Phosphorylation of anticancer nucleoside analogs by human mitochondrial deoxyguanosine kinase

The kinetic properties of recombinant human mitochondrial deoxyguanosine kinase (dGK, EC 2.7.1.113) for 2'-deoxyguanosine and the clinically important nucleoside analogs 2-chloro-2'-deoxyadenosine (CdA), 9-beta-D-arabinofuranosylguanine (araG) and 2',2',-difluorodeoxyguanosine (dFdG) were determined. The Michaelis-Menten kinetic parameters, comparing ATP and UTP as phosphate donors, demonstrated a marked increase in phosphorylation efficiency (VmaxKm) with UTP in comparison with ATP for both CdA and araG. The difluoro analog dFdG was an efficient substrate for recombinant dGK with an apparent Km of 16 microM with ATP as phosphate donor. We compared the kinetic properties of dGK with those of the related enzyme deoxycytidine kinase (dCK, EC 2.7.1.74). Although the purines 2'-deoxyguanosine (dGuo) and 2'-deoxyadenosine are substrates for both dGK and dCK, only CdA among the purine nucleoside analogs tested was an efficient substrate for both dCK and dGK. In competition with dGuo, the most efficient analog for phosphorylation by dGK was araG, as indicated by a lower Ki value than for CdA and dFdG. Of the purine analogs tested as substrates for dCK, only CdA could compete with 2'-deoxycytidine (dCyd). No inhibition of dCK-mediated dCyd phosphorylation was found by either araG or dFdG. In crude cell extract of HeLa and Capan 2 cells, the major CdA phosphorylation was contributed by dCK, while most araG phosphorylation was a result of dGK activity. Our study with pure recombinant enzymes confirms that dGK is mainly responsible for araG and dFdG phosphorylation, whereas dCK is the most important enzyme for activation of CdA and 2',2'-difluorodeoxycytidine (dFdC).

Measuring two-dimensional receptor-ligand binding kinetics by micropipette

We report a novel method for measuring forward and reverse kinetic rate constants, kf0 and kr0, for the binding of individual receptors and ligands anchored to apposing surfaces in cell adhesion. Not only does the method examine adhesion between a single pair of cells; it also probes predominantly a single receptor-ligand bond. The idea is to quantify the dependence of adhesion probability on contact duration and densities of the receptors and ligands. The experiment was an extension of existing micropipette protocols. The analysis was based on analytical solutions to the probabilistic formulation of kinetics for small systems. This method was applied to examine the interaction between Fc gamma receptor IIIA (CD16A) expressed on Chinese hamster ovary cell transfectants and immunoglobulin G (IgG) of either human or rabbit origin coated on human erythrocytes, which were found to follow a monovalent biomolecular binding mechanism. The measured rate constants are Ackf0 = (2.6 +/- 0.32) x 10(-7) micron 4 s-1 and kr0 = (0.37 +/- 0.055) s-1 for the CD16A-hIgG interaction and Ackf0 = (5.7 +/- 0.31) X 10(-7) micron 4 s-1 and kr0 = (0.20 +/- 0.042) s-1 for the CD16A-rIgG interaction, respectively, where Ac is the contact area, estimated to be a few percent of 3 micron 2.

A targeted DNA-PKcs-null mutation reveals DNA-PK-independent functions for KU in V(D)J recombination

The DNA-dependent protein kinase (DNA-PK) consists of Ku70, Ku80, and a large catalytic subunit, DNA-PKcs. Targeted inactivation of the Ku70 or Ku80 genes results in elevated ionizing radiation (IR) sensitivity and inability to perform both V(D)J coding-end and signal (RS)-end joining in cells, with severe growth retardation plus immunodeficiency in mice. In contrast, we now demonstrate that DNA-PKcs-null mice generated by gene-targeted mutation, while also severely immunodeficient, exhibit no growth retardation. Furthermore, DNA-PKcs-null cells are blocked for V(D)J coding-end joining, but retain normal RS-end joining. Finally, while DNA-PK-null fibroblasts exhibited increased IR sensitivity, DNA-PKcs-deficient ES cells did not. We conclude that Ku70 and Ku80 may have functions in V(D)J recombination and DNA repair that are independent of DNA-PKcs.

[The protective effects of baicalin on pertussis bacilli-induced brain edema in rats]

OBJECTIVE

To evaluate the inhibitory effect of baicalin on iron-dependent lipid peroxidation (IDLPO) and the protective effect on pertussis bacilli-induced brain edema in rats.

METHODS

In vitro, the inhibitory effect of baicalin and deferoxamine (DFX) was studied at different concentrations on IDLPO in brain homogenates of Sprague-Dawley rats. In vivo, the protective effect was studied of baicalin and DFX on brain edema induced by injecting purtussis bacilli into the left internal carotid artery in rats. Forty Sprague-Dawley rats were randomly divided into four groups. Group 1 (NS, n = 10), as control; Group 2 (PB, n = 10), pertussis bacilli control; Group 3 (DFX, n = 10), PB + deferoxamine; and Group 4 (BAI, n = 10), PB + baicalin.

