Regulation of inducible nitric oxide synthase by dietary phytoestrogen in MCF-7 human mammary cancer cells

We examined the effects of the phytoestrogen biochanin A on the growth of the MCF-7 human breast cancer cell line. The results showed that biochanin A treatment induced dose- and time-dependent inhibition on MCF-7 cell growth at concentrations above 20 microg x mL(-1). An examination of treated MCF-7 cell morphology revealed condensation of the chromosome and dehydration of the cytoplasm, suggesting apoptosis as an important factor in biochanin A-related cell growth inhibition. The results also showed that at a concentration of 40 microg x mL(-1), biochanin A decreased the levels of inducible nitric oxide synthase, thus inhibiting the production of nitric oxide, a known second messenger and inducer of apoptosis, and affecting the overall cell protein pattern. No significant difference in superoxide dismutase protein levels were, however detected at concentrations of 40 or 100 microg x mL(-1) of biochanin A. The data suggest that the inhibitory effects of biochanin A on human breast cancer cell growth are linked to inducible nitric oxide synthase and the associated production of nitric oxide.

Use of digoxigenin-labelled probes for the quantitation of HBV-DNA in antiviral drug evaluation

The use of digoxigenin-labelled probes was studied for quantitation of HBV-DNA during antiviral drug evaluation. Digoxigenin (dig)-labelled probes were generated either via incorporation of dig-dUTP in a polymerase chain reaction (PCR) or a random priming reaction. Using the PCR-labelled probe (delineating a 523 bp fragment in the core gene of the HBV) as little as 1 pg of immobilized HBV-DNA could be detected following an 8 h exposure of the hybridized membrane. A close correlation (r = 0.95) was found between the amount of HBV-DNA (range 2.5-200 pg) and the signal generated by the probe hybridized to its target DNA. By using a probe that was labelled with digoxigenin via random priming, the minimal quantity of immobilized HBV plasmid DNA that could be detected following an 8 h exposure was 4 pg, whereas a 32P-labelled probe, generated in parallel by random priming, allowed the detection of 16 pg of HBV plasmid DNA following a 4-day exposure. The PCR-generated digoxigenin-labelled probe proved to be useful for antiviral drug evaluation, i.e. to detect HBV-DNA in total cellular DNA from HBV-positive hepatoma cells (HepG2.2.15) that had either been treated with reference antiviral agents or left untreated. The 50% effective concentrations (EC50) that were calculated for inhibition of HBV-DNA production by lamivudine (3TC), penciclovir (PCV), lobucavir (LBV), adefovir (PMEA) and tenofovir (PMPA) were comparable to those reported in the literature. The use of digoxigenin-labelled probes thus appears to be a simple, convenient, rapid, reliable and non-radioactive method for use for anti-HBV screening. In addition, and in contrast to 32P-labelled probes, digoxigenin-labelled probes can be stored for >1 year without loss of specific activity, which makes these probes particularly attractive for large-scale antiviral drug evaluation purposes.

MyoD and Myf-5 define the specification of musculature of distinct embryonic origin

Mounting evidence supports the notion that Myf-5 and MyoD play unique roles in the development of epaxial (originating in the dorso-medial half of the somite, e.g. back muscles) and hypaxial (originating in the ventro-lateral half of the somite, e.g. limb and body wall muscles) musculature. To further understand how Myf-5 and MyoD genes cooperate during skeletal muscle specification, we examined and compared the expression pattern of MyoD-lacZ (258/2.5lacZ and MD6.0-lacZ) transgenes in wild-type, Myf-5, and MyoD mutant embryos. We found that the delayed onset of muscle differentiation in the branchial arches, tongue, limbs, and diaphragm of MyoD-/- embryos was a consequence of a reduced ability of myogenic precursor cells to progress through their normal developmental program and not because of a defect in migration of muscle progenitor cells into these regions. We also found that myogenic precursor cells for back, intercostal, and abdominal wall musculature in Myf-54-/- embryos failed to undergo normal translocation or differentiation. By contrast, the myogenic precursors of intercostal and abdominal wall musculature in MyoD-/- embryos underwent normal translocation but failed to undergo timely differentiation. In conclusion, these observations strongly support the hypothesis that Myf-5 plays a unique role in the development of muscles arising after translocation of epithelial dermamyotome cells along the medial edge of the somite to the subjacent myotome (e.g., back or epaxial muscle) and that MyoD plays a unique role in the development of muscles arising from migratory precursor cells (e.g., limb and branchial arch muscles, tongue, and diaphragm). In addition, the expression pattern of MyoD-lacZ transgenes in the intercostal and abdominal wall muscles of Myf-5-/- and MyoD-/- embryos suggests that appropriate development of these muscles is dependent on both genes and, therefore, these muscles have a dual embryonic origin (epaxial and hypaxial).

