Improved tolerance of maize plants to salt stress by arbuscular mycorrhiza is related to higher accumulation of soluble sugars in roots

The effect of colonization with the arbuscular mycorrhizal (AM) fungus Glomus mosseae (Nicol. & Gerd.) Gerdemann & Trappe on the growth and physiology of NaCl-stressed maize plants ( Zea mays L. cv. Yedan 13) was examined in the greenhouse. Maize plants were grown in sand with 0 or 100 mM NaCl and at two phosphorus (P) (0.05 and 0.1 mM) levels for 34 days, following 34 days of non-saline pre-treatment. Mycorrhizal plants maintained higher root and shoot dry weights. Concentrations of chlorophyll, P and soluble sugars were higher than in non-mycorrhizal plants under given NaCl and P levels. Sodium concentration in roots or shoots was similar in mycorrhizal and non-mycorrhizal plants. Mycorrhizal plants had higher electrolyte concentrations in roots and lower electrolyte leakage from roots than non-mycorrhizal plants under given NaCl and P levels. Although plants in the low P plus AM fungus treatment and those with high P minus AM fungus had similar P concentrations, the mycorrhizal plants still had higher dry weights, soluble sugars and electrolyte concentrations in roots. Similar relationships were observed regardless of the presence or absence of salt stress. Higher soluble sugars and electrolyte concentrations in mycorrhizal plants suggested a higher osmoregulating capacity of these plants. Alleviation of salt stress of a host plant by AM colonization appears not to be a specific effect. Furthermore, higher requirement for carbohydrates by AM fungi induces higher soluble sugar accumulation in host root tissues, which is independent of improvement in plant P status and enhances resistance to salt-induced osmotic stress in the mycorrhizal plant.

[The existing state and methodological development of measurement of lipid peroxide in biotic system]

The mechanisms of lipid peroxide (LPO) genesis in biotic system and the measurement of LPO were reviewed briefly. Emphasis was focused on the prevailing methods of LPO measurement, their advantage and disadvantage. Base on the discussion, the authors suggested that 2 or more than 2 methods for LPO measurement should be carried out simultaneously.

[Amplifying variable region gene of light chain of monoclonal antibody against human retinoblastoma by PCR]

OBJECTIVE

To acquire the variable region gene of light chain of monoclonal antibody against human retinoblastoma.

METHODS

Total RNA were extracted from hybridoma cells secreting specific monoclonal antibody(McAb) against human retinoblastoma(RB), then transcripted reversely into cDNA with random primers. The variable region of the light chain(VL) gene fragments were ampliflied using polymerase chain reaction(PCR) method. Agrose gel electrophoresis was confirmed.

RESULTS

1.5% agrose gel electrophoresis indicated that VL gene was about 340 base pairs.

CONCLUSION

The light chain variable region gene of the McAb against human RB was amplified successfully, which lays a good basis for construction of a recombinant antibody.

Diminished expression of S100A2, a putative tumor suppressor, at early stage of human lung carcinogenesis

To identify and understand early events in lung carcinogenesis, we used a cDNA array to screen for genes that are expressed differentially in normal human bronchial epithelial (NHBE) cells and a tumorigenic cell line (1170-I) derived from immortalized HBE cells after exposure to cigarette smoke condensate in vivo. Among these genes, we have identified the S100A2 gene, which encodes a nuclear calcium-binding protein, as being down-regulated in the 1170-I cells. Because this gene has been implicated as a tumor suppressor in breast cancer, we examined its potential role as a tumor suppressor in lung carcinogenesis. Levels of S100A2 transcript and protein, which were high in NHBE cells, decreased by up to 50% in immortalized HBE cells (BEAS-2B and 1799) and to low to nearly undetectable levels in transformed (1198) and tumorigenic (1170-I) HBE cells. Furthermore, S100A2 mRNA and protein were undetectable in 8 and expressed at a reduced level in 3 of 11 non-small cell lung cancer (NSCLC) cell lines. Positive immunohistochemical staining of S100A2 was detected in the majority (75-83%) of normal and hyperplastic lung tissues, whereas it was detected in <10% of metaplastic lung tissues, squamous cell carcinoma, and adenocarcinoma. Treatment of 1170-I HBE and NSCLC cells with 5-aza-2'-deoxycytidine resulted in partial restoration of S100A2 expression in seven of eight cell lines. Indeed, CpG methylation was detected in the promoter region of the S100A2 gene. Our results suggest that S100A2 expression is suppressed early during lung carcinogenesis, possibly by hypermethylation of its promoter, and that its loss may be a contributing factor in lung cancer development or a biomarker of early changes in this process.

[Study on the inclusion interaction of beta-cyclodextrin with phosphatidylcholine by UV spectra]

A kind of cyclic oligosaccharides, beta-cyclodextrin (beta-CD) was found to possess inclusion ability with phosphatidylcholine (PC). The inclusion compound of beta-CD with PC was studied by elemental analysis of solid inclusion compound and UV spectra of different mole ratios beta-CD/PC in H2O-MeOH solution. The results indicate that two moles of beta-CD include one mole PC to form inclusion compound by Van Der Waals force, hydrophobic interaction and hydrogen bounds, etc. The selective binding ability of beta-CD with PC has been discussed from the viewpoint of size/shape-fitting and geometry fitting between the host cavity and the gust molecular. The solubility in aqueous solution, the oxidation stability of PC was increased by inclusion with beta-CD.

