Guillain-Barré syndrome in northern China. Relationship to Campylobacter jejuni infection and anti-glycolipid antibodies

Guillain-Barré syndrome has been considered to be primarily an acute inflammatory demyelinating polyneuropathy (AIDP). Our experience with Guillain-Barré syndrome in northern China differs from the traditional concept. Electrophysiologically and pathologically, most of our patients have motor axonal degeneration with minimal cellular inflammation, which we have termed 'acute motor axonal neuropathy' (AMAN). The current studies were undertaken to characterize prospectively the clinical, electrophysiological, and serological features of Guillain-Barré syndrome, defined clinically, in northern China. In 1991 and 1992, we characterized by electrodiagnostic criteria 129 Chinese patients with Guillain-Barré syndrome. The AMAN form was present in 65% of patients, the AIDP form in 24% and 11% were unclassifiable. For the 38 patients who presented from January to October, 1992, we performed serological assays for antibodies to Campylobacter jejuni and to glycolipids. Of these 38 patients, 55% had AMAN, 32% had AIDP and 13% were unclassifiable. Sixty-six percent of the 38 had serological evidence of recent C. jejuni infection as compared with 16% of village controls (P = 0.001). Seventy-six percent of AMAN patients and 42% of AIDP patients were seropositive. IgG anti-GM1 antibodies were more frequent in Guillain-Barré syndrome patients compared with village controls (42% versus 6%; P < 0.01). However, no statistically significant correlations were found between the pattern of disease, AMAN or AIDP, anti-glycolipid antibodies, or C. jejuni antibodies. Based on electrophysiological criteria, Guillain-Barré syndrome in northern China can be divided into two predominant forms: AIDP and AMAN. The AMAN form is more common and predominates in the yearly summer outbreaks of Guillain-Barré syndrome.(ABSTRACT TRUNCATED AT 250 WORDS)

Vascular risk factors promote conversion from mild cognitive impairment to Alzheimer disease

OBJECTIVE

Growing evidence suggests that vascular risk factors (VRF) contribute to cognitive decline. The aim of this study was to investigate the impact of VRF on the conversion from mild cognitive impairment (MCI) to Alzheimer disease (AD) dementia.

METHODS

A total of 837 subjects with MCI were enrolled at baseline and followed up annually for 5 years. The incidence of AD dementia was investigated. A mixed random effects regression model was used to analyze the association between VRF and the progression of MCI assessed with Mini-Mental State Examination and instrumental Activities of Daily Living. Cox proportional hazard models were used to identify the association between VRF and dementia conversion, and to examine whether treatment of VRF can prevent dementia conversion.

RESULTS

At the end of the follow-up, 298 subjects converted to AD dementia, while 352 remained MCI. Subjects with VRF had a faster progression in cognition and function relative to subjects without. VRF including hypertension, diabetes, cerebrovascular diseases, and hypercholesterolemia increased the risk of dementia conversion. Those subjects with MCI in whom all VRF were treated had a lower risk of dementia than those who had some VRF treated. Treatment of individual VRF including hypertension, diabetes, and hypercholesterolemia was associated with the reduced risk of AD conversion.

CONCLUSION

VRF increased the risk of incident AD dementia. Treatment of VRF was associated with a reduced risk of incident AD dementia. Although our findings are observational, they suggest active intervention for VRF might reduce progression in MCI to AD dementia.

