[Study on the relationship between primary Sjögren syndrome and HLA-DRbeta gene]

The pathogenesis of primary Sjögren syndrome (PSS) is unclear yet. In order to investigate the role of genetic factor playing in the mechanism of this disorder, we studied the HLA-DR beta gene distributed in 70 patients with PSS and 136 normal subjects by using PCR-SSP technique. The results showed that the gene frequences of HLA-DR3, DR52 and DR2 in patients with PSS were significantly higher than that in normal controls. However, the gene frequencies of HLA-DR5 and DR9 in PSS patients were lower than that in the control group. There were the same genetic phenomena in the siblings of two PSS patients' families. We also found the relationship between HLA-DR52 and the anti-antibodies of SSA or SSB. Our results concluded that the genetic factor is involved in the pathogenesis of primary Sjögren syndrome.

Uncoupled phosphorylation and activation in bacterial chemotaxis. The 2.3 A structure of an aspartate to lysine mutant at position 13 of CheY

An aspartate to lysine mutation at position 13 of the chemotaxis regulatory protein CheY causes a constitutive tumbly phenotype when expressed at high copy number in vivo even though the mutant protein is not phosphorylatable. These properties suggest that the D13K mutant adopts the active, signaling conformation of CheY independent of phosphorylation, so knowledge of its structure could explain the activation mechanism of CheY. The x-ray crystallographic structure of the CheY D13K mutant has been solved and refined at 2.3 A resolution to an R-factor of 14.3%. The mutant molecule shows no significant differences in backbone conformation when compared with the wild-type, Mg2+-free structure, but there are localized changes within the active site. The side chain of lysine 13 blocks access to the active site, whereas its epsilon-amino group has no bonding interactions with other groups in the region. Also in the active site, the bond between lysine 109 and aspartate 57 is weakened, and the solvent structure is perturbed. Although the D13K mutant has the inactive conformation in the crystalline form, rearrangements in the active site appear to weaken the overall structure of that region, potentially creating a metastable state of the molecule. If a conformational change is required for signaling by CheY D13K, then it most likely proceeds dynamically, in solution.

[Clinical observation of trabeculectomy without conjunctival incision]

OBJECTIVE

To reduce the formation of cicatrization of filtering bleb and elevate the successful rate of filtration surgery of glaucoma.

METHODS

Trabeculectomy without conjunctival incision was performed on 37 eyes of 35 patients with glaucoma.

RESULTS

They were followed up for 3-16 months. The rate of control of the intraocular pressure was 94.6%, and the operative complications were few and mild.

CONCLUSION

The results show that the trabeculectomy without conjunctival incision is a safe and effective anti-glaucoma technique.

[Liquid chromatographic separation of pepsinogens]

In this work, we reported a method for the purification of pepsinogens from human gastric mucosa with high pressure gel filtration chromatography (HPLC) and medium pressure anion exchange chromatography (MPLC). First, the two fractions of Pg1 and mixture of PGI and PGII were separated from pepsinogens with HPLC on a Bio-Sil SEC-125 column within 50min. Then the mixture of fractions of PGI and PGII was further separated with MPLC on a Bio-Scale Q2 column within 30min.

[An analysis of maicaodi by high performance liquid chromatography]

Maicaodi has recently been developed and produced by the pesticide plant of Nanjing Agricultural University. The quantitative analysis of the effective components--tribenuron methyl and R (-)napropamide in wettable powder of Maicaode, by a high performance liquid chromatographic method was carried out with a Lichrosorb Si-60 20cm x 0.46cm i.d. column, mobile phase of petroleum ether/isopropanol/methanol/acetonitrile/chloroform mixture solvent (80:5:5:5:5) and internal standard of diisooctyl phthalate. The sample was detected by ultraviolet absorption at 254 nm. The retention times of tribenuron methyl and R (-)napropamide were 10-11min and 6-7min respectively. The coefficient of variation of this analysis was 0.34% with a recovery of 99.51%-100.32%. The coefficient of linear correlation was 0.9999.

Mutant human protein disulfide isomerase assists protein folding in a chaperone-like fashion

Human protein disulfide isomerase with an extra 10 amino acid residues of AEITRIDPAM at the N-terminal was expressed in E. coli as a soluble protein comprising 20% of total cell proteins, and was purified to near homogeneity through one step of DEAE-Sephacel chromatography. The mutant enzyme, which had the same CD spectrum and comparable disulfide isomerase and thiol-protein oxidoreductase activities with that of the wild type human and bovine protein disulfide isomerases, also showed chaperone-like activity in stimulating the refolding of proteins containing no disulfide bond. The overall yield of the active product is about 20 mg 1-1 culture.

