divided into three groups according to their gastric emptying: the delayed group, the normal group, and the rapid group. In the delayed and rapid gastric emptying groups, the emptying and symptom scores were improved significantly by eradication. There was no improvement in symptom scores in the normal gastric emptying NUD group by the eradication therapy. CONCLUSIONS: Disturbed gastric emptying and antral myoelectrical activity play roles in NUD. H. pylori-induced disturbed gastric emptying may cause some NUD symptoms. Gastric emptying and symptom scores are improved by H. pylori eradication therapy in NUD patients with disturbed gastric emptying; H. pylori eradication therapy is effective in H. pylori-positive NUD patients with disturbed gastric emptying.

Acetaminophen↗

PubMed1999

The effect of helicobacter pylori eradication therapy on gastric antral myoelectrical activity and gastric emptying in patients with non-ulcer dyspepsia.

BACKGROUND: Dysmotility of the gastroduodenal region and delayed gastric emptying have been considered to play roles in non-ulcer dyspepsia. In addition, it has been reported that Helicobacter pylori induced inflammation of the gastric mucosa may affect gastric motility. AIM: To evaluate the effects of H. pylori eradication therapy on gastrointestinal motility and symptoms in non-ulcer dyspepsia patients. METHODS: A total of 46 non-ulcer dyspepsia patients were examined for gastric emptying, antral myoelectrical activity, H. pylori infection, and symptom scores. In H. pylori-positive non-ulcer dyspepsia patients, gastric emptying, antral myoelectrical activity, and symptom scores were also analysed 2 months after being cured of H. pylori infection. RESULTS: A total of 67.4% of the non-ulcer dyspepsia patients were H. pylori-positive. Both abnormal gastric emptying and antral myoelectrical activity were observed in non-ulcer dyspepsia patients. H. pylori-positive non-ulcer dyspepsia patients were divided into three groups according to their gastric emptying: the delayed gastric emptying group, the normal gastric emptying group, and the rapid gastric emptying group. In the delayed and rapid gastric emptying groups, the gastric emptying and symptom scores were improved significantly by the eradication therapy. However, there was no improvement in symptom scores in the normal gastric emptying non-ulcer dyspepsia group by the eradication therapy. CONCLUSIONS: Disturbed gastric emptying and antral myoelectrical activity play roles in non-ulcer dyspepsia. Helicobacter pylori infection, inducing disturbed gastric emptying, may cause some non-ulcer dyspepsia symptoms. Gastric emptying and symptom scores are improved by H. pylori eradication therapy in non-ulcer dyspepsia patients with disturbed gastric emptying. H. pylori eradication therapy is effective in H. pylori-positive non-ulcer dyspepsia patients with disturbed gastric emptying.

Adult↗

PubMed1999

Finite element analysis of the effect of vertical curvature on half-oval cast clasps.

High stresses in half-oval cast clasps are the main causes of deformation or fracture. A vertical curvature in clasps is said to be effective in reducing stress. However, such claims lack scientific basis. The purpose of the present study was to evaluate stress and stiffness in a three-dimensional (3D) finite element analysis (FEA) model of clasps with different vertical curvatures, cross-sectional forms and tapers, and to clarify the effect of vertical curvature on the half-oval cast clasp. Circumferential clasp arms for the mandibular second premolar were analysed by 3D FEA. The clasp arms were approximated by curved cantilever beams with a half-oval cross-section around a cylinder. The radius of curvature was set at 4 mm and the angle subtended by the clasp arm was 120 degrees. The clasp tip was set at a point 2 mm lower than the base. In the 'No-taper' half-oval clasp arm, stress increased and stiffness decreased with the increase in vertical curvature. In the shape of a preformed wax pattern (thickness/width = 0.80, tip/base = 0.70), stress and stiffness decreased slightly. In an 'Original' form (thickness/width = 0.33, tip/base = 0.80), vertical curvature had a very slight effect on stress and stiffness, and stress was the lowest. These findings suggest the superiority of the 'Original' form, with less stress and no effect of vertical curvature.

Dental Casting Technique↗

PubMed1999

A unique primary structure, cDNA cloning and function of a galactose-specific lectin from ascidian plasma.

The complete amino acid sequence of a galactose-specific lectin from the plasma of the ascidian Halocynthia roretzi has been determined by sequential Edman degradation analysis of peptide fragments derived by proteolytic fragmentation and chemical cleavage of the reductive S-pyridylethylated lectin. Peptide fragments were separated by reverse-phase HPLC. The N-terminal and C-terminal amino acid sequences were determined by Edman degradation and enzymatic digestion. The H. roretzi plasma lectin is a single-chain protein consisting of 327 amino acids and four disulfide bonds, one of which was found to be cross-linked intramolecularly. A comparison of the amino acid sequence of the H. roretzi plasma lectin with the sequences of other proteins reveals that the H. roretzi lectin has a structure consisting of a twice-repeated sequence, a fibrinogen-related sequence and a C-type lectin-homologous sequence. The above amino acid sequence was verified by cDNA cloning of this lectin. Three cDNA clones that have single ORFs encoding the lectin precursor were isolated from an H. roretzi hepatopancreas cDNA library. The deduced amino acid sequences in the three cDNA clones contain the same sequence of the mature lectin molecule and the same putative signal sequence. In addition, it was demonstrated that this lectin can enhance phagocytosis by H. roretzi hemocytes. Thus, the plasma lectin is constructed into an oligomer structure via intermolecular disulfide bonds and plays a role in the biological defense of H. roretzi as a defense molecule.