RESULTS

The baicalin was possessed of an inhibitory effect on IDLPO in rat brain homogenate, moreover, the inhibitory potency of baicalin was approximately 20 times higher than DFX treated alone. In vivo, the increase in the content of water(CW) and Evans blue (EB) was attenuated in groups DFX and BAI (CW: 79.8 +/- 0.7)% and (79.5 +/- 0.6)%; (EB: 11 +/- 7 micrograms/g and 12 +/- 5 micrograms/g) as compared with the group PB (CW: 80.4 +/- 0.9%, EB: 24 +/- 10 micrograms/g). The content of iron was significantly lower than in the left hemispheres (injected side) in the group DFX and the group BAI (79 +/- 9 micrograms/g and 77 +/- 10 micrograms/g) than in the left hemispheres in the group PB(132 +/- 28 micrograms.d-1.g), P < 0.05. The activation of CuZn-SOD (L155 +/- 36 U/mg pr, R177 +/- 75 U/mg pr) was decreased in the group BP compared with the group NS(L 201 +/- 49 U/mg pr, R 249 +/- 49 U/mg pr), P < 0.05. The activation of CuZn-SOD was significantly higher in the left brain tissues in the groups DFX and BAI (222 +/- 49 U/mg pr and 230 +/- 45 U/mg pr, respectively) than in the left brain tissues of the group of PB (P < 0.05).

CONCLUSION

The baicalin and DFX have a protective effects on the pertussis bacilli-induced brain edema in rats, and the protective effects are related to the inhibitory effect on IDLPO, chelating Fe2+, and activated CuZn-SOD.

[Resection of cranial base tumors]

This article reports 10 cases of cranial base tumors resected by pre-or retro-auricular intratemporal approach. Among them four were neuronomas, two meningiomas, one malignant giant cell tumor of bone, one osteochondnoma, one parotid mixed neoplasm and one poorly-differentiated squamors cell carcinoma. Total resection in 9 cases and one subtotal resection were performed without operative mortality and serious surgical complications. The surgical management of cranial base tumor and indications for selecting operative approaches were discussed.

Enhanced cytotoxicity of nucleoside analogs by overexpression of mitochondrial deoxyguanosine kinase in cancer cell lines

The cytotoxic anti-cancer purine nucleoside analogs 2-chloro-2'-deoxyadenosine (CdA), 9-beta-D-arabinofuranosylguanine (araG), and 2',2'-difluorodeoxyguanosine (dFdG) are phosphorylated by human mitochondrial deoxyguanosine kinase (dGK) in vitro. We overexpressed dGK as a fusion protein to the green fluorescent protein in the human pancreatic cancer cell lines PanC-1 and MIA PaCa-2 to determine the importance of dGK-mediated nucleoside analog phosphorylation. The transfected cells showed mitochondrial fluorescence patterns, and the mitochondrial locations of endogenous and overexpressed dGK were verified by Western blot analysis of cell extracts with polyclonal anti-dGK antibodies. The increase of dGK activity in the overexpressing cells was approximately 4-fold. These cell lines exhibited increased sensitivity to CdA, araG, and dFdG as compared with the untransfected parent cell lines. This is, to our knowledge, the first demonstration of a correlation between the activity of a mitochondrial deoxyribonucleoside kinase and the cytotoxicity of nucleoside analogs. Our data imply that the dGK activity is rate-limiting for the efficacy of nucleoside analogs in the cell lines investigated.

Analysis of the DNA-binding site for Xenopus glucocorticoid receptor accessory factor. Critical nucleotides for binding specificity in vitro and for amplification of steroid-induced fibrinogen gene transcription

In addition to the glucocorticoid receptor, DNA-binding proteins called accessory factors play a role in hormone activation of many glucocorticoid-responsive genes. Hormonal regulation of the gamma-fibrinogen subunit gene from the frog Xenopus laevis requires a novel DNA sequence that binds a liver nuclear protein called Xenopus glucocorticoid receptor accessory factor (XGRAF). Here we demonstrate that the recognition site for XGRAF encompasses GAGTTAA at positions -175 to -169 relative to the start site of transcription. This sequence is not closely related to the binding sites for known transcription factors. The two guanosines make close contact with XGRAF, as shown by the methylation interference assay. Single-point mutagenesis of every nucleotide in the 9-base pair region from positions -177 to -169 showed an excellent correlation between ability to bind XGRAF in vitro and ability to amplify hormone-induced transcription from DNA transfected into Xenopus primary hepatocytes. Conversely, XGRAF had little or no effect on basal transcription of the gamma-fibrinogen gene. Maximal hormonal induction also requires three half-glucocorticoid response elements (half-GREs) homologous to the downstream half of the consensus GRE. Interestingly, the XGRAF-binding site is immediately adjacent to the most important half-GRE. This close proximity suggests a new mechanism for activation of a gene lacking a conventional full GRE.

[Radioimmunological image in tumor bearing nude mice with monoclonal antibody against human laryngeal carcinoma]

OBJECTIVE

To investigate the specific autoradiographic diagnosis of laryngeal carcinoma and its metastasis.

METHODS

Three strains of the mixed monoclonal antibodies against human laryngeal carcinoma (McAbLC9, 11, 12) labelled with 131I were injected(intraperitoneally) into the nude mice bearing squamous cell carcinoma. The tumor autoradiography was done by single photo-emission computed tomography (ECT). The percent injected dose/g of tumor were measured, and the radioactivity ratio of tumor to non-tumor tissues(T/NT) were calculated.

RESULTS

The 131I-McAbLC 9, 11, 12 can accumulate in the area of the laryngeal carcinoma within limited time, and demonstrate a satisfactory tumor imaging at 96 h. In experimental groups: The %ID/g of tumor tissues (mean +/- s, n = 6) was 18.8 +/- 0.61; The %ID/g of tumor tissues in the control group was 4.46 +/- 0.82 (mean +/- s, n = 6) at 96 h. The difference was statistically significant (P < 0.01, t = 34.97).