[The effect of chlamydia trachomatis infection in pregnant women on pregnant outcome and neonates]

OBJECTIVE

To determine the prevalence of chlamydia trachomatis (CT) in pregnant women and its effect on pregnant outcome and neonate.

METHODS

Specimen of cervical swab were collected and detected for CT by polymerase chain reaction (PCR) method meanwhile relevant factors were investigated. Pregnant outcome and neonatal situation were also followed up.

RESULTS

The infection rates of CT in pregnant women were 35.90%. The Incidence of abnormal pregnant outcome (premature delivery and abortion) was significantly higher in CT positive groups (24.72%) than that in negative groups (12.20%) (P < 0.05). Incidence of neonatal conjunctivitis and pneumonia were significantly higher in CT positive groups (17.98%) than that of negative groups (0.61%) (P < 0.01). There was statistically significant difference in the prevalence of low birth weight (< 2,500 g) between the two groups (13.48% versus 4.88%) (P < 0.05), and mode of delivery also had influence on neonatal morbidity.

CONCLUSION

Prevalence of CT infection in pregnant women is rather common, and it may cause adverse pregnancy outcome.

Myogenic determination occurs independently in somites and limb buds

Gene targeting has indicated that the bHLH transcription factors Myf-5 and MyoD are required for myogenic determination because skeletal myoblasts and myofibers are entirely ablated in mouse embryos lacking both Myf-5 and MyoD. Entrance into the skeletal myogenic program during development occurs following the independent transcriptional induction of either Myf-5 or MyoD. To identify sequences required for the de novo induction of MyoD transcription during development, we investigated the expression patterns of MyoD-lacZ transgenes in embryos deficient in both Myf-5 and MyoD. We observed that a 258-bp fragment containing the core of the -20-kb MyoD enhancer activated expression in newly formed somites and limb buds in compound mutant embryos lacking both Myf-5 and MyoD. Importantly, Myf-5- and MyoD-deficient presumptive muscle precursor cells expressing beta-galactosidase were observed to assume nonmuscle fates primarily as precartilage primordia in the trunk and the limbs, suggesting that these cells were multipotential. Therefore, cells are recruited into the MyoD-dependent myogenic lineage through activation of the -20-kb MyoD enhancer and this occurs independently in somites and limb buds.

Interaction between estrogen receptor and Pit-1 protein is influenced by estrogen in pituitary cells

The estrogen responsiveness of the rat prolactin gene expression requires the presence of both the estrogen receptor (ER) and the tissue-specific transcription factor, Pit-1 protein. We performed protein interaction assays using anti-rat Pit-1 antiserum (a-rPit-1) to investigate the physical interactions which occur between ER and Pit-1 proteins following estrogen treatment. After fusing maltose binding protein (MBP) and Pit-1 protein, we used the resulting MBP Pit-1 fusion protein to prepare a-rPit-1. Our results show that the estrogen receptor readily co-precipitated with the Pit-1 protein drawn from the lysates of two prolactin-expressing pituitary cell lines GH3 and PR1. The rate of precipitation appears to be both estrogen- and time-dependent. Cellular levels of estrogen receptors and Pit-1 proteins did not show significant changes during the time of estrogen treatment. We therefore suggest that an estrogen-dependent physical interaction between ER and Pit-1 protein exists in vivo, and that this interaction may play an important role in the regulation of prolactin gene expression.

Differential display screening for specific gene expression induced by dietary nonsteroidal estrogen

The dietary phytoestrogen, daidzein, produced a biphasic response in cell proliferation of cultured, estrogen-responsive human breast carcinoma MCF-7 cells. Cell growth was stimulated at a daidzein concentration of 0.25 microg/ml whereas the addition of daidzein at concentrations >25 microg/ml significantly inhibited cell growth in a dose-dependent fashion, resulting in an IC50 value of 50 microg/ml. Upon exposure to 50 microg/ml of daidzein, cell morphology was severely altered, cell volume decreased, and condensation of the chromosomes was clearly noticeable. To identify genes whose expression were inhibited by daidzein, a differential display reverse transcriptase polymerase chain reaction assay (DD-RT-PCR) was performed and the cDNA fragments of several daidzein-regulated genes were visualized. The sequence of one of the cloned cDNA fragments that showed differential mRNA expression level in response to daidzein at a concentration of 50 microg/ml had a high homology with a cDNA expressed in fetal human brain, EST 06411.

