[The changes of plasma endothelin concentration and its clinical significance in pulmonary hypertension associated with congenital heart defects]

Plasma endothelin (ET) concentration was measured by means of radioimmunoassay in 38 patients with congeital heart defects among whom 15 patients with pulmonary hypertension (PH) and 23 patients without pulmonary hypertension (non-PH). Blood samples were obtained separately from the femoral vein, right atrium, right ventricle, main pulmonary artery and the femoral artery during catherization. Plasma ET concentration in the PH group was significantly higher than that in the non-PH group at all four sampling sites. In the PH group plasma ET concentration in the pulmonary artery showed higher than that of the right ventricle and the femoral artery, which was significantly in positive correlation with pulmonary artery pressure. It is considered that the elevation of ET plays an important physiological role in the formation of pulmonary hypertension.

Recording of second-harmonic index gratings in photorefractive (K(0.5) Na(0.5))(0.2) (Sr(0.75) Ba(0.25))(0.9) Nb(2)O(6) crystals

We propose and demonstrate a novel method for recording second-harmonic volume index gratings in photorefractive crystals. The fundamental component of the index grating is eliminated by means of a pi -phase shifted double-exposure process that uses the Mach-Zehnder interferometric technique. Experimental results for (K(0.5) Na(0.5)) (0.2)(Sr> (0.75)Ba (0.25))(0.9)Nb (2)O(6) crystals are presented and discussed.

[Effect of tongbiling on synoviocyte function in adjuvant arthritis rats]

OBJECTIVE

To study the effect of Tongbiling (TBL) on the proliferation of synovial fibroblast and interleukin-1 (IL-1), tumor necrosis factor-alpha (TNF-alpha) and postaglandin E2(PGE2) secretion by synoviocytes in adjuvant arthritis (AA) rats.

METHODS

Synovial fibroblasts was derived from culture of tissue piece. The effect of primary synoviocyte culture supernatants on the fibroblast proliferation were assayed and IL-1, TNF-alpha bioactivity and PGE2 content of supernatants of cultured synoviocytes were measured.

RESULTS

TBL could inhibit significantly the synovial fibroblast proliferation (P < 0.001), and down-regulated IL-1, TNF-alpha and PGE2 productions (P < 0.01); indomethacin could promote obviously the synovial fibroblast proliferation (P < 0.001). It inhibited significantly PGE2 production, but further up-regulated the IL-1 and TNF-alpha secretion by synoviocytes (P < 0.01).

CONCLUSION

The therapeutical effect of TBL on AA might be associated with its down-regulating the secretory function of synoviocyte, then restoring the abnormal proliferation of fibroblast to normal levels.

Protective alterations in phase 1 and 2 metabolism of aflatoxin B1 by oltipraz in residents of Qidong, People's Republic of China

BACKGROUND

Residents of Qidong, People's Republic of China, are at high risk for development of hepatocellular carcinoma, in part due to consumption of foods contaminated with aflatoxins, which require metabolic activation to become carcinogenic. In a randomized, placebo-controlled, double-blind phase IIa chemoprevention trial, we tested oltipraz, an antischistosomal drug that has been shown to be a potent and effective inhibitor of aflatoxin-induced hepatocarcinogenesis in animal models.

METHODS

In 1995, 234 adults from Qidong were enrolled. Healthy eligible individuals were randomly assigned to receive by mouth 125 mg oltipraz daily, 500 mg oltipraz weekly, or a placebo. Sequential immunoaffinity chromatography and liquid chromatography coupled to mass spectrometry or to fluorescence detection were used to identify and quantify phase 1 and phase 2 metabolites of aflatoxin B1 in the urine of study participants. Reported P values are two-sided.

RESULTS

One month of weekly administration of 500 mg oltipraz led to a 51% decrease in median levels of the phase 1 metabolite aflatoxin M1 excreted in urine compared with administration of a placebo (P = .030), but it had no effect on levels of a phase 2 metabolite, aflatoxin-mercapturic acid (P = .871). By contrast, daily intervention with 125 mg oltipraz led to a 2.6-fold increase in median aflatoxin-mercapturic acid excretion (P = .017) but had no effect on excreted aflatoxin M1 levels (P = .682).

