Upregulation of drug sensitivity of multidrug-resistant SGC7901/VCR human gastric cancer cells by bax gene transduction

OBJECTIVE

To investigate the role of bax in a vincristine (VCR)-induced multidrug-resistant (MDR) human gastric cancer cell line, SGC7901/VCR, in which the Bax protein expression level was significantly lower compared with that in parent cells.

METHODS

A bax eukaryotic expression vector was constructed and transfected into SGC7901/VCR cells by lipofectamine, and resistant clones were selected by G418. Western blotting detected Bax expression in transfectants. Tetrazolium blue (MTT) assay evaluated the differences in drug sensitivity and cell cycle changes of transfectants were analyzed using flowcytometry (FCM).

RESULTS

The bax eukaryotic expression vector was constructed and transfected into SGC7901/VCR cells. Through G418 selection, resistant clones were obtained. Western blotting demonstrated that the expression of Bax protein was markedly increased in bax transduced cells. These cells were more sensitive to adriamycin (ADR) and VCR than mock vector transducted cells. Moreover, bax transfection enhanced ADR-induced apoptosis and VCR-induced G2/M phase arrest of SGC7901/VCR cells.

CONCLUSION

Bax was involved in the MDR of SGC7901/VCR cells.

Homer proteins regulate coupling of group I metabotropic glutamate receptors to N-type calcium and M-type potassium channels

Group I metabotropic glutamate receptors (mGluR1 and 5) couple to intracellular calcium pools by a family of proteins, termed Homer, that cross-link the receptor to inositol trisphosphate receptors. mGluRs also couple to membrane ion channels via G-proteins. The role of Homer proteins in channel modulation was investigated by expressing mGluRs and various forms of Homer in rat superior cervical ganglion (SCG) sympathetic neurons by intranuclear cDNA injection. Expression of cross-linking-capable forms of Homer (Homer 1b, 1c, 2, and 3, termed long forms) occluded group I mGluR-mediated N-type calcium and M-type potassium current modulation. This effect was specific for group I mGluRs. mGluR2 (group II)-mediated inhibition of N-channels was unaltered. Long forms of Homer decreased modulation of N- and M-type currents but did not selectively block distinct G-protein pathways. Short forms of Homer, which cannot self-multimerize (Homer 1a and a Homer 2 C-terminal deletion), did not alter mGluR-ion channel coupling. When coexpressed with long forms of Homer, short forms restored the mGluR1a-mediated calcium current modulation in an apparent dose-dependent manner. Homer 2b induced cell surface clusters of mGluR5 in SCG neurons. Conversely, a uniform distribution was observed when mGluR5 was expressed alone or with Homer short forms. These studies indicate that long and short forms of Homer compete for binding to mGluRs and regulate their coupling to ion channels. In vivo, the immediate early Homer 1a is anticipated to enhance ion channel modulation and to disrupt coupling to releasable intracellular calcium pools. Thus, Homer may regulate the magnitude and predominate signaling output of group I mGluRs.

[Simultaneous detection and differentiation of O1 classical E1 Tor, O139 and nonO1 nonO139 strains of Vibrio cholerae by using multiplex PCR]

OBJECTIVE

To explore the rapid and sensitive procedures for detection and differentiation of O1 classical(CVC), El Tor(EVC), O139 and nonO1 nonO139 strains of Vibrio cholerae.

METHODS

Four pairs of primers were designed from toxin sub-unit A(ctxA) gene, O139 special gene, Haemolytic subunit A gene and Toxin coregulated pilus subunit A gene. Multiplex PCR was established to simultaneously detect those four genes. CVC, EVC, O139 and nonO1 nonO139 strains can be detected and differentiated by the size and numbers of Multiplex PCR bands via electrophoresis. Two pairs of inside primers were designed from ctx A and O139 special gene, and a nested PCR was established.

RESULTS

60 EVC, 2 CVC, 15 O139 and 30 nonO1 nonO139 strains isolated from patients were detected with multiplex PCR and nested PCR, and the results were correct. 10 EVC and 15 O139 strains isolated from environment samples were detected, and the results meant that EVC were toxic and O139 were non-toxic. The sensitivity of multiplex PCR reached 100 cfu, and that of nested PCR reached 1-10 cfu.

CONCLUSION

This method is rapid, specific, and sensitive, and possess great value for practical application.

Polymorphism of human platelet alloantigen in Chinese patients with acute myocardial infarction and acute ischemic stroke

OBJECTIVE

To investigate the gene frequencies of 5 major human platelet alloantiqens (HPA 1-5) in Chinese population and to assess if polymorphism of HPA was associated with Chinese acute myocardial infarction (AMI) and acute ischemic stroke (AIS).

METHODS

HPA 1-5 genotyping was performed by PCR using allele specific primers and restriction enzyme digestion based on PCR products in 95 AMI cases, 188 AIS cases and 270 normal controls. Gene frequency distribution was tested by Hardy-Weinberg equilibrium and comparison of HPA gene frequencies between the patient and control groups by chi 2 test.

RESULTS

The gene frequencies of HPA 1-5 were the followings: HPA1a: 91%; 1b: 9%; HPA 2a: 94%; 2b: 6%; HPA 3a: 83%; 3b: 17%; HPA 4a: 98%; 4b: 2%; HPA5a: 97%; 5b: 3%. We found there were no significant differences in HPA 1-5 gene frequencies between AMI patients and normal controls. In AIS patients group HPA-2a allele frequency was significant higher than in controls, but this allele gene frequency in two groups (0.94 and 0.99) was very close and too many subjects in these two groups were overlapped. Otherwise no differences was found in other 4 HPA systems between cases and controls.

CONCLUSION

Polymorphism of HPA were not inherited risky factors and not associated with chinese arterial thrombotic diseases such as AMI and AIS.

