[The 38,000 protein of Mycobacterium tuberculosis is overexpressed in Escherichia coli]

OBJECTIVE

To obtain recombinant 38,000 protein in large quantities and to study its immunologic characteristics by stable expression of the gene encoding for 38,000 antigen of Mycobacterium tuberculosis in E. coli.

METHODS

Expression plasmid was constructed with DNA recombinant technique. Positive clones were screened using double digestion and polymerase chain reaction. Recombinant plasmid was transformed into E. coli. Then E. coli carrying recombinant plasmid were induced. The expression of 38,000 antigen was identified by SDS-polyacrylamid gel electrophoresis (PAGE) and immunoblotting. Stained gel was scanned to detect expression level of recombinant antigen.

RESULTS

Gel stained with coomassie blue G-250 showed that the induced E. coli carrying recombinant plasmid can produce 38,000 protein at high level. Gel scan showed that 38,000 antigen expression in E. coli was about 36% - 40% of total cellular protein. The recombinant 38,000 antigen existed mostly in inclusion bodies. The recombinant antigen can react with antibodies: serum of pulmonary tuberculosis patients and the goats immuned with Mycobacterium tuberculosis.

CONCLUSIONS

Constructed recombinant E. coli can overproduce 38,000 antigen of Mycobacterium tuberculosis. Inclusion bodies are easy to purify and can protect the recombinant antigen from protease, on the other hand, it has not biological activity unless the denatured protein is accurately folded.

A novel superoxide dismutase-based trap for peroxynitrite used to detect entry of peroxynitrite into erythrocyte ghosts

Peroxynitrite (ONOO-) is a relatively stable oxidant produced by activated macrophages and neutrophils. To detect peroxynitrite, a novel human superoxide dismutase (SOD) trap was developed by substituting a tyrosine near the copper in the active site. The copper can catalyze nitration of this tyrosine by peroxynitrite. The nitrated tyrosine can serve as a reporter for peroxynitrite by measuring the extent of nitration with Western blots developed with a nitrotyrosine antibody. The new SOD mutant differs from bovine SOD whose sole tyrosine is far removed from the active site. Nitration of bovine SOD was second-order with respect to SOD concentration, whereas nitration of the new mutant SODs followed first-order kinetics with respect to peroxynitrite. The tyrosine SODs were used to assess whether peroxynitrite crosses erythrocyte membranes through the band 3 anion exchange protein. Tyrosine-containing SOD entrapped within normal human erythrocyte ghosts became nitrated in proportion to peroxynitrite concentration. The band 3 anion exchange protein inhibitors, phenyl isothiocyanate (PITC) and 4, 4'-diisothiocyanatostilbene-2,2'-disulfonate (DIDS), inhibited up to 90% of the nitration. The erythrocyte membrane proteins, spectrin, band 3 anion exchange protein, and proteins 4.1 and 4.2, were also nitrated. Nitration of erythrocyte membrane proteins was also inhibited by PITC and DIDS. These data suggest that the band 3 anion exchange protein is the major route for the entry of peroxynitrite into erythrocytes. The ability of peroxynitrite to cross cell membranes can contribute to its toxicity by allowing access to intracellular target molecules.

[A clinical study on vaccine of Mycobacterium vaccae in treating pulmonary tuberculosis]

OBJECTIVE

To study the effect of vaccine of Mycobacterium vaccae on cell-mediated immunity and on treating patients with pulmonary tuberculosis.

METHODS

Seventy cases of pulmonary tuberculosis with smear positive and initial treatment were classified randomly into group I (35 cases) and group II (35 cases), receiving 2HRZS/4HR and 2HRZS/4HR plus vaccine of Mycobacterium vaccae regimens respectively. Thirty-one multi-drug resistant pulmonary tuberculosis cases were classified into group III, receiving 4 - 6 sensitive antituberculous drugs and vaccine of Mycobacterium vaccae. Improvement of clinical symptoms, resolution of pulmonary lesions, negative conversion of sputum and changes of immunological functions were observed.

RESULTS

No significant difference in improvement of symptoms was found in group I and group II (P > 0.05), and the improvement rate of clinical symptoms in group III was found more than 50%. X-ray resolution rates in 4th month were 83% and 89%, and cavity reducing rates 40% and 50% respectively in group I and group II, and no significant differences were found (P > 0.05). X-ray resolution rate was 29%, cavity reducing rate 7% and no deteriorated case was found in group III. Sputum negative conversion rates in 1st, 2nd, 3rd and 4th month were 23%, 51%, 83% and 97% respectively in group I, while 31%, 77%, 89% and 100% in group II, and 3%, 16%, 29% and 32% in group III. Significant difference was found between group I and group II in sputum negative conversion rate in 2nd month after treatment (P < 0.05). After treatment, values of lymphocyte transformation test (LTT), CD(3), CD(4) and CD(4)/CD(8) of the above 3 groups were all higher than that before the treatment (P < 0.05), level of tumor necrosis factor decreased in group II and IL-2, IL-6 increased in group III.

CONCLUSIONS

Vaccine of Mycobacterium vaccae is a good immunotherapy preparation, which promotes sputum negative conversion and activation of cell-mediated immunity.

[The relationship of insulin resistance and the pathogenesis and perinatal outcome of pregnancy induced hypertension]

OBJECTIVE

To study the insulin resistance in the pathogenesis of pregnancy induced hypertension (PIH), and its relationship to perinatal outcome.

METHODS

In 111 PIH and 155 control group, the concentration of C peptide and insulin of maternal blood samples before and after 32 gestational weeks, and fetal blood samples just after delivery was determined. Fetal outcomes were assessed by the neonatal weight at delivery, Apgar scores and the quality and quantity of amniotic fluid.