Pathology of the motor-sensory axonal Guillain-Barré syndrome

The concept of a severe motor-sensory neuropathy of acute onset caused by an immune attack on the axon ("axonal" Guillain-Barré syndrome) has been advanced primarily based on electrodiagnostic and limited pathological data, but remains controversial. At autopsy some cases demonstrate unusually severe inflammatory demyelinating neuropathy. There are conflicting data about whether antecedent Campylobacter jejuni infection is associated with "axonal" Guillain-Barré syndrome. We report 4 individuals from Hebei Province, China, who died 7, 7, 18, and 60 days after onset of a syndrome diagnosed clinically as Guillain-Barré syndrome. High titers of antibodies recognizing C. jejuni, consistent with recent infection, were found in the 2 patients tested. At autopsy the 3 with early disease had ongoing wallerian-like degeneration of fibers in the ventral and dorsal roots and in the peripheral nerves, with only minimal demyelination or lymphocytic infiltration. All 3 had numerous macrophages in the periaxonal space of myelinated internodes, and rare intraaxonal macrophages as well. Examination of the patient having the syndrome for 60 days confirmed the extensive loss of large fibers in the spinal roots and nerves, and the paucity of demyelination and remyelination. These observations confirm predictions that some patients with severe motor-sensory Guillain-Barré syndrome, as defined clinically, have predominantly axonal lesions of both motor and sensory fibers, even in the early stages of the disease, and that axonal Guillain-Barré syndrome can follow C. jejuni infection. The pathology supports the possibility that such cases of motor-sensory axonal Guillain-Barré syndrome represent the most severe end of a spectrum of immune attack directed toward epitopes on the axon.

Identification of a blue photoluminescent composite material from a combinatorial library

A quaternary combinatorial masking strategy was used in conjunction with photolithography to generate compositionally diverse thin-film phosphor libraries containing 1024 different compositions on substrates 2.5 centimeters square. A parallel imaging system and scanning spectrophotometer were used to identify and characterize compositions in the library with interesting luminescent behavior. Optimal compositions were identified with the use of gradient libraries, in which the stoichiometry of a material was varied continuously. This process led to the identification of an efficient blue photoluminescent composite material, Gd3Ga5O12/SiO2. Experimental evidence suggests that luminescence in this material may arise from interfacial effects between SiO2 and Gd3Ga5O12.

Guillain-Barré syndrome in northern China. The spectrum of neuropathological changes in clinically defined cases

The pathology of the Guillain-Barré syndrome remains controversial, and autopsied cases available for study by contemporary techniques are uncommon. Large numbers of cases clinically diagnosed as Guillain-Barré syndrome occur in northern China. In this study we examined the neuropathological changes in 12 autopsied cases from Hebei Province, China. Eleven died early in the course of their disease. In all cases tissue was specially handled and fixed for electron microscopy and for immunocytochemistry. Three of these 12 cases had typical acute inflammatory demyelinating polyneuropathy (AIDP) with lymphocytic infiltration and macrophage-mediated demyelination, reproducing the pathological picture most often reported in Guillain-Barré syndrome in North America, Europe, and Australia. Six cases had predominantly axonal involvement, characterized by Wallerian-like degeneration of nerve fibres, with only minimal demyelination and with minimal inflammation in five. Three cases, even though paralysed at the time of death, had only very mild changes in the spinal roots and sciatic nerves. Within the group of six predominantly axonal cases, there were important differences both in the severity of the abnormalities and in the classes of fibres involved. Three cases had extensive Wallerian-like degeneration of sensory as well as motor fibres [acute motor-sensory axonal neuropathy (AMSAN)], while in the other three cases the fibre degeneration affected the motor nerve fibres almost exclusively. These latter cases establish a structural basis for the clinical and electrophysiological picture termed the acute motor axonal neuropathy (AMAN) pattern. In both the AMAN and the AMSAN patterns, a prominent feature was the presence of macrophages within the periaxonal space, surrounding or displacing the axon, and surrounded by an intact myelin sheath. These studies show that the early pathological changes in cases clinically diagnosed as the Guillain-Barré syndrome are diverse and not restricted to the well-known pattern of AIDP, and that the predominant pathological patterns may differ in different parts of the world. The differences in pathological findings between acute inflammatory demyelinating polyneuropathy and the axonal patterns are likely to reflect differences in the pathogenetic mechanisms. The periaxonal macrophages in the axonal patterns suggest that an important epitope may be localized to the axolemma or periaxonal space. The mild cases indicate that severe paralysis can occur early in Guillain-Barré syndrome without prominent structural changes along the nerve, suggesting that physiological block or nerve terminal changes may be implicated.