Complete genomic sequence of 195 Kb of human DNA containing the gene GABRG2

GABA (gamma-aminobutyric acid), as the main inhibitory neurotransmitter in the brain, plays an essential role for the overall balance between neuronal excitation and inhibition by acting on GABAA receptors, which are ligand-gated chloride channels. Impaired GABAergic function contributes to certain forms of epilepsy, schizophrenia, Alzheimer's Disease, and other neurological disorders. In order to identify possible genetic features and to further study biological regulation of GABAA receptor genes whose promoter elements and sequence anomalies may contribute to epileptic disorders, as an initial step, we shot-gun sequenced a BAC clone, dj082c10 (195,909-bp in size), encompassing human gamma(2) subunit of GABAA receptor (GABRG2). It is, we believe, the first genomic sequence of the GABA receptor gamma subunit family. Four contigs were assembled from 2950 reads prior to gap in an average redundancy of eight folds over the entire region. The precision of the consensus sequence was predicted to be 99.999% after closing gaps and finishing weak regions. The nine exons of GABRG2 spans an 85-kb region that had 81 SINEs comprising 22.32%, and nine L1 elements comprising 3.40%, respectively. However, the density of L1 in the regions flanking GABRG2 gene (29.45% by 45 elements) is significantly higher than that within the gene. The length of GABRG2 introns varies in the range of 1.5 kb to 38.1 kb.

A multi-resolution wireless force sensing system based upon a passive SAW device

Referring to the technology of SAW wireless identification systems, a multi-resolution wireless force sensing system, including a passive time-delay SAW device and a specific interrogation unit, is introduced in this paper. Using an IDT, which connects with an antenna, as the force sensing element is a design to transduce the electromagnetic wave into surface acoustic wave and vice versa. Several reflectors are designed to get multi-resolution. Sample/hold devices are used instead of high-speed A/D converter to construct a low-cost interrogation system. Properties of the sensing system are theoretically predicted and experimentally verified.

Pathological, ultrastructural and immunohistochemical observations of adenoma of retinal pigment epithelium

PURPOSE

To Study the clinical, pathological, ultrastructural and immunohistchemical characters of adenoma of the retinal pigment epithelium in order to offer evidence to diagnose this tumor.

METHODS

Routine paraffin slices HE stain, histochemistry PAS and VG stain, transmission electron microscopy, and immunohistochemistry for S-100 and vimentin with LSAB method were used.

RESULTS

The tumor cells were oval and cuboidal in shape. Part of the tumor had a tubular arrangement. Around the sheets of tumors cells there was a large amount of uniform red stick-like substances. The above matter represented positive in PAS stain. Most of the above matter was yellow, while less of the matter showed red in VG stain. Transmission electron microscopy showed that there were tight junctions between tumor cells. Immunohistochemistry showed positive for S-100, negative for vimentin.

CONCLUSIONS

The ultrastructural and immunohistochemical characters of the adenoma of retinal pigment epithelium are consistent with the retinal pigment epithelium.

Force-frequency coefficient of symmetrical incomplete circular quartz crystal resonator

The changes in the resonance frequencies of the thickness-shear vibration of symmetrical incomplete circular AT-cut quartz crystal resonators (QXRs), which are used as sensing elements in digital force sensors or pressure transducers, by the application of diametrical forces are discussed by considering the piezoelectric effect and the anistropic characteristics of crystal plates. Two-dimensional motion equations for predicting the frequency changes are derived from three-dimensional piezoelectricity equations, and equations deduced by Janiaud for solving the stress distribution in crystal plates are used to calculate the force-frequency coefficients of incomplete circular resonators. The results show that the piezoelectric effect of crystal plates decreases the force-frequency coefficient of the azimuth angle 0 degrees by 7% as compared with no piezoelectricity assumption. The incomplete circular shape can be applied to a larger load than the circular disc because the flat regions of the incomplete shape provide a distributed load application without the problems of stress concentration of a point force inherent to a circular disc. The incomplete shape gives an increased force sensitivity when compared with the complete disc near azimuth angle 0 degrees. The theoretical curves agree well with Ratajski's experimental results.

[A simple and reliable spectrophotometric method for quantification of pyridine nucleotides in serum]

Pyridine nucleotides plays an important role in the maintenance of cellular homeostasis and its disturbance also involves in many perturbance of metabolism, so a simple and reliable assay for determination of oxidized and reduced pyridine nucleotides in serum would be significantly necessary in understanding the redox status of body. A novel modified method, which is based on Nisselbam and making use of a cycling enzymatic reaction and spectrophotometric assay to measure the pyridine nucleotides in serum, showed good results. The standard curve has fine linear relationship; the recovery of added standard samples is almost perfect. Twenty-seven samples from 27 normal subjects were examined by the method. The results were: NADPH 8.385 +/- 1.516 nmol/ml, NADP+ 3.624 +/- 0.985 nmol/ml, and NADPH/NADP+ 2.3612 +/- 0.8057; no significant difference in the variables was found between the male and female. This is a sensitive, simple, reliable and easy-practicing method for oxidized and reduced pyridine nucleotides assay.