RESULTS

The maternal concentration of C peptide and insulin in PIH was higher than that of control group (P < 0.05, or P < 0.01). In PIH group, the maternal concentration of C peptide and insulin in the subgroup of adverse perinatal outcomes tended to be higher than that in the subgroup of good perinatal outcomes; but in control group, there was no significantly difference between these two subgroups.

CONCLUSIONS

Insulin resistance may be one of the factors which couse PIH, and it has significant relationship with advese perinatal outcomes.

[Effect of Salvia Miltiorrhiza injection on umbilical artery hemodynamics during fetal distress in ewe]

OBJECTIVE

To study the effect of Salvia Miltiorrhiza injection (SMI) on umbilical artery hemodynamics during fetal distress in ewe.

METHODS

Intrauterine surgery were performed at 116-125 gestational days in 3 pregnancy sheep for insertion of vascular catheters at abdominal aorta from femoral artery and for implantation of a electromagnetic flowmetre probe around umbilical artery. Gelatin microsphere injection to abdominal aorta through vascular catheter for obstruction of placental-fetal circulation. 2 ml of SMI was used 6 times(2 times each sheep), and the signs of umbilical artery blood flow and wave forms of fetal abdominal aorta blood pressure were recorded before and after injections of gelatin microsphere or SMI. The fast Fourier translation (FFT) was used to turn signs in time domain into powers spectral of input impedance in frequency domain for resistance and characteristic impedance of umbilical artery.

RESULTS

After the SMI was injected into fetal abdominal aorta, the resistance of umbilical artery was significantly reduced (P < 0.05), and the changes of resistance was significantly relative with the resistance before SMI injected (r = -0.85, P < 0.001). But there were no significantly different impedance between before and after SMI treatment (P > 0.05).

CONCLUSIONS

The SMI to fetal abdominal aorta can decrease umbilical artery blood flow resistance and the changes of resistance was significantly relative to that before SMI treatment.

[Study on the karyotype and recurrence risk of malformed newborns]

OBJECTIVE

To survey the karyotype and recurrence risk of malformed newborns.

METHODS

Karyotypes of 104 malformed newborns were analyzed using G-banding. All cases were devided into two groups depending on their karyotypes: Group 1 with normal karyotype (n = 51) and group 2 with abnormal (n = 53). Clinical data were compared between malformed groups and control. Women who had the second babies after delivering a malformed (n = 20) were included in the statistics of recurrence risk.

RESULTS

(1) Of 104 cases, 53 had abnormal karyotype (50.96%). They were trisomy 21, trisomy 18, 45X, 1q+ and 5p+ (n = 41, 9, 1, 1, 1, seperately). (2) Within group 2, women's mean delivery age was elder, while premature delivery rate was higher than that of control (P < 0.01, 0.05). In group 1, the proportion of women with abnormal pregnancy history increased as compared with control (P < 0.05). The rate of fetal distress, poly/oligohydramnios and small for gestational age (SGA) of two malformed groups was higher apparently than that of control. The birth weight of two malformed groups declined obviously. (3) Within 20 second babies being born after their malformed siblings, 6 were malformed too. The total recurrence rate was 30%.

CONCLUSION

(1) Abnormal karyotype is an important cause of congenital malformations; (2) The age pregnant women abnormal pregnancy history, IUGR and poly/oligohydramnios all may be the high risk factors of congenital malformations; (3) The recurrence rate of malformations rises after the first malformed newborn's birth.

[A study of maternal and fetal peroxidation in elderly primigravidea]

OBJECTIVE

To analyze the rlationship between the age of pregnant women and maternal and fetal peroxidation.

METHODS

Pregnant 164 women in their third trimester were collected and divided into 3 groups according to maternal ages: in group 1, maternal age less than 35, n = 71; group 2, maternal age 35-39, n = 63; group 3, 40 or over, n = 30. All the women had no other high risk factors. Maternal and umbilical blood samples were drawn during delivery, and the concentration of superoxide enzyme (SOD) and Lipid peroxidate produce (LPO) were determined.

RESULTS

There were no significant differences in neonatal Apgar scores, birth weight, and the volume and quality of amniotic fluid among the 3 groups, but the cesarean scetion rate increased along with maternal age. The fetal SOD concentration was significantly higher than that in maternal serum, but the LPO level was lower. There was significant correlation between maternal age and maternal serum SOD and LPO levels (r1 = 0.15, P < 0.05; r2 = 0.2299, P < 0.01). The maternal LPO levels in group 2 and 3 were significantly higher than that in group1 (P < 0.05), and the concentration of SOD in group 3 was significantly lower than that in group 1 (P < 0.05).

CONCLUSION

The activity and concentration of free radicals were higher in mother than that in fetus, and the ability of anti-oxidation was lower in mother. The maternal age is associated with SOD and LPO levels during pregnancy.

[Studies on mutation of rifampicin-resistant genes in M. tuberculosis]

OBJECTIVE

To understand mutation of rifampicin-resistant genes in M. tuberculosis clinical isolates, and to develop a new method for detecting drug resistance.

METHOD

Analyzing the rpoB genes in 50 M. tuberculosis clinical isolates with polymerase chain reaction-single-stranded conformation polymorphism (PCR-SS-CP) and PCR-direct sequencing(PCR-DS) techniques. M. tuberculosis strain H37Rv was used as control.