CONCLUSION

The results suggest that 131I McAbLC9, 11, 12 is specific and sensitive in recognising human laryngeal carcinoma cell, and the area and size of tumor can be easily detected by ECT. It is feasible for localization of tumor and its metastasis.

[Resources investigation of Actinidia in Hunan Province]

Based on the resources investigation and taxonomic research on the plants of Actinidia in Hunan Province, 15 species and 5 varieties together with their distribution and utilization are reported. A key is set forth according to the differences among the above species and varieties.

Minimax partial distortion competitive learning for optimal codebook design

The design of the optimal codebook for a given codebook size and input source is a challenging puzzle that remains to be solved. The key problem in optimal codebook design is how to construct a set of codevectors efficiently to minimize the average distortion. A minimax criterion of minimizing the maximum partial distortion is introduced in this paper. Based on the partial distortion theorem, it is shown that minimizing the maximum partial distortion and minimizing the average distortion will asymptotically have the same optimal solution corresponding to equal and minimal partial distortion. Motivated by the result, we incorporate the alternative minimax criterion into the on-line learning mechanism, and develop a new algorithm called minimax partial distortion competitive learning (MMPDCL) for optimal codebook design. A computation acceleration scheme for the MMPDCL algorithm is implemented using the partial distance search technique, thus significantly increasing its computational efficiency. Extensive experiments have demonstrated that compared with some well-known codebook design algorithms, the MMPDCL algorithm consistently produces the best codebooks with the smallest average distortions. As the codebook size increases, the performance gain becomes more significant using the MMPDCL algorithm. The robustness and computational efficiency of this new algorithm further highlight its advantages.

[Polymorphism analysis of D6S366 STR locus]

The polymorphic STR locus D6S366 was analyzed using PCR and PAG electrophoresis and 7 alleles were detected from 200 unrelated individuals in Wuhan. The allete distribution of the locus was in accordance with Hardy-Weinberg equilibrium. The H, Dp, P, E, and PIC of the D6S366 were calculated in this paper.

Determining force dependence of two-dimensional receptor-ligand binding affinity by centrifugation

Analyses of receptor-ligand interactions are important to the understanding of cellular adhesion. Traditional methods of measuring the three-dimensional (3D) dissociation constant (Kd) require at least one of the molecular species in solution and hence cannot be directly applied to the case of cell adhesion. We describe a novel method of measuring 2D binding characteristics of receptors and ligands that are attached to surfaces and whose bonds are subjected to forces. The method utilizes a common centrifugation assay to quantify adhesion. A model for the experiment has been formulated, solved exactly, and tested carefully. The model is stochastically based and couples the bond force to the binding affinity. The method was applied to examine tumor cell adherence to recombinant E-selectin. Satisfactory agreement was found between predictions and data. The estimated zero-force 2D Kd for E-selectin/carbohydrate ligand binding was approximately 5 x 10(3) microm(-2), and the bond interaction range was subangstrom. Our results also suggest that the number of bonds mediating adhesion was small (<5).

[Anti-virus effect of hepatocyte stimulating substance (HSS) on duck hepatitis B virus in vivo]

We used one day old Beijing ducklings infected by duck hepatitis B virus as experimental model to observe anti-virus effect of HSS. Beijing ducklings hatched within one day were injected intravenously with duck hepatitis B virus (DHBV). Positive DHBV-DNA in ducklings' sera were detected 7 days later. Serum samples were obtained from all ducklings before, during and after drug treatment at different times and stored at -70 degrees C. The collected samples were detected DHBV-DNA by dot-blot hybridization test at the same time. The therapeutic effects were evaluated by OD value of dot-blot and by the inhibitory rate of DHBV-DNA. The results showed that HSS (with 50 mg/kg/day and 200 mg/kg/day) were effective in inhibition of DHBV-DNA during and after drug treatment, especially in the HSS group of large dosage. The inhibitory effect appeared early and high dynamic. The inhibitory rate of DHBV-DNA during and after drug treatment were higher than the NS group (P < 0.05). No inhibitory effect was observed in NS group. The hepatic biopsy showed HSS groups had milder damage than NS group, indicating that the HSS could inhibit the replication of DHBV-DNA in Beijing ducklings.

A critical period of ear development controlled by distinct populations of ciliated cells in the zebrafish

The zebrafish (Danio rerio) is a useful model system for analyzing development of the inner ear. A number of mutations affecting the inner ear have been identified. Here we investigate the initial stages of otolith morphogenesis in wild-type embryos as well as in monolith (mnl) mutant embryos, which fail to form anterior otoliths but otherwise appear normal. Otolith growth is initiated at 18-18.5 h by localized accretion of free-moving precursor particles. This process, referred to as otolith seeding, is regulated by two classes of cilia: First, kinocilia of precociously forming hair cells (tether cells) bind seeding particles, thereby localizing otolith formation. Tether cells usually occur in pairs at the anterior and posterior ends of the ear. Despite the presence of functional kinocilia, tether cells initially appear immature and do not acquire the characteristics of mature hair cells until approximately 21.5 h. Second, beating cilia distributed throughout the ear agitate seeding particles, thereby inhibiting premature agglutination. Constraining particles with laser tweezers caused them to fuse into large untethered masses. Bringing such masses into contact with tethered otoliths caused them to fuse, greatly enhancing otolith growth. Selectively enhancing one otolith greatly inhibited growth of the second, creating an imbalance that persisted for many days. Seeding particles and beating cilia disappear soon after 24 h, and the rate of otolith growth decreases by nearly 90%. In mnl mutant embryos, tethers and beating cilia are distributed normally, but anterior otoliths fail to form in 80-85% of mutant ears. The binding properties of seeding particles appear normal, as shown by their ability to fuse when entrapped by laser tweezers and their binding to posterior tethers. We infer that anterior tethers have a weakened ability to bind seeding particles in mnl embryos. Immobilizing mnl embryos with the anterior end of the ear oriented downward effectively concentrated the dense seeding particles near the anterior tethers and permitted all to form anterior otoliths. However, immobilizing mnl embryos after 24 h when seeding particles were depleted did not facilitate anterior otolith formation. Together, these data demonstrate that the ability to initiate otolith formation is limited to a critical period, from 18.5 to 24 h, and that interfering with the functions of tether cell kinocilia or beating cilia impairs otolith seeding and subsequent otolith morphogenesis.