Severe cardiomyopathy in mice lacking dystrophin and MyoD

The mdx mouse, a mouse model of Duchenne muscular dystrophy, carries a loss-of-function mutation in dystrophin, a component of the membrane-associated dystrophin-glycoprotein complex. Unlike humans, mdx mice rarely display cardiac abnormalities and exhibit dystrophic changes only in a small number of heavily used skeletal muscle groups. By contrast, mdx:MyoD-/- mice lacking dystrophin and the skeletal muscle-specific bHLH transcription factor MyoD display a severe skeletal myopathy leading to widespread dystrophic changes in skeletal muscle and premature death around 1 year of age. The severely increased phenotype of mdx:MyoD-/- muscle is a consequence of impaired muscle regeneration caused by enhanced satellite cell self-renewal. Here we report that mdx:MyoD-/- mice developed a severe cardiac myopathy with areas of necrosis associated with hypertrophied myocytes. Moreover, heart tissue from mdx:MyoD-/- mice exhibited constitutive activation of stress-activated signaling components, similar to in vitro models of cardiac myocyte adaptation. Taken together, these results support the hypothesis that the progression of skeletal muscle damage is a significant contributing factor leading to development of cardiomyopathy.

Strain-dependent myeloid hyperplasia, growth deficiency, and accelerated cell cycle in mice lacking the Rb-related p107 gene

To investigate the function of the Rb-related p107 gene, a null mutation in p107 was introduced into the germ line of mice and bred into a BALB/cJ genetic background. Mice lacking p107 were viable and fertile but displayed impaired growth, reaching about 50% of normal weight by 21 days of age. Mutant mice exhibited a diathetic myeloproliferative disorder characterized by ectopic myeloid hyperplasia in the spleen and liver. Embryonic p107(-/-) fibroblasts and primary myoblasts isolated from adult p107(-/-) mice displayed a striking twofold acceleration in doubling time. However, cell sort analysis indicated that the fraction of cells in G1, S, and G2 was unaltered, suggesting that the different phases of the cell cycle in p107(-/-) cells was uniformly reduced by a factor of 2. Western analysis of cyclin expression in synchronized p107(-/-) fibroblasts revealed that expression of cyclins E and A preceded that of D1. Mutant embryos expressed approximately twice the normal level of Rb, whereas p130 levels were unaltered. Lastly, mutant mice reverted to a wild-type phenotype following a single backcross with C57BL/6J mice, suggesting the existence of modifier genes that have potentially epistatic relationships with p107. Therefore, we conclude that p107 is an important player in negatively regulating the rate of progression of the cell cycle, but in a strain-dependent manner.

Strain-dependent embryonic lethality in mice lacking the retinoblastoma-related p130 gene

The retinoblastoma-related p130 protein is a member of a conserved family, consisting of Rb, p107 and p130, which are believed to play important roles in cell-cycle control and cellular differentiation. We have generated a null mutation in p130 by gene targeting and crossed the null allele into Balb/cJ and C57BL/6J strains of mice. In an enriched Balb/cJ genetic background, p130(−/−) embryos displayed arrested growth and died between embryonic days 11 and 13. Histological analysis revealed varying degrees of disorganization in neural and dermamyotomal structures. Immunohistochemistry with antibody reactive with Islet-1 indicated markedly reduced numbers of neurons in the spinal cord and dorsal root ganglia. Immunohistochemistry with antibody reactive with desmin indicated a similar reduction in the number of differentiated myocytes in the myotome. The myocardium of mutant embryos was abnormally thin and resembled an earlier staged two-chambered heart consisting of the bulbus cordis and the ventricular chamber. TUNEL analysis indicated the presence of extensive apoptosis in various tissues including the neural tube, the brain, the dermomyotome, but not the heart. Immunohistochemistry with antibody reactive with PCNA revealed increased cellular proliferation in the neural tube and the brain, and decreased proliferation in the heart. The placentas of p130(−/−) embryos did not display elevated apoptosis and were indistinguishable from wild type suggesting that the phenotype was not due to placental failure. Following a single cross with the C57BL/6 mice, p130(−/−) animals were derived that were viable and fertile. These results indicate that p130 in a Balb/cJ genetic background plays an essential role that is required for normal development. Moreover, our experiments establish that second-site modifier genes exist that have an epistatic relationship with p130.