RESULT

Of 3 drug-sensitive isolates and 2 non-rifampicin-resistant isolates selected, only 1 drug-sensitive isolate with abnormal rpoB SSCP profile had TCG-->TTG mutation at codon 531. Of 45 rifampicin-resistant isolates, 35 isolates with abnormal SSCP profiles had mutations in rpoB sequences, in which 14 isolates displayed TCG-->TTG or TGG or TAC mutations at codon 531, 14 had CAC-->TAC or GAC or CCC or CTC or GTC mutations at codon 526, 2 had GAC-->GTC or TAC mutations at codon 516, 2 had two point mutations, and 3 had different rpoB sequences from that of M. tuberculosis.

CONCLUSION

Resistance to rifampicin in most M. tuberculosis isolates is due to the mutations on the genes encoding the RNA polymerase subunit (rpoB). PCR-SSCP and PCR-DS techniques might become simple, rapid and reliable diagnostic tests for rifampicin resistance in clinical isolates.

Functional replacement of the mouse E2A gene with a human HEB cDNA

The mammalian E2A, HEB, and E2-2 genes encode a unique class of basic helix-loop-helix (bHLH) transcription factors that are evolutionarily conserved and essential for embryonic and postnatal development. While the structural and functional similarities among the gene products are well demonstrated, it is not clear why deletion of E2A, but not HEB or E2-2, leads to a complete arrest in B-lymphocyte development. To understand the molecular basis of the functional specificity between E2A and HEB/E2-2 in mammalian development, we generated and tested a panel of E2A knockin mutations including subtle mutations in the E12 and E47 exons and substitution of both E12 and E47 exons with a human HEB cDNA. We find that the alternatively spliced E12 and E47 bHLH proteins of the E2A gene play similar and additive roles in supporting B lymphopoiesis. Further, we find that HEB driven by the endogenous E2A promoter can functionally replace E2A in supporting B-cell commitment and differentiation toward completion. Finally, the postnatal lethality associated with E2A disruption is fully rescued by the addition of HEB. This study suggests that the functional divergence among E12, E47, and HEB in different cell types is partially defined by the context of gene expression.

Synthesis of novel oximes of 2-aryl-6-methoxy-3,4-dihydronaphthalene and their evaluation as inhibitors of 17 alpha-hydroxylase-C17,20-lyase (P450 17)

The synthesis and biological evaluation of oximes of 2-aryl-6-methoxy-3,4-dihydronaphthalene (7a, 7b, 14a, 14b) as nonsteroidal inhibitors of 17 alpha-hydroxylase-C17,20-lyase (P450 17, CYP 17) is described. The target compounds were synthesized and identified by 1H NMR and MS. The preparation of the key intermediates 5a and 5b was accomplished by coupling 4a and 4b with 1 (2-hydroxy-6-methoxy-3,4-dihydronaphthalene-2-trifluoromethanesulfonate) using the palladium complex Pd(PPh3)4 as catalyst. Hydrolysis of 5a and 5b in THF-HCl solution at room temperature gave the corresponding keto compounds 6a and 6b. The other important intermediates--the substituted (E)-2-methyl-ene-1-tetralones 10a and 10b--were obtained by condensation of 1-tetralone with the corresponding aromatic aldehydes (9a and 9b). Hydrogenation (H2), followed by reduction (NaBH4), and subsequent hydrolysis and elimination led to the keto compounds 13a and 13b. The title compounds, the oximes 7a, 7b and 14a, 14b were formed by reaction of hydroxylamine hydrochloride with the corresponding keto compounds. Using a microsomal fraction of human testicular enzyme, 7a, 7b, 14a, and 14b inhibited the target enzyme only marginally.

High incidence of T-cell tumors in E2A-null mice and E2A/Id1 double-knockout mice

The basic-helix-loop-helix (bHLH) proteins encoded by the E2A gene are broadly expressed transcription regulators which function through binding to the E-box enhancer sequences. The DNA binding activities of E2A proteins are directly inhibited upon dimerization with the Id1 gene product. It has been shown that disruption of the E2A gene leads to a complete block in B-lymphocyte development and a high frequency of neonatal death. We report here that nearly half of the surviving E2A-null mice develop acute T-cell lymphoma between 3 to 10 months of age. We further show that disruption of the Id1 gene improves the chance of postnatal survival of E2A-null mice, indicating that Id1 is a canonical negative regulator of E2A and that the unbalanced ratio of E2A to Id1 may contribute to the postnatal death of the E2A-null mice. However, the E2A/Id1 double-knockout mice still develop T-cell tumors once they reach the age of 3 months. This result suggests that E2A may be essential for maintaining the homeostasis of T lymphocytes during their constant renewal in adult life.

[Study on the molecular mechanism of multi-drug resistance in clinical isolates of Mycobacterium tuberculosis]

OBJECTIVE

To study the molecular mechanism of multi-drug resistance in M. Tuberculosis, and to develop a new method for detecting genes related with multi-drug resistance.

METHOD

The ropB, rpsL, katG genes and inhA regulatory sequence in clinical isolates of M. tuberculosis were analyzed with PCR and PCR-SSCP techniques.

RESULT

The sensitivity of amplifing the drug-resistant genes with PCR was 1-10 pg DNA. Of the 20 multiple resistant strains with reduced sensitivity to streptomycin, rifampin and isoniazid, 90% showed mutations in more than two genetic markers associated with resistance to each of these three drugs, 10% revealed only mutations in rpoB gene.

CONCLUSION

Multi-drug resistance in M. tuberculosis could be caused by an accumulation of mutations in chromosomal genes encoding drug targets or an alteration at a single multiple resistance locus. PCR and PCR-SSCP techniques might become simple, rapid and reliable diagnostic tests for multi-drug resistance.