[Cerebrospinal fluid cytology of acute viral encephalitis and meningitis]

Using cytological examination, the cerebrospinal fluid(CSF) of 98 patients with acute viral encephalitis was investigated. We found 81.4% activated lymphocytes and 5.8% plasma cells in CSF in the first week. In addition, various lymphoid features were disclosed in association: mitosis, binucleation, abnormal nuclear lobulation, Russell bodies, and morula in plasma cells. These cellular changes specifically existed in CSF of acute viral encephalitis, which were helpful to distinguish the said disease from tuberculous melitis and multiple sclerosis.

Homer: a link between neural activity and glutamate receptor function

The proteins of the Homer family bind to proline-rich sequences in group I metabotropic glutamate receptors, inositol trisphosphate receptors, ryanodine receptors, and Shank family proteins. Homer proteins also self associate and function as adaptors to couple interacting proteins. Recent observations indicate a role for Homer complexes in signal transduction, synaptogenesis and receptor trafficking.

Dissecting the nucleotide binding properties of Escherichia coli 6-hydroxymethyl-7,8-dihydropterin pyrophosphokinase with fluorescent 3'(2)'-o-anthraniloyladenosine 5'-triphosphate

6-hydroxymethyl-7,8-dihydropterin pyrophosphokinase (HPPK) catalyzes the transfer of pyrophosphate from ATP to 6-hydroxymethyl-7, 8-dihydropterin, the first reaction in the folate biosynthetic pathway. Like other enzymes in the folate pathway, HPPK is an ideal target for development of antimicrobial agents because the enzyme is essential for microorganisms but is absent from humans and animals. Using 3'(2')-o-anthraniloyladenosine 5'-triphosphate as a fluorescent probe, a fluorometric competitive binding assay has been developed for measuring the dissociation constants of various compounds that bind to the ATP site of HPPK. The fluorometric assay has been used to determine the nucleotide specificity and dissect the energetics of the binding of MgATP. The order of affinity of various nucleoside triphosphates for HPPK is MgATP>MgGTP>MgITP>MgXTP approximately MgUTP approximately MgCTP. The affinity of MgATP for HPPK (K(d)=2.6+/-0.06 microM) is 260-fold higher than that of MgGTP and more than 1000-fold higher than those of the other nucleoside triphosphates, indicating that HPPK is highly specific with respect to the base moiety of the nucleotide. The affinity of ATP for HPPK in the presence of Mg(2+) is 15 times that in the absence of Mg(2+), indicating that the metal ion is important for the binding of the nucleotide. Removal of the gamma-phosphate from MgATP reduces its affinity for HPPK by a factor of approximately 21. The affinity of AMP for HPPK is about one third that of ADP and almost the same as that of adenosine. The result suggests that among the three phosphoryl groups of MgATP, the gamma-phosphoryl group is most critical for binding to HPPK and the alpha-phosphoryl group contributes little to the binding of the nucleotide. The affinity of MgATP is 18 times that of MgdATP, indicating that the 2'-hydroxyl group of MgATP is also important for binding. van't Hoff analysis suggests that binding of MgATP is mainly driven by enthalpy at 25 degrees C and the entropy of binding is also in favor of the formation of the HPPK.MgATP complex.

Microencapsulation and characterization of tramadol-resin complexes

Tramadol was complexed with a sulfonic acid cation-exchange resin by a column method. Microencapsulation of tramadol-resin complexes (TRC) was carried out by the spray-drying method. The effect of ethylcellulose (EC) of various viscosities, different solvent systems and addition of plasticizers on microencapsulation were investigated. The morphology of microcapsules was characterized by scanning electron microscopy (SEM). Selected solvents having similar toxicity levels while various physico-chemical properties resulted in greatly different microcapsules. Regular particle morphology and sustained-release behavior were obtained when dichloromethane or ethyl acetate was used as the solvent system, whereas ethanol produced a substantial number of coalesced microcapsules and acetone produced apparently surface-smooth monomicrocapsules with faster release behavior. Three kinds of plasticizers affected the drug release rate similarly. On the addition of plasticizer (DEP), the drug release rate from the microcapsule obtained from low viscosity-grade EC reduced, while there was no alternation for those obtained from middle viscosity-grade EC. Compared to EC with a viscosity of 100 cP, which produced multi-microcapsules and released 60% of the drug within 1 h, microcapsules prepared with 10, 20 and 45 cP viscosity-grade EC showed slower drug release and regular and smooth morphology.

Structure of the Homer EVH1 domain-peptide complex reveals a new twist in polyproline recognition

Homer EVH1 (Ena/VASP Homology 1) domains interact with proline-rich motifs in the cytoplasmic regions of group 1 metabotropic glutamate receptors (mGluRs), inositol-1,4,5-trisphosphate receptors (IP3Rs), and Shank proteins. We have determined the crystal structure of the Homer EVH1 domain complexed with a peptide from mGluR (TPPSPF). In contrast to other EVH1 domains, the bound mGluR ligand assumes an unusual conformation in which the side chains of the Ser-Pro tandem are oriented away from the Homer surface, and the Phe forms a unique contact. This unusual binding mode rationalizes conserved features of both Homer and Homer ligands that are not shared by other EVH1 domains. Site-directed mutagenesis confirms the importance of specific Homer residues for ligand binding. These results establish a molecular basis for understanding the biological properties of Homer-ligand complexes.

[Detecting the level of Actinobacillus actinomycetemcomitans leukotoxin]

OBJECTIVE

To detect the level of Actinobacillus actinomycetemcomitans (Aa) leukotoxin and distinguish the highly and the minimally toxic strains.

METHODS

The polymerase chain reaction (PCR) assay was used to detect the difference of the nucleotide sequence of Aa leukotoxic promoter. 68 Aa isolates were examined, including 17 serotype b, 42 serotype c and 9 serotype a strains. The positive control strains were the highly toxic strain JP2 and 7 minimally toxic strains such as ATCC43717; the negative control strains were 12 other species of reference strains.

RESULTS

The PCR fragments of JP2 was about 492 bp and that of the other Aa reference strains and 68 clinical isolates were 1,022 bp. PCR products not found in 12 other species.

CONCLUSION

All of the 68 clinical isolates were minimally toxic strains.

