[Current situation and prospect of researches on tumor cell differentiation induced by Chinese herbal medicine].
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Animals↗
Biomedical subjects
L Luo
Publications and source records attributed to L Luo.
[A clinico-pathological study of granulomatous amoebic encephalitis].
OBJECTIVE: To study the clinico-pathological characteristics and differential diagnosis of granulomatous meningioencephalitis caused by acanthamoeba. METHODS: The clinical features, CT scan findings and post mortem pathological changes of 3 patients afflicted with granulomatous amoebic encephalitis (GAE) were analysed. RESULTS: GAE is a chronic clinical entity. Clinical manifestations include headache, low fever, seizures, hemiparesis and coma leading to death. CSF: pressure slightly elevated with presence of lymphocytes and plasma cells, glucose usually low with moderately high protein levels. CT scans were non specific. Clinical course insidious and may mimic bacterial meningitis or tuberculous meningitis. Post mortem pathological examinations showed that acanthamoeba produced a chronic or subacute granulomatous meningioencephalitis. Acanthamoebic trophoziotes and cysts were found within the hemorrhagic necrotic cerebral tissues. In some cases there is severe angitis and fibrinoid necrosis of the vascular wall with perivascular cuffing by lymphocytes and plasma cells. Trophozoites and cysts were found within the perivascular space. CONCLUSIONS: Acanthamoeba is an opportunistic pathogenic free living amoeba which can produce fatal GAE.
Acanthamoeba↗
[Measurement of soluble Fas in patients with hematological malignancy].
We measured serum levels of soluble Fas(sFas) in 68 patients with hematological malignancy by using sandwich ELISA and detected bone marrow mononuclear cell membrane Fas(mFas) positive cells in 46 patients with acute leukemias by immunohistochemical technic. It was found that sFas levels were significantly higher in acute lymphoblastic leukemia(ALL) patients(median 10.48 +/- 5.89 ng.ml-1) and non-Hodgkin's lymphoma(NHL) patients(median 18.26 +/- 16.47 ng.ml-1) than those in healthy donors (median 0.92 +/- 0.88 ng.ml-1) (P < 0.05). Elevated sFas levels were correlated with the disease stage and progress, but not with other clinical parameters. According to the follow-up of five ALL patients, their serum sFas levels decreased after complete remissions. We conclude that sFas has prognostic value and is an effective clinical parameter with ALL or NHL patients. In addition, sFas levels in the sera of acute non-lymphoblastic leukemia patients were also found to be unchanged compared with those in the normal control.
Adolescent↗
[The effect of mobile phase on the enantiomeric separation of cyfluthrin by chiral high performance liquid chromatography].
The enantiomeric separation of cyfluthrin on chiral stationary phase(CSP), derived from (R)-N-(3,5-dinitrobenzoyl) phenylglycine (Prikle type 1-A CSP) has been studied by using different hexane-alcohol mixtures as mobile phase. Mobile phase strength and composition have shown an important role in the chromatographic separation of eight isomers of cyfluthrin. Increase of the mobile phase strength reduces the retention of the eight isomers, while the diastereomeric selectivity is decreased and the enantiomeric selectivity remains almost unchanged. Also, the resolution varies in accordance with the steric hindrance of the alcohol. Secondary or tertiary alcohols impart a greater resultion to the CSP than primary alcohols. Peak shapes are better with the lower alcohols than the higher alcohols. For the enantiomeric separation of cyfluthrin on Pirkle type 1-A CSP, hexane-tert-butanol and hexane-2-propanol are better binary mobile phases.
Chromatography, High Pressure Liquid↗
[Effects of chitin and chitosan on degradation of DL-polylactide in vitro].
The authors assessed the variations of pH-values of the physiological saline used for in vitro degradation tests of DL-Polylactide (DL-PLA)/chitin and DL-PLA/chitosan composites and DL-PLA. The weight-loss rations, the appearance and morphology of the tested specimens, and the molecular weights of DL-PLA in composites and pure DL-PLA were alse investigated. The results showed that both chitin and chitosan had significant inhibitory effects on the degradation of DL-PLA, and the effect of chitosan was stronger than that of chitin. A discussion on the mechanism of such inhibition is presented.
Biocompatible Materials↗
[Neural cluster structure with single component prediction in multiple variable systems for X-ray fluorescence spectrometry].