Asynchronous synapse elimination in neonatal motor units: studies using GFP transgenic mice

In developing muscle, synapse elimination reduces the number of motor axons that innervate each postsynaptic cell. This loss of connections is thought to be a consequence of axon branch trimming. However, branch retraction has not been observed directly, and many questions remain, such as: do all motor axons retract branches, are eliminated branches withdrawn synchronously, and are withdrawing branches localized to particular regions? To address these questions, we used transgenic mice that express fluorescent proteins in small subsets of motor axons, providing a unique opportunity to reconstruct complete axonal arbors and identify all the postsynaptic targets. We found that, during early postnatal development, each motor axon loses terminal branches, but retracting branches withdraw asynchronously and without obvious spatial bias, suggesting that local interactions at each neuromuscular junction regulate synapse elimination.

Glial cell line-derived neurotrophic factor administration in postnatal life results in motor unit enlargement and continuous synaptic remodeling at the neuromuscular junction

Overexpression of glial cell line-derived neurotrophic factor (GDNF) in embryonic muscle fibers causes dramatic hyperinnervation of neuromuscular junctions. However, it is not known whether GDNF induces the extra innervation by regulation of axonal branching and/or synaptic maintenance. To address this issue, high levels of circulating GDNF were established by administering subcutaneous injections starting either at birth or later and continuing for up to 40 d. Treatment with exogenous GDNF beginning in the first week, but not later, increased the number of axons converging at neuromuscular junctions. The effect of GDNF on the branching pattern of individual motor axons was determined by reconstructing labeled axonal arbors from transgenic mice expressing yellow fluorescent protein in subsets of motor neurons. Whereas, at postnatal day 8 (P8) individual axons in control animals branched to sporadically innervate junctions within circumscribed regions of the muscle, motor units from GDNF injected animals had significantly more axonal branches and exhibited a high degree of localized arborization such that adjacent muscle fibers were often innervated by the same axon. Administration beginning at P0 and continuing through P40 prolonged multiple innervation of most fibers throughout the period of injection. Between P30 and P40 there was no net change in multiple innervation, although there was evidence of retraction bulbs, suggesting that axon extension and retraction were in equilibrium. We conclude that GDNF has a developmentally regulated effect on presynaptic branching and that sustained administration of GDNF induces a state of continuous synaptic remodeling.

The novel gene locus for agenesis of permanent teeth (He-Zhao deficiency) maps to chromosome 10q11.2

He-Zhao deficiency has been recently characterized with a distinct form of agenesis of permanent teeth that is different from other previously reported disorders of tooth agenesis. This inherited abnormality suggests that some gene(s) associated with the development of permanent teeth may mutate. In this study, we map the gene locus to chromosome 10q11.2. The DNA pooling method combined with two-point and multi-point linkage analysis has been successfully applied. The maximum LOD (Zmax) scores for two-point and multi-point analyses are 13.29 (on marker D10S196) at recombination fraction (theta) = 0 and 18.09 (between markers D10S1772 and D10S1766), respectively. Haplotype analysis confined the locus within an interval of 5.5 cM flanked by markers D10S604 and D10S568. This study has demonstrated a novel gene locus responsible for He-Zhao deficiency and provides a good likelihood for the discovery of one of the genes determining permanent tooth formation and development.

Mutations in IHH, encoding Indian hedgehog, cause brachydactyly type A-1

Brachydactyly type A-1 (BDA-1; MIM 112500) is characterized by shortening or missing of the middle phalanges (Fig. 1a). It was first identified by Farabee in 1903 (ref. 2), is the first recorded example of a human anomaly with Mendelian autosomal-dominant inheritance and, as such, is cited in most genetic and biological textbooks. Here we show that mutations in IHH, which encodes Indian hedgehog, cause BDA-1. We have identified three heterozygous missense mutations in the region encoding the amino-terminal signaling domain in all affected members of three large, unrelated families. The three mutant amino acids, which are conserved across all vertebrates and invertebrates studied so far, are predicted to be adjacent on the surface of IHH.

Identification of SNPs in human gamma aminobutyric acid A receptor gamma2 gene

Gamma aminobutyric acid (GABA) is a major inhibitory neurotransmitter. Because of its importance and diverse functions, studies of single nucleotide polymorphisms in the GABA receptor genes are of great significance, which may produce useful molecular markers for genetic analysis of neurological disease, and possibly lead to the discovery of pathogenic mutations. We identified eleven SNPs in the entire exon regions, immediate intron regions and promoter region of human GABA receptor gamma2 gene by direct sequencing. In this discovery, 2 non-synonymous cSNPs and 1 splicing variant are found.

[Effect of VAM fungi on phosphatase activity in maize rhizosphere]

The effect of VAM fungi on phosphatase activity in maize rhizosphere was examined by pot culture experiment, in which, three-compartment-pots were used, the central compartment being separated from the outer two by a nylon net with 30 microns mesh. Plants were harvested 70 days after planting. Soil acid and alkaline phosphatase were measured at different distances from root surface. The results showed that VAM increased the activities of soil acid and alkaline phosphatase in the rhizosphere. It was found that different phosphorous sources had different effects on phosphatase activity.

Rowed to recovery: the use of phonological and orthographic information in reading Chinese and English

To examine how readers of Chinese and English take advantage of orthographic and phonological features in reading, the authors investigated the effects of spelling errors on reading text in Chinese and English using the error disruption paradigm of M. Daneman and E. Reingold (1993). Skilled readers in China and the United States read passages in their native language that contained occasional spelling errors. Results showed that under some circumstances very early phonological activation can be identified in English, but no evidence for early phonology was found in Chinese. In both languages, homophone errors showed a benefit in measures of later processing, suggesting that phonology helps readers recover from the disruptive effects of errors. These results suggest that skilled readers take advantage of the special features of particular orthographies but that these orthographic effects may be most pronounced in the early stages of lexical access.