p53 regulates the expression of the tumor suppressor gene maspin

Maspin has been shown to inhibit tumor cell invasion and metastasis in breast tumor cells. Maspin expression was detected in normal breast and prostate epithelial cells, whereas tumor cells exhibited reduced or no expression. However, the regulatory mechanism of maspin expression remains unknown. We report here a rapid and robust induction of maspin expression in prostate cancer cells (LNCaP, DU145, and PC3) and breast tumor cells (MCF7) following wild type p53 expression from an adenovirus p53 expression vector (AdWTp53). p53 activates the maspin promoter by binding directly to the p53 consensus-binding site present in the maspin promoter. DNA-damaging agents and cytotoxic drugs induced endogenous maspin expression in cells containing the wild type p53. Maspin expression was refractory to the DNA-damaging agents in cells containing mutant p53. These results, combined with recent studies of the tumor metastasis suppressor gene KAI1 and plasminogen activator inhibitor 1 (PAI1), define a new category of molecular targets of p53 that have the potential to negatively regulate tumor invasion and/or metastasis.

CMV-beta-actin promoter directs higher expression from an adeno-associated viral vector in the liver than the cytomegalovirus or elongation factor 1 alpha promoter and results in therapeutic levels of human factor X in mice

Although AAV vectors show promise for hepatic gene therapy, the optimal transcriptional regulatory elements have not yet been identified. In this study, we show that an AAV vector with the CMV enhancer/chicken beta-actin promoter results in 9.5-fold higher expression after portal vein injection than an AAV vector with the EF1 alpha promoter, and 137-fold higher expression than an AAV vector with the CMV promoter/enhancer. Although induction of the acute-phase response with the administration of lipopolysaccharide (LPS) activated the CMV promoter/enhancer from the context of an adenoviral vector in a previous study, LPS resulted in only a modest induction of this promoter from an AAV vector in vivo. An AAV vector with the CMV-beta-actin promoter upstream of the coagulation protein human factor X (hFX) was injected intravenously into neonatal mice. This resulted in expression of hFX at 548 ng/ml (6.8% of normal) for up to 1.2 years, and 0.6 copies of AAV vector per diploid genome in the liver at the time of sacrifice. Neonatal intramuscular injection resulted in expression of hFX at 248 ng/ml (3.1% of normal), which derived from both liver and muscle. We conclude that neonatal gene therapy with an AAV vector with the CMV-beta-actin promoter might correct hemophilia due to hFX deficiency.

Leisure activity and risk of cognitive impairment: The Chongqing aging study

The authors followed 5,437 people aged 55 years and older with normal baseline Mini-Mental State Examination score annually for 5 years. The mean incidence of cognitive impairment was 2.3% per year. Cognitive activities in both the individual item (playing board games and reading) and the composite measure were associated with the reduced risk of cognitive impairment, while watching television was associated with an increased risk of cognitive impairment.

The molecular mechanism of microRNA-145 to suppress invasion-metastasis cascade in gastric cancer

Invasion and metastasis are the major features of malignant tumors that are responsible for 90% of cancer-related deaths. Recently, microRNAs have been discovered to have a role in suppressing tumor metastasis. This study's aim was to clarify the roles of miR-145 in gastric carcinomas and its underlying molecular mechanism in regulating tumor metastasis. Here, we demonstrate a stepwise downregulation of miR-145 level in nontumorous gastric mucosa, primary gastric cancers and their secondary metastases. In vitro analysis of miR-145's ectopic expression and loss-of-function suggests that it suppresses gastric cancer cell migration and invasion. In vivo spontaneous metastasis and experimental metastasis assay further confirm its function in suppressing the invasion-metastasis cascade, including impairing local invasion and inhibiting hematogenous metastasis in gastric cancers. Furthermore, we identified a novel mechanism of miR-145 to suppress metastasis. N-cadherin (CDH2) was proved to be a direct target of miR-145, using luciferase assay and western blot. Re-expressing N-cadherin in miR-145-transfected cells reverses their migration and invasion defects. Although not a direct target of miR-145, matrix metallopeptidase 9 (MMP9), but not MMP2, was also significantly decreased in miR-145-expressing cells. We suggest that miR-145 suppresses tumor metastasis by inhibiting N-cadherin protein translation, and then indirectly downregulates its downstream effector MMP9.