RFLP mapping and race specificity of bacterial blight resistance genes (QTLs) in rice

By using a set of 315 recombinant inbred lines (RILs) from the cross Lemont (japonica) x Teqing (indica) and a complete linkage map with 186 well distributed RFLP markers and 3 morphological markers, a major gene (Xa4) and 10 QTLs and 9 pairs of epistasis loci conferring horizontal resistance to three strains of Xanthomonas oryxa pv oryza (Xoo) were mapped. The Teqing allele at Xa4 on chromosome 11 acts as a dominant resistant gene against pathogen race CR4 and CX08, but as an additive QTL with a significantly (47%) reduced effect against the virulent strain, CR6. The major gene Xa4 exhibited stronger degree of race specificity. Most QTLs showed consistent levels of resistance against all three Xoo strains. The results suggest that a high level durable resistance to Xoo may be achieved by cumulative effects of multiple QTL.

Inheritance and mapping of embryo sac abortion in hybrid between Indica and Japonica rice (Oryza sativa L.)

A doubled haploid (DH) population derived from anther culture of F(1)'s between an Indica var. Zhai-Ye-Qing 8 and a Japonica var. Jing-Xi17 as well as two backcross populations derived from this DH population were used to investigate inheritance of the embryo sac abortion at early megagametogenesis occurring in Indica/Japonica rice crosses. Two major loci, dominant and complementaryesa-1 andesa-2, located on chromosomes 6 and 12 respectively, were detected. Genetic analysis indicated that embryo sac fertility is mainly regulated by the gametophytic genotype at these two loci.

Repression of GCN5 histone acetyltransferase activity via bromodomain-mediated binding and phosphorylation by the Ku-DNA-dependent protein kinase complex

GCN5, a putative transcriptional adapter in humans and yeast, possesses histone acetyltransferase (HAT) activity which has been linked to GCN5's role in transcriptional activation in yeast. In this report, we demonstrate a functional interaction between human GCN5 (hGCN5) and the DNA-dependent protein kinase (DNA-PK) holoenzyme. Yeast two-hybrid screening detected an interaction between the bromodomain of hGCN5 and the p70 subunit of the human Ku heterodimer (p70-p80), which is the DNA-binding component of DNA-PK. Interaction between intact hGCN5 and Ku70 was shown biochemically using recombinant proteins and by coimmunoprecipitation of endogenous proteins following chromatography of HeLa nuclear extracts. We demonstrate that the catalytic subunit of DNA-PK phosphorylates hGCN5 both in vivo and in vitro and, moreover, that the phosphorylation inhibits the HAT activity of hGCN5. These findings suggest a possible regulatory mechanism of HAT activity.

MyoD and Myf-5 differentially regulate the development of limb versus trunk skeletal muscle

The myogenic progenitors of epaxial (paraspinal and intercostal) and hypaxial (limb and abdominal wall) musculature are believed to originate in dorsal-medial and ventral-lateral domains, respectively, of the developing somite. To investigate the hypothesis that Myf-5 and MyoD have different roles in the development of epaxial and hypaxial musculature, we further characterized myogenesis in Myf-5- and MyoD-deficient embryos by several approaches. We examined expression of a MyoD-lacZ transgene in Myf-5 and MyoD mutant embryos to characterize the temporal-spatial patterns of myogenesis in mutant embryos. In addition, we performed immunohistochemistry on sectioned Myf-5 and MyoD mutant embryos with antibodies reactive with desmin, nestin, myosin heavy chain, sarcomeric actin, Myf-5, MyoD and myogenin. While MyoD(−/−) embryos displayed normal development of paraspinal and intercostal muscles in the body proper, muscle development in limb buds and brachial arches was delayed by about 2.5 days. By contrast, Myf-5(−/−) embryos displayed normal muscle development in limb buds and brachial arches, and markedly delayed development of paraspinal and intercostal muscles. Although MyoD mutant embryos exhibited delayed development of limb musculature, normal migration of Pax-3-expressing cells into the limb buds and normal subsequent induction of Myf-5 in myogenic precursors was observed. These results suggest that Myf-5 expression in the limb is insufficient for the normal progression of myogenic development. Taken together, these observations strongly support the hypothesis that Myf-5 and MyoD play unique roles in the development of epaxial and hypaxial muscle, respectively.