Estrogen receptor-negative breast cancer cells transfected with estrogen receptor exhibit decreased tumour progression and sensitivity to growth inhibition by estrogen

Breast cancer containing estrogen receptors (ER) are responsive to antiestrogen treatment and have a better prognosis compared with ER-negative tumors. The loss of estrogen receptors appears to be associated with a progression to less-differentiated cells. We transfected the human ER into the ER-negative breast cancer cell line MDA-MB-231 cells. We found that expression of adequate ER is strong associated with the ability of human breast cancer cell growth inhibition and progression. Compared with nontransfected or mock-transfected cells, ER-transfected cells exhibited growth slower, forming smaller colonies in soft agar and growth inhibited by estrogen and tamoxifen. Therefore reactivation or transfection of the estrogen receptor gene can be considered as therapeutic approaches to hormone-independent breast cancer.

[In situ DNA labeling apoptosis in breast cancer as related to prognosis]

OBJECTIVE

This study was undertaken to determine the expression of apoptosis in breast cancer and to evaluate it's significance as a prognostic marker.

METHODS

A series of 91 invasive breast cancer was analysed for the expression of apoptosis by using the 3-end-labeling method of DNA in tissue sections. The apoptotic indexes were the percentages of apoptotic cells among tumor cells.

RESULTS

The end-labeling method allowed a precise evaluation of the expression of apoptosis. Apoptosis occurred in 91.2% of breast cancer patients, and apoptotic indexes were divided into two groups, 0-0.21 and 0.28-0.62. Low apoptotic index was related to axillary lymph node metastasis (P < 0.01). In survival analysis, higher apoptotic index was related to disease free survival (P = 0.0095) and overall survival (P = 0.0348) in the entire cohort. Cox's analysis showed apoptotic index had no independent prognostic value.

CONCLUSION

The apoptosis was a spontaneous phenomenon in breast cancer tissue, and the expression was different from each other. Further analysis was needed to clarify the relationship between apoptosis and prognosis, especially the response to adjuvent therapy.

On the molecular basis and regulation of cellular capacitative calcium entry: roles for Trp proteins

During the last 2 years, our laboratory has worked on the elucidation of the molecular basis of capacitative calcium entry (CCE) into cells. Specifically, we tested the hypothesis that CCE channels are formed of subunits encoded in genes related to the Drosophila trp gene. The first step in this pursuit was to search for mammalian trp genes. We found not one but six mammalian genes and cloned several of their cDNAs, some in their full length. As assayed in mammalian cells, overexpression of some mammalian Trps increases CCE, while expression of partial trp cDNAs in antisense orientation can interfere with endogenous CCE. These findings provided a firm connection between CCE and mammalian Trps. This article reviews the known forms of CCE and highlights unanswered questions in our understanding of intracellular Ca2+ homeostasis and the physiological roles of CCE.

Inhibition of spontaneous apoptosis in human breast cancer

Breast tumorigenesis proceeds through an accumulation of specific genetic alteration. Breast malignant transformation is dependent on not only the rate of cell production but also on apoptosis, a genetically programed process of autonomous cell death. We investigated whether breast tumorigenesis involved an altered susceptibility to apoptosis and proliferation by examining normal breast epithelium and breast cancer samples. We found there is a great inhibition of spontaneous apoptosis in breast cancer cells compared with normal breast epithelium. The inhibition of apoptosis in breast cancer may contribute to neoplastic transformation.

Inhibition of apoptosis in human breast cancer as related to prognosis

Breast tumorigenesis proceeds through an accumulation of specific genetic alterations. Breast malignant transformation is dependent on not only the rate of cell production but also on apoptosis, a genetically programmed process of autonomous cell death. It may also be important in the overall growth dynamics of neoplastic cells, both in the natural history and when they are exposed to chemotherapy or radiation. This study evaluated the biological and clinical implications of spontaneous apoptosis in human breast cancer. Apoptosis was measured in 8 normal breast tissues and 91 human breast cancer samples by Apoptag end labeling method. We found there was a significant inhibition of spontaneous apoptosis in breast cancer cells compared with normal breast epithelium. In 91 breast cancer samples, apoptotic index (AI) was strongly associated with lymph node metastasis; Low apoptosis of tumor cells was more frequent in poorly differentiated tumors and has a poor outcome.