CONCLUSIONS

Intermittent, high-dose oltipraz inhibited phase 1 activation of aflatoxins, and sustained low-dose oltipraz increased phase 2 conjugation of aflatoxin, yielding higher levels of aflatoxin-mercapturic acid. While both mechanisms can contribute to protection, this study highlights the feasibility of inducing phase 2 enzymes as a chemopreventive strategy in humans.

Level of retinoblastoma protein expression correlates with p16 (MTS-1/INK4A/CDKN2) status in bladder cancer

Recent studies have shown that patients whose bladder cancer exhibit overexpression of RB protein as measured by immunohistochemical analysis do equally poorly as those with loss of RB function. We hypothesized that loss of p16 protein function could be related to RB overexpression, since p16 can induce transcriptional downregulation of RB and its loss may lead to aberrant RB regulation. Conversely, loss of RB function has been associated with high p16 protein expression in several other tumor types. In the present study RB negative bladder tumors also exhibited strong nuclear p16 staining while each tumor with strong, homogeneous RB nuclear staining were p16 negative, supporting our hypothesis. To expand on these immunohistochemical studies additional cases were selected in which the status of the p16 encoding gene had been determined at the molecular level. Absent p16 and high RB protein expression was found in the tumors having loss of heterozygosity within 9p21 and a structural change (mutation or deletion) of the remaining p16 encoding gene allele, confirming the staining results. These results strongly support the hypothesis that the RB nuclear overexpression recently associated with poor prognosis in bladder cancer is also associated with loss of p16 function and implies that loss of p16 function could be equally deleterious as RB loss in bladder and likely other cancers.

[Single-catheter approach to radiofrequency current ablation of accessory pathway in Wolff-Parkinson-White syndrome with recurrent rapid atrial fibrillation]

Twelve patients with WPW were treated by single-catheter ablation. Eight patients had the histories of recurrent rapid atrial fibrillation(Af) and refractory to antiarrhythmic agents. Ventricular rate varied between 250-300 bpm. Defibrillation was needed in three patients, and one had syncope. All patients were treated successfully by ablation of accessory pathway with single-catheter approach and no Af occurred during the procedures. This result suggests that the single-catheter ablation may be an effective and feasible treatment for these patients with WPW and may be helpful in avoiding Af in multiple-catheter introducing procedure.

[Expression of Schistosoma japonicun fatty acid binding protein gene in silkworm cells and larvae]

AIM

To express the fatty acid binding protein (Sj14FABP) gene of Schistosoma japonicun in the silkworm cells and larvae.

METHODS

A 600 bp DNA fragment containing Sj14FABP gene was cloned into baculovirus transfer vector of pBacPAK His1 to construct recombinant transfer vector Sj14-pBac PAK His1. Coinfection was accomplished with this vector and Bombyx mori nuclear polyhedrosis virus (BmNPV) DNA in BmN cells. The recombinant virus of Bm-Sj14 was screened using dot-blotting. The BmN cells and silkworm larvae were infected with Bm-Sj14 to express Sj14FABF gene. Western blotting and ELISA were used to identify the antigenicity of the recombinant protein.

RESULTS

Sj14FABP gene was successfully expressed in the BmN cells and silkworm larvae infected with Bm-Sj14. The product was a 18 kDa fusion protein. The yield in BmN cells was about 100 micrograms/1 x 10(6) cells and 33 micrograms/ml cell supernatant. In silkworm larvae, the product yield was 4 mg/ml haemolymph as well as 4.6 mg/g silkworm tissue. The recombinant protein could be recognized by Western blotting and ELISA using the sera from mice immunized with SWAP.

CONCLUSION

Sj14FABP gene has been successfully expressed in BmNPV system and the product has high antigenicity.