[Study on the dynamic changes of retinoblastoma gene of SO-Rb50 cell line]

PURPOSE

To study the dynamic changes of Retinoblastoma Gene of SO-Rb50 cell line.

METHODS

1) Southern blot hybridization was used to analyse the tumor cell DNA of 327th passage of SO-Rb50 cell line. 2) A promoter and 27 exons of Rb gene were screened exon-by-exon by using PCR-SSCP at 415th and 713th passages of SO-Rb50 cell line. 3) Three cell cloning strains named as MC2, MC3 and MC4 were isolated by single cell cloning technique from the SO-Rb50-775, and mutation of Rb gene were also screened exon-by-exon by using PCR-SSCP-HA in MC2-11, MC3-11, MC4-11 and MC3-138.

RESULTS

The 3.5 Kb, 2.9 Kb and 1.0 Kb bands were deleted in the DNA of SO-Rb50-327 tumor cells, showing the deletion of Rb gene in SO-Rb50 cell line. Exon23 of 451th passage cells decreased one band; but exon 25 of 713th passage cells decreased two bands, indicating that exon 25 had new mutation. PCR-SSCP-HA analysis of exon24 showed that MC4-11 and MC3-138 had abnormal bands, but MC2-11 and MC3-11 weren't found mutation of Rb gene. This result suggested that new mutation occurred to exon24 of MC3 during a long-term culture in vitro.

CONCLUSION

Retinoblastoma gene mutation of SO-Rb50 cell line had dynamic changes during a long-term culture.

Gephyrin-independent clustering of postsynaptic GABA(A) receptor subtypes

Gephyrin has been shown to be essential for the synaptic localization of the inhibitory glycine receptor and major GABA(A) receptor (GABA(A)R) subtypes. However, in retina certain GABA(A)R subunits are found at synaptic sites in the absence of gephyrin. Here, we quantitatively analyzed GABA(A)R alpha1, alpha2, alpha3, alpha5, beta2/3, and gamma2 subunit immunoreactivities in spinal cord sections derived from wild-type and gephyrin-deficient (geph -/-) mice. The punctate staining of GABA(A)R alpha1 and alpha5 subunits was unaltered in geph -/- mice, whereas the numbers of alpha2-, alpha3-, beta2/3-, and gamma2-subunit-immunoreactive synaptic sites were significantly or even strikingly reduced in the mutant animals. Immunostaining with an antibody specific for the vesicular inhibitory amino acid transporter revealed that the number of inhibitory presynaptic terminals is unaltered upon gephyrin deficiency. These data show that in addition to gephyrin other clustering proteins must exist that mediate the synaptic localization of selected GABA(A)R subtypes.

Audio-visual enhancement of speech in noise

A key problem for telecommunication or human-machine communication systems concerns speech enhancement in noise. In this domain, a certain number of techniques exist, all of them based on an acoustic-only approach--that is, the processing of the audio corrupted signal using audio information (from the corrupted signal only or additive audio information). In this paper, an audio-visual approach to the problem is considered, since it has been demonstrated in several studies that viewing the speaker's face improves message intelligibility, especially in noisy environments. A speech enhancement prototype system that takes advantage of visual inputs is developed. A filtering process approach is proposed that uses enhancement filters estimated with the help of lip shape information. The estimation process is based on linear regression or simple neural networks using a training corpus. A set of experiments assessed by Gaussian classification and perceptual tests demonstrates that it is indeed possible to enhance simple stimuli (vowel-plosive-vowel sequences) embedded in white Gaussian noise.

[A study on the resistance of Staphylococcus aureus and the mechanisms of its resistance to fluoroquinolone]

OBJECTIVE

To investigate the resistance of Staphylococcus aureus(SA) and the mechanisms of its resistance to fluoroquinolones (FQ).

METHODS

The susceptibility of SA (200 strains) to 12 antibiotics was detected by disc diffusion, The minimal inhibitory concentrations (MICs) of 52 strains to three FQ were determined by agar dilution method. 52 strains resistant to ciprofloxacin (MIC> or =4 mg/L) were studied for the presence of point mutations in the gyrA gene and grlA gene by polymerase chain reaction-restriction fragment length polymorphisms (PCR-RFLP) method and for the expression of norA gene by reserpine reverse test respectively.

RESULTS

34% of the strains were resistant to oxacillin(methicillin resistant Staphylococcus aureus, MRSA) and other antimicrobials as well, but no vancomycin resistant strain was found. The resistance rate of MRSA to ciprofloxacin was 79.4% and cross-resistance existed. It was found that 42 strains (80.8%) had a mutation at gyrA codon 84 (TCA-->TTA or GCA). Mutations at grlA codon 80 (TCC-->TAC or TTC) and codon 84 (GAA-->AAA)were observed in 10 (19.2%) and 14 strains(26.9%) respectively.Strains containing mutations in gyrA or both gyrA and grlA gene showed a higher level of ciprofloxacin resistance than those with alternation in grlA gene but with wild type gyrA or non-gyrA mutants (P < 0.01). Decreased MICs to ciprofloxacin, norfloxacin and levofloxacin in reserpine reverse test indicated the presence of norA phenotype.