Growth retardation and leaky SCID phenotype of Ku70-deficient mice

Ku70, Ku80, and DNA-PKcs are subunits of the DNA-dependent protein kinase (DNA-PK), an enzyme implicated in DNA double-stranded break repair and V(D)J recombination. Our Ku70-deficient mice were about 50% the size of control littermates, and their fibroblasts were ionizing radiation sensitive and displayed premature senescence associated with the accumulation of nondividing cells. Ku70-deficient mice lacked mature B cells or serum immunoglobulin but, unexpectedly, reproducibly developed small populations of thymic and peripheral alpha/beta T lineage cells and had a significant incidence of thymic lymphomas. In association with B and T cell developmental defects, Ku70-deficient cells were severely impaired for joining of V(D)J coding and recombination signal sequences. These unanticipated features of the Ku70-deficient phenotype with respect to lymphocyte development and V(D)J recombination may reflect differential functions of the three DNA-PK components.

Interaction of ATF6 and serum response factor

Serum response factor (SRF) is a transcription factor which binds to the serum response element (SRE) in the c-fos promoter. It is required for regulated expression of the c-fos gene as well as other immediate-early genes and some tissue-specific genes. To better understand the regulation of SRF, we used a yeast interaction assay to screen a human HeLa cell cDNA library for SRF-interacting proteins. ATF6, a basic-leucine zipper protein, was isolated by binding to SRF and in particular to its transcriptional activation domain. The binding of ATF6 to SRF was also detected in vitro. An ATF6-VP16 chimera activated expression of an SRE reporter gene in HeLa cells, suggesting that ATF6 can interact with endogenous SRF. More strikingly, an antisense ATF6 construct reduced serum induction of a c-fos reporter gene, suggesting that ATF6 is involved in activation of transcription by SRF. ATF6 was previously partially cloned as a member of the ATF family. The complete cDNA of ATF6 was isolated, and its expression pattern was described.

A longitudinal study of tooth wear in orthodontically treated patients

The primary objective of this study was to determine whether there is a relationship between incisal/occlusal tooth wear during the mixed dentition and subsequent wear of the adult dentition. Pretreatment orthodontic records taken during the mixed dentition (T1), as well as follow-up records taken an average of 20 years later (T2), were available for 223 orthodontically treated patients. Incisal/occlusal tooth wear was measured on a tooth-by-tooth basis from T1 and T2 stone casts with a four-category scoring system. Multiple regression analysis (R2 = 0.33) indicated that wear could be predicted at a given age during adulthood from wear observed on the deciduous mandibular canines and molars at T1 (p < 0.0001). This predictive relationship was modified by the age at which the T1 wear was observed (p = 0.029) and possibly by the sex of the patient (p = 0.10). These results indicate that adult tooth wear is not independent of the tooth wear that occurred as a child. Bruxism is suggested as a possible common etiologic mechanism that may account for the relationship between childhood and adult tooth wear.

[Pharmacognostical identification on fruits of Actinidia species (II)]

The observation of powder were carried out on fruits of 10 kinds of plants belonging to Genus Actinidia. The results pointed out obvious difference among the above species, which could be considered as one of the important evidence for identification.

V(D)J recombination in Ku86-deficient mice: distinct effects on coding, signal, and hybrid joint formation

Ku, a heterodimer of 70 and 86 kDa subunits, plays a critical but poorly understood role in V(D)J recombination. Although Ku86-deficient mice are defective in coding and signal joint formation, rare recombination products have been detected by PCR. Here, we report nucleotide sequences of 99 junctions from Ku86-deficient mice. Over 90% of the coding joints, but not signal or hybrid joints, exhibit short sequence homologies, indicating that homology is required to join coding ends in the absence of Ku86. Our results suggest that Ku86 may normally have distinct functions in the formation of these different types of junctions. Furthermore, Ku86(-/-) joints are unexpectedly devoid of N-region diversity, suggesting a novel role for Ku in the addition of N nucleotides by terminal deoxynucleotidyl transferase.

[Alterations of substance P-immune reaction positive neurons of cerebral tissues in epileptic rats]

Employing the immunocytochemical analysis, we observed the alterations of Substance P-Immune Reaction (SP-IR) positive neurons of the cerebral cortex, hippocampus and amygdala in rats suffering from epilepsy induced by Penicillin (PEN). The result showed that the number of neurons of epileptic group was higher than that of the control group and no significant change in the rumber of neurons was observed in the group in which PEN was given after injection of Nimodine. It indicates that SP and Ca2+ participate in the process of epileptogenesis.