Effect of 1-phenyl-3-methyl-5-pyrazolone labeling on the fragmentation behavior of asialo and sialylated N-linked glycans under electrospray ionization conditions

The advantages of labeling free N-linked oligosaccharides with 1-phenyl-3-methyl-5-pyrazolone (PMP), for high performance liquid chromatography (HPLC) and electrospray ionization mass spectrometry (ESI-MS) are discussed. The study focuses on some asialo and sialylated sugars, and compares the HPLC and ESI-MS behaviors of the PMP-labeled substances vs. the native compounds. It is pointed out that native free N-linked carbohydrates have very low affinities for the C18 reversed phases commonly used in HPLC. Native asialo oligosaccharides yield good ESI-MS sensitivity, although they are very susceptible to in-source collision-induced dissociation (CID), and the fragments are produced from any of the branches of the molecules, i.e. do not give specific structural information. Native N-linked standards bearing one sialic acid residue yield a 10-fold loss of ESI-MS sensitivity vs. asialo compounds, and native sugars with two sialic acid moieties were not detectable. The PMP labeling of asialo and sialylated sugars yielded higher affinities for HPLC C18 columns and, even at the early stages of method development, it was possible to separate three PMP-labeled standards to a useful extent. In ESI-MS, PMP-asialo sugars did not yield a significant increase in sensitivity vs. the native species; however, fragmentation produced by in-source CID was more directed as all predominant fragment ions contained the bis-PMP label. This feature is particularly useful when structural determination of an unknown sugar is required. PMP-sialylated sugars gave rise to very clean and informative ESI mass spectra. The monosialo sugar yielded a 100-fold sensitivity improvement vs. its native analog and, in the case of the disialylated compound, a 100% improvement was obtained in the positive mode. Most fragment ions were informative and contained the reducing end on the molecules, thus facilitating spectral interpretation. The combination of PMP derivatization with on-line HPLC/ESI-MS is a promising method for the analysis of asialo and sialylated carbohydrate mixtures.

GnRH agonist. Increasing the pregnancy rate after combined treatment with hMG/hCG and direct intraperitoneal insemination

OBJECTIVE

To evaluate the efficacy of the GnRH agonist (GnRHa) administered in conjunction with human menopausal gonadotropin/human chorionic gonadotropin hMG/hCG and direct intraperitoneal insemination (DIPI) in women with long-standing unexplained infertility.

STUDY DESIGN

A prospective, randomized, non-blind analysis. During the period May 1995-December 1996, couples with unexplained infertility who failed to conceive following superovulation combined with IUI for at least seven cycles were prospectively enrolled and followed. Pregnancy rates per cycle and per patient of DIPI were compared between groups of hMG/hCG with (GnRHa[+] controlled ovarian hyperstimulation [COH] group) or without (GnRHa[-] COH group) GnRHa.

RESULTS

Thirty-four women (59 cycles) underwent COH with hMG and GnRHa, and 31 women (49 cycles) received hyperstimulation with hMG alone. The pregnancy rates for the women administered GnRHa significantly exceeded those of the patients who did not receive GnRHa both per treatment cycle (35.6% versus 14.3%) and per couple (55.9% versus 22.5%).

CONCLUSION

The use of GnRHa with hMG/hCG and DIPI treatment significantly increased the pregnancy rate in women with long-standing infertility.

A new method of ATP regeneration rate measurement using a pH meter

A new method was developed for measuring the ATP regeneration rate by creatine kinase from creatine phosphate and ADP. The ATP regeneration rate was calculated to be 0.20 mM x s(-1) at room temperature from the pH change of the regeneration mixture.