CONCLUSIONS

It is clear that emergence of resistant SA strains will continue to be a problem, especially in MRSA which was resistant to most of the antibiotics. Fluoroquinolones are not the choice for MRSA now. The resistance to fluoroquinolones in clinical isolates of SA are due to the mutations of the gyrA and grlA gene encoding the target enzyme of fluoroquinolones and cell membrane resistance. Mutations of grlA gene may differ in different districts.

Experiment study of effect of perfluorohexyloctane on corneal endothelial cells

PURPOSE

To investigate the effect of Perfluorohexyloctane (F6H8) on corneal endothelial cells(CEC) of rabbit eyes.

METHODS

Fifteen New Zealand white rabbits were divided into two groups: experimental group(F6H8) and control group(BSS). All rabbits underwent anterior chamber injection of 0.15 ml F6H8 or BSS. Slit-lamp biomicroscopy and corneal endothelium photography were performed pre-operatively and postoperatively. Histopathological examination and Transmission electron microscopy(TEM) were done after the rabbits were sacrificed.

RESULTS

All the corneas were clear. Since 4 weeks after operation, the endothelial cells were markedly irregular in size and shape and the number of endothelial cells was markedly decreased. Multilayered retrocorneal membranes(RCM) grew gradually 2 weeks after surgery. Vacuolar degeneration was seen in some endothelial cells. Nuclear degeneration and edema of plasma were seen in TEM.

CONCLUSION

Corneal endothelial cell degenerated after contacting with F6H8 for 2-4 weeks. As a silicone solvent, it should be removed completely after injection. We don't recommend it to be used as a new intraocular temponade.

Histopathological study of trabeculum after excimer laser trabeculectomy ab interno

PURPOSE

To study the clinical manifestations and histopathologic changes of trabeculum after excimer laser trabeculectomy ab interno (ELT), and to investigate the mechanisms of ELT in reducing intraocular pressure.

METHODS

ELT was performed on ten rabbit eyes and postoperative responses were documented. Corneoscleral tissue samples were harvested consecutively each week until the 5th postoperative week and these samples were examined under light and electrical microscopy.

RESULTS

Mild stimulation signs were present postoperatively in nine of ten eyes, but no serious complications were experienced. Obvious inflammation was observed in one rabbit eye as a result of iris damage during the surgical manipulations. Local fractures on the trabecular meshwork and openings into Schlemm's canal were detected in all tissue samples under light microscope. Mitochondria were found to be turgescent and dilated like vacuoles and endoplasmic reticula were found to be dilated under electrical microscope in the early postoperative period. Later, all trabecular cells returned normal and no fibroblast cells were ever detected.

CONCLUSIONS

Permanent openings through trabecular meshwork into the inner wall of Schlemm's canal can be created with ELT. The outflow resistance of aqueous humor can be reduced with these openings and intraocular pressure can be controlled thereafter.

Is ApoE gene a risk factor for vascular dementia in Han Chinese?

We have compared the apolipoprotein E (ApoE) genotypes of Han Chinese with late-onset sporadic Alzheimer's disease (LOAD, n=191), and vascular dementia (VaD, n=124) to controls (n=218) with a similar age distribution. The frequency of ApoE epsilon4 allele in the LOAD group was significantly higher than that in the control group (30.1% versus 10.55%, p<10-7). The risk rate of LOAD was 3.5 times higher for carriers with at least one ApoE epsilon4 allele than for non-epsilon4 bearing controls. ApoE epsilon4 allele was also significantly associated with vascular dementia (OR=1.75, p=0.026). Our findings support previous reports of a positive association between ApoE epsilon4 and both Alzheimer's disease and vascular dementia in Han Chinese.

Association between angiotensin-converting enzyme gene and late onset Alzheimer's disease in Han chinese

There is now overwhelming evidence that the varepsilon4 allele of apolipoprotein (APOE) gene is a major risk factor for late-onset Alzheimer's disease (AD). However, the APOE locus only accounts for a proportion of the overall genetic risk for AD. The angiotensin-converting enzyme (ACE) is widely expressed in the brain and may have a role in AD. Recently an insertion/deletion (I/D) DNA polymorphism at the intron 16 of ACE gene has been found associated with late-onset AD, but the results are not consistent. We have examined ACE gene in a cohort of Han Chinese AD cases and controls. We have found the ACE-I allele was enriched in our cases compared to controls (odds ratio (OR)=2.09, P=0.0043). The phenomenon was restricted to cases presenting with AD after the age of 70 years (P<0.0005), and was independent of APOE genotype. We conclude that ACE genotype is a risk factor for late onset AD.

[Application of cellulose acetate membrane with the technique of impression cytology combined with immunohistochemical staining for detection of dry eye]

PURPOSE

To evaluate the conjunctival cells by impression cytology with cellulose acetate membrane.

METHODS

The expression of the TGF-beta 1 in conjunctival epithelium of 24 patients with dry eye were studied by impression cytology combined with immunohistochemical staining and observed by microscope.

RESULT

The cellulose acetate membrane is very transparent under the microscope. Cell's membrane by TGF-beta 1 staining is clear, cytoplasm brown and nuclei blue.

CONCLUSION

The method of impression cytology with cellulose acetate membrane is simple and has no injury to the ocular surface. Combined with immunohistochemistry staining, it is suitable to observe the conjunctival cells by this technique which has an important value for the examination of the ocular surface disease.