Synthesis of Z- and E-1-methyl-2-(1-hydroximinoethyl)-6-methoxy-3,4-dihydronaphthalene and evaluation as inhibitors of 17 alpha-hydroxylase-C17,20-lyase (P450 17)

The synthesis and biological evaluation of Z- and E-1-methyl-2-(1-hydroximinoethyl)-6-methoxy-3,4-dihydro-naphtha len e (Z-1 and E-1) as nonsteroidal inhibitors of 17 alpha-hydroxylase-C17,20-lyase (P450 17, CYP 17) is described. Z-1 and E-1 were separated by column chromatography and identified by 1H NMR. The synthesis of the key compound 3 was accomplished by a new reaction acetylating the 1-methyl-6-methoxy-3,4-dihydronaphthalene compound 2 under Friedel-Crafts conditions. Compound 2 was obtained from the 1-tetralone via Wittig reaction. Using a microsomal fraction of human testicular enzyme, Z-1 and E-1 inhibited the target enzyme only marginally.

Decreased zinc affinity of amyotrophic lateral sclerosis-associated superoxide dismutase mutants leads to enhanced catalysis of tyrosine nitration by peroxynitrite

Mutations to Cu/Zn superoxide dismutase (SOD) linked to familial amyotrophic lateral sclerosis (ALS) enhance an unknown toxic reaction that leads to the selective degeneration of motor neurons. However, the question of how >50 different missense mutations produce a common toxic phenotype remains perplexing. We found that the zinc affinity of four ALS-associated SOD mutants was decreased up to 30-fold compared to wild-type SOD but that both mutants and wild-type SOD retained copper with similar affinity. Neurofilament-L (NF-L), one of the most abundant proteins in motor neurons, bound multiple zinc atoms with sufficient affinity to potentially remove zinc from both wild-type and mutant SOD while having a lower affinity for copper. The loss of zinc from wild-type SOD approximately doubled its efficiency for catalyzing peroxynitrite-mediated tyrosine nitration, suggesting that one gained function by SOD in ALS may be an indirect consequence of zinc loss. Nitration of protein-bound tyrosines is a permanent modification that can adversely affect protein function. Thus, the toxicity of ALS-associated SOD mutants may be related to enhanced catalysis of protein nitration subsequent to zinc loss. By acting as a high-capacity zinc sink, NF-L could foster the formation of zinc-deficient SOD within motor neurons.

Analysis of the role of E2A-encoded proteins in insulin gene transcription

Pancreatic beta-cell type-specific transcription of the insulin gene is mediated, in part, by factors in the basic helix-loop-helix (bHLH) family that act on a site within the insulin enhancer, termed the E1-box. Expression from this element is regulated by a heteromeric protein complex containing ubiquitous (i.e. the E2A- and HEB-encoded proteins) and islet-enriched members of the bHLH family. Recent studies indicate that the E2A- and HEB-encoded proteins contain a transactivation domain, termed AD2, that functions more efficiently in transfected beta-cell lines. In the present report, we extend this observation by demonstrating that expression of full-length E2A proteins (E47, E12, and E2/5) activates insulin E element-directed transcription in a beta-cell line-selective manner. Stimulation required functional interactions with other key insulin gene transcription factors, including its islet bHLH partner as well as those that act on the RIPE3b1 and RIPE3a2 elements of the insulin gene enhancer. The conserved AD2 domain in the E2A proteins was essential in this process. The effect of the E2A- and HEB-encoded proteins on insulin gene expression was also analyzed in mice lacking a functional E2A or HEB gene. There was no apparent difference in insulin production between wild type, heterozygote, and homozygous mutant E2A or HEB mice. These results suggest that neither the E2A- or HEB-encoded proteins are essential for insulin transcription and that one factor can substitute for the other to impart normal insulin E1 activator function in mutant animals.

[Alkaloid production of cultured coptis cells by two-stage suspension-culture]

In this study the asexual cell line H292 induced and selected from Coptis gulinensis had rapid growth rate and could stably produce alkaloids. By the one-stage method, after the cell suspensions were cultured on the same medium for six weeks, the increased dry and fresh weights of the cells were 20.96 g/L and 174.92 g/L respectively. The content of the total alkaloids in the cells was 14.79 mg/g cell dw. Per litter liquid medium could provide 323 mg alkaloid. In contrast, the cells were cultured by two-stage method. After having been cultured on the medium which contributed to the growth of the cells for three weeks, the cells were transferred to the medium which contributed to the production of the alkaloid and cultured for three weeks. Six weeks later, the dry and fresh weights of the cells were 16.72 g/L and 127.44 g/L, respectively. The biomass was lower than that by one-stage method, but the content of the total alkaloids was as high as 31.76 mg/g cell dw, which was much more than that by one-stage method. In addition, the content of the alkaloid in the medium was 25.31 mg/L. Per litter liquid medium could provide 556 mg alkaloid. The total yield of alkaloid obtained by two-stage method was 1.72 times than that by one-stage method.

[Detection of M. tuberculosis streptomycin-resistant gene]

OBJECTIVE

To observe the mutations of rpsL gene in M. tuberculosis streptomycin-resistant isolates, and to develop a new method for detecting drug resistance.

METHOD

Detecting the rpsL genes with PCR-SSCP and analyzing their codons 43 by PCR-RFLP.

RESULTS

Strain H37Rv was used as a control. In 22 M. tuberculosis clinical isolates, the rpsL PCR fragments from 5 drug-susceptible isolates had no differences in the SSCP profiles with strain H37Rv, and were restricted by Mbo II. 11 of the 13 streptomycin-resistant isolates showed apparent differences in the SSCP profiles and were not digested with Mbo II. 1 of the 4 other drug-resistant isolates also had apparent SSCP differences and was not digested by Mbo II.

CONCLUSIONS

The results suggested that the rpsL gene mutation was frequently observed in M. tuberculosis streptomycin-resistant isolates, and usually situated at codon 43, PCR-SSCP and PCR-RFLP might become a simple, rapid and reliable diagnostic test for drug resistance.