Effects of meloxicam, compared with other NSAIDs, on cartilage proteoglycan metabolism, synovial prostaglandin E2, and production of interleukins 1, 6 and 8, in human and porcine explants in organ culture

Some non-steroidal anti-inflammatory drugs (NSAIDs) can accelerate joint damage in osteoarthritis by enhancing the production of pro-inflammatory cytokines or inhibiting cartilage proteoglycan synthesis. Meloxicam, a new NSAID, was compared with standard NSAIDs for its effect on proteoglycan synthesis and degradation in human and porcine cartilage explants, as well as the production of prostaglandin E2 (PGE2) and interleukins 1 and 6 by human synovial tissue explants in-vitro. Meloxicam at submicromolar concentrations inhibited synovial PGE2 production but, up to therapeutic drug concentrations (< or = 4 microM), did not affect synovial production of the pro-inflammatory cytokine IL-1. In contrast, hydrocortisone, 10 microM, a positive control, inhibited release of this cytokine, and indomethacin, 100 microM, increased its production. The lack of effects of meloxicam were evident irrespective of intrinsic IL-1 bioactivity of the synovia, production of IL-1 inhibitors or time of incubation. Production of the part anti-inflammatory cytokine IL-6, was significantly increased by therapeutic concentrations of meloxicam, as well as by indomethacin. Another major pro-inflammatory cytokine, IL-8, was unaffected by therapeutic concentrations of meloxicam. Meloxicam, 0.1-4.0 microM, did not affect cartilage proteoglycan production whereas indomethacin, 100 microM, significantly reduced synthesis of these macromolecules. Thus meloxicam, at concentrations within the therapeutic range and at which pronounced inhibition of prostaglandin production is evident, affects neither cartilage proteoglycan production nor the production of those cytokines likely to be important in cartilage destruction.

A newly isolated family of short interspersed repetitive elements (SINEs) in coregonid fishes (whitefish) with sequences that are almost identical to those of the SmaI family of repeats: possible evidence for the horizontal transfer of SINEs

The SmaI family of repeats is present only in the chum salmon and the pink salmon, and it is not present in five other species in the same genus or in other species in closely related genera. In the present study, we showed that another short interspersed repetitive elements (SINEs) family, which is almost identical to the SmaI family, is present in all fishes in the subfamily Coregoninae, being regarded as the most primitive salmonids. This new family of SINEs was designated the SmaI-cor family (SmaI family of repeats in coregonids). The consensus sequence of the SmaI-cor family was found to be 98.6% homologous to that of the SmaI family. Accordingly, it is difficult to explain the high degree of homology between these two families of SINEs by any mechanism other than the horizontal transfer of SINEs. The estimates of the rate of neutral mutation of nuclear genes, comparing chum salmon and European whitefish, confirmed this possibility. Our results strongly suggest that a member(s) of the SmaI-cor family might have been transferred horizontally from one coregonid species to a common ancestor of chum and pink salmon or to these two species independently, to allow subsequent amplification of the SmaI family in their respective genomes.

Histone acetyltransferase activity is conserved between yeast and human GCN5 and is required for complementation of growth and transcriptional activation

Yeast and human ADA2 and GCN5 (y- and hADA2 and y- and hGCN5, respectively) have been shown to potentiate transcription in vivo and may function as adaptors to bridge physical interactions between DNA-bound activators and the basal transcriptional machinery. Recently it was shown that yGCN5 is a histone acetyltransferase (HAT), suggesting a link between enzymatic modification of nucleosomes and transcriptional activation. In this report, we demonstrate that hGCN5 is also an HAT and has the same substrate specificity as yGCN5. Since hGCN5 does not complement functional defects caused by deletion of yGCN5, we constructed a series of hGCN5-yGCN5 chimeras to identify human regions capable of activity in yeast. Interestingly, only the putative HAT domain of hGCN5, when fused to the remainder of yGCN5, complemented gcn5- cells for growth and transcriptional activation. Moreover, an amino acid substitution mutation within the HAT domain reduced both HAT activity in vitro and transcription in vivo. These findings directly link enzymatic histone acetylation and transcriptional activation and show evolutionary conservation of this potentially crucial pathway in gene regulation.