Limitation of nitric oxide production: cells from lymph node and spleen exhibit distinct difference in nitric oxide production

Many types of cells in the immune system have been found to produce nitric oxide (NO), which performs multiplex functions. However, in myelin basic protein peptide 68-86 (MBP 68-86)-induced experimental autoimmune encephalomyelitis (EAE) in Lewis rats, we found that elevated NO production was generated from spleen cells (SC), not from lymph node cells (LNC). LNC expressed lower NO synthase 2 (NOS2) and produced lower levels of NO than SC upon MBP 68-86 stimulation. Expression of B7-1(CD80) and B7-2(CD86) molecules was much lower on LNC than on SC. Blocking of B7-1 or B7-2 ligation resulted in reduced NO production by SC. Unlike SC, LNC were resistant to interferon-gamma- or lipopolysaccharide-induced NO production. NO derived from SC suppressed cell proliferation and induced apoptosis in vitro. Addition of N(omega)-nitrol-L-arginine methylester (L-NAME) into cell cultures promoted cell expansion and reduced apoptosis. These results indicate that NO production originates from SC, but not from LNC. Low expression of co-stimulatory molecules and NOS2 of LNC limits NO induction. The high levels of NO derived from SC are involved in the self-limiting mechanisms of autoimmune responses by inhibiting cell expansion and promoting cell apoptosis.

[A study of polysaccharide-protein complex and glycosyls in the tissue surrounding titanium implant of rabbit]

OBJECTIVE

The absorption of the polysaccharide-protein complex to the implant surface may be the first reaction between the implant and the surrounding tissue. So we observed the distribution and the relative amount of the polysaccharide-protein complex and glycosyls in order to find out the possible functions and changing rules of these substances.

METHODS

12 rabbits were selected according to the age, sex, weight, and health conditions. Bilateral mandibular premolar teeth of rabbits were extracted under abdomen anesthesia (2% glutababituratic acid), then 12 titanium implants were placed into the teeth extraction holes of one side and left the other side to be the control one. All of the implants were required to be placed 2 mm below the alveolar crest, and tissue closure was achieved with mattress and interrupted single sutures. Antibiotic injections were given to the rabbits in the following 3 days. The animals were sacrificed at the end of 1 week, 4 weeks and 24 weeks. Tissue blocks (4 mm x 4 mm x 4 mm) containing the titanium implants and the control ones were removed, then fixed with 10% formaldehyde for 2 weeks, and decalcified with 10% EDTA (pH7.0) for 8 weeks. Carefully removed the titanium implants, the tissue blocks were embedded into the paraffin wax, then the sections were obtained and stained using following methods. 1. Alcian Blue Method: Alcian blue (pH 2.5) staining displayed the acidic proteoglycans; Alcian blue (pH 1.0) displayed the proteoglycans containing sulfonyl; Alcian blue/periodix acid-shiff staining demonstrated the acidic and neutral proteoglycans respectively. Alcian blue-MgCl2 with different ionic concentration identified the different kinds of proteoglycans. 2. Lectin Method: 5 kinds of lectins were used to locate 5 kinds of glycosyls. 2.5 micrograms/ml ConA located the glucose; 10 micrograms/ml PNA located the galactose; 10 micrograms/ml WGA located the N-acetylglucosamine; 25 micrograms/ml PHA-E located N-acetylgalactosamine, 10 micrograms/ml WPL loacted the fucose.

RESULTS

High level of proteoglycans and glycosyls were observed in the peri-implant connective tissue during all phases of the experiment. It was also observed that polysaccharide-protein complex and glycosyls reached a high level in new bone matrix as well as osteoblasts.

CONCLUSION

Polysaccharide-protein complex and glycosyls do play an important role in the implant-bone attachment, and titanium compatibility and may be closely related to the bone metabolic activity.

[The role of heat shock protein 70 and its autoantibody in experimental autoimmune inner ear disease]

OBJECTIVE

To examine the effect of antigen stimulation on induction of the heat shock protein 70(HSP70) in the guinea pig cochlea and to explore the role of HSP70 and its autoantibody in the pathogenesis and diagnosis of autoimmunize inner ear disease (AIED).

METHODS

To establish the animal model of AIED, homologous crude inner ear antigen was used to immunize the guinea pig. The expression of HSP70 was detected by immunocytochemistry and the relative staining densities were quantified with a light microscope image analysis system. The autoantibodies against HSP71 in the plasma of animals were tested by Western blot using purified recombinant human HSP71 as antigen.

RESULTS

HSP70 presented in the normal guinea pig cochlea at a lower level. After immunological challenge, the levels of HSP70 immunoreactivity in the immunized animals were significantly increased as compared with control animals. Optical densities of cochleae of immunized animals were significantly greater than those of animals in the control group (P < 0.01). Most of the immunized animals had developed autoantibodies against HSP71. The incidence of autoantibody in the experimental group was significantly different (P < 0.01) from the control group.

CONCLUSION

Antigen stimulation could lead to an increase in the synthesis of HSP70 in the guinea pig cochlea. The detection of autoantibody against HSP71 might have significance in the diagnosis of AIED.

Phase-1 studies of malariotherapy for HIV infecton

OBJECTIVE

To determine whether malariotherapy (an old therapy for treatment of neurosyphilis) improves some clinical and laboratory parameters of HIV-positive patients without iatrogenic complications.

METHODS

Total 8 asymptomatic HIV-1 positive subjects whose CD4 cell counts were over 250 x 10(6) cells/L were selected for the phase-1 studies of malariotherapy and were intravenously injected Plasmodia vivax to induce artificial malaria. Malaria was terminated with chloroquine after 10 to approximately 20 malarial fever episodes. Cell-bound CD4 levels were measured by APAAP (a solid-phase enzyme essay) and levels of neopterin (NPT), beta-2-microglobulin (B2M), soluble tumor necrosis factor receptor-2 (sTNF-RII), interleukin-2 (IL-2) and HIV P24 antigen were measured by ELISA. Patients were followed up to 24 to approximately 30 months.