Pain control in recovering alcoholics: effects of local anesthesia

OBJECTIVE

The medical literature suggests that alcoholics may present greater challenges to achieving clinical pain control than nonalcoholics. This study was undertaken to test the hypotheses that: (1) significant differences exist between alcoholics and nonalcoholics on detection and pain thresholds during electric tooth stimulation; (2) group differences exist in the depth and time course of pulpal anesthesia; and (3) responses to tooth stimulation are associated with severity of alcoholism and/or other psychological factors.

METHOD

Male alcoholics (n = 22) in aftercare treatment (mean length of sobriety = 113 days) and age-matched nonalcoholics (n = 22) received 1.0 ml of 3% mepivicaine at the apex of a maxillary lateral incisor and saline placebo at the apex of the contralateral incisor.

RESULTS

At baseline no group differences were found on sensory thresholds. During drug intervention significant drug and time effects for both detection threshold (p < .0001) and pain threshold (p < .0001) were found, but group differences and interactive effects were not significant. By exploratory regression analysis of alcoholic subjects, history of depression/unhappiness was significantly associated with shallower pulpal anesthesia, whereas high need for control/low actual control and frequency of treatment for detoxification were associated with deeper anesthesia.

CONCLUSIONS

Our findings suggest alcoholics in recovery are not at increased risk for inadequate pain control with local anesthesia.

The Sex-lethal early splicing pattern uses a default mechanism dependent on the alternative 5' splice sites

The Sex-lethal (Sxl) early transcripts have a unique 5' exon and a splicing pattern that differs from that of the late transcripts. While the late transcripts are regulated sex specifically by control of exon 3 inclusion, the early transcripts are not. While the late transcripts include exon 3 by default, the early transcripts skip exon 3. Splicing patterns of a reporter gene that mimics the early transcript, and its variants, were analyzed in Drosophila transformants and tissue culture cells. The results demonstrate that the early, in contrast to the late, splicing pattern is not regulated by stage-specific or sex-specific trans-acting factors, and so the pattern appears to arise from some type of intrinsic splice site preference or compatibility. Inclusion or exclusion of exon 3 is determined by the identity of the upstream 5' splice site region as late or early. The important region of the early exon lies within 233 nucleotides of the immediately adjacent intron.

Identification of redox/repair protein Ref-1 as a potent activator of p53

p53 can be isolated from cells in a form that is inert for binding to DNA but that can be stimulated dramatically by phosphorylation, antibody binding, or short single strands of DNA. This suggests that upon genotoxic stress, cells can convert latent p53 to one that is active for DNA binding. Surprisingly, we observed that latent p53 is as effective in activating transcription in vitro as is active p53. We found that HeLa nuclear extracts can stimulate DNA binding by latent p53 and have purified from them a p53-stimulating protein that we have determined to be the product of the Ref-1 gene. Interestingly, Ref-1 is a dual function protein that can both regulate the redox state of a number of proteins and function as a DNA repair (A/P) endonuclease. We observed that oxidized forms of full-length and carboxy-terminally truncated p53 (p53 delta30), which are inactive for DNA binding, are both stimulated by the Ref-1 protein. However, in the presence of reducing agent, Ref-1 is an extremely potent stimulator of full-length p53 but not p53 delta30. These and additional data indicate that Ref-1 protein stimulates p53 by both redox-dependent and -independent means and imply a key role for it in p53 regulation. Importantly, we have also determined that Ref-1 can stimulate p53 transactivation in vivo. This is the first example of a noncovalent protein modifier of p53 function identified in cells.

Effect of dexamethasone on Glu-IR and GABA-IR neurons of hippocampus in rats

Dexamethasone (Dex) was injected into the rat lateral ventricle and the changes of glutamate-immunoreactivity (Glu-IR) and gamma-aminobulyric acid immunoreactivity (GABA-IR) neurons in the hippocampus were immunocytochemically examined 2 h after injection. The results showed that Glu-IR neurons increased and GABA-IR neurons did not show marked change. The mechanism remains to be further studied.

Thymocyte differentiation in gamma-irradiated severe-combined immunodeficient mice: characterization of intermediates and products of V(D)J recombination at the T cell receptor alpha locus

Treatment with DNA-damaging agents promotes rescue of V(D)J recombination, limited thymocyte differentiation, and development of thymic lymphomas in severe-combined immunodeficient (SCID) mice. One intriguing aspect of this system is that irradiation rescues rearrangements at the T cell receptor (TCR) beta, gamma and delta loci, but not at the TCR alpha locus. Current models posit that only those loci that are recombinationally active at the time of irradiation can be rescued. Here, we employ sensitive, semiquantitative ligation-mediated polymerase chain reaction assays to detect a specific class of recombination intermediates, hairpin coding ends, at the TCR alpha locus. We found that J alpha-coding ends are undetectable in unirradiated SCID thymocytes, but accumulate after irradiation at times coincident with the emergence of a CD4+ CD8+ thymocyte population. Coding joints produced by joining of these ends, however, are extremely rare. To test whether the presence of hairpin coding ends at TCR alpha is sufficient for irradiation-mediated rescue of coding joint formation, we administered a second dose of gamma-irradiation after abundant CD4+ CD8+ thymocytes and hairpin TCR alpha coding ends had accumulated. This treatment failed to stimulate rescue of TCR alpha coding joints. Thus, the presence of hairpin coding ends at the time of irradiation, while perhaps necessary, is not sufficient for rescue of V(D)J rearrangements. These results support a refined model for irradiation-mediated rescue of TCR rearrangements in SCID mice.