Estrogen-induced changes in rRNA accumulation and RNA polymerase I activity in the rat pituitary: correlation with pituitary tumor susceptibility

Chronic treatment with the synthetic estrogen diethylstilbestrol induces pituitary tumors in rats and the susceptibility to such tumors is highly strain dependent. The Fischer 344 (F344) strain, which is particularly susceptible, develops pituitary tumors after 30-55 days of estrogen treatment. In contrast, the Sprague-Dawley (SD) strain is relatively resistant to such tumors. DES implants (5 mg) were placed in 21-day-old male rats over a 10-day period and changes in their testes and pituitaries were monitored. Both F344 and SD strains responded similarly by exhibiting a measurable decrease in testes weight to one-third that of controls on day 10. In F344 rats, DNA synthesis in the pituitary increased to 228% as compared with controls after 3 days of DES treatment and remained high on days 7 and 10. In SD rats, DNA synthesis increased to only 150% of that exhibited by controls on day 3 and started to decline on day 7. Surprisingly, total RNA accumulation also responded to DES differentially between these two strains. In F344 rats, the RNA level was 250% as compared with that of controls after 3 days of DES treatment and continued to increase gradually on days 7 and 10. The RNA level in the SD strain increased only slightly from the same DES treatment. A nuclear run-on assay showed elevated pituitary transcription of ribosomal DNA in the F344 rats after 3 days of estrogen administration. The enzymatic activity of pituitary RNA polymerase I, the enzyme responsible for initiating rRNA synthesis, increased twofold in F344 rats when measured after 3 days of estrogen treatment whereas no increase was observed in the SD rats. These results suggest that estrogen-induced changes in the accumulation of rRNA occur at a very early stage in tumorigenesis, prior to any visible tumor growth in the rat pituitary.

Expression and localization of inhibin/activin and activin receptors in GH3 cells, a rat pituitary adenocarcinoma cell line

Inhibins and activins are members of the transforming growth factor beta (TGF beta) superfamily. Since TGF beta has been shown to be a potent proliferation-inhibiting agent for the pituitary adenocarcinoma cell line, GH3, we determined whether this cell line (a) transcribes mRNAs coding for inhibin/activin subunits (alpha and beta A) and activin receptors I, II, and IIB; and (b) produces inhibin and/or activin proteins. Messenger RNAs for the alpha- and beta A-subunits of inhibin and activin receptors I, II, and IIB in GH3 cells were detected and localized using the reverse transcription-polymerase chain reaction (RT-PCR) analysis and in situ hybridization, respectively. The identity of the RT-PCR products was confirmed by DNA sequencing of PCR products. Immunocytochemically, inhibin and activin were localized in these cells. Our findings indicate that messenger RNAs encoding inhibin alpha- and beta A-subunits and activin receptors I, II, and IIB were expressed, and inhibin/activin proteins were produced, by GH3 cells, imply that these gonadal growth factors may have paracrine/autocrine functions in rat pituitary adenocarcinoma. Further, these observation suggest that these growth factors may be involved in regulating the growth and differentiational of rat pituitary adenocarcinoma cells.

Effects of 5-lipoxygenase inhibitors on interleukin production by human synovial tissues in organ culture: comparison with interleukin-1-synthesis inhibitors

Prostaglandins and leukotrienes differentially regulate the production of interleukin-1 (IL-1) in monocytes. It was, therefore, decided to investigate the effects of some 5-lipoxygenase inhibitors compared with standard IL-1 synthesis inhibitors on the production of IL-1 by human synovial tissue explants in organ culture. Human synovial (from hip/knee arthroplasty) or porcine tibio-tarsal joint synovial explants were incubated in organ culture in Dulbecco's Modified Eagle's Medium + 5% foetal calf serum in the presence of the test compounds or solvents (controls), or media alone for 1-5 days. Total bioactive IL-1 was assayed in the medium (following serial dilution or with polyethylene glycol 8000 added in some assays to remove inhibitors) using the D-10 T-cell bioassay. Some assays of interleukins 1 alpha, 1 beta, 6 or 8 were performed by ELISA. Of the 5-lipoxygenase inhibitors investigated, MK-886(3-(1-(4-chlorobenzyl)-3-tert-butyl-thio-5-isopropylindol-2- yl)-2,2 -dimethyl propanoic acid), L-656,224 ((7-chloro-2-[4-methoxypenyl]methyl)-3 -methyl-5-propyl-4-benzofuranol), PF-5901 and tepoxalin were the most potent inhibitors of IL-1 production. While the PF-5901 was effective at 5-30 microM and tepoxalin was effective at 1-10 microM, the others were the most potent having minimal inhibitory activity in the range of 0.01-0.1 microM. The presumed IL-1-synthesis inhibitors, tenidap and IX-207,887, were inactive at concentrations of 30-50 microM. Leukotriene B4 (1-100 ng/mL-1) added to MK-886 (5 microM)-treated cultures reversed the inhibitory effects of the latter on IL-1, confirming the role of 5-lipoxygenase products in the regulation of IL-1 production. Addition of polyethylene glycol 8000 to MI-886-treated cultures eliminated the inhibitory effects of this drug, suggesting that this drug exerts its effects by promoting production of IL-1 inhibitors. MK-886 also inhibited synovial production of two other pleiotrophic cytokines which it regulates, IL-6 and IL-8. The results suggest that some 5-lipoxygenase inhibitors may be usefully employed in regulating production of those interleukins involved in joint cartilage destruction.