[Application of PCR-SSCP technique in detection of rpoB gene mutation in rifampin-resistant Mycobacterium tuberculosis]

OBJECTIVE

To evaluate rpoB gene mutation in rifampin-resistant Mycobacterium tuberculosis and its relationship with rifampin resistance.

METHODS

Forty clinical isolates of Mycobacterium tuberculosis were analyzed by PCR-SSCP technique, with H37Rv reference strains as control group.

RESULTS

The sensitivity of amplication products of 411bp and 258bp were found to be 5 pg/microliters, 500 organisms per milliliter and 1 pg/microliter, 500 organisms per milliliter respectively. rpoB gene belongs to genus specificity. Characteristics of SSCP graph of 258bp fragment: Ten sensitive strains were the same as H37 Rv. Thirty strains of rifampin-resistant or multidrug resistance, including rifampin, were different from H37Rv except for three strains. Positive rate was 90%, while specificity 100%.

CONCLUSIONS

Results showed that PCR-SSCP technique could detect rPOB gene mutation, which might associate with rifampin resistance and be helpful to rapid detection and research of rifampin-resistant Mycobacterium tuberculosis.

[Callus induction of Coptis species and generation of alkaloids]

Callus induction and tissue culture of six medicinal Coptis species have been carried out and a comparative analysis of berberine, jatrorrhizine, coptisine, palmatine and epiberberine in calli and crude drugs have been made by TLC and HPLC.

B-lymphocyte development is regulated by the combined dosage of three basic helix-loop-helix genes, E2A, E2-2, and HEB

B-lymphocyte development requires the basic helix-loop-helix proteins encoded by the E2A gene. In this study, the control mechanism of E2A was further explored by disruption of the E2A-related genes, E2-2 and HEB. In contrast to E2A, E2-2 and HEB are not essential for the establishment of the B-cell lineage. However, both E2-2 and HEB are required for the generation of the normal numbers of pro-B cells in mouse embryos. Breeding tests among mice carrying different mutations revealed that E2-2 and HEB interact with E2A in many developmental processes including generation of B cells. Specifically, mice transheterozygous for any two mutations of these three genes produced fewer pro-B cells than the singly heterozygous littermates. This study indicates that B-cell development is dependent not only on an essential function provided by the E2A gene but also on a combined dosage set by E2A, E2-2, and HEB.

Analysis of mechanisms that determine dominant negative estrogen receptor effectiveness

To analyze the mechanisms by which estrogen receptor (ER) activity is suppressed by dominant negative mutants, we examined the role of specific ER functions and domains in transcriptional repression. We previously described three transcriptionally inactive human ER mutants (the frameshift mutant S554fs, the point mutant L540Q, and the truncated receptor ER1-530), which act as effective dominant negative mutants, inhibiting the activity of wild type ER when they are coexpressed in mammalian cells. After additional mutational modifications, the ability of the ER mutants to suppress the activity of wild type ER was analyzed in cotransfection assays of the dominant negative mutants and wild type ER and an estrogen-responsive reporter gene (2ERE-TATA-CAT or 2ERE-pS2-CAT). Eliminating the ability of the three dominant negative mutants to bind to estrogen response element (ERE) DNA (by introducing three point mutations in their DNA binding domains) dramatically reduced, but did not completely abolish, the dominant negative activity of the ER mutants. The mutation G521R, which rendered the three mutants incapable of binding estradiol, also reduced, but did not abolish, their dominant negative activity. Immunoprecipitation with monoclonal or flag antibodies followed by Western blotting demonstrated that each of the original dominant negative ER mutants formed heterodimers with wild type ER. Rendering the dominant negative mutants dimerization deficient by the mutation L507R strongly reduced, but did not eliminate, their dominant negative activity. Deletion of the N-terminal A/B domain resulted in the nearly complete loss of inhibitory activity of the three dominant negative mutants. However, these double mutants retained their ability to heterodimerize with wild type ER, suggesting that dominant negative interference also occurs at an additional step beyond dimerization. Our data indicate that competition for ERE binding, formation of inactive heterodimers, and specific transcriptional silencing can all contribute to the dominant negative phenotype and that these receptors suppress the activity of wild type ER by acting at multiple steps in the ER-response pathway.

Targeted deletion of 5'HS2 of the murine beta-globin LCR reveals that it is not essential for proper regulation of the beta-globin locus

The beta-globin locus control region (LCR) is a complex regulatory element that is essential for the appropriate red cell-specific expression of all cis-linked beta-globin genes. Of the five hypersensitive sites that define the LCR, only 5'HS2 has been shown to augment gene expression in vitro in both transient and stable assays, as well as in transgenic mice. Thus, 5'HS2 has been assumed to be an important element for the function of the LCR in vivo. We have utilized homologous recombination in murine embryonic stem (ES) cells and phenotypic analysis in derived mice to investigate the function of 5'HS2 in its normal chromosomal position in the murine beta-globin locus. Replacement of 5'HS2 with a selectable marker gene (delta HS2 + neo) causes a 2-5-fold reduction in expression of all of the genes in the locus, and a more pronounced effect (10-12-fold) on the most 5' embryonic globin gene, Ey, when expression of this gene is first detectable during embryogenesis. The mutation produces no alterations in the developmental timing of expression of the globin genes. When homozygous, the deletion/replacement mutation is lethal in utero, with the embryos dying during the stage of yolk sac and early fetal liver erythropoiesis. To distinguish phenotypic effects resulting from the deletion of 5'HS2 from those attributable to insertion of the selectable marker, the selectable marker was removed by expressing the FLP site-specific recombinase in ES cells harboring the homologous recombination event. Mice derived from these ES cells (delta HS2 delta neo) demonstrated nearly full expression of all the beta-like globin genes on the mutated chromosome. These results indicate that although 5'HS2 demonstrates significant regulatory activities in a variety of assays, deletion of this element from the endogenous beta-globin locus has no significant effect on the timing or extent of expression of the locus. In addition, this result emphasizes that when using homologous recombination to analyze complex regulatory elements in vivo, the inserted selectable marker must be removed to avoid influencing the phenotype of the mutation.