Patterns of recovery in the Guillain-Barre syndromes

Clinical, electrodiagnostic, and pathologic studies indicate that the Guillain-Barre syndromes (GBSs) include both primary demyelinating and primary axonal forms. The axonal forms are usually thought to have a poorer prognosis, with less chance for rapid or complete recovery. In northern China, epidemics of one axonal form, acute motor axonal neuropathy (AMAN), occur annually in the summer. Autopsy studies in some fatal cases have demonstrated wallerian-like degeneration of motor roots and motor fibers in the peripheral nerves. Recovery of such patients would require axonal regeneration along the entire length of the nerve fiber. In a 2-year prospective study of GBS at a single hospital in northern China, 42 patients were classified as having either AMAN (32 patients), acute inflammatory demyelinating polyneuropathy (AIDP) (8 patients), or as undetermined (2 patients) by electrodiagnostic criteria. Their recoveries were monitored clinically. The recovery times of AMAN and AIDP patients were similar: the median time to regain the ability to walk 5 meters with assistance was 31 days for patients classified as having AMAN and 32 days for those classified as having AIDP. These rapid recovery times are incompatible with severe wallerian degeneration of the ventral roots and motor nerve fibers. The rapid recoveries observed in AMAN patients could be explained by relatively quickly reversible immune-mediated changes at nodes of Ranvier in motor fibers, by degeneration and regeneration of intramuscular motor nerve terminals, or both.

High MMP-1, MMP-2, and MMP-9 protein levels in osteoarthritis

Our study examined the relationship between the expression of matrix metalloproteinases (MMP)-1, MMP-2, and MMP-9 proteins and the pathogenesis of osteoarthritis (OA). We employed rigorous inclusion and exclusion criteria in computer-based bibliographic databases to extract published studies relevant to this investigation. The STATA 12.0 software was used for the statistical analyses. A total of 1408 studies were initially searched, and 10 studies with 458 OA patients and 295 healthy controls were included in this meta-analysis. The meta-analysis results suggested that the protein levels of MMP-1, MMP-2, and MMP-9 were higher in patients with OA than those in the control group. A subgroup analysis according to ethnicity showed that the protein levels of MMP-1 and MMP-2 were higher in Asian patients with OA than in controls. Caucasians showed no statistically significant differences in protein expression of MMP-1 and MMP-2 between the OA patient group and the control group. Interestingly, the protein levels of MMP-9 in patients with OA were higher than those in the control group in both Asians and Caucasians. A sample-source analysis suggested that the serum levels of MMP-2 and MMP-9 proteins were higher in patients with OA than in controls, while MMP-1 and MMP-9 protein expressions were higher in the synovial joint fluid of patients with OA than in controls. In conclusion, our meta-analysis results suggested that the increased expression of MMP-1, MMP-2, and MMP-9 proteins might be associated with the pathogenesis of OA.

Gene expression of alpha1-6 fucosyltransferase in human hepatoma tissues: a possible implication for increased fucosylation of alpha-fetoprotein