RESULTS

CD4 levels increased in 5, NPT decreased in 7 of 8 patients; IL-2 increased in 5 of 6 patients after malariotherapy. The total trends of B2M and sTNF-RII basically remained stable. HIV P24 antigen remained undetectable in 6, remained detectably low level in 1 and experienced increase in 1 of 8 patients after malariotherapy. No any severe complications occurred in all 8 patients.

CONCLUSIONS

The results indicate that malariotherapy basically is safe for HIV infection and it seems that the therapy improves some immunological parameters of HIV patients.

[Investigation on interaction between Streptococcus sanguis and Porphyromonas gingivalis in specific pathogen-free rats]

OBJECTIVE

To examine whether endogenous S. sanguis could prevent, or reduce the colonization of the virulent P. gingivalis strain.

METHODS

First, 10 specific pathogen-free Wistar rats were divided into 2 groups. Doxycycline was administered in the drinking water for 7 days. Successful implantation of the endogenous strain of S. sanguis, isolated from one of the rats before doxycycline administration, and P. gingivalis 381 within 14 days of observation were demonstrated in the rats of each group respectively. Then, 30 SPF rats were divided into 6 groups. Doxycycline was administered in the drinking water for 7 days to all the rats. Afterwards, the rats in group A and B were inoculated orally once a day for 5 days with P. gingivalis, the rats in group C and E were inoculated orally once a day for 5 days with S. sanguis. Then, the rats in group A were inoculated for 5 days with S. sanguis, and rats in group C and D were inoculated for 5 days with P. gingivalis. The rats in group F served as negative control. After inoculation, the levels of S. sanguis and P. gingivalis in the mouths of the rats were determined after 12, 24, 36 hours, 7 days and 14 days.

RESULTS

Both pre-colonization of S. sanguis and superinfection with S. sanguis did reduce the level of P. gingivalis in experimental rats. However, the reduction only maintained quite short time, about 36 hours. It was not caused by the decreased level of S. sanguis after 36 hours because the level of S. sanguis kept stable during the observation period of 14 days.

CONCLUSION

That S. sanguis function as the effector strain requires the successful implantation of S. sanguis as well as S. sanguis producing antagonistic action efficiently in vivo.

Dendritic cell-derived nitric oxide is involved in IL-4-induced suppression of experimental allergic encephalomyelitis (EAE) in Lewis rats

Cytokines play a crucial role in initiating and perpetuating EAE, an animal model of multiple sclerosis (MS). A low dose of IL-4, administered by the nasal route over 5 days (100 ng/rat per day) prior to immunization, improved clinical scores of EAE induced in Lewis rats with myelin basic protein (MBP) peptide 68-86 (MBP 68-86). We examined whether dendritic cells (DC) may have contributed to the amelioration of the disease process. These professional antigen-presenting cells (APC) not only activate T cells, but also tolerize T cells to antigens, thereby minimizing autoimmune reactions. We found that IL-4 administration enhanced proliferation of DC. In comparison with DC of PBS-treated rats, DC from IL-4-treated rats secreted high levels of interferon-gamma (IFN-gamma) and IL-10. Nitric oxide (NO) production by DC was also strongly augmented in IL-4-treated rats. In vitro studies showed that IL-4 stimulated DC expansion and that IFN-gamma enhanced NO production by DC. DC-derived NO promoted apoptosis of autoreactive T cells. These results indicate that nasal administration of IL-4 promotes activation of DC and induces production of IFN-gamma and IL-10 by DC. IL-10 suppresses antigen presentation by DC, while IFN-gamma induces NO production by DC which leads to apoptosis in autoreactive T cells. Such a DC-derived negative feedback loop might contribute to the clinical improvement observed in EAE.

[New method for the isolation of astroglial cells and oligodendrocytes]

Based on the different properties of cellular adhesions, developmental time-courses and growth pattern of astroglial cells and oligodendrocytes, a method of isolating glial cells in vitro was developed. The observations under inverted light microscope and scan electronic microscope identified that the morphology of isolated cells were consistent with the previous description. Immunocytochemical examination showed the expressions of markers, the glial fibrillary acidic protein (GFAP) of astroglia cells and the myelin basic protein (MBP) of oligodendrocytes were consistent with the isolated cells. All parameters showed that the isolated glial cells were pure, and the new methods were easy and reliable.

Crystal structure of a murine glutathione S-transferase in complex with a glutathione conjugate of 4-hydroxynon-2-enal in one subunit and glutathione in the other: evidence of signaling across the dimer interface

mGSTA4-4, a murine glutathione S-transferase (GST) exhibiting high activity in conjugating the lipid peroxidation product 4-hydroxynon-2-enal (4-HNE) with glutathione (GSH), was crystallized in complex with the GSH conjugate of 4-HNE (GS-Hna). The structure has been solved at 2.6 A resolution, which reveals that the active site of one subunit of the dimeric enzyme binds GS-Hna, whereas the other binds GSH. A marked asymmetry between the two subunits is evident. Most noticeable are the differences in the conformation of arginine residues 69 and 15. In all GST structures published previously, the guanidino groups of R69 residues from both subunits stack at the dimer interface and are related by a (pseudo-) 2-fold axis. In the present structure of mGSTA4-4, however, the two R69 side chains point in opposite directions, although their guanidino groups remain in contact. In the subunit with bound GSH, R69 also interacts with R15, and the guanidino group of R15 points away from the active site, whereas in the subunit that binds GS-Hna, R15 pivots into the active site, which breaks its interaction with R69. According to our previous results [Nanduri et al. (1997) Arch. Biochem. Biophys. 335, 305-310], the availability of R15 in the active site assists the conjugation of 4-HNE with GSH. We propose a model for the catalytic mechanism of mGSTA4-4 in conjugating 4-HNE with GSH-i.e., the guanidino group of R15 is available in the active site of only one subunit at any given time and the stacked pair of R69 residues act as a switch that couples the concerted movement of the two R15 side chains. The alternate occupancy of 4-HNE in the two subunits has been confirmed by our kinetic analysis that shows the negative cooperativity of mGSTA4-4 for 4-HNE. Disruption of the signaling between the subunits by mutating the R69 residues released the negative cooperativity with 4-HNE.