[The studies on the effect of proliferative response of peripheral blood lymphocyte of healthy persons by preparations of M. vaccea]

This paper present that preparations of M. vaccea, which included suspensions of live bacilli, irradiation-killed bacilli and high temperature killed bacilli, for the effect on lymphocyte proliferative response of peripheral blood in healthy persons were compared by 3H-TdR incorporation method. CPM of control was 448 +/- 131, CPM adding suspensions of live M. vaccea, irradiation-killed bacilli and high temperature killed bacilli were 1037 +/- 194, 2299 +/- 140, 1819 +/- 528, 994 +/- 186, respectively. Stimulative index of all four preparations were more than 2.0, specially suspensions of live and irradiation killed M. vaccea is more effective than BCG and high temperature killed M. vaccea, which were 5.13, 4.06, respectively. In another experiment, suspensions of live, irradiation-killed and high temperature killed M. vaccea plus rIL-2 were found more effective than rIL-2 alone. CPM of them were 9544 +/- 1727, 8530 +/- 714, 8230 +/- 1035, and 3721 +/- 1336, respectively, but BCG was 6904 +/- 1218. The results show that preparations of M. vaccea tested have distinctly promotive effect for proliferative response of lymphocyte in vitro. The addition of rIL-2 to suspendions of live M. vaccea, irradiation killed and high temperature killed M. vaccea cooperatively increased the effects of proliferative response mentioned above.

Estrogen receptor mutants which do not bind 17 beta-estradiol dimerize and bind to the estrogen response element in vivo

To investigate the stage in estrogen receptor (ER) action at which hormone functions, we prepared human ER mutants unable to bind 17 beta-estradiol. In transfected Chinese Hamster Ovary (CHO) cells, two of the ER mutants exhibited less than 5% of the ability to activate transcription shown by wild type ER. Immunoprecipitation followed by Western blotting with monoclonal antibodies was used to examine the ability of the ER mutants to form heterodimers with a truncated form of wild type ER. The non-hormone-binding mutants formed heterodimers with the truncated ER as efficiently as wild type ER. We used a promoter interference assay to measure the interaction of the ER with the estrogen response element (ERE) in vivo. Expression plasmids encoding the ER mutants and wild type ER were transfected into CHO cells across a range of concentrations, resulting in both high and low levels of promoter interference. The ER mutants and wild type ER elicited similar levels of promoter interference, indicating that although they were unable to bind ligand, the ER mutants bound to the ERE in vivo as effectively as wild type ER. Additional evidence that the non-hormone-binding ER mutants are not in a functionally inactive complex comes from their ability to suppress the activity of wild type ER, when they were coexpressed in the same cells. These data support a model for ER action in which the unliganded ER is free to dimerize and bind to the ERE. In this model, the primary role of 17 beta-estradiol in ER action is to induce a conformational change which activates the ligand-dependent transactivation domain.

[The evaluation of various fetal blood flow velocity waveforms in predicting perinatal outcomes]

One hundred and four women in their third trimester of pregnancy were examined with colour Doppler ultrasound for their fetal blood flow velocity waveforms (FVWs) of the umbilical artery (UA), renal artery (RA), and middle cerebral artery (MCA) in relation to the perinatal outcomes. The Doppler parameters studied included their pulsatile indexes (PI) and the PI ratio of MCA/UA (M/U PI) and of MCA/RA (M/R PI). The criteria for adverse perinatal outcome were set as follows: (1) Apgar score < 7; (2) birth weight < or = 10th % percentile of same gestational age; (3) oligaohydramnio or meconium staining. All the studied Doppler parameters were correlative to the perinatal outcomes (P < 0.05), but as shown by the best cut off point of each parameter, the difference between the specificity of the Doppler parameters in prediction was of no significance (P > 0.05). However the ratio M/R PI and M/U PI were significantly more sensitive than the UA PI RA PI and MCA PI (P < 0.05). The results indicated that though relationship exists between each Doppler parameter and the perinatal outcome, M/R PI and M/U PI are better indexes in predicting adverse perinatal outcome, when compared with UA PI RA PI and MCA PI. Maybe the M/R PI and M/U PI are less affected by the blood flow input impedance.

The helix-loop-helix gene E2A is required for B cell formation

Heterodimers between tissue-specific basic-helix-loop-helix proteins and the gene products of E2A play major roles in determining tissue-specific cell fate. To understand the broad role of E2A in development, we have generated E2A mutant mice following homologous recombination in embryonic stem cells. Homozygous mutant mice develop to full term without apparent abnormalities, but then display a high rate of postnatal death. The surviving mice show retarded postnatal growth. Detailed examination of hematopoiesis reveals that the homozygous mutant mice contain no B cells while other lineages including T cell, granulocyte, macrophage, and erythroid are intact. The block to B cell differentiation occurs prior to immunoglobulin gene DH-JH rearrangement and the expression of the B lineage-specific marker B220. Surprisingly, heterozygous embryos contain, on average, about half as many B cells as wild-type embryos, suggesting the existence of a counting mechanism that translates levels of E2A into numbers of B cells.