The 1-6 fucosylated -fetoprotein (AFP) present in serum of patients with hepatocellular carcinoma (HCC) has been employed for the differential clinical diagnosis of HCC from chronic liver diseases. The molecular mechanism by which this alteration occurs, however, remains largely unknown. To address this issue, we purified GDP-L-Fuc:N-acetyl-beta-D-glucosaminide 1-6 fucosyltransferase (1-6 FucT), an enzyme involved in the 1-6 fucosylation of N-glycans from porcine brain, as well as from a human gastric cancer cell line, and cloned their genes. In this study, levels of 1-6 FucT mRNA expression and the activity of this enzyme for 12 human HCC tissues were examined and compared with that in surrounding tissues and normal livers. The mean +/- SD for 1-6 FucT activity was 78 +/- 41 pmol/h/mg in normal control liver, 202 +/- 127 pmol/h/mg in adjacent uninvolved liver tissues (chronic hepatitis: 181 +/- 106 pmol/h/mg; liver cirrhosis: 233 +/- 164 pmol/h/mg), and 195 +/- 72 pmol/h/mg in HCC tissues. The mRNA expression of 1-6 FucT was also enhanced in proportion to enzymatic activity except for a few cases, suggesting that 1-6 FucT expression is increased in chronic liver diseases, especially liver cirrhosis. Transfection of 1-6 FucT gene into cultured rat hepatocytes markedly increased 1-6 FucT activity and led to an increase in lens culinaris agglutinin (LCA) binding proteins in both cell lysates and condition media. When the 1-6 FucT gene was transfected into a human HCC cell line, Hep3B, which originally showed low levels of 1-6 FucT expression, 1-6-fucosylated AFP was dramatically increased in the condition media. Collectively, these results suggest that the enhancement of 1-6 FucT expression increased the fucosylation of several proteins, including AFP, and that the level of 1-6-fucosylated AFP in patients with HCC was in part caused by up-regulation of the 1-6 FucT gene expression.

Making artificial antibodies: a format for phage display of combinatorial heterodimeric arrays

The gene VII protein (pVII) and gene IX protein (pIX) are associated closely on the surface of filamentous bacteriophage that is opposite of the end harboring the widely exploited pIII protein. We developed a phagemid format wherein antibody heavy- and light-chain variable regions were fused to the amino termini of pVII and pIX, respectively. Significantly, the fusion proteins interacted to form a functional Fv-binding domain on the phage surface. Our approach will be applicable to the display of generic peptide and protein libraries that can form combinatorial heterodimeric arrays. Consequently, it represents a first step toward artificial antibodies and the selection of novel biological activities.

Biological cells as templates for hollow microcapsules

Microcapsules in the micrometer size range with walls of nanometer thickness are of both scientific and technological interest, since they can be employed as micro- and nano-containers. Liposomes represent one example, yet their general use is hampered due to limited stability and a low permeability for polar molecules. Microcapsules formed from polyelectrolytes offer some improvement, since they are permeable to small polar molecules and resistant to chemical and physical influences. Both types of closed films are, however, limited by their spherical shape which precludes producing capsules with anisotropic properties. Biological cells possess a wide variety of shapes and sizes, and, thus, using them as templates would allow the production of capsules with a wide range of morphologies. In the present study, human red blood cells (RBC) as well as Escherichia coli bacteria were used; these cells were fixed by glutardialdehyde prior to layer-by-layer (LbL) adsorption of polyelectrolytes. The growth of the layers was verified by electrophoresis and flow cytometry, with morphology investigated by atomic force and electron microscopy; the dissolution process of the biological template was followed by confocal laser scanning microscopy. The resulting microcapsules are exact copies of the biological template, exhibit elastic properties, and have permeabilities which can be controlled by experimental parameters; this method for microcapsule fabrication, thus, offers an important new approach for this area of biotechnology.

Hepatocyte transplantation in rats with decompensated cirrhosis

Hepatocyte transplantation improves the survival of laboratory animals with experimentally induced acute liver failure and the physiological abnormalities associated with liver-based metabolic deficiencies. The role of hepatocyte transplantation in treating decompensated liver cirrhosis, however, has not been studied in depth. To address this issue, cirrhosis was induced using phenobarbital and carbon tetrachloride (CCL(4)) and animals were studied only when evidence of liver failure did not improve when CCL(4) was held for 4 weeks. Animals received intrasplenic transplantation of syngeneic rat hepatocytes (G1); intraperitoneal transplantation of syngeneic rat hepatocytes (G2); intraperitoneal transplantation of a cellular homogenate of syngeneic rat hepatocytes (G3); intraperitoneal transplantation of syngeneic rat bone marrow cells (G4); or intrasplenic injection of Dulbecco's modified Eagle medium (DMEM) (G5). After transplantation, body weight and serum albumin levels deteriorated over time in all control (G2-G5) animals but did not deteriorate in animals receiving intrasplenic hepatocyte transplantation (G1) (P <.01). Prothrombin time (PT), total bilirubin, serum ammonia, and hepatic encephalopathy score were also significantly improved toward normal in animals receiving intrasplenic hepatocyte transplantation (P <. 01). More importantly, survival was prolonged after a single infusion of hepatocytes and a second infusion prolonged survival from 15 to 128 days (P <.01). Thus, hepatocyte transplantation can improve liver function and prolong the survival of rats with irreversible, decompensated cirrhosis and may be useful in the treatment of cirrhosis in humans.