A neural cluster structure with single component prediction (NCSCP) was proposed for X-ray fluorescence spectrometry in a multivariable system. The neural cluster structure is built by the collection of a group of neurons which have close relationships among one another. In X-ray fluorescence analysis, the structure is constructed by choosing the elements in which there exist serious matrix effects, and deleting the components containing large noise. The predictability of the neural cluster structure was compared with that of the classical backward error propagation algorithm with single component prediction. The results show that the neural cluster structure is significantly superior to the classical algorithm in prediction accuracy, antidisturbance and the predictabilty to outliers.
English Abstract↗
Contribution of individual residues to formation of the native-like tertiary topology in the alpha-lactalbumin molten globule.
Molten globules are partially folded forms of proteins that have native-like secondary structure and a compact geometry, but often without rigid, specific side-chain packing. Recently, the molten globule of alpha-lactalbumin (alpha-LA) has been shown to adopt a native-like tertiary topology, mainly localized in the alpha-helical domain. This native-like topology is reflected by the high effective concentration (Ceff) for formation of the 28-111 disulfide bond, which is approximately 10 to 40 times higher than the Ceff for formation of any non-native disulfide bond in the alpha-helical domain. In order to understand the mechanism for formation of the native-like tertiary topology, we substituted alanine for each of the 23 buried residues in the alpha-helical domain of alpha-LA and determined the effect of these substitutions on the Ceff for formation of the 28-111 disulfide bond. Our results indicate that a subset of hydrophobic residues is most important for formation of the native-like topology. These residues form a densely packed core in the three-dimensional structure of alpha-LA. In contrast, the less important residues consist of both hydrophobic and hydrophilic amino acids located at peripheral positions. These results suggest that a relatively small number of hydrophobic residues may be sufficient for specifying the overall structure of a protein during early stages of protein folding.
Cysteine↗
Structural characterization and mapping of the normal epithelial cell-specific 1 gene.
The normal epithelial cell-specific 1 (NES1) gene is a recently identified novel serine protease-like gene which is down-regulated during breast cancer progression. The gene product has 34-42% identity with the members of three distinct serine protease families: the trypsin-like family, activators of kringle domain-containing growth factors, and the kallikrein family (X. L. Liu et al., (1996) Cancer Res 56, 3371-3379). Although the cDNA of this gene has been cloned, its genomic structure and chromosomal position are not as yet known. Here, we report the genomic characterization and mapping of the NES1 gene. By subcloning and sequencing a PAC clone containing the complete NES1 gene, we were able to characterize the structure of this gene. The NES1 gene spans 5.5 kb and is composed of five coding exons and one untranslated exon. The positions of the introns were similar to trypsinogen, prostate specific antigen (PSA), and tissue plasminogen activator (TPA). NES1 gene was also localized with somatic cell mapping, radiation hybrid mapping, and fluorescence in situ hybridization techniques to chromosome 19q13.3-q13.4, the same region where the human kallikrein gene family resides. Taken together, our results suggest that the NES1 gene originates from the same ancestor as trypsinogen, PSA, and TPA, but remains in close proximity to PSA.
Amino Acid Sequence↗
Ataxia-telangiectasia and T-cell leukemias: no evidence for somatic ATM mutation in sporadic T-ALL or for hypermethylation of the ATM-NPAT/E14 bidirectional promoter in T-PLL.
The ATM gene deficient in ataxia-telangiectasia, a recessive multisystem disease associated with a high risk of lymphomas and leukemias, was found previously to be inactivated in a rare sporadic malignancy, T-cell prolymphocytic leukemia (T-PLL), which is often associated with cytogenetic aberrations of chromosome 14. The ATM gene was shown to sustain frequent loss-of-function mutations in T-PLL tumor cells, consistent with functioning as a tumor suppressor gene in this leukemia. To investigate the possibility of nonmutational or nonrecombinational mechanisms of T-PLL development, we have used bisulfite genomic sequencing to analyze DNA methylation in the putative bidirectional promoter region of the closely linked ATM and NPAT/E14 genes within the CpG island at 11q22-q23. We show that this region is completely demethylated in lymphocytes expressing ATM; however, no extensive hypermethylation was found in 9 T-PLL tumor DNA samples without evidence of ATM/p53 mutations. Because acute T-cell lymphoblastic leukemias (T-ALL) were also observed in ataxia-telangiectasia patients and T-ALL tumor cells contain chromosome 14 abnormalities, 19 presentation samples of T-ALL patients were analyzed for ATM mutations. Although T-ALL patients exhibited rare nucleotide substitutions not previously found in ATM, all were identified in the germ-line, indicating constitutional polymorphisms, potentially confined to ethnic subpopulations. The absence of somatic nucleotide changes in ATM in T-ALL as compared with T-PLL suggests a distinct pattern of genetic events in the development of the two leukemias.