[Expression and significance of MMP2 and type IV collagen in gastric cancer]

OBJECTIVE

To evaluate the relationship between the expression of MMP(2), type IV collagen, and invasion and metastasis of gastric cancer.

METHODS

The expression of MMP(2) and Type IV collagen was observed by using immunohistochemistry technique.

RESULTS

The MMP(2) expression clearly appeared in the poor-differentiated adenocarcinoma and tubular adenocarcinoma (85.7%, 77.7%). Type IV collagen destruction was observed simultaneously. MMP(2) was highly expressed in patients with cancer embolus in blood vessel and lymphatic vessel or with lymph node metastasis (83.3%, 86.7%).

CONCLUSIONS

The high expression of MMP(2) was significantly associated with infiltration and metastasis of gastric cancer. The extracellular matrix, especially type IV collagen was destroyed in the cases of high expression of MMP(2). These results suggest that monitoring the level of MMP(2) expression may be an index for evaluation of prognosis.

Imaging neuronal subsets in transgenic mice expressing multiple spectral variants of GFP

We generated transgenic mice in which red, green, yellow, or cyan fluorescent proteins (together termed XFPs) were selectively expressed in neurons. All four XFPs labeled neurons in their entirety, including axons, nerve terminals, dendrites, and dendritic spines. Remarkably, each of 25 independently generated transgenic lines expressed XFP in a unique pattern, even though all incorporated identical regulatory elements (from the thyl gene). For example, all retinal ganglion cells or many cortical neurons were XFP positive in some lines, whereas only a few ganglion cells or only layer 5 cortical pyramids were labeled in others. In some lines, intense labeling of small neuronal subsets provided a Golgi-like vital stain. In double transgenic mice expressing two different XFPs, it was possible to differentially label 3 neuronal subsets in a single animal.

[The role of membrane-type 1 matrix metalloproteinase in the invasion and metastasis of hepatocellular carcinoma]

OBJECTIVE

To study the role of membrane-type 1 matrix metalloproteinase (MT(1)-MMP) in the invasion and metastasis of hepatocellular carcinoma (HCC), and find a method to judge the invasion and metastasis of HCC through MT(1)-MMP.

METHODS

RT-PCR was used to study the expression of MT(1)-MMP mRNA in the HCC and in HCC nude mice model with higher metastasis potential (LCI-D20) and lower metastasis potential (LCI-35), and statistical methods were used to analyse the association between the expression of MT(1)-MMP mRNA and the pathological indexes of HCC.

RESULTS

MT(1)-MMP mRNA was expressed by all the normal liver tissue (1.12 +/- 0.73), HCC (3.51 +/- 0.97), surrounding liver parenchyma (1.19 +/- 0.57), tumor embolus, and HCC nude mice model with LCI-D20, LCI-D35. The overexpression of MT(1)-MMP mRNA in HCC, embolus, LCI-D20 was related to the invasion and metastasis of HCC. The expression of MT(1)-MMP mRNA in HCC being higher than that in surrounding liver parenchyma was an important index to judge the invasion and metastasis of the HCC.

CONCLUSION

MT(1)-MMP is related to the invasion and metastasis of HCC. The expression of MT(1)-MMP mRNA in HCC being higher than that in surrounding liver parenchyma could be acted as an important index to judge the invasion and metastasis of HCC.

[Effect of AM fungi on water and nutrition status of corn plants under salt stress]

Under NaCl stress, the dry matter production of corn plants inoculated with or without arbuscular mycorrhizal (AM) fungus (Glomus mosseae) was decreased, but the decrement for non-mycorrhizal plants was 10% higher than that for mycorrhizal ones. Under salt stress condition, the dry weights of root system and aboveground part of mycorrhizal corn and its leaf water potential were higher than those of non-mycorrhizal corn, while the proline content of mycorrhizal corn was less than that of non-mycorrhizal corn. The contribution of hypha to P uptake of plants decreased from 45.3% to 42.6%, while the effect of AM fungi on plant growth increased from 30.9% to 63.5% under salt stress condition. The above-mentioned results indicated that the mechanism that AM fungi enhance the salt-resistance of corn is related with the improvements of water and P nutrition conditions. Meanwhile, it was found whether under salt stress or not, the ratio of P accumulation of root system to aboveground part of mycorrhizal corn was higher than that of non-mycorrhizal corn, indicating that the infection of AM fungi changed the P distribution pattern in plant bodies, which is beneficial to increase the salt-resistance of plants.

Autoimmunity to gephyrin in Stiff-Man syndrome

Stiff-Man syndrome (SMS) is a rare disease of the central nervous system (CNS) characterized by chronic rigidity, spasms, and autoimmunity directed against synaptic antigens, most often the GABA-synthesizing enzyme glutamic acid decarboxylase (GAD). In a subset of cases, SMS has an autoimmune paraneoplastic origin. We report here the identification of high-titer autoantibodies directed against gephyrin in a patient with clinical features of SMS and mediastinal cancer. Gephyrin is a cytosolic protein selectively concentrated at the postsynaptic membrane of inhibitory synapses, where it is associated with GABA(A) and glycine receptors. Our findings provide new evidence for a close link between autoimmunity directed against components of inhibitory synapses and neurological conditions characterized by chronic rigidity and spasms.