Homer 1b regulates the trafficking of group I metabotropic glutamate receptors

The molecular basis for glutamate receptor trafficking to the plasma membrane is not understood. In the present study, we demonstrate that Homer 1b (H1b), a constitutively expressed splice form of the immediate early gene product Homer (now termed Homer 1a) regulates the trafficking and surface expression of group I metabotropic glutamate receptors. H1b inhibits surface expression of the metabotropic glutamate receptor mGluR5 in heterologous cells, causing mGluR5 to be retained in the endoplasmic reticulum (ER). In contrast, mGluR5 alone or mGluR5 coexpressed with Homer 1a successfully travels through the secretory pathway to the plasma membrane. In addition, point mutations that disrupt mGluR5 binding to H1b eliminate ER retention of mGluR5, demonstrating that H1b affects metabotropic receptor localization via a direct protein-protein interaction. Electron microscopic analysis reveals that the group I metabotropic receptor mGluR1alpha is significantly enriched in the ER of Purkinje cells, suggesting that a similar mechanism may exist in vivo. Because H1b is found in dendritic spines of neurons, local retention of metabotropic receptors within dendritic ER provides a potential mechanism for regulating synapse-specific expression of group I metabotropic glutamate receptors.

[Changes of placental nitric oxide synthase in patients with pregnancy induced hypertension]

The objective of this study was to determine whether the expression of placental endothelial nitric oxide synthase (eNOS) and/or inducible nitric oxide synthase (iNOS) are changed in pregnancy induced hypertension (PIH). The placentas of 32 patients with PIH and 32 normal pregnancies were studied by immunohistochemistry (Avidin-Biotin-Complex method). The results showed there were eNOS and iNOS antigens in placental tissues from PIH and normal pregnancy. They were all localized in placental villi and syncytiotrophoblast cells. The expression of placenta eNOS decreased significantly in patients with PIH as compared with that of normal pregnancy. The expression of placenta eNOS in mild PIH was higher than that of moderate or severe PIH (P < 0.025, P < 0.005, respectively). There was a negative correlation between blood pressure and the expression of eNOS in placenta (P < 0.0005). There was no significant difference between the expression of iNOS in placenta with PIH and that in normal pregnancy. Also, there was no significant difference of the expression of iNOS in placenta between the mild and moderate PIH, or the mild and severe PIH. Furthermore, there was no correlation between blood pressure and the expression of iNOS in placenta with PIH. It is concluded that the decrease of the expression of eNOS in placenta may be associated with the pathogenesis of PIH.

Structure and function of residue 104 and water molecules in the xenobiotic substrate-binding site in human glutathione S-transferase P1-1

Two variants of human class pi glutathione (GSH) S-transferase 1-1 with either isoleucine or valine in position 104 (hGSTP1-1[I104] and hGSTP1-1[V104]) have distinct activity toward (+)-anti-7, 8-dihydroxy-9,10-oxy-7,8,9,10-tetrahydrobenzo[a]pyrene [(+)-anti-BPDE]. To elucidate their structure-function relationship, we determined the crystal structures of the two variants in complex with GSBpd, the GSH conjugate of (+)-anti-BPDE, at 2.1 and 2.0 A resolution, respectively. The crystal structures reveal that residue 104 in the xenobiotic substrate-binding site (H-site) dictates the binding modes of the product molecule GSBpd with the following three consequences. First, the distance between the hydroxyl group of Y7 and the sulfur atom of GSBpd is 5.9 A in the hGSTP1-1[I104].GSBpd complex versus 3.2 A in the V104 variant. Second, one of the hydroxyl groups of GSBpd forms a direct hydrogen bond with R13 in hGSTP1-1[V104].GSBpd; in contrast, this hydrogen bond is not observed in the I104 complex. Third, in the hydrophilic portion of the H-site of the I104 complex, five H-site water molecules [Ji, X., et al. (1997) Biochemistry 36, 9690-9702] are observed, whereas in the V104 complex, two of the five have been displaced by the Bpd moiety of GSBpd. Although there is no direct hydrogen bond between Y108 (OH) and the hydroxyl groups of GSBpd, indirect hydrogen bonds mediated by water molecules are observed in both complexes, supporting the previously suggested role of the hydroxyl group of Y108 as an electrophilic participant in the addition of GSH to epoxides.

Coupling of mGluR/Homer and PSD-95 complexes by the Shank family of postsynaptic density proteins

Shank is a recently described family of postsynaptic proteins that function as part of the NMDA receptor-associated PSD-95 complex (Naisbitt et al., 1999 [this issue of Neuron]). Here, we report that Shank proteins also bind to Homer. Homer proteins form multivalent complexes that bind proline-rich motifs in group 1 metabotropic glutamate receptors and inositol trisphosphate receptors, thereby coupling these receptors in a signaling complex. A single Homer-binding site is identified in Shank, and Shank and Homer coimmunoprecipitate from brain and colocalize at postsynaptic densities. Moreover, Shank clusters mGluR5 in heterologous cells in the presence of Homer and mediates the coclustering of Homer with PSD-95/GKAP. Thus, Shank may cross-link Homer and PSD-95 complexes in the PSD and play a role in the signaling mechanisms of both mGluRs and NMDA receptors.

Shank, a novel family of postsynaptic density proteins that binds to the NMDA receptor/PSD-95/GKAP complex and cortactin

NMDA receptors are linked to intracellular cytoskeletal and signaling molecules via the PSD-95 protein complex. We report a novel family of postsynaptic density (PSD) proteins, termed Shank, that binds via its PDZ domain to the C terminus of PSD-95-associated protein GKAP. A ternary complex of Shank/GKAP/PSD-95 assembles in heterologous cells and can be coimmunoprecipitated from rat brain. Synaptic localization of Shank in neurons is inhibited by a GKAP splice variant that lacks the Shank-binding C terminus. In addition to its PDZ domain, Shank contains a proline-rich region that binds to cortactin and a SAM domain that mediates multimerization. Shank may function as a scaffold protein in the PSD, potentially cross-linking NMDA receptor/PSD-95 complexes and coupling them to regulators of the actin cytoskeleton.