Reverse use dependence of Kv4.2 blockade by 4-aminopyridine

4-Aminopyridine (4AP) can block various K channels with different state dependences; block occurs in the activated state or in the closed state. The use of K channel clones to study the mechanism and structural determinants responsible for the state dependence of 4AP actions has been hampered by the fact that, for all the K channel clones examined so far, 4AP binding and unbinding occur mainly in the activated state. We report here that 4AP binding to a fast inactivating K channel encoded by Kv4.2 in Xenopus oocytes occurred exclusively in the closed state. The binding rate was slow and independent of membrane voltage in the range from -80 to -120 mV. The binding rate was linearly related to 4AP concentration, yielding apparent binding and unbinding rate constants of 0.012 mM-1 s-1 and 0.062 s-1, respectively. 4AP dissociation from Kv4.2 occurred in two processes, a slow process in the closed state (in a voltage range from -70 to -40 mV) and a fast process in the activated state, which suggested that the closure of the activation gate of Kv4.2 did not prevent the entry or exit of 4AP molecules but slowed these processes. 4AP slowed the rate of Kv4.2 decay during depolarization, consistent with the notion that channel inactivation occurred only after 4AP dissociation. Inactivating Kv4.2 channels prevented 4AP binding. Therefore, 4AP binding and Kv4.2 inactivation were mutually exclusive. This, in conjunction with the observation that 4AP blocked Kv4.2 channels from the intracellular side of the cell membrane, suggests that the 4AP binding site is on the cytoplasmic surface of the Kv4.2 channel at, or adjacent to, the domains involved in channel inactivation. The distinct features of 4AP actions on the time course of transient outward current in human ventricular myocytes suggest that Kv4.2-like subunits are important in the formation of these channels in human heart.

Activation of locus coeruleus enhances the responses of olfactory bulb mitral cells to weak olfactory nerve input

The main olfactory bulb (MOB) receives a dense projection from the pontine nucleus locus coeruleus (LC), the largest collection of norepinephrine (NE)-containing cells in the brain. LC is the sole source of NE innervation of MOB. Previous studies of the actions of exogenously applied NE on mitral cells, the principal output neurons of MOB, are contradictory. The effect of synaptically released NE on mitral cell activity is not known, nor is the influence of NE on responses of mitral cells to olfactory nerve inputs. The goal of the present study was to assess the influence of LC activation on spontaneous and olfactory nerve-evoked activity of mitral cells. In methoxyflurane-anesthetized rats, intracoerulear microinfusions of acetyicholine (ACh) (200 mM; 90-120 nl) evoked a four- to fivefold increase in LC neuronal discharge, and a transient EEG desynchronization and decrease in mitral cell discharge. LC activation increased excitatory responses of mitral cells evoked by weak (i.e., perithreshold) nasal epithelium shocks (1.0 Hz) in 17/18 cells (mean Increase = 67%). The discharge rate of mitral cells at the time that epithelium-evoked responses were increased did not differ significantly from pre-LC activation baseline values. Thus, changes in mitral baseline activity do not account for the increased response to epithelium stimulation. These findings suggest that increased activity in LC-NE projections to MOB may enhance detection of relatively weak odors.

Synchronization of two passively mode-locked erbium-doped fiber lasers by an acousto-optic modulator and grating scheme

We synchronize two passively mode-locked erbium-doped fiber lasers by adjusting only the cavity length to correct both the repetition rate and the phase. The interlaser jitter is less than 6 ps (1.3 times the pulse width) and is extracted from the cross correlation of the two lasers. The lock can be maintained for extended periods of time. These results are obtained by use of a novel acousto-optic-modulator-grating scheme, which provides an equivalent of 300 microm in cavity length tuning with a bandwidth of 10 kHz. These parameters are 30 times the length and 10 times the bandwidth of a typical piezoelectric transducer.

Localization of the human RGR opsin gene to chromosome 10q23

The human RGR gene encodes an opsin protein (retinal G protein-coupled receptor), which is expressed in Müller cells and the retinal pigment epithelium and is thought to play a role in the visual process. To investigate a possible linkage of the RGR gene to retinal dystrophies, the locus of the gene was mapped on human metaphase chromosomes. Genomic and cDNA fragments of the human RGR gene were used as probes for fluorescence in situ hybridization. Analysis of the fluorescence signals on high-resolution banded chromosomes showed that the RGR gene is localized to human chromosome 10q23. This result now provides for the rapid analysis of this gene with respect to inherited diseases of the retina.

trp, a novel mammalian gene family essential for agonist-activated capacitative Ca2+ entry

SUMMARY

Capacitative calcium entry (CCE) describes CA2+ influx into cells that replenishes CA2+ stores emptied through the action of IP3 and other agents. It is an essential component of cellular responses to many hormones and growth factors. The molecular basis of this form of Ca2+ entry is complex and may involve more than one type of channel. Studies on visual signal transduction in Drosophila led to the hypothesis that a protein encoded in trp may be a component of CCE channels. We reported the existence of six trp-related genes in the mouse genome. Expression in L cells of small portions of these genes in antisense orientation suppressed CCE. Expression in COS cells of two full-length cDNAs encoding human trp homologs, Htrp1 and Htrp3, increased CCE. This identifies mammalian gene products that participate in CCE. We propose that trp homologs are subunits of CCE channels, not unlike those of classical voltage-gated ion channels.