Psychological long-term effects of sterilization on anxiety and depression

Two-thousand cases (500 women and 500 men with sterilization; 500 women and 500 men without sterilization) in two counties and two cities in Sichuan, China, were investigated between 15 September 1992 and 30 April 1993. Information was obtained about their age, parity, marriage, contraceptives, social behavior, and present psychological characteristics. CES-D, SAS, and E.P.Q. scales were used to assess the depressive symptomatology, anxiety, and personality of the subjects. The results revealed that sterilization psychologically affected the depressive symptoms and anxiety under the neutral personality. In addition, depressive symptoms and anxiety were related to the subjects' age, educational level, income, operative doctors' attitudes to sterilization acceptors, and subjects' understanding of the sterilization.

The estimation of caries prevalence in small areas

National surveys have been effective for the estimation of caries prevalence in broad regions of the US. However, it is unclear if data from such surveys can be used to estimate prevalences in small areas such as states or counties because of small sample sizes within individual areas. In this study, we applied specialized statistical methods to the estimation of small-area caries measures using data from an oral health survey conducted in the State of Washington. Dental exams to assess caries and the presence of sealants and fluorosis were performed on 2921 third-grade students in 84 public schools selected by a stratified random sample from all 39 counties in the state. Statistical methods for small-area estimation were used to estimate disease and sealant utilization measures for each of the counties. Adjustment was made for covariates measured at the school level, including ethnicity and the proportion of children in the Federally sponsored school lunch program. Substantial variability in disease and sealant utilization between counties was found. The estimated number of decayed and filled surfaces per child was 4.7 (inter-county range, 2.4 to 7.4). The estimated number of surfaces of untreated decay was 1.2 per child overall (range, 0.5 to 3.1). Thirty percent of the children had restorative treatment needs (range, 15 to 54%). The prevalence of sealants on one or more permanent molars was estimated to be 34% (range, 19 to 46%). Overall, only 8% of children showed evidence of fluorosis. The results demonstrate the usefulness of small-area estimation methods for oral health surveys.

Protoplast culture and plant regeneration ofPinellia ternata

A study was undertaken to develop a protoplast regeneration system for pinellia. A yield of 19 29 x 10(5) protoplasts/g F. W. could be obtained from cell suspension cultures incubated in a digestion enzyme solution with 2% cellulase Onzuka R-10, 10% pectinase (Sigma), 0.01% pectolyase Y23. K8P and modified MS media were used to culture protoplasts in: a) liquid, b) liquid-solid double layer, or c) agarose embedded protoplast culture. The former two were conducive to colony formation from protoplast-derived cells. The frequency of cell division was about 8% after 3 days in culture. Gradually adding fresh medium of lower osmotic pressure into the medium for protoplast culture favored cell division. Calli (1-2 mm in diameter) formed after 30-40 days in culture. The calli transferred onto medium supplemented with KT (0.5 mg 1(-1)) and NAA (0.2 mg 1)(-1)) could regenerate plants after 40-50 days. Of 47 plantlets transplanted into plots, 29 flowered and were fertile.

Kashin-Beck disease: radiographic appearance in the hands and wrists

PURPOSE

To review the radiographic changes of Kashin-Beck disease (KBD) in the hands and wrists and provide a method for the diagnosis, staging, and evaluation of the effectiveness of prevention and treatment of this disease. To perform radiographic-histologic correlation to facilitate an early diagnosis of KBD.

MATERIALS AND METHODS

Hand and wrist radiographs in 300 children and five autopsy cases with KBD from an endemic area of China were analyzed for radiographic changes in the epiphyseal plates, bone ends, epiphyses, and carpal bones. Histopathologic sections of the hand and wrist from five autopsies were studied for comparison with corresponding radiographs.

RESULTS

The chief histopathologic changes in KBD included chondronecrosis, secondary repair, and remodeling processes. These histopathologic stages occurred in isolation or simultaneously in a patient. The radiographic and histopathologic changes within cartilage were related specifically to the different sites of cartilage.

CONCLUSION

Radiographic changes in the hands and wrists in patients with KBD result from atrophy and necrosis of chondrocytes and their subsequent repair processes in the deep layer of growing cartilage.

Detection and localization of the EaeA protein of attaching and effacing Escherichia coli O45 from pigs using a monoclonal antibody

The eaeA-positive, attaching and effacing (A/E) O45 E. coli isolates from pigs express an EaeA protein with an estimated molecular weight of 97 kDa. In the present study, a monoclonal antibody was raised against the EaeA protein of an A/E O45 isolate. Cross reaction of the monoclonal antibody with the EaeA protein of A/E strain of the rabbit (RDEC-1), but not with those of A/E strains of the human (E2348/69) and dog (89-4221), was observed. Reactions of the monoclonal antibody to A/E isolates in the O45 serogroup on the ELISA varied among isolates and appeared to be correlated with in vivo A/E capacity of these isolates. The EaeA protein of A/E O45 E. coli has an apparent isoelectric point of 8.4 and is exposed on the bacterial surface. The monoclonal antibody provides a useful tool for characterization of the EaeA protein of E. coli isolates from pigs.