Roles for ephrins in positionally selective synaptogenesis between motor neurons and muscle fibers

Motor axons form topographic maps on muscles: rostral motor pools innervate rostral muscles, and rostral portions of motor pools innervate rostral fibers within their targets. Here, we implicate A subfamily ephrins in this topographic mapping. First, developing muscles express all five of the ephrin-A genes. Second, rostrally and caudally derived motor axons differ in sensitivity to outgrowth inhibition by ephrin-A5. Third, the topographic map of motor axons on the gluteus muscle is degraded in transgenic mice that overexpress ephrin-A5 in muscles. Fourth, topographic mapping is impaired in muscles of mutant mice lacking ephrin-A2 plus ephrin-A5. Thus, ephrins mediate or modulate positionally selective synapse formation. In addition, the rostrocaudal position of at least one motor pool is altered in ephrin-A5 mutant mice, indicating that ephrins affect nerve-muscle matching by intraspinal as well as intramuscular mechanisms.

Colchicine protects mice from the lethal effect of an agonistic anti-Fas antibody

The aim of this study was to determine whether colchicine, which has been reported to protect against various hepatotoxic insults, influences the susceptibility of mice to the agonistic anti-Fas antibody, Jo2. All mice that were pretreated with colchicine (2 mg/kg) survived the lethal challenge of intraperitoneal administration of 10 microg of Jo2, whereas all control mice pretreated with gamma-lumicolchicine succumbed to the challenge. Twelve micrograms of Jo2 killed less than half of colchicine-pretreated mice and its lethal effects were delayed relative to control mice, which all died within 8 hours. Other microtubule-disrupting agents such as Taxol, vinblastine, and nocodazole also improved the survival of mice treated with the lethal dose of Jo2. Histologic examination showed that colchicine protected against Jo2-induced fulminant liver injury, and TUNEL assay demonstrated that colchicine protected against massive apoptosis of hepatocytes. Hepatocytes isolated from colchicine-pretreated mice exhibited decreased susceptibility to Jo2-induced apoptosis. In addition, colchicine pretreatment reduced surface expression of Fas and decreased Jo2- and TNF-alpha-induced apoptosis of cultured hepatocytes in the presence of actinomycin D, but did not affect the susceptibility of cultured sinusoidal endothelial cells to Jo2-induced apoptosis. Remarkably, Fas and TNF receptor-1 mRNA and intracellular protein levels increased after colchicine treatment, indicating that colchicine protects against death ligand-induced apoptosis in the liver by decreasing death-receptor targeting to the cell surface.

Congenital absence of permanent teeth in a six-generation Chinese kindred

We report on rare, heritable, permanent tooth agenesis in a large Chinese kindred. The congenital absence of permanent teeth except the first and second accessory teeth was observed in 52 individuals through six successive generations in the kindred comprising 328 members. Clinical assessments were carried out, and inheritance mode and spousal influence of the anomaly on their offspring were analyzed. Consequently, the anomaly was transmitted in an autosomal dominant fashion with incomplete penetrance (P = 0.88), and no significant clinical manifestations other than the oligodontia were found. A geographical or environmental effect on the affected individuals was obviously eliminated, because any who are related to the kindred but live under the same conditions are fully healthy. The disorder we describe, therefore, differs from any previously reported oligodontia/anodontia syndromes. The oligodontia ranged from a few teeth to the whole set of teeth, and usually occurred at a period from age 7 or 8 years, the time when primary teeth are normally replaced by permanent teeth, to the forties. Roentgenography of the affected persons indicated that only the first and/or second accessory teeth with tooth buds developed as permanent teeth. In fact, the diphyodontic germination sometimes occurred in the oral cavity of the affected individuals.

[CT virtual endoscopy: A study of the capability to display the structures and abnormalities in nasal cavity]

To evaluate displaying ability of virtual endoscopy and its clinical application in comparison with fiberoptic nasal endoscopy, 11 patients (22 nasal cavities) were examined by virtual endoscopy after axial spiral CT scanning was performed. Virtual endoscopy was performed by Explorer software package in a computer workstation. 9 patients (18 nasal cavities) underwent fiberoptic endoscopy. Results showed virtual endoscopy could clearly demonstrate the anatomical structures in nasal cavity, septal deviation, nasal meatus narrowing and obstruction, turbinate hyperplasia, and pathological masses larger than 3 mm in diameter. However, the "false adhesions" may appear with virtual endoscopy. The main limitation of virtual endoscopy was inability to evaluate mucosa and lack of histological diagnosis. Virtual endoscopy is a new and non-invasive method for demonstrating anatomical structures and diseases in nasal cavity. Its displaying ability is comparable with fiberoptic nasal endoscopy. It can serve as a supplementary method of fiberoptic nasal endoscopy.

[Observation of the endothelial healing in rabbit corneal alkali wounds by alizarin red S-trypan blue staining method]

PURPOSE

To study the healing of the corneal endothelial cells in rabbit corneal alkali wounds.

METHODS

26 New Zealand white rabbits were used. A alkali wound was created with a round filter paper, 8 mm in diameter, which was soaked in 0.5 N NaOH for 5 seconds and was placed centrally on the cornea for 60 seconds. The rabbits were killed in 20 minutes; 1, 2, 6, 12 h; 1, 2, 3, 5, 7, 10, 14, 30 days after injury. The corneal endothelium was examined in the light microscope using a lizarin red S-trypan blue staining method.