An antibody exo Diels-Alderase inhibitor complex at 1.95 angstrom resolution

A highly specific Diels-Alder protein catalyst was made by manipulating the antibody repertoire of the immune system. The catalytic antibody 13G5 catalyzes a disfavored exo Diels-Alder transformation in a reaction for which there is no natural enzyme counterpart and that yields a single regioisomer in high enantiomeric excess. The crystal structure of the antibody Fab in complex with a ferrocenyl inhibitor containing the essential haptenic core that elicited 13G5 was determined at 1.95 angstrom resolution. Three key antibody residues appear to be responsible for the observed catalysis and product control. Tyrosine-L36 acts as a Lewis acid activating the dienophile for nucleophilic attack, and asparagine-L91 and aspartic acid-H50 form hydrogen bonds to the carboxylate side chain that substitutes for the carbamate diene substrate. This hydrogen-bonding scheme leads to rate acceleration and also pronounced stereoselectivity. Docking experiments with the four possible ortho transition states of the reaction explain the specific exo effect and suggest that the (3R,4R)-exo stereoisomer is the preferred product.

Immunoreactivity of Hu proteins facilitates identification of myenteric neurones in guinea-pig small intestine

Hu proteins, together with neurone-specific enolase (NSE), protein gene product 9.5 (PGP-9.5), microtubule-associated protein-2 (MAP-2) and tubulin beta III isoform, were evaluated immunohistochemically as neuronal markers in whole-mount preparations and cultures obtained from the myenteric plexus of guinea-pig small intestine. Anti-Hu immunostaining marked the ganglion cell somas and nuclei without staining of the neuronal processes in the whole-mounts and cultures. The ganglion cell bodies were not obscured by staining of multiple neuronal fibres and this facilitated accurate counting of the neurones. MAP2 immunostaining also provided clear images of individual neurones in both whole mounts and cultures. Immunoreactivity for NSE, PGP-9.5 and tubulin beta III isoform provided sharp images of the ganglion cells in culture, but not in whole-mount preparations. Strong staining of the neuronal processes in the whole-mount preparations obscured the profiles of the ganglion cell bodies to such an extent that accurate counting of the total neuronal population was compromised. Anti-Hu immunostaining was judged to be an acceptable method for obtaining reliable estimates of total numbers of myenteric neurones in relation to other specific histochemical properties such as histamine binding.

Electric-field control of nonvolatile magnetization in Co40Fe40B20/Pb(Mg(1/3)Nb(2/3))(0.7)Ti(0.3)O3 structure at room temperature

We report a large and nonvolatile bipolar-electric-field-controlled magnetization at room temperature in a Co(40)Fe(40)B(20)/Pb(Mg(1/3)Nb(2/3))(0.7)Ti(0.3)O(3) structure, which exhibits an electric-field-controlled looplike magnetization. Investigations on the ferroelectric domains and crystal structures with in situ electric fields reveal that the effect is related to the combined action of 109° ferroelastic domain switching and the absence of magnetocrystalline anisotropy in Co(40)Fe(40)B(20). This work provides a route to realize large and nonvolatile magnetoelectric coupling at room temperature and is significant for applications.