The evaluation and calculation of intermediate energy nuclear data for 56Fe(p,n), 63Cu(p,n), and 65Cu(p,n) monitor reactions

Proton monitor reactions have been widely used in accelerator target flux and beam energy monitoring, medical radioisotope production, research on radiation damage, and activation analysis. The excitation functions of 56Fe, 63Cu, and 65Cu(p,n) reactions were calculated and evaluated at incident energies up to 1,200 MeV, 11,500 MeV, and 1,820 MeV, respectively.

Transmembrane signals and protooncogene induction evoked by carcinogenic metals and prevented by zinc

Cd2+ provokes an immediate production of inositol trisphosphate and the release of Ca2+ from internal stores in human fibroblasts and some other mammalian cells. Ni2+, Co2+, Fe2+, and Mn2+ evoke the release of stored Ca2+, but are less potent than Cd2+ (apparent K0.5 = 40 nM). Zn2+ and Cu2+ competitively inhibit Ca2+ release evoked by Cd2+ without affecting Ca2+ release by hormones such as bradykinin. Zn2+ has the same apparent Ki value (80-90 nM) towards the five agonist metals, which suggests that the metals interact with the same site. Many other divalent cations neither released stored Ca2+ nor affected Cd(2+)-evoked Ca2+ release. The agonist metals appear to activate phospholipase C via a G protein rather than a tyrosine kinase. The production of reactive oxygen species is probably not involved in Ca2+ release by the metals. Cd2+ and other stimuli that raise cytosolic-free Ca2+ induce cyclic (AMP) production, apparently by activating a calmodulin-dependent adenylyl cyclase. We suggest that an orphan receptor mediates the hormonelike responses to Cd2+ and the other agonist metals. The receptor is referred to as an orphan because its physiological stimulus is unknown. Growth of the fibroblasts in high Zn2+ desensitizes them to the five agonist metals without affecting Ca2+ release by bradykinin or histamine. A several hour incubation in culture medium with normal Zn2+ fully restores responsiveness to the five active metals. Growth in high Zn2+ appears to repress the synthesis of the putative orphan receptor because inhibitors of RNA or protein synthesis, or asparagine-linked glycosylation, prevented the restoration of metal responsiveness.(ABSTRACT TRUNCATED AT 250 WORDS)

Apolipoprotein(a) phenotypes in cardio-cerebrovascular diseases

We report apolipoprotein(a) (apo(a)) phenotypes of 69 myocardial infarction survivors and 56 stroke patients, and compare them with those of 190 healthy Chinese. The results indicate that the distribution of apo(a) phenotype frequency in cardio-cerebrovascular disease patients is different from those of controls. The frequency of the phenotypes B, S1 and S2 in patients is remarkably higher than those in controls within the same single-band apo(a) phenotype. Moreover, the Lp(a) serum concentrations in CCVD patients are significantly higher than those in controls within the same single-band apo(a) phenotype. The apo(a) phenotype analyses of two pedigrees are shown as a typical autosomal dominant inheritance.

Powerful dominant negative mutants of the human estrogen receptor

We have identified and characterized three human estrogen receptor (ER) mutants, which, at low concentrations, are capable of blocking the intracellular activity of wild type ER. The mutants, a truncated ER (ER1-530), a point mutant (L540Q), and a frameshift (S554fs), were generated by random chemical mutagenesis of the ER hormone binding domain and screened first for low activity in a yeast selection system. In transient co-transfection assays using ER-deficient Chinese hamster ovary cells, all three mutants exhibited less than 10% of the transcription activation activity of wild type ER, and when co-expressed with wild type ER, each of the mutants effectively suppressed the ability of wild type ER to activate transcription of an estrogen-regulated reporter plasmid. When equal amounts of plasmid encoding the ER mutants and wild type ER were used, S554fs, ER1-530, and L540Q suppressed the activity of wild type ER by 80, 55, and 75%, respectively. At a ratio of 1 part S554fs to 10 parts wild type ER, transcription was still inhibited by 40%. Western blot analysis showed that all three mutants were expressed at approximately the same level as wild type ER. Suppression of transcription was specific for ER, since the mutants did not inhibit progesterone receptor-mediated transcription. Not all mutations leading to inactive ER confer the dominant negative phenotype, as five ER mutants rendered transcriptionally inactive by point mutations between residues 516 and 524 of the ER hormone binding domain were poor inhibitors of wild type ER activity. Binding studies showed that the L540Q and S554fs dominant negative mutants bound 17 beta-estradiol with wild type affinity (Kd = 0.3-0.5 nM), whereas ER1-530 exhibited a 15-fold reduction in affinity for estradiol. The three dominant negative ERs showed significant ability to interact with the estrogen response element (ERE) in promoter interference assays, but ER1-530 and S554fs displayed little or no binding to the ERE in gel mobility shift assays where higher affinity for the DNA may be required for the receptor-ERE complex to remain associated during the electrophoresis. These data support the idea that, in all three mutants, it is loss of function of the COOH-terminal transactivation domain which leads to the dominant negative phenotype. S554fs, a powerful dominant negative mutant, is a good candidate for further studies aimed at suppressing the estrogen-dependent growth of human breast cancer cells.