[Effects of alcohol on membrane lipid fluidity of astrocytes and oligodendrocytes]

To explore the mechanism of neuron development retardation and myelination abnormality caused by alcohol, the membrane lipid fluidity of astrocytes and oligodendrocytes which is related to neuron and myelin development were measured by using DPH fluorescence probe. The results showed that 5 mmol/L alcohol could lead to decrease the polarization of fluorescence (Pr) and increase the lipid fluidity unit of membrane in both cells. The alteration was in obvious dose-response relationship. The effect of alcohol on astrocytes was stronger than that of oligodendrocytes. It indicated that alcohol could change lipid fluidity of cell membrane. Alcohol probably plays major role in the dysfunction of astrocytes and oligodendrocytes.

Multiple sclerosis: levels of interleukin-10-secreting blood mononuclear cells are low in untreated patients but augmented during interferon-beta-1b treatment

The cytokine interleukin (IL)-10 has immune response down-regulatory properties, which include suppression of the synthesis of pro-inflammatory cytokines such as interferon (IFN)-gamma and of major histocompatibility complex (MHC) class II expression on monocytes. To further elucidate the involvement of IL-10 in multiple sclerosis (MS), an enzyme-linked immunospot assay was adopted to enumerate IL-10-secreting mononuclear cells (MNC) in peripheral blood. IFN-gamma secreting MNC were detected in parallel. Levels of IL-10-secreting cells were lower in patients with MS compared with other neurological diseases (OND) and healthy subjects. This difference was seen only in patients with untreated MS, and not in those undergoing treatment with IFN-beta-1b. No differences were observed when subgrouping the patients with MS regarding clinical phase (exacerbation, remission, secondary progression), duration of MS or disability status. Levels of IFN-gamma-secreting blood MNC did not differ in patients with MS, irrespective of treatment with IFN-beta-1b, compared with OND and healthy subjects. Patients with MS, but not the two groups of controls, had elevated numbers of IL-10- and IFN-gamma-secreting cells upon stimulation with MBP compared with culture in the absence of antigen. The data suggest that IL-10 is decreased in MS and that treatment resulting in its up-regulation beneficially influence the disease.

PCR assay for the inversion causing severe Hemophilia A and its application

OBJECTIVE

To develop a new technique based on long distance polymerase chain reaction (LD-PCR) to replace Southern blotting method to detect Factor VIII (FVIII) gene inversion leading to severe Hemophilia A (HA) and carrier.

METHODS

Four primers P, Q, A&B were designed and synthesized. P&Q is specific for 5' and 3' flanking regions of F8A1 respectively. A&B is specific for 5' and 3' flanking regions of F8A2/F8A3 respectively. LD-PCR with 3 primers and 3 temprature was set up, optimized and used to detect the inversion.

RESULTS

The LD-PCR with primers P, Q, A&B, P, Q&B and P, Q&A can be used to detect the gene inversion and discriminate carrier from wild type. A blind analysis of 53 DNA samples from HA families was carried out by the LD-PCR and Southern blotting respectively. Two sets of the results were completely identical. They were 23 cases of inversion, 27 cases of wild type and 3 cases of carriers. The sensitivity and specificity of LD-PCR are both 100%. Three inversion hemizygotes and 4 female carriers were identified from 5 HA families by the LD-PCR technology.

CONCLUSIONS

The LD-PCR with primer P, Q&B or P, Q, A&B can be used to detect the gene inversion and the carrier of inversion. Compared with Southern blotting, this technique is simple, rapid, inexpensive, more sensitive, accurate and non-isotopic.

Crystal structure of 6-hydroxymethyl-7,8-dihydropterin pyrophosphokinase, a potential target for the development of novel antimicrobial agents

BACKGROUND

Folate cofactors are essential for life. Mammals derive folates from their diet, whereas most microorganisms must synthesize folates de novo. Enzymes of the folate pathway therefore provide ideal targets for the development of antimicrobial agents. 6-Hydroxymethyl-7,8-dihydropterin pyrophosphokinase (HPPK) catalyzes the transfer of pyrophosphate from ATP to 6-hydroxymethyl-7,8-dihydropterin (HP), the first reaction in the folate biosynthetic pathway.

RESULTS

The crystal structure of HPPK from Escherichia coli has been determined at 1.5 A resolution with a crystallographic R factor of 0.182. The HPPK molecule has a novel three-layered alpha beta alpha fold that creates a valley approximately 26 A long, 10 A wide and 10 A deep. The active center of HPPK is located in the valley and the substrate-binding sites have been identified with the aid of NMR spectroscopy. The HP-binding site is located at one end of the valley, near Asn55, and is sandwiched between two aromatic sidechains. The ATP-binding site is located at the other end of the valley. The adenine base of ATP is positioned near Leu111 and the ribose and the triphosphate extend across and reach the vicinity of HP.

CONCLUSIONS

The HPPK structure provides a framework to elucidate structure/function relationships of the enzyme and to analyze mechanisms of pyrophosphoryl transfer. Furthermore, this work may prove useful in the structure-based design of new antimicrobial agents.

[Effect of lead on the expression of immediate early genes in different regions of rat brain]

In order to study the role of immediate early genes (IEG) in the neurotoxic mechanism of lead, expression of c-fos and c-jun genes in different regions of rat brain treated with lead (13 and 130 mg/kg) were observed by using immuno-histochemical method. The observation and image analysis showed that after rats treated by lead for 2 hours, the c-fos and c-jun expression in cortex, CA3 area of hippocampus and cerebellum of rats were higher than those of control rats significantly (P < 0.05). The results indicated that IEG, as a transcription regular factor, may participate in the neurological toxicity damaging the learning and memory ability induced by lead. The study provided experimental basis for revealing the molecular neurotoxic mechanism of lead.