Amino Acid Sequence↗

PubMed1999

Genetic dissection of the complex pathological manifestations of collagen disease in MRL/lpr mice.

An MRL strain of mice bearing a Fas-deletion mutant gene, lpr, MRL/MpJ-lpr/lpr (MRL/lpr) develops collagen disease involving vasculitis, glomerulonephritis, arthritis and sialoadenitis, each of which has been studied as a model for polyarteritis, lupus nephritis, rheumatoid arthritis and Sjögren's syndrome, respectively. Development of such lesions seems dependent on host genetic background since the congenic C3H/HeJ-lpr/lpr (C3H/lpr) mice rarely develop them. To identify the gene loci affecting each lesion, a genetic dissection of these complex pathological manifestations was carried out. First, histopathological features in MRL/lpr, C3H/lpr, (MRL/lpr x C3H/lpr) F1 intercross, and MRL/lpr x (MRL/lpr x C3H/lpr) F1 backcross mice were analyzed. Genomic DNA of the backcross mice were subjected to association studies by Chi-squared analysis for determining which polymorphic microsatellite locus occurs at higher frequency among affected compared to unaffected individuals for each lesion. As a result, gene loci recessively associated with each lesion were mapped on different chromosomal positions. We concluded that each of these lesions in MRL/lpr mice is under the control of a different set of genes, suggesting that the complex pathological manifestations of collagen disease result from polygenic inheritance.

Animals↗

PubMed1999

Implantation of the undulation pump total artificial heart in the goat.

The undulation pump total artificial heart (UPTAH) was developed by using small-size continuous-flow displacement-type blood pumps (undulation pump). To clarify and improve the problems accompanied by the implantation in the chest, 14 animal experiments were performed on goats weighing 41.3-79.2 kg. The UPTAH could be implanted in the chest of all goats and was driven with a modulation pulsatile mode. The first problem was the atrial suction effect. This problem could be prevented to some extent by developing the soft disk and by improving atrial cuffs. An automatic detection and releasing of the atrial suction effect was also tried. The next problem was acute lung edema accompanied by the postural change of the animal. Development of the automatic control of left atrial pressure could prevent this problem. Small blood leakage from a pinpoint hole in the seal membrane was the next problem. Improvement of the manufacturing procedure of the membrane prevented this. With these improvements, a 10 day survival could be obtained with this unique implantable total artificial heart.

Acute Disease↗

PubMed1999

Present status of the total artificial heart at the University of Tokyo.

At the University of Tokyo, various types of total artificial heart (TAH) systems have been studied since 1959. At the present time, 2 types of implantable TAH have been developed. One is an undulation pump TAH (UPTAH) and the other is a flow transformed pulsatile TAH (FTPTAH). Using the UPTAH, 14 cases of implantation were performed in goats and 10 days' survival obtained. The new type of FTPTAH is under a prototype study. To prevent ring thrombus, a polyurethane membrane valve, a jellyfish valve, has been developed. The longest in vivo experiences with this valve in the TAH blood pump have been 312 days in the left side blood pump and 414 days in the right side blood pump. Conductance and arterial pressure based control (1/R control) can realize the physiological control of the TAH. Using 1/R control, 532 days of survival could be obtained in a goat with a paracorporeal TAH. The technique required to apply this control method to a implantable TAH is under development. We have proposed a new 5 year research project of the implantable TAH entitled "Comprehensive Basic Research on the Development of a Japanese Original Implantable Total Artificial Heart" to The Ministry of Welfare.

Animals↗

PubMed1999

Differential activation of microglia after experimental spinal cord injury.

This study sought to experimentally clarify time-dependent, differential microglial activation at various spinal cord locations in response to injury. The spinal cords of Wistar rats were either sharply transected at the Th 11 or subjected to compression at the same site. Immediately to 4 weeks after injury, each spinal cord was fixed and cut into longitudinal frozen sections, and was immunostained with OX42 for resident and activated microglia, OX-6 for activated microglia, GFAP for activated astrocytes, and biotinylated BS-I, a lectin for both resident and activated microglia. From three to 24 hours after injury, we observed a narrow belt around the transection site in which OX42 positive microglia were dramatically reduced in number, or often absent. BS-I labeling of the zone disclosed the rapid transformation of those microglia possessing typical antler-like processes to macrophage-like cells. At day 1 and thereafter, the zone of reduced OX42 immunoreactivity was gradually replaced by macrophage-like OX42-positive round cells, and the lesion itself was ultimately capped by fibrogliotic scar tissue. By 2-4 weeks postinjury, another phase of microglial activation was observed in those white matter tracts undergoing Wallerian degeneration. These microglia characterized by the presence of newly-expressed MHC class II antigens. We posit that the decreased OX42 immunoreactivity suggests that CR3 is quickly saturated by activated iC3b and internalized, but not down-regulated. The trigger for this transformation most likely occurs through signaling by iC3b-saturated CR3. In contrast, microglia activation along those degenerating tracts undergoing Wallerian degeneration does not appear to be CR3-related, as the CR3 is upregulated. These observations indicate microglia have at least two different spatial and temporal patterns of activation. One is rapid and most likely involves the blood-borne complement activating system. The other accompanies Wallerian degeneration and is independent of the blood-borne complement system.

Animals↗