Cloning, sequencing and expression of the CAMP factor gene of Streptococcus uberis

The gene coding for the CAMP factor from a strain of Streptococcus uberis (ATCC 9927) was cloned in Escherichia coli. Chromosomal DNA from Streptococcus uberis was used to construct a gene library in plasmid pTZ18R and six CAMP-reaction positive clones were obtained from a total of 10,000 transformants. One clone, pJLD21, was subcloned and the CAMP factor gene was located in a 3.2 kb BamHI fragment. The nucleotide sequence of Streptococcus uberis CAMP factor gene was determined and the deduced amino acid sequence is highly homologous to the corresponding Streptococcus agalactiae protein. Immunoblot analysis revealed that the recombinant strain pJLD21 expressed a protein with a molecular weight of 28 000. Antibodies raised against purified Streptococcus uberis CAMP factor cross-reacted with Streptococcus agalactiae protein B.

Laser demonstration of diode-laser-pumped neodymium-doped strontium fluorovanadate

The laser properties of diode-laser-pumped neodymium-doped strontium fluorovanadate samples cut perpendicular to the x(a) and y axes have been investigated. A slope efficiency of 36% for the 1.065-µm laser line and a lasing threshold of 6.8 mW have been measured for the x(a)-axis-cut crystal. Data are also presented for the laser's performance as a function of crystal temperature and for the variation of the central peak wavelength with the incident pump power.

[CT scanning and treatment of intracranial tuberculoma]

OBJECTIVE

To evaluate the value of CT scanning and the efficacy of anti-tuberculosis short-course chemotherapy in intracranial tuberculoma patients.

METHOD

The CT manifestations and the clinical characteristics of 55 intracranial tuberculoma patients were analysed.

RESULTS

44 out of 55 patients were cured. Among them, 40 patients' lesions were entirely resolved, while other 11 cases, clinical symptoms were subsided and still under treatment. In the contrast enhancing CT scanning, plate shaped or ring-form shadows were shown surrounding the lesions of tuberculoma. The characteristical features were more special for diagnosis and the positive rate was higher than that of other laboratory findings. The incidence of intracranial tuberculoma was found to be higher in children and juvenile patients who lived in rural areas.

CONCLUSIONS

Enhancing CT scanning is valuable for diagnosis of intracranial tuberculoma. The anti-tuberculosis short-course chemotherapy used nowadays with which almost all the intracranial tuberculoma patients can be cured and only few of them need surgical operation.

Mice deficient for the amyloid precursor protein gene

To understand the in vivo function of the amyloid precursor protein (APP) we generated an APP null mutation in mice by homologous recombination in embryonic stem (ES) cells. We show here that homozygous APP deficient mice were produced at expected frequencies. Neither APP mRNA nor protein could be detected in these animals. Yet the homozygous APP mutant mice are fertile and do not show overt abnormalities at up to 12 weeks of age. Neuroanatomical studies of the brain did not reveal significant differences in the knockout mice as compared to the wild-type controls. These results argue against an essential function of APP in mouse embryonic and early neuronal development.

Inhibition of rabies virus infection by an oligodeoxynucleotide complementary to rabies virus genomic RNA

To develop antirabies virus-specific agents, eight oligodeoxynucleotides (ODN) complementary to either rabies virus genomic RNA (negative polarity) or rabies virus transcripts (mRNA) were synthesized and tested for their activity to inhibit rabies virus infection in cell cultures. It was found that the ODN RH+1 complementary to rabies virus genomic RNA blocked almost completely rabies virus infection at concentrations as low as 2 microM, whereas ODN complementary to viral transcripts did poorly even at concentrations as high as 20 microM. The antigenomic ODN also has the ability to inhibit cell-to-cell spread of rabies virus, which is an indicator for protection of rabies virus infection in vivo. These results indicate that ODN complementary to rabies virus genomic RNA have strong ability to inhibit rabies virus infection in cell culture and may have the potential to be used for therapy in clinical rabies.