Slow excitatory synaptic transmission mediated by P2Y1 receptors in the guinea-pig enteric nervous system

Electrophysiological recording was used to study a type of slow excitatory postsynaptic potential (slow EPSP) that was mediated by release of ATP and its action at P2Y1 receptors on morphologically identified neurones in the submucosal plexus of guinea-pig small intestine. MRS2179, a selective P2Y1 purinergic receptor antagonist, blocked both the slow EPSP and mimicry of the EPSP by exogenously applied ATP. Increased conductance accounted for the depolarization phase of the EPSP, which occurred exclusively in neurones with S-type electrophysiological behaviour and uniaxonal morphology. The purinergic excitatory input to the submucosal neurones came from neighbouring neurones in the same plexus, from neurones in the myenteric plexus and from sympathetic postganglionic neurones. ATP-mediated EPSPs occurred coincident with fast nicotinic synaptic potentials evoked by the myenteric projections and with noradrenergic IPSPs evoked by sympathetic fibres that innervated the same neurones. The P2Y1 receptor on the neurones was identified as a metabotropic receptor linked to activation of phospholipase C, synthesis of inositol 1,4,5-trisphosphate and mobilization of Ca2+ from intracellular stores.

Cyclins, cyclin-dependent kinases and differentiation

Cyclin-dependent kinases and their regulatory subunits, the cyclins, are known to regulate progression through the cell cycle. Yet these same proteins are often expressed in non-cycling, differentiated cells. This review surveys the available information about cyclins and cyclin-dependent kinases in differentiated cells and explores the possibility that these proteins may have important functions that are independent of cell cycle regulation.

A new human chondrosarcoma cell line (OUMS-27) that maintains chondrocytic differentiation

A new human chondrosarcoma cell line, OUMS-27, was established. Monolayer cultures consisted of elongated polygonal cells with a doubling time of 41 hr and a plating efficiency of 2.1%. After reaching confluence, the cells continued to slowly proliferate and formed nodule-like structures, which showed metachromasia when stained with toluidine blue, indicating the presence of proteoglycan. The cells in the nodules were round to polygonal in shape, multilayered and surrounded by abundant extracellular matrix. Types I, II and III collagens were identified by Northern blotting and immunostaining. The cells formed colonies (0.1%) in 0.3% soft-agar medium 3 weeks after inoculation. Inoculation of cells into athymic mice resulted in the formation of tumors at the injection site, resembling the original chondrosarcoma. These results demonstrated that OUMS-27 cells expressed a differentiated chondrocytic phenotype. Moreover, OUMS-27 cells had p53-gene mutation. Thus, the OUMS-27 cell line can provide a useful model not only for studies on human chondrocyte but also for basic studies on the diagnosis, treatment and etiology of human chondrosarcoma.

Phage-display library selection of high-affinity human single-chain antibodies to tumor-associated carbohydrate antigens sialyl Lewisx and Lewisx

mAbs against tumor-associated carbohydrate antigens have the potential to play a prominent role in cancer immunotherapy. However, it has not been possible to fully exploit the clinical utility of such antibodies primarily, because those of adequate affinity could be derived only from murine sources. To address this problem, we prepared a single-chain Fv (scFv) antibody library from the peripheral blood lymphocytes of 20 patients with various cancer diseases. Completely human high-affinity scFv antibodies were then selected by using synthetic sialyl Lewisx and Lewisx BSA conjugates. These human scFv antibodies were specific for sialyl Lewisx and Lewisx, as demonstrated by ELISA, BIAcore, and flow cytometry binding to the cell surface of pancreatic adenocarcinoma cells. Nucleotide sequencing revealed that at least four unique scFv genes were obtained. The Kd values ranged from 1.1 to 6.2 x 10(-7) M that were comparable to the affinities of mAbs derived from the secondary immune response. These antibodies could be valuable reagents for probing the structure and function of carbohydrate antigens and in the treatment of human tumor diseases.