[Radiofrequency catheter ablation of idiopathic ventricular tachycardia]

Thirteen consecutive patients with idiopathic ventricular tachycardia underwent radiofrequency catheter ablation. This group included 9 idopathic left ventricular tachycardia (ILVT) and 4 idiopathic right ventricular tachycardia (IRVT). Five ILVT patients with left axis deviation and one with right axis deviation were ablated successfully. By pace mapping, two IRVT patients with ventricular tachycardia originating from right ventricular out-flow tract were ablated. No complications occured. By means of follow-up of 3-22 months one case showed recurrence with successful reablation. It indicates that radiofrequency catheter ablation therapy is an effective and safe procedure in patients with idiopathic ventricular tachycardia.

Selection and function of CD4+ T lymphocytes in transgenic mice expressing mutant MHC class II molecules deficient in their interaction with CD4

Interactions of the T cell coreceptors, CD4 and CD8, with MHC molecules participate in regulating thymocyte development and T lymphocyte activation and differentiation to memory T cells. However, the exact roles of these interactions in normal T cell development and function remain unclear. CD4 interacts with class II MHC7 molecules via several noncontiguous regions in both the class II MHC alpha- and beta-chains. We have introduced a double mutation that disrupts interaction with CD4 into the I-A(beta)k gene and used this construct to generate transgenic mice expressing only mutant class II MHC. Although CD4+ thymocytes matured to the single-positive stage in these mice, their frequency was reduced by threefold compared with that of wild-type transgenics. Positive selection of CD4+ T cells in the mutant transgenic mice may have been mediated by TCRs with a higher than usual affinity for class II MHC/Ag complexes. In A(beta)k mutant transgenics, peripheral CD4+ lymphocytes promoted B cell differentiation to plasma cells. These CD4+ T cells also secreted IFN-gamma in response to various stimuli (e.g., protein Ag, bacterial superantigen, and alloantigen), but were deficient in IL-2 secretion. Interactions between CD4 and class II MHC molecules appeared to regulate lymphokine production, with a strong bias toward IFN-gamma and against IL-2 in the absence of these interactions. Our results have implications for the manipulation of T cell-dependent immune responses.

TGF-beta-induced phosphorylation of Smad3 regulates its interaction with coactivator p300/CREB-binding protein

Smads are intermediate effector proteins that transduce the TGF-beta signal from the plasma membrane to the nucleus, where they participate in transactivation of downstream target genes. We have shown previously that coactivators p300/CREB-binding protein are involved in TGF-beta-mediated transactivation of two Cdk inhibitor genes, p21 and p15. Here we examined the possibility that Smads function to regulate transcription by directly interacting with p300/CREB-binding protein. We show that Smad3 can interact with a C-terminal fragment of p300 in a temporal and phosphorylation-dependent manner. TGF-beta-mediated phosphorylation of Smad3 potentiates the association between Smad3 and p300, likely because of an induced conformational change that removes the autoinhibitory interaction between the N- and C-terminal domains of Smad3. Consistent with a role for p300 in the transcription regulation of multiple genes, overexpression of a Smad3 C-terminal fragment causes a general squelching effect on multiple TGF-beta-responsive reporter constructs. The adenoviral oncoprotein E1A can partially block Smad-dependent transcriptional activation by directly competing for binding to p300. Taken together, these findings define a new role for phosphorylation of Smad3: in addition to facilitating complex formation with Smad4 and promoting nuclear translocation, the phosphorylation-induced conformational change of Smad3 modulates its interaction with coactivators, leading to transcriptional regulation.

The mammalian Rad24 homologous to yeast Saccharomyces cerevisiae Rad24 and Schizosaccharomyces pombe Rad17 is involved in DNA damage checkpoint

Cell cycle checkpoint proteins play critical roles in maintaining genomic stability and integrity to prevent the development of cancer and hereditary diseases. Here we report the isolation of a novel mouse gene encoding the protein MmRad24 [MmRad24 is the mouse homologue of HRad17, which was described recently by A. E. Parker et al. (J. Biol. Chem., 273: 18340-18346, 1998)], which shares significant sequence and structural homology with the budding yeast Rad24 and its fission yeast counterpart Rad17, both of which are required for DNA damage checkpoints. Confocal microscopy revealed that the green fluorescent protein-tagged MmRad24 protein is localized to the nucleus in living cells. Fluorescence-activated cell-sorting analysis showed that overexpression of the wild-type MmRad24 in diploid fibroblast WI-38 cells caused a significant G2 arrest of the cell cycle, whereas overexpression of a mutant MmRad24 (mutated on the nucleotide-binding site) that likely functions as a dominant-negative protein resulted in a defect in cell cycle arrest after DNA damage treatment as measured by bromodeoxyuridine pulse-chase labeling experiments. Taken together, these results suggest that the mammalian Rad24 protein may function as a critical gatekeeper in DNA damage checkpoint control.