Expression and localization of activin beta A-subunit and activin receptors in TM3, a mouse Leydig cell line

We have determined whether TM3 cells, a cell line derived from a murine Leydig cell tumor, (a) transcribe messenger RNAs encoding the beta A-subunits of inhibin/activin, and activin receptors I, II, and IIB, and (b) produce activin-A protein. Messenger RNAs for inhibin/activin beta A-subunits and activin receptors II, and IIB in TM3 cells were localized and expressed using in situ hybridization and the reverse transcription-polymerase chain reaction (RT-PCR) analysis, respectively. The identify of the RT-PCR products was confirmed by DNA sequencing of PCR products. Immunocytochemically, activin-A was localized in these cells. We observed that messenger RNAs encoding activin beta A-subunit as well as activin receptors II, and IIB were expressed and activin protein was produced by TM3 cells. These findings suggest that activin-A may have autocrine functions in TM3 cells and that activin-A may be involved in regulating the growth and differentiation of mouse Leydig cells.

DNA topology regulates rat prolactin gene transcription

A cell-free transcription system was used to examine the effects of DNA negative supercoiling on transcription from rat prolactin promoters. The mRNA was faithfully transcribed from prolactin promoters that contained the DNA fragment spanning from -1960 to -10 base pairs upstream of the prolactin transcription start site. Prolactin promoters in supercoiled form, prepared from Escherichia coli, have a higher transcriptional efficiency than the promoter in the relaxed form. Deletion of DNA sequences containing the estrogen response element and putative non-B form DNA elements from the upstream region of the prolactin gene did not alter this effect of DNA topology on prolactin transcription. We further separated transcription into preinitiation and elongation steps by using sarkosyl and found that more preinitiation complexes were assembled on the supercoiled prolactin promoters than on the relaxed promoters. DNA supercoiling therefore plays an important role in controlling prolactin gene expression by facilitating the formation of preinitiation complexes on the promoters.

Purification and reconstitution of the methyl-accepting chemotaxis proteins from Bacillus subtilis

The methyl-accepting chemotaxis proteins (MCPs) from Bacillus subtilis, designated as H1, H2, and H3, have been purified to near homogeneity. These purified MCPs were reconstituted into proteoliposome vesicles using a detergent dilution procedure. The ability of the reconstituted MCPs to be methylated in vitro strongly suggests that they are in a functionally active conformation. The MCPs of B. subtilis are considerably larger than those of Escherichia coli, with molecular weights of the purified proteins being 76, 86, and 97 kDa for H3, H2, and H1, respectively. Two-dimensional electrophoresis demonstrates that the isoelectric point of H1 and H2 is 5.1, while H3 is slightly more basic, having an isoelectric point of 5.3. Immunoblot analysis using the cross reacting E. coli anti-Trg antibody reveals that maximal MCP expression occurs approx. 4 h after the onset of stationary phase, and remains relatively stable thereafter. However, the ability of the MCPs to be methylated in vivo is significantly reduced.

Selective effects of some 5-lipoxygenase inhibitors on synovial interleukin-1 (IL-1) production compared with IL-1 synthesis inhibitors

To determine the role of 5-LO regulation of IL-1 in synovial tissues, we examined the effects of 5-LO inhibitors compared with standard IL-1 synthesis inhibitors on IL-1 production by human synovial tissue explants from patients with inflammatory arthropathies. MK886, L-656,224, PF-5901, and tepoxalin all inhibited IL-1 production in concentrations up to 10 microM, whereas other 5-LO inhibitors (ICI-211,965, zileuton), as well as IL-1 synthesis inhibitors (IX-207,887, tenidap), were inactive. LT products, thus regulate IL-1 production and inhibition thereof is one strategy for inhibiting this cytokine.