Strain dynamics of ultrathin VO₂ film grown on TiO₂ (001) and the associated phase transition modulation

Tuning the metal insulator transition (MIT) behavior of VO2 film through the interfacial strain is effective for practical applications. However, the mechanism for strain-modulated MIT is still under debate. Here we directly record the strain dynamics of ultrathin VO2 film on TiO2 substrate and reveal the intrinsic modulation process by means of synchrotron radiation and first-principles calculations. It is observed that the MIT process of the obtained VO2 films can be modulated continuously via the interfacial strain. The relationship between the phase transition temperature and the strain evolution is established from the initial film growth. From the interfacial strain dynamics and theoretical calculations, we claim that the electronic orbital occupancy is strongly affected by the interfacial strain, which changes also the electron-electron correlation and controls the phase transition temperature. These findings open the possibility of an active tuning of phase transition for the thin VO2 film through the interfacial lattice engineering.

P2X(7) receptors in the enteric nervous system of guinea-pig small intestine

The P2X(7) purinergic receptor subtype has been cloned and emphasized as a prototypic P2Z receptor involved in neurotransmission in the central nervous system and ATP-mediated lysis of macrophages in the immune system. Less is known about the neurobiology of P2X(7) receptors in the enteric nervous system (ENS). We studied the distribution of the receptor with indirect immunofluorescence and used selective agonists and antagonists to analyze pharmacologic aspects of its electrophysiologic behavior as determined with intracellular "sharp" microelectrodes and patch-clamp recording methods in neurons identified morphologically by biocytin injection in the ENS. Application of ATP or 2'- (or-3'-) O-(4-benzoylbenzoyl) adenosine 5'-triphosphate (BzBzATP) activated an inward current in myenteric neurons. Brilliant blue G, a selective P2X(7) antagonist, suppressed the responses to both agonists. Potency of the antagonist was greatest (smaller IC(50)) for the current evoked by BzBzATP. The P2X(7) antagonists 1-[N,O-bis (1,5-isoquinolinesulfonyl)-N-methyl-l-tyrosyl]-4-piperazine (KN-62) and oxidized ATP also suppressed the BzBzATP-activated current. Micropressure application of BzBzATP evoked rapidly activating depolarizing responses in intracellular studies with "sharp" microelectrodes. Oxidized-ATP suppressed these responses in both myenteric and submucosal neurons. Rapidly activating depolarizing responses evoked by application of nicotinic, serotonergic 5-HT(3), or gamma-aminobutyric acid A (GABA(A)) receptor agonists were unaffected by brilliant blue G. Immunoreactivity for the P2X(7) receptor was widely distributed surrounding ganglion cell bodies and associated with nerve fibers in both myenteric and submucous plexuses. P2X(7) immunoreactivity was colocalized with synapsin and synaptophysin and surrounded ganglion cells that contained either calbindin, calretinin, neuropeptide Y, substance P, or nitric oxide synthase. The mucosa, submucosal blood vessels, and the circular muscle coat also showed P2X(7) receptor immunoreactivity.

NMDA receptor activation results in tyrosine phosphorylation of NMDA receptor subunit 2A(NR2A) and interaction of Pyk2 and Src with NR2A after transient cerebral ischemia and reperfusion

Transient ischemia increases tyrosine phosphorylation of N-methyl-D-aspartate (NMDA) receptor. Several tyrosine kinases are involved in this process. In this study, effect of ischemia and reperfusion (I/R) on tyrosine phosphorylation of NMDA receptor subunit 2A (NR2A) and the interaction of two tyrosine kinases, Src and Pyk2, with NR2A was investigated. Four-vessel occlusion was used to produce transient (15 min) cerebral ischemia in SD rats. Tyrosine phosphorylation of NR2A in hippocampus was enhanced after 15 min of reperfusion and reached its peak level at 6 h of reperfusion. The increase sustained for at least 24 h. Src and Pyk2 co-immunoprecipitated with NR2A and the binding increased after I/R, which also reached a peak at 6 h of reperfusion. Besides, Src and Pyk2 were activated after I/R. These increases were prevented by ketamine, a selective NMDA receptor antagonist, which was administered to the SD rats 20 min before ischemia. Moreover, Src and Pyk2 coprecipitated with each other. These data show that NR2A, Src and Pyk2 might form a protein complex in vivo and the interaction suggests a possible mechanism of signal transduction in the postischemic hippocampus.