[Anthraquinone production and analysis in the hairy root cultures of Rheum palmatum L]

Hairy root culture of the medicinal plant Rheum palmatum L. was established by genetic transformation with Agrobacterium rhizogenes. The effects of various media with different pH on growth of the hairy roots and biosynthesis of free anthraquinones were investigated. The experimental results showed that MS agar medium with pH 5.5-5.8 is suitable for growth of the hairy roots. Dark condition is favourable and 62.5-fold increase in fresh weight was reached within a culture period of 25 days. Auxin (0.1 mg.L-1 IAA) activated the hairy root growth but inhibited the biosynthesis of free anthraquinones. About 28% of the total free anthraquinones was released into the liquid medium from the rhubarb hairy roots.

Debromosceptrin, an alkaloid from the Caribbean sponge Agelas conifera

As the result of a structurally guided isolation to identify lead compounds for the treatment of opportunistic infections of AIDS, the dihydrochloride salt of a new symmetrical pyrrole dimer debromosceptrin (1), and two known pyrrole analogues (2 and 3) were isolated from the Caribbean sponge Agelas coniferacollected from Belize. The structure of debromosceptrin was identified by analysis of spectral data. 15N spectral data assignments were made for compounds 1-3. Compounds 2 and 3 showed marginal inhibition of Mycobacterium tuberculosis.

Attachment, morphology, and protein expression of rat marrow stromal cells cultured on charged substrate surfaces

Although surface charge has been shown to affect the adhesion and morphology of a variety of cell types, the interactions of bone marrow stromal cells with charged surfaces still remain unclear. A novel electrical stimulation system was used to investigate the interactions between rat bone marrow stromal cells and charged substrates in this study. A conductive and transparent indium tin oxide (ITO) coating was used as an electret substrate. Rat marrow stromal cells were cultured on positive, negative, and uncharged ITO surfaces. Cell attachment, morphology, alkaline phosphatase activity, and expression of osteopontin and collagen type III were assessed using histochemical staining, immunolabeling, and fluorescence microscopy. Voltages of 0.7, 0.8, 0.9, and 1.0 V applied to the substrates created surface potentials but were insufficient to decompose the media. On positively charged ITO, cell attachment was enhanced in serum-supplemented and serum-free media. Furthermore, decreases in cell spreading, alkaline phosphatase activity, and osteopontin were observed in cells grown on the positively charged ITO. These data indicate that positively charged surfaces enhance cell attachment but suppress cell spreading and differentiation of rat marrow stromal cells.

Extracellular Ca2+ regulates the respiratory burst of human neutrophils

The role of extracellular calcium in the activation of respiratory burst in human neutrophils was studied by using the receptor agonist, N-formyl-methionyl-leucyl-phenylalanine (fMLP), and the activator of protein kinase C phorbol myristate acetate (PMA). The level of intracellular free calcium was measured by using both cell suspensions and single cells in the presence and absence of extracellular calcium. The Ca2+-ATPase inhibitor, thapsigargin, was used to activate higher Ca2+ influx, while a novel calcium channel blocker, panax notoginseng saponins (PNGS) was used to block the Ca2+ entry from extracellular space during the responding period of cells. It was found that about two-thirds of the activation of respiratory burst initiated by the receptor agonist were attributed to the Ca2+ influx under normal physiological conditions. The higher Ca2+ influx resulted in tremendous enhancement of the intensity of respiratory burst initiated by fMLP and marked acceleration of the onset of the respiratory burst stimulated by PMA. It is evident that both intra- and extracellular Ca2+ are required for full activation of the respiratory burst of human neutrophils, and the Ca2+ influx from extracellular space plays an important role either in generation of reactive oxygen metabolites or in activation of protein kinase C.