Mechanisms of skin rashes from fenbufen

Fenbufen-induced skin rash was investigated by determining the metabolism of the drug to reactive products. At least five lipophilic products (unidentified), the active metabolite of this drug, biphenyl acetic acid (BPAA), and a gamma-hydroxylated derivative (gamma-hydroxy[1,1'-biphenyl]-4-butanoic acid) were identified in keratinocytes in vitro and in skin of rats and guinea pigs in vivo. The gamma-OH derivatives of BPAA and fenbufen were recovered from papain digests of the prior ether-extracted keratinocyte proteins. Fenbufen and its gamma-OH metabolite stimulated the production of interleukin-1 from keratinocytes exposed to UV radiation but BPAA did not. Inflammatory reactions from fenbufen may therefore, arise from production of its metabolites which yield IL-1 upon exposure to UV radiation.

Impact of large-dose vitamin A supplementation on childhood diarrhoea, respiratory disease and growth

One hundred and seventy-two 0.5-3.0-year-old children in a mountainous area of northern Hebei Province of China were randomly assigned to a vitamin A supplementation group (n = 98) or a control group (n = 74) for a 1 year double-blind study. Capsules containing 200,000 IU vitamin A and 40 IU vitamin E were given to the children in the experimental group 3 and 9 months after baseline examination. During the 12 month study period, there was a significant reduction in the incidence of diarrhoea (P < 0.01) and respiratory disease (P < 0.01) in the children of the experimental group compared to the control. Risk of diarrhoea and respiratory disease were respectively 2.5 and 3.4 times higher in the control children. Serum retinol and IgA levels of the treatment group were significantly higher than that of control group (P < 0.01) 7 weeks after first supplementation. There was no significant difference in saliva IgA level between groups. No significant differences in growth were observed. It was concluded that supplementation with large doses of vitamin A decreased the incidence and severity of diarrhoea and respiratory disease in these children, possibly through enhanced activity of the immune system, but had no effect on growth over 1 year.

Perturbations in the model of estrogen receptor regulation of gene expression

Estrogen receptors are key elements in the mechanisms of action of estrogenic hormones. Models of how estrogens and their receptors interact and subsequently modify gene expression should be reevaluated to explain new data currently available. The following review discusses nuclear localization, DNA binding, and protein structural changes of the estrogen receptor induced by estrogen binding. We also discuss how these phenomena relate to the induction of changes in gene expression.

Gene-protein relationships in the flagellar hook-basal body complex of Bacillus subtilis: sequences of the flgB, flgC, flgG, fliE and fliF genes

The nucleotide sequence of five genes from the major Bacillus subtilis chemotaxis locus has been determined. Four of these genes encode proteins that are homologous to the Salmonella typhimurium FlgB, FlgC, FlgG and FliF proteins. One gene encodes a protein that is homologous to the Escherichia coli FliE protein. The data from S. typhimurium and E. coli suggest that all of these proteins form part of the hook-basal body (HBB) complex of the bacterial flagella. The FlgB, FlgC and FlgG proteins are components of the proximal and distal rods. The FliF protein forms the M-ring that anchors the rod assembly to the membrane. The role of the FliE protein within the HBB complex has not yet been determined. The similarity between the B. subtilis and S. typhimurium proteins suggests that the structure of the M-ring and the rod may be similar in the two species. However, we observed some differences in size and amino acid composition between some of the corresponding homologues that suggest the basal body proteins may be organized slightly differently within B. subtilis.

Low levels of prostaglandins in human milk after purification by high performance liquid chromatography

In order to validate methodology for quantifying arachidonic acid metabolites in human milk, we measured five prostaglandins (PGs) using radioimmunoassay (RIA): PGE2, PGF2 alpha, thromboxane B2 (TXB2), 6-keto-PGF1 alpha (6KF1 alpha) and 13,14-dihydro-15-keto-PGF2 alpha (DHKF2 alpha). RIA was performed after extraction with C18 Sep-Pak cartridge and/or further purification with reverse-phase high performance liquid chromatography (rp-HPLC). Recovery was monitored throughout the purification steps. Confirming findings of previously reported studies, we found PGE and the PGF2 alpha metabolite, DHKF2 alpha to be the major PGs in extracted human milk. After HPLC purification, however, no predominant PG was found, and the PG levels, especially those of PGE2 and DHKF2 alpha, were considerably lower than levels in the extracted sample. A noteworthy finding was the presence of immunoreactive substances in HPLC fractions not within the area of the PG peak; this suggests that the decreased levels of PGs in human milk measured by RIA after rp-HPLC are due to the elimination of the nonspecific immunoreactive materials present in the sample.