Stable expression of the cardiac sodium-calcium exchanger in CHO cells

A line of Chinese hamster ovary (CHO) cells called CK1.4 was produced by transfection with the gene for the bovine cardiac Na(+)-Ca2+ exchanger. CK1.4 cells stably expressed substantial exchange activity and exchanger protein as shown by immunoprecipitation. Exchange activity was quantified as 45Ca2+ influx that depended on both increasing intracellular Na+ and lowering the concentration of external Na+. Replacing external Na+ with K+ slightly increased 45Ca2+ uptake by CK1.4 cells with basal Na+ and greatly increased 45Ca2+ uptake by Na(+)-loaded cells. Neither exchange activity nor exchanger protein was detected in the nontransfected parental line. By contrast to CK1.4 cells, replacing external Na+ with K+ decreased 45Ca2+ uptake in the nontransfected cells whether or not they were Na+ loaded. Changes in cytosolic free Ca2+ determined with fura-2 were consistent with the 45Ca2+ uptake data. Analysis of poly(A)(+)-RNA by Northern blot confirmed that CK1.4 cells, but not the parental line, expressed the exchanger. Expression of the exchanger was also observed in aortic myocytes and a renal epithelial cell line (LLC-MK2) but not in other lines of renal epithelial cells (MDCK, LLC-PK1) or human dermal fibroblasts. The cardiac exchanger produced substantial 45Ca2+ efflux from CK1.4 cells in response to hormone-evoked release of stored Ca2+. CK1.4 cells are an attractive model for studies of the regulation of the cardiac exchanger because they stably express sufficient exchanger for biochemical and immunological analysis.

The status of elderly women in families viewed from the rate of their heading the household

The author assesses the socioeconomic status of elderly women in China, with a focus on marital status, educational level, and employment. "In family and population studies, the methodology for research on household head rate is held as superior to household size and generation distribution indexes in understanding the change of family structures. This paper attempts to apply this methodology to the study of elderly women's familial status."

Helix-loop-helix transcription factors E12 and E47 are not essential for skeletal or cardiac myogenesis, erythropoiesis, chondrogenesis, or neurogenesis

E12 and E47 are two non-tissue-specific helix-loop-helix (HLH) transcription factors encoded by the E2A gene. Previous studies suggested that they are involved in regulation of differentiation in many tissue types including muscle, blood, and nerve through direct heterodimer interactions with tissue-specific HLH proteins. To gain further genetic insight into the functions of E12 and E47 during cell differentiation, we mutated both copies of the E2A gene in mouse embryonic stem (ES) cells and then tested the effect on differentiation in vitro. We find that the ES cells lacking functional E12 and E47 are capable of differentiating into both skeletal and cardiac muscle, erythrocytes, neurons, and cartilage that the same extent as wild-type cells. These results indicate that the E2A gene is not essential for differentiation of these cell types and suggest that redundant genes may control these developmental pathways.

[Detection of Mycobacterium tuberculosis in sputum specimens of pulmonary tuberculosis by DNA amplification]

The PCR was used to detect M. tuberculosis DNA sequences in uncultured clinical specimens. Two oligonucleotide primers with 20 bp each amplified target template DNA of M. tuberculosis. Amplified DNA product was 245 bp which was identified by agarose gel electrophoresis. The sensitivity of detection of M. tuberculosis genomic DNA and bacteria suspension by PCR was lpg and 13 viable bacteria cell/ml, respectively. In specificity experiments, only M. tuberculosis, M. bovis and BCG were positive by PCR, but all other 14 Mycobacterium tested, including streptomyces lividans and E. coli plasmid PUC19 were negative. The sensitivity of detection of M. tuberculosis by PCR was determined by comparing the fast-acid staining and culture on total 54 sputum specimens of pulmonary tuberculosis and 12 nontuberculosis lung disease. The positive rate of PCR in pulmonary tuberculosis were 37.0%, culture method showed only 14.8%, fast-acid staining were 16.7%. Nontuberculosis lung disease were negative. The results show that DNA amplification is a superior method with high degree of sensitivity and specificity for rapid diagnosis of pulmonary tuberculosis.

Reversible desensitization of fibroblasts to cadmium receptor stimuli: evidence that growth in high zinc represses a xenobiotic receptor

The xenobiotic Cd2+ triggers the production of inositol trisphosphate and releases stored Ca2+ in certain cell types, apparently by binding to a zinc site in the external domain of an "orphan" receptor (no known endogenous stimulus). Cd2+ and bradykinin evoke similar spikes in cytosolic free Ca2+. Growth in high Zn2+ (100-200 microM) abolished the free Ca2+ spike evoked by Cd2+ without affecting the spike produced by bradykinin. Growth in high Zn2+ almost abolished Cd(2+)-evoked production of [3H]inositol mono-, bis-, and trisphosphate. Bradykinin-evoked [3H]inositol phosphate production was not affected by growth in high Zn2+. Growth in high Zn2+ nearly prevented the stimulation of 45Ca2+ efflux by Cd2+ without affecting the stimulation of 45Ca2+ efflux by bradykinin or histamine. Removing Zn2+ from the culture medium and incubating the cells for several hours fully restored responsiveness to Cd2+. Cycloheximide, actinomycin D, or tunicamycin prevented the restoration of Cd2+ responsiveness, indicating that resensitization requires macromolecular synthesis. Growth in high Zn2+ reversibly abolished Ca2+ mobilization evoked by two additional stimuli: a decrease in extracellular pH or Na+ concentration. These findings support the hypothesis that the three stimuli (Cd2+ or a decrease in external pH or Na+ concentration) activate the same orphan receptor. Growth in high Zn2+ apparently desensitizes the cells to the Cd2+ receptor stimuli by repressing receptor synthesis.

[Determination and clinical significance of lipoprotein(a) in cardio-cerebrovascular diseases]

We determined the level of lipoprotein (a) [Lp(a)] in 1,266 healthy persons and established the reference value of Lp(a) in various groups of age and sex. The analysis of lipids in myocardial infarction survivors and stroke survivors suggest that increased Lp(a) is an independent risk factor in cardio-cerebrovascular diseases. The characteristics of abnormal lipids in cardio-cerebrovascular diseases are discussed.