[Experimental study on carotid artery resection with vascular replacement by an autogenous vein graft]

OBJECTIVE

In order to observe the survival rate and the histologic changes of the reestablished common carotid artery system.

METHOD

A planned resection of the carotid artery was done and the common carotid artery system was reestablished by interposing an autogenous external jugular vein graft in 15 white rabbits.

RESULT

12 survived, the other 3 rabbits died from graft thrombosis, the survival rate was 80%. Histologic examination demonstrated the smooth internal tunic in the anastomotic part of the carotid-jugular and no graft thrombosis. Angiography demonstrated the free circulation of the blood and no aneurysm in the anastomotic vein.

CONCLUSION

It is concluded that it is possible that in selected patients, a planned resection of the carotid artery with replacement by interposing an autogenous external jugular vein graft will be done.

Amplified fragment length polymorphism analysis on D5S436 locus and its application to linkage analysis in gene diagnosis of asthma

OBJECTIVES

To detect the polymorphism of D5S436 locus, and to carry out an amplified fragment length polymorphism (Amp-FLP) genotyping linkage analysis in asthma families.

METHODS

Allele and genotype frequencies of the high polymorphic D5S436 locus were determined in 92 unrelated Chinese individuals by using polymerase chain reaction (PCR). The amplified fragments were separated by denaturing polyacrylamide gel electrophoresis and silver staining techniques.

RESULTS

Eight alleles and 22 genotypes were observed in this population. The heterozygosity was 78.26%. The polymorphism information content (PIC) was 0.76. Amp-FLP genotyping linkage analyses were carried out in four asthma families, demonstrating that the locus was inherited according to Mendel's law and had a clear result.

CONCLUSION

The PIC of D5S436 is high in Chinese individuals, so it could be used as a genetic marker of asthma in Chinese and might be useful in the gene diagnosis of asthma.

[Electromyogram (EMG) and muscle biopsy in patients with chronic spinal muscular atrophy]

The clinicopathological changes were investigated by electromyogram (EMG) and muscle biopsy in 30 cases of chronic spinal muscular atrophy. The results showed that the denervating changes were demonstrated in EMG in all patients but two. The light microscope discovered manifestation of neurogenic atrophy, and the electron microscope revealed a reduction of myofibrils, thickening and wavy appearance of Z-lines and dilation of mitochondria and endoplasmic reticula.

Quality of life and personality in adults with epilepsy

PURPOSE

This study was undertaken to understand the quality of life, personality, and associated factors in patients with epilepsy.

METHODS

117 patients with epilepsy and 84 healthy people were studied and tested using the Social Support Scale, the General Well-being Schedule, the Life-Event Scale, the Behavior Pattern Scale, and the Eysenck Personality Questionnaire (EPQ).

RESULTS

There were no significant differences between the patients with epilepsy and the control group in the Social Support Scale results. The General Well-being Schedule scores were lower for the case patients than for the control group (p < 0.01). Scores for patients with frequent seizures (once a month or more) were lower than those without frequent seizures (less than once per month). The case patients had higher negative scores in the family-related problem section of the Life Events Scale, compared with the control group (p < 0.05). The patients with epilepsy were also more likely to lie (p < 0.05); their emotions were more changeable (p < 0.01), and their character more introverted (p < 0.05), although their behavior patterns were similar to the controls. We also studied associated factors related to personality, general well-being, and familial-negative life-events.

CONCLUSIONS

These results provide information about patients with epilepsy that may be useful in their psychological treatment.

Homer regulates the association of group 1 metabotropic glutamate receptors with multivalent complexes of homer-related, synaptic proteins

Homer is a neuronal immediate early gene (IEG) that is enriched at excitatory synapses and binds group 1 metabotropic glutamate receptors (mGluRs). Here, we characterize a family of Homer-related proteins derived from three distinct genes. Like Homer IEG (now termed Homer 1a), all new members bind group 1 mGluRs. In contrast to Homer 1a, new members are constitutively expressed and encode a C-terminal coiled-coil (CC) domain that mediates self-multimerization. CC-Homers form natural complexes that cross-link mGluRs and are enriched at the postsynaptic density. Homer 1a does not multimerize and blocks the association of mGluRs with CC-Homer complexes. These observations support a model in which the dynamic expression of Homer 1a competes with constitutively expressed CC-Homers to modify synaptic mGluR properties.

[Application of coronal CT scan and three-dimensional reconstruction in rhinology]

To display the structure of the Ostiomeatal Complex (OMC) more clearly, and provide clearer and more living imaging for safe functional endoscopic sinus operation and thoroughly eliminating the focus of disease, coronal CT scanning and 3-dimensional reconstruction were performed in 168 sinusitis patients (290 sides) and 107 patients with sinusitis and nasal polyposis (175 sides). The CT findings were compared with endoscopic examination and normal people were taken as control. The found of coronal CT and endoscopic examination are consistent in recognizing mucosal thickening within nasal cavity and sinuses. Three-dimensional CT is more living than common coronal CT in displaying the uncinate process and turbinates. Our conclusion is that coronal CT scan processes high values for recognizing nasal sinus disease, anatomical variants, disease extent and adjacent structures of OMC. Three-dimensional reconstructed CT make the image of OMC more stereoscopic, audio-visual and living.

Homer binds a novel proline-rich motif and links group 1 metabotropic glutamate receptors with IP3 receptors

Group I metabotropic glutamate receptors (mGluRs) activate PI turnover and thereby trigger intracellular calcium release. Previously, we demonstrated that mGluRs form natural complexes with members of a family of Homer-related synaptic proteins. Here, we present evidence that Homer proteins form a physical tether linking mGluRs with the inositol trisphosphate receptors (IP3R). A novel proline-rich "Homer ligand" (PPXXFr) is identified in group 1 mGluRs and IP3R, and these receptors coimmunoprecipitate as a complex with Homer from brain. Expression of the IEG form of Homer, which lacks the ability to cross-link, modulates mGluR-induced intracellular calcium release. These studies identify a novel mechanism in calcium signaling and provide evidence that an IEG, whose expression is driven by synaptic activity, can directly modify a specific synaptic function.