[Tau protein in cerebrospinal fluid--a potential marker of Alzheimer's disease]

Levels of the microtubule-associated protein tau in cerebrospinal fluid (CSF-tau) were measured in samples from 87 patients with Alzheimer's disease (AD), 114 patients with non-AD neurological diseases, and 22 normal control subjects, by sandwich enzyme-linked immunosorbent assay. The CSF-tau level was significantly higher in patients with AD than in patients with non-AD neurological diseases and in controls. High CSF-tau levels were found irrespective of age at onset, apolipoprotein E genotype, clinical stage, and ethnic group. Western blots of AD CSF proteins revealed two to three immunoreactive bands with apparent molecular mass between 50 and 65 kDa, which is consistent with phosphorylated CSF-tau. These results suggest that CSF-tau reflects progressive accumulation of tau due to the progressive death of neurons in the AD brain. Assay of CSF-tau may prove to be a reliable diagnostic test for AD.

Ku86-deficient mice exhibit severe combined immunodeficiency and defective processing of V(D)J recombination intermediates

Ku is a heterodimeric DNA end binding complex composed of 70 and 86 kDa subunits. Here, we show that Ku86 is essential for normal V(D)J recombination in vivo, as Ku86-deficient mice are severely defective for formation of coding joints. Unlike severe combined immunodeficient (scid) mice, Ku86-deficient mice are also defective for signal joint formation. Both hairpin coding ends and blunt full-length signal ends accumulate. Contrary to expectation, Ku86 is evidently not required for protection of either type of V(D)J recombination intermediate. Instead, V(D)J recombination appears to be arrested after the cleavage step in Ku86-deficient mice. We suggest that Ku86 may be required to remodel or disassemble DNA-protein complexes containing broken ends, making them available for further processing and joining.

[Influence of processing on quercetin content in flos Sophorae immaturus]

The HPLC method was applied to determine the quercetin content in Flos Sophorae Immaturus. The technology for processing Flos Sophorae Immaturus was selected based on orthogonal experiment design. The result has shown that the better technology is to bake Flos Sophorae Immaturus for 11 min at the temperature of 180 degrees C.

p53 is required for both radiation-induced differentiation and rescue of V(D)J rearrangement in scid mouse thymocytes

The murine scid mutation affects both V(D)J recombination and DNA repair. This mutation has been mapped to the gene encoding the catalytic subunit of the DNA-dependent protein kinase (DNA-PK), which is activated by DNA damage in normal cells. In scid mice, antigen receptor gene rearrangements are initiated normally, but impaired joining of coding ends prevents assembly of functional receptor genes, resulting in arrest of B- and T-cell development. Others have shown that exposure of scid mice to genotoxic agents such as gamma-irradiation rescues rearrangement at the T-cell receptor (TCR) beta locus and promotes thymocyte development. Here we demonstrate that irradiation rescues rearrangements at multiple TCR loci, suggesting a general effect on the recombination mechanism. Furthermore, our data show that p53 is required for irradiation-mediated rescue of both thymocyte development and V(D)J recombination. We also find that thymocyte proliferation and differentiation in the absence of DNA damage do not require p53 and are not sufficient to rescue V(D)J recombination. These results suggest that exposure to ionizing radiation facilitates a partial bypass of the scid defect, perhaps by inducing p53-dependent DNA damage response pathways.

Genotypic and phenotypic characterization of Escherichia coli isolates from dogs manifesting attaching and effacing lesions

Thirteen Escherichia coli isolates from dogs manifesting attaching and effacing lesions were characterized genetically with respect to the presence of the following virulence determinants associated with human enteropathogenic E. coli (EPEC): eaeA, encoding the outer membrane protein intimin; eaeB, which is necessary for inducing signal transduction; bfpA, encoding the bundle-forming pilus; and the EAF (stands for EPEC adherence factor) plasmid. These isolates were also analyzed phenotypically with respect to adherence to mammalian cells in vivo and in vitro. Nine of these 13 isolates were found to be eaeA positive by PCR: four of these nine were eaeB positive. The 5' end, but not the 3' end, of the eaeA gene was amplified by PCR when primers derived from the eaeA gene of EPEC were used. Six and eight of these 13 isolates were found to be bfpA positive and EAF positive, respectively. The bfpA gene and EAF locus were found on high-molecular-weight plasmids, whereas the eaeA and eaeB genes were chromosomally located when present. Only one canine E. coli isolate, 4221, which was positive for eaeA, eaeB, bfpA, and EAF, adhered to HEp-2 cells in a localized manner and was positive in the fluorescence actin staining test. The nine eaeA-positive isolates adhered to the mucosal surface of piglet ileal explants and induced some microvillus effacement. However, when tested in experimentally inoculated gnotobiotic piglets, isolate 4221 did not induce attaching and effacing lesions at any level of the intestinal tract. Our results indicate that canine E. coli isolates associated with attaching and effacing lesions share some properties with human EPEC but form a heterogeneous group.

Ligand binding and phagocytosis by CD16 (Fc gamma receptor III) isoforms. Phagocytic signaling by associated zeta and gamma subunits in Chinese hamster ovary cells