Ataxia Telangiectasia↗
Drug-induced autoimmune myasthenia gravis.
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Animals↗
Localization of mRNA encoding the P2X2 receptor subunit of the adenosine 5'-triphosphate-gated ion channel in the adult and developing rat inner ear by in situ hybridization.
Localization of expression of the adenosine 5'-triphosphate (ATP)-gated ion channel P2X2 receptor subunit (P2X2R) in the rat inner ear at different stages of development was achieved by using in situ mRNA hybridization. In the adult, P2X2R mRNA was strongly expressed in many of the cells bordering the cochlear endolymphatic compartment. This included the interdental cells of the spiral limbus, all cells of the inner sulcus and organ of Corti, and cells of the spiral prominence. In the vestibular labyrinth, strong expression was noted in the transitional cells at the base of the crista ampullaris and in the sensory epithelium of the crista and maculae. During development, P2X2R mRNA expression was evident in the precursors of these structures at the earliest period studied, embryonic day 12 (E12). Expression increased during the ontogeny in both the cochlear and the vestibular end organs. In addition, both the spiral and vestibular ganglia showed developmental expression. In contrast to the supporting cells of the organ of Corti, both inner and outer hair cells exhibited P2X2R mRNA only after postnatal day 10 (P10) through P12, concomitant with the onset of hearing. P2X2R expression levels in all cells fell from a maximum at P12-P18 to lower levels in the adult. In the adult, P2X2R mRNA levels were modest in outer hair cells in the basal (high-frequency) encoding region of the cochlea, and inner hair cell labeling was low throughout the cochlea. Reissner's membrane, which maintains an electrochemical barrier between scala vestibuli and scala media, showed considerable expression of P2X2R mRNA in early postnatal development, and expression was maintained at moderate levels in the adult cochlea. These data are consistent with a role for the P2X2R subunit in the processes of labyrinthine development and the regulation of the electrochemical gradients supporting auditory and vestibular sensory transduction.
Adenosine Triphosphate↗
Developmental expression of alpha 9 acetylcholine receptor mRNA in the rat cochlea and vestibular inner ear.
Expression of alpha9 acetylcholine receptor (AChR) mRNA was studied by in situ hybridization in the rat adult and developing cochlea and vestibular inner ear. Alpha9 AChR mRNA was first observed in cochlear hair cells (HCs) at embryonic day 18 (E18), increased markedly after birth, stayed high until postnatal day 10 (P10), and decreased to substantially lower adult levels by P14. High levels of alpha9 AChR mRNA expression were also noted in the developing nonneuronal structures of the inner sulcus, chondrocytes, and/or osteoblasts in the cochlear capsule and interscalar laminae. Both developing and adult bone marrow cells also expressed intense alpha9 AChR mRNA. In the vestibular system, alpha9 AChR mRNA was first observed in HCs at E16 in all sensory epithelia, increased to its highest levels by P0-P4, then decreased slightly to reach adult levels by P10. The results are consistent with the alpha9 AChR subserving efferent neurotransmission to both cochlear and vestibular HCs. The observation of alpha9 AChR mRNA in cochlear HCs 2 weeks prior to functional onset in the cochlea further suggests that expression of this gene is not related to HC activity. The observation of substantial nonneuronal expression of alpha9 AChR mRNA suggests that this receptor also has functions separate from its role in neurotransmission.
Animals↗
Requirements of focal adhesions and calcium fluxes for interleukin-1-induced ERK kinase activation and c-fos expression in fibroblasts.