RESULTS

Twenty minutes after the wound, the corneal endothelial cells were destroyed. 72 hours following the wound, the endothelial cells surrounding the burns became larger, irregular and started to migrate onto the denuded descemet's membrane. The endothelial cells covered the burn with the spindle-shaped cells 7 days after wound.

CONCLUSION

The endothelial damage is healed by the division and migration of remaining endothelial cells at the margin of the wound, which has some characters of fibroblast.

[Virus interaction in HBV and HCV super infection]

OBJECTIVE

To investigate virus interaction in HBV and HCV superinfection.

METHODS

The changes of serum markers of 30 patients with HBV and HCV superinfetion were observed. Meanwhile, mutation of HBV precore region at nt 1,896 and the amount of TNF alpha and IL-6 in sera were also investigated.

RESULTS

Compared with HBV or HCV single infection, positive rates of HBeAg, HBV DNA and HCV RNA in superinfectim were lower, positive rates of anti-HBe was higher, the average titers of HBsAg, anti-HBcIgG and anti-HCV were significantly lower, too. In some patients, HBsAg were seronegatively convested. Occurrence rate of HBV precore region mutation at nt1896 and levels of TNF alpha and IL-6 in sera were higher in super infection than those in single infection.

CONCLUSION

Interference existed between HBV and HCV superinfection, conversion from HBeAg to anti-HBe was not only due to the suppression by HCV but also to the mutation of HBV precore region, and HCV may be a reason causing HBV precore region mutation through increasing the pressure of the body's immunosystem.

Rapid diagnosis of chlamydial conjunctivitis in laboratory

PURPOSE

To evaluate the techniques of rapid and accurate diagnosis of chlamydial conjunctivitis.

METHODS

Total 100 conjunctivitis patients (200 eyes) were studied. Twenty-two of 100 cases were diagnosed as chlamydial conjunctivitis. The infected epithelia were scraped from tarsal conjunctiva of both eyes and stained separately with Giemsa (100 cases) and immunofluorescence (anti-chlamydial antigen monoclonal antibody, 100 cases).

RESULT

In immunofluorescent staining, 38 cases were seen positive staining and 62 were negative. In Giemsa staining, 29 were positive, and 71 were negative. In 22 cases with clinical diagnosis of chlamydial conjunctivitis, 13 cases were confirmed, and 9 were excluded by immunofluorescent staining. Technically, immunofluorescent and Giemsa stain takes 45 and 40 minutes, respectively.

CONCLUSION

Comparing to Giemsa stain, 38 of 100 scraping specimens were positive (38%) by immunofluorescent staining, 29 of 100 per cent were positive by Giemsa staining. Giemsa staining takes 5 minutes less than immunofluorescent staining (40 versus 45 minutes), however, the positive staining in immunofluorescent staining is much easier to be recognized than Giemsa staining.

[Analysis of 2-acrylamido-2-methyl propane sulfonic acid by thin layer chromatography]

A method for the analysis of 2-acrylamido-2-methyl propane sulfonic acid(AMPS) by TLC is described. The plate was Silica GF254. We selected benzene/methanol as developing agent from several developing systems and fixed the best ratio: V(benzene):V(methanol) = 2:1. The experiment indicated that the Rf value of AMPS was 0.36 while that of AM(acrylamide), the main impurity in crude AMPS sample, was 0.64. The minimum detectable limit of AMPS was 5 micrograms and the developing time was about 25 minutes. Compared with ether/methanol and chloroform/methanol, benzene/methanol system has the advantages of more easily controlling its ratio, better repeatability and much rapid developing rate. This method may be helpful in the control of AMPS in quality.

Differentiation of embryonic stem cells into neurons and retina-like structure in nude mice

PURPOSE

To investigate the intraocular growth and biological characteristics of mice embryonic stem cells in nude mice.

METHODS

Murine embryonic stem cells (D3 cell line) were cultured and maintained in an undifferentiated state in vitro, then transplanted into the anterior chamber of nude mice. Mophological and immunohistochemical examinations were implemented.

RESULTS

Two to three days after transplantation, yellow-white floating granules, sheets and masses were seen inside the anterior chamber and vitreous cavity, and enlarged gradually. 14-20 days later, the mice were executed. Morphological examination showed that there were undifferentiated cells and some round or polygonal differentiated cells in anterior chamber and vitreous cavity. The morphology of these differentiated cells were similar to that of the retina. The cells were highly positive in NSE staining.

CONCLUSION

The transplanted embryonic stem cells could grow in the eyes of nude mice with tendency to differentiate into neurons and retina-like structure.

Modification of isolation and culture of human retinal pigment epithelial cells

PURPOSE

To modify the isolation of human retinal pigment epithelial (RPE) cells and to increase the purification and production of cultured RPE cells.

METHODS

The human eyecups were fixed on a rubber holder. After digestion by trypsin, RPE cells were collected, then cultured and identified by morphology, immunohistochemistry and electron microscopy.

RESULTS

The cultured RPE cells grew actively in the early stage with transparent nucleus and abundant melanin particles in cytoplasm. These cells were positive in DOPA oxidase reaction and in anti-pancytokeratin antibody staining. Cellular microvilli and tight junctions could be seen through transmission electron microscopy.

CONCLUSION

We developed a rubber holder to fix the eyecup. Using this holder, more and purer cultured RPE cells can be obtained. These cultured RPE cells are similar to those in vivo in morphology and immunohistochemical staining.