CD16, the low affinity Fc gamma receptor III for IgG (Fc gamma RIII), exists as a polypeptide-anchored form (Fc gamma RIIIA or CD16A) in human natural killer cells and macrophages and as a glycosylphosphatidylinositol-anchored form (Fc gamma RIIIB or CD16B) in neutrophils. CD16A requires association of the gamma subunit of Fc epsilon RI or the zeta subunit of the TCR-CD3 complex for cell surface expression. The CD16B is polymorphic and the two alleles are termed NA1 and NA2. In this study, CD16A and the two alleles of CD16B have been expressed in Chinese hamster ovary (CHO) cells and their ligand binding and phagocytic properties analyzed. The two allelic forms of CD16B showed a similar affinity toward human IgG1. However, the NA1 allele showed approximately 2-fold higher affinity for the IgG3 than the NA2 allele. Although all three forms of CD16 efficiently bound rabbit IgG-coated erythrocytes (EA), only CD16A coexpressed with the gamma subunit phagocytosed EA. The phagocytosis mediated by CD16A expressed on CHO cells was independent of divalent cations but dependent on intact microfilaments. CHO cells expressing CD16A-gamma and CD16A-zeta chimeras also phagocytosed EA. The phagocytosis was specifically inhibited by tyrphostin-23, a tyrosine kinase inhibitor. In summary, our results demonstrate that glycosylphosphatidylinositol-anchored CD16B alleles differ from CD16A in their ability to mediate phagocytosis. Furthermore, since studies with other Fc gamma Rs have shown that CHO cells lack the phagocytic pathway mediated by the cytoplasmic domain of Fc gamma Rs, the phagocytosis of EA by CHO cells stably transfected with CD16A and CD16A-subunit chimera provides an ideal system to dissect the phagocytic signaling pathways mediated by these Fc gamma R-associated subunits.

Hairpin opening by single-strand-specific nucleases

DNA molecules with covalently sealed (hairpin) ends are probable intermediates in V(D)J recombination. According to current models hairpin ends are opened to produce short single-stranded extensions that are thought to be precursors of a particular type of extra nucleotides, termed P nucleotides, which are frequently present at recombination junctions. Nothing is known about the activities responsible for hairpin opening. We have used two single-strand-specific nucleases to explore the effects of loop sequence on the hairpin opening reaction. Here we show that a variety of hairpin ends are opened by P1 nuclease and mung bean nuclease (MBN) to leave short, 1-2 nt single-stranded extensions. Analysis of 22 different hairpin sequences demonstrates that the terminal 4 nt of the hairpin loop strongly influence the sites of cleavage. Correlation of the nuclease digestion patterns with structural (NMR) data for some of the hairpin loops studied here provides new insights into the structural features recognized by these enzymes.

[Establishment and clinical application of Chinese language clear degree]

This study was established the Chinese language of clear degree.The subjects of this study consisted of 50 patients with postoperative of cleft lip and palate,congenital velopharyngeal incompetence,and 30 control group were normal articulation of persons.The results of this study may be helpful for further clinic of the cleft lip and palate patients of speech therapeutics.

Changes of endothelin during cerebral vasospasm after experimental subarachnoid hemorrhage

Laser-Doppler flowmetry was employed in the observation of regional cortical blood flow (rCBF) after experimental subarachnoid hemorrhage (SAH) in anesthetized rats and the contents of endothelin (ET) in the cerebral-spinal fluid (CSF), plasma, hypothalamus, cerebral cortex, cerebellum and medulla were simultaneously measured. There was a biphasic change of rCBF after SAH. The contents of ET in CSF, plasma and hypothalamus rose prominently in the early stage after SAH, and the ET-increase in CSF and hypothalamus was earlier than that in plasma. The changes of ET contents in CSF correlated well with that in hypothalamus. Our results suggest that ET probably is an early important factor which induces cerebral vasospasm (CVS) after SAH. The increase of ET in CSF, which may originate from the hypothalamus, might play a more important role in the development of CVS after SAH than that in plasma.

Identification of EaeA protein in the outer membrane of attaching and effacing Escherichia coli O45 from pigs

We have previously reported that the production of attaching and effacing lesions by Escherichia coli O45 isolates from pigs is associated with the eaeA (E. coli attaching and effacing) gene. In the present study, expression of the EaeA protein, the eaeA gene product, among swine O45 E. coli isolates was examined. The majority (20/22) of attaching and effacing positive, eaeA+ E. coli O45 isolates, but none of ten attaching and effacing negative, eaeA- or eaeA+ isolates, expressed a 97-kDa outer membrane protein as revealed by sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) and Western blot analysis. Amino-terminal amino acid sequencing demonstrated a high homology between this 97-kDa protein of swine E. coli O45 and the EaeA protein (intimin) of human enteropathogenic E. coli and enterohemorrhagic E. coli. In addition, a serological relationship between the EaeA proteins of swine O45, rabbit (RDEC-1) and human (E2348/69) attaching and effacing E. coli strains was observed. Our results indicate an association between expression of the EaeA protein and attaching and effacing activity among O45 E. coli isolates. The data also suggest an antigenic relatedness of the EaeA proteins of swine, rabbit, and human attaching and effacing E. coli.

[Coriaria lactone on gamma-aminobutyric acid secretion and glutamic acid decarboxylase and its receptor binding in rat]

The effects of coriaria lactone (CL) on gamma-aminobutyric acid (GABA) secretion, glutamic acid decarboxylase (GAD) activity and glutamate (Glu) receptor binding were studied by using cultured neurons, P2 component and synaptic membranes from rat cerebral cortex. It was found that GABA secretion was depressed by CL, the depression rate was 8.3%, 10.6%, 14.5% at 12h 24h 48h respectively. GAD activity was depressed by CL in concentration of 0.15-150 mumol/L. The depression rate was 1.32%, 5.96%, 13.24%, 18.76% respectively. The Glu receptor binding capability was decreased by CL with obvious dose-effect relation in the extent of 2.8-350 mumol/L; the decrease rate was 4.4%, 12.7%, 15.2%, 19.5% respectively. The difference was significant as compared to control (P < 0.01).