Interleukin-1 (IL-1) is an important inflammatory mediator and plays a central role in the destruction of connective tissue matrices in diseases such as arthritis and periodontitis. It is well established that IL-1 activation of the mitogen-activated protein (MAP) kinase pathway and induction of c-fos expression is a required step in the induction of matrix metalloproteinase expression involved in tissue degradation. Previous studies in our laboratory showed that IL-1-induced calcium flux is dependent on focal adhesion formation, suggesting a matrix-dependent restriction system for IL-1 signaling. Therefore, in the present study, we examined the consequences of this restriction on IL-1-mediated activation of the MAP kinase family and on c-fos expression. Treatment of human gingival fibroblasts with IL-1 activated extracellular signal-regulated kinases (ERK), c-Jun N-terminal kinase (JNK), and p38 kinase activity and induced c-fos expression in a dose- and time-dependent fashion. Plating cells on poly-L-lysine prevented focal adhesion formation, eliminated IL-1-induced calcium influx, abolished ERK stimulation, and blocked c-fos expression. Cells in suspension and hence with no suitable substratum for focal adhesion formation also showed no ERK activation or enhanced c-fos expression in response to IL-1. In contrast, eliminating focal adhesion formation or calcium depletion in cells plated on fibronectin had no effect on IL-1 stimulation of JNK and p38 kinases, demonstrating that their activation was mediated through pathways independent of focal adhesions and calcium. Calcium depletion abolished IL-1-induced calcium uptake, ERK activation, and c-fos expression. The focal adhesion dependence of IL-1-induced ERK activation and c-fos expression could be circumvented in cells plated on poly-L-lysine by simultaneous incubation with IL-1 and the calcium ionophore ionomycin. In transfection studies, IL-1 stimulation of serum responsive element (SRE) transcriptional activity was dependent on the presence of extracellular calcium. This is consistent with a requirement for calcium in the activation of ERKs and their involvement in the induction of c-fos expression through the SRE site on the 5' promoter of the c-fos gene. Our results demonstrate that in cells attached to substrates by focal adhesions, IL-1-mediated calcium flux is required for ERK activation and c-fos expression but not for JNK or p38 activation. We conclude that cellular interactions with the extracellular matrix play an important role in restricting ERK and c-fos-dependent processes.
Blood↗
ATM is usually rearranged in T-cell prolymphocytic leukaemia.
T-prolymphocytic leukaemia (T-PLL) is a rare, sporadic leukaemia similar to a mature T-cell leukaemia seen in some patients with Ataxia Telangiectasia (A-T), a recessive multisystem disorder caused by mutations of the ATM gene at chromosome 11q23. ATM sequence mutations have been reported in 46% of T-PLL cases, but some cases also have karyotypic abnormalities at 11q, including 11q23. This led us to investigate the structure of the ATM locus in a panel of eight cases, two of which had 11q23 abnormalities. As expected, nucleotide changes were detected in some samples. Two remission samples were wild type. To test for structural lesions, DNA fibres were hybridized with a contig of four labelled cosmids spanning the ATM locus. In all samples there were structural lesions and in four samples both alleles were affected. This provides strong evidence for our suggestion that ATM acts as a tumour suppressor during T-PLL tumorigenesis. Some additional role for ATM during T-PLL tumorigenesis is possible since nucleotide changes were present in addition to structural lesions disrupting both alleles. The mechanism of inactivation appeared to be unusual because multiple structural lesions on one allele were often observed.
Ataxia Telangiectasia Mutated Proteins↗
Phantom sensations generated by thalamic microstimulation.
Many amputees have a sense of their missing 'phantom' limb. Amputation can alter the representation of the body's surface in the cerebral cortex and thalamus, but it is unclear how these changes relate to such phantom sensations. One possibility is that, in amputees who experience phantom sensations, the region of the thalamus that originally represented the missing limb remains functional and can give rise to phantom sensations even when some thalamic 'limb' neurons begin to respond to stimulation of other body regions. Here we use microelectrode recording and microstimulation during functional stereotactic mapping of the ventrocaudal thalamus in amputees to determine both the responses of the neurons to stimulation of the skin and the perceptual effects of electrical activation of these neurons. Thalamic mapping revealed an unusually large thalamic stump representation, consistent with the findings from animal experiments. We also found that thalamic stimulation in amputees with a phantom limb could evoke phantom sensations, including pain, even in regions containing neurons responsive to tactile stimulation of the stump. These findings support the hypothesis that the thalamic representation of the amputated limb remains functional in amputees with phantoms.
Adult↗
Induction of V3-specific cytotoxic T lymphocyte responses by HIV gag particles carrying multiple immunodominant V3 epitopes of gp120.