Study on Haemophilus influenzae type b diseases in China: the past, present and future

Meningitis caused by Haemophilus influenzae type b (Hib) is a common and serious disease for which there now are WHO-certified vaccines that are recommended for universal infant immunization in North America and European countries. If these vaccines are to be recommended in Asia, it is necessary to know the incidence, age distribution and clinical outcome of Hib meningitis and other systemic infections in this region. Data on Hib disease in China are scanty. Hib meningitis was common during the 1950s in China, accounting for up to 16% of all of pyogenic meningitis (up to 38% of cases were caused by unknown pathogens), despite severe epidemics of meningococcal meningitis during that period. Since 1989 we have conducted hospital- and community-based etiologic and epidemiologic studies of bacterial meningitis. Hib accounts for 30 to 50% of bacterial meningitis in China. The incidence of Hib meningitis in Hefei City was 10.4 per 100000 children <5 years, a result relatively lower than in the West but higher than the rate of 2.7 found in a retrospective study in Hong Kong. Pneumonia is the primary cause of death for Chinese children. From 1991 to 1993 the average mortality of children<5 years because of pneumonia was 1563.2 per 100000. To achieve the goal of reducing the death rate of children by one-third by the year 2000, greater efforts should be made to reduce the mortality of children with pneumonia. Our preliminary study showed that about one-fourth to one-third of cases of pneumonia in Chinese children might be caused by Hib. Therefore Hib vaccination for infants and children in China might be an effective and valuable procedure to achieve the goal.

Photorefractive properties of Cu-doped KNSBN crystal with fluorine replacing oxygen

We report the photorefractive properties of a new kind of Cu-doped KNSBN crystal in which a small fraction of oxygen (O) atoms are replaced with fluorine (F) atoms. The replacement of oxygen with fluorine in Cu:KNSBN crystals leads to a much shorter response time of 30 ms at an incident intensity of 5 W/cm(2). We also discuss the effect of electron-hole competition on the coupling constant.

Complementation of the Arabidopsis pds1 mutation with the gene encoding p-hydroxyphenylpyruvate dioxygenase

Plastoquinone and tocopherols are the two major quinone compounds in higher plant chloroplasts and are synthesized by a common pathway. In previous studies we characterized two loci in Arabidopsis defining key steps of this biosynthetic pathway. Mutation of the PDS1 locus disrupts the activity of p-hydroxyphenylpyruvate dioxygenase (HPPDase), the first committed step in the synthesis of both plastoquinone and tocopherols in plants. Although plants homozygous for the pds1 mutation could be rescued by growth in the presence of homogentisic acid, the product of HPPDase, we were unable to determine if the mutation directly or indirectly disrupted HPPDase activity. This paper reports the isolation of a cDNA, pHPPD, encoding Arabidopsis HPPDase and its functional characterization by expression in both plants and Escherichia coli. pHPPD encodes a 50-kD polypeptide with homology to previously identified HPPDases, including 37 highly conserved amino acid residues clustered in the carboxyl region of the protein. Expression of pHPPD in E. coli catalyzes the accumulation of homogentisic acid, indicating that it encodes a functional HPPDase enzyme. Mapping of pHPPD and co-segregation analysis of the pds1 mutation and the HPPD gene indicate tight linkage. Constitutive expression of pHPPD in a pds1 mutant background complements this mutation. Finally, comparison of the HPPD genomic sequences from wild type and pds1 identified a 17-bp deletion in the pds1 allele that results in deletion of the carboxyterminal 26 amino acids of the HPPDase protein. Together, these data conclusively demonstrate that pds1 is a mutation in the HPPDase structural gene.