[A comparison study on the sensitivity of lung tumor short-term induction test in three strains of mice]

To compare the sensitivities of lung tumor short-term induction in different strains of mice, the carcinogenicity risk was evaluated with the incidence rate and the average number of tumors. Three different strains of mice (KM, BALB/c and A/J) were injected with a single different dose of urethane i.p. The results demonstrated that the lowest dose for increasing tumor risk was 100 mg/kg in KM, 200 mg/kg in BALB/c, and lower than 25 mg/kg in A/J strain. So, the sensitivity of A/J strain is the highest and that of BALB/c is the lowest.

Effect of once weekly administration of mifepristone on ovarian function in normal women

The effects of mifepristone on ovarian function during a once weekly oral administration regimen were studied in nine healthy women. Each received 25 mg mifepristone on cycle days 3, 10, 17, and 24. Ovulation, as documented by hormonal measurements and ultrasonography, was inhibited during treatment in five subjects, with a midcycle surge of luteinizing hormone and ovulation occurring 6-18 days after the last pill was administered in four of the five subjects. These five treatment cycles were prolonged 9-26 days. The other four subjects had normal cycles as judged by serum hormone levels, ultrasonography, and cycle length. All nine subjects had delayed endometrial growth as indicated by ultrasonography. There was a significant correlation between concentrations of serum mifepristone (10 h and 58 h) and alpha 1-acid glycoprotein, the protein to which mifepristone binds in circulation. Response to mifepristone did not depend on its circulating levels. We conclude that once weekly administration of 25 mg mifepristone can interfere with normal follicular development and function, but the inhibition of ovulation was inconsistent.

[Effects of lanthanum and cerium on malignant proliferation and expression of tumor-related gene]

Cultured human gastric cancer cell line PAMC82 was studied in vitro to further verify anti-tumor effect sof rare-earth elements and explore their mechanism of tumor inhibition. Inhibitory effects of elements lanthanum and cerium on cell growth, reverse effects of them on reduction of malignancy and effects of them on level of expression of oncogene and cancer suppressor gene were observed. Lanthanum chloride, cerium chloride and mixed rare-earth chloride at levels of 0.5 to 1.5 mmol/L could inhibit obviously growth of cancer cells and change cell morphology and microtubule structure of PAMC82, similar to that of normal cells, their colony-forming ability lowered in soft agar, and expression of tumor suppressor gene p53, p16 and p21 increased and that of gene nm23 lowered.

Contraceptives for lactating women: a comparative trial of a progesterone-releasing vaginal ring and the copper T 380A IUD

From approximately one week before normal ovulation resumes, lactating women require protection against pregnancy by a contraceptive that is safe for both infant and mother in a multicenter one-year study, the natural hormone, progesterone, delivered vaginally by a sequence of four contraceptive rings designed for continuous use, was evaluated as a contraceptive for nursing mothers in comparison with the Copper T 380A IUD. Individual rings release in effective average dose of 10 mg day for a 3 month period. Evaluation included measures of lactational performance as well as of contraceptive efficacy and safety to mother and child. Nine participating clinics enrolled 802 ring users and 734 IUD acceptors between postpartum days 29 and 63. Life table analyses were performed with parallel decrements for ring and IUD subjects. Continuation in the study and analysis required that subjects not stop breastfeeding. The ring, with a one-year pregnancy rate of 1.5 per 100, did not differ significantly from the IUD with respect to contraceptive effectiveness (p > 0.05). More than half of the ring subjects were continuing at 6 months post admission and a quarter (23.5 per hundred) were still using the ring and breastfeeding one year after admission. Women with the IUD, however, had higher continuation rates (p < 0.001) at both time points. The largest single decrement for each method was that for weaning. Ring users had more complaints of vaginal problems but had fewer vaginal disorders on examination. At 12 months postpartum, 46 per 100 continuing ring users remained in amenorrhea. Lactation performance and the health and weight gain of the infants were similar among users of either regimen.

Isolation and identification of chicken infectious anemia virus in China

A chicken infectious anemia virus (CIAV) isolate was obtained from broiler flocks aged 25-40 days with anemia and poor performance and was designated SR43. The CIAV isolate was resistant to treatment with chloroform and induced thymus atrophy, bone marrow aplasia, and low hematocrit values when inoculated into 1-day-old, susceptible, specific-pathogen-free chicks. CIAV-specific antigens could be demonstrated in SR43-infected MDCC-MSB-1 cells, a cell line derived from a Marek's disease lymphoma, with the use of a monoclonal antibody specific for CIAV. CIAV DNA in infected MDCC-MSB-1 cell cultures was detected by using a polymerase chain reaction assay. These findings demonstrate that CIAV is present in China.

Safety, efficacy, and acceptability of medical abortion in China, Cuba, and India: a comparative trial of mifepristone-misoprostol versus surgical abortion

OBJECTIVE

We investigated safety, efficacy, and acceptability of an oral regimen of medical abortion compared with surgical abortion in three developing countries.

STUDY DESIGN

Women (n = 1373) with amenorrhea < or = 56 days chose either surgical abortion (as provided routinely) or 600 mg of mifepristone followed after 48 hours by 400 micrograms of misoprostol. This is the appropriate design for studying safety, efficacy, and acceptability among women selecting medical abortion over available surgical services.

RESULTS

The medical regimen had more side effects, particularly bleeding, than did surgical abortion but very few serious side effects. Failure rates for medical abortion, although low, exceeded those for surgical abortion: 8.6% versus 0.4% (China), 16.0% versus 4.0% (Cuba), and 5.2% versus 0% (India). Nearly half of failures among medical clients were not true drug failures, however, but surgical interventions not medically necessary (acceptability failures or misdiagnoses). Women were satisfied with either method, but more preferred medical abortion.

CONCLUSION

Medical abortion can be safe, efficacious, and acceptable in developing countries.