Effort to develop a vaccine to prevent infection of human immunodeficiency virus (HIV) have focused on the induction of neutralizing antibodies. In our previous study, we reported that chimeric gag-env virus-like particles (VLPs) induce neutralizing antibodies which block HIV infection. In addition to the neutralizing antibodies, the cytotoxic T-lymphocyte (CTL) response is considered to be another major immune defense mechanism required for recovery from many different viral infections. In the present study, we have constructed chimeric fusion proteins using HIV-2 gag precursor protein with (1) four neutralizing epitopes from HIV-1 gp160; (2) three tandem copies of consensus V3 domain, which have been derived from 245 different isolates of HIV-1 and carries both the principal neutralizing determinant (PND) and CTL epitopes; and (3) V3 domains from HIV-1IIIB, HIV-1MN, HIV-1RF, and HIV-1SF2. These chimeric fusion proteins were expressed in a large quantity within insect cells, and released as VLPs into the cell culture medium. The purified gag-env VLPs from all three constructs appear to be spherical particles similar to immature HIV but slightly larger than the gag VLPs. Immunoprecipitation analysis showed that the chimeric proteins were recognized not only by HIV-1 positive patient sera, but also by monoclonal and polyclonal antisera raised against V3 peptides of HIV-1IIIB, HIV-1MN, HIV-1RF, and the gp120 antiserum against HIV-1SF2. Balb/C mice immunized with these chimeric VLPs successfully induced CTL activity against V3 peptide-stimulated target cells. In addition, a high degree of cross-reactivity was observed among the four different strains of HIV-1 V3 domain, indicating that the tandem multiple consensus V3 peptide sequence carried by HIV-2 gag can be used as a potential HIV vaccine against various HIVs.
Animals↗
Focal delivery of fibroblast growth factor-1 by transfected cells induces spiral ganglion neurite targeting in vitro.
Sensory cells in the cochlea of the rat transiently express acidic fibroblast growth factor (FGF-1) during the developmental period of terminal innervation in the sensory epithelium. To explore the potential role of FGF-1 in terminal innervation events, the response of cochlear ganglion neurons to FGF-1 was evaluated in culture. Explants from the spiral ganglion of postnatal day 5 rats were cultured in the presence of exogenous FGF-1, with or without heparin. FGF-1 in the culture medium produced a dose-dependent increase in the number and length of neurites produced by spiral ganglion neurons, a response that was enhanced by heparin. To assess the effects of FGF-1 produced by a focal, cellular source, additional explants were cocultured with 3T3 cell transfectants that secrete FGF-1. Neurites that came into contact with FGF-1 secreting cells branched, formed bouton-like terminal swellings on the surface of the transfectants, and stopped extending. The results suggest that FGF-1 may stimulate neurite extension into the sensory epithelium of the cochlea and that focal production of FGF-1 may contribute to the formation of contacts on sensory cells by developing neurites.
3T3 Cells↗
Anti-BSA antibodies do not cross-react with the 69-kDa islet cell autoantigen ICA69.
In contrast to several previously published reports, we demonstrate by a variety of antibody assays that bovine serum albumin (BSA) is not antigenically cross-reactive with the 69-kDa islet cell autoantigen (ICA69). Fast protein liquid chromatography purified BSA and highly purified recombinant human ICA69 were used to establish sensitive Western blot and ELISA assays in order to detect antibodies against these two proteins. The assays excluded BSA or powdered milk as blocking agents, since these would interfere with antibody binding. A panel of sera from diabetic individuals, first degree relatives, and normal controls showed that the majority (approximately 70%) of individuals from each group had antibodies against ICA69 as assayed by Western blots, whereas considerably fewer (approximately 13%) had anti-BSA antibodies on Western blots, and individuals with antibodies to both proteins occurred only rarely (2-3%). To explore this issue further we immunized a total of 16 individual rats, representing four different strains (bio-breeding diabetes resistant and diabetes prone, Wistar-Furth, and Sprague-Dawley), with either BSA (n = 2 of each strain) or with recombinant ICA69 (n = 2 of each strain), and for each animal pre- and postimmune antibody titres against BSA and against ICA69 were assayed separately by enzyme-linked immunoabsorbent assay. In rats immunized with BSA, anti-BSA titres increased about 100,000-fold over preimmune levels, whereas anti-ICA69 reactive antibodies were unchanged over preimmune levels. Similarly, in rats immunized with ICA69, anti-ICA69 titres rose about 100,000-fold over preimmune levels, whereas anti-BSA antibodies were unchanged over preimmune levels. Thus we find no evidence for the existence of antibody cross-reactivity between ICA69 and BSA, either in humans or in immunized rats. When our rat anti-BSA antisera were used to probe Western blots made from rat islets isolated in the strict absence of fetal calf serum, we were unable to detect a 69-kDa band, even when the islets were preincubated with gamma-interferon, a treatment which has been reported to induce the BSA cross-reactive islet antigen. We conclude that BSA is not antigenically cross-reactive with ICA69 at the antibody level, and it is highly unlikely that BSA is antigenically cross-reactive with some other 69 kD islet cell antigen.
Animals↗