[A report of 7 cases of toxic liver disease caused by mixed gas in a shoe factory]

Trichloromethane and dichloromethane have toxic effects on the liver, and incidents of toxic liver disease caused by them have been reported from time to time. In November 2021, an occupational chemical poisoning incident occurred in a shoe factory in Huidong County, Guangdong Province. After testing the air at the scene and analyzing the clinical data of the poisoning patients, it was preliminarily determined that the poisoning was caused by a mixed gas poisoning incident dominated by trichoromethane. At admission, the liver function of 7 patients was tested for different degrees of impairment (alanine aminotransferase 145-2501 IU/L, aspartate aminotransferase 66-1286 IU/L). The volatile organic components of on-site raw and auxiliary materials were analyzed. The percentages of trichloromethane and dichloromethane detected in 103A powder glue used in the poisoning workshop site accounted for 21.11% and 6.77% respectively.

[A multicenter study of the condition of children's rheumatic disease associated medical resources in Fujian province]

Objective: To investigate general condition of children's rheumatic disease associated medical resources in Fujian Province. Methods: This questionnaire-based survey was conducted in 19 hospitals in Fujian province from December 2, 2018 to May 1, 2019. The questionnaire was designed to survey the general condition of the medical resources and the hospitalization of patients with rheumatic diseases from January 1, 2014 to December 1, 2018. Results: In the 19 hospitals, there were 15 general hospitals and 4 children's hospitals, and only 5 hospitals had children's rheumatic specialist clinic. There were only 53-62 beds for rheumatic disease patients in the 19 hospitals, accounting for 1.7%-2.0% of the total inpatient beds (3 137). There are 29 pediatric rheumatologists in total, accounting for 2.6% (29/1 120) of the total pediatricians. In the past five years, 613 patients with rheumatic diseases, accounting for 0.1% (613/625 214) of total hospitalized patients, were treated in these hospitals. Among them, 201 had juvenile idiopathic arthritis, 295 had systemic lupus erythematosus, 39 had dermatomyositis, 7 had scleroderma, and 57 had inflammatory bowel disease, 9 had Sjogren's syndrome, 5 had Behcet's disease, and none had overlap syndrome or mixed connective tissue disease. Conclusion: The medical resources of children rheumatic diseases in Fujian province are insufficient which need to be developed.

Impact of meteorological and geographical factors on the distribution of Phlebotomus chinensis in northwestern mainland China

Phlebotomine sandflies (Diptera: Phlebotomidae) are vectors of the zoonotic disease leishmaniasis. To better understand the distribution of phlebotomine sandflies in order to facilitate control of leishmaniasis transmission, the present study explored the impacts of climate and landscape on local abundances of Phlebotomus chinensis in northwestern mainland China. Identification records were used to create a geodatabase for the locations at which P. chinensis had been collected in the region, and a regional-scale map was developed to show the distribution of P. chinensis. Location data and data on environmental factors during the years in which the samples were collected were incorporated, and a presence-only modelling method was used to evaluate the species' habitat preferences and to predict its potential distribution in northwestern mainland China. Jackknife analysis revealed that several meteorological variables, including maximum temperature in the warmest quarter, precipitation in the driest month, daily average temperature and daily precipitation, significantly affected the presence of this species. Moreover, the presence of P. chinensis was significantly associated with grassland and shrubland. Probability distributions using maximum entropy were used to map the distribution ranges of P. chinensis based on suitable habitats in northwestern mainland China. The models generated can be used to develop detailed strategies for the prevention and control of leishmaniasis.

Association between the rs3795879 G/A polymorphism of the SERPINE2 gene and chronic obstructive pulmonary disease: a meta-analysis

The present study aimed to investigate the effects of the rs3795879 polymorphism of the SERPINE2 gene on the development of chronic obstructive pulmonary disease (COPD) based on a systematic meta-analysis. An extensive literature search was performed to retrieve previously published case-control studies on the polymorphisms of SERPINE2 in COPD patients. Odds ratios (ORs) with 95% confidence intervals (CIs) were used to assess the association between SERPINE2 polymorphisms and risk of developing COPD. A total of 5 studies including 3034 COPD cases and 3068 controls were incorporated in the present meta-analysis. Generally, no significant association was identified between the rs3795879 polymorphism of SERPINE2 and the risk of developing COPD (G allele vs A allele: OR = 1.23, 95%CI = 0.97-1.32; GG vs GA: OR = 1.19, 95%CI = 0.81-1.76; GG vs AA: OR = 1.23, 95%CI = 0.89-1.70; dominant model: OR = 1.18, 95%CI = 0.85- 1.62; recessive model: OR = 1.19, 95%CI = 0.85-1.66). In addition, subgroup analyses according to different ethnicities and the source of controls suggest no statistically significant association between the rs3795879 polymorphism of SERPINE2 and COPD risk. The results suggest that the rs3795879 polymorphism of SERPINE2 is not a risk factor for COPD.

Odorant-binding protein (OBP) genes affect host specificity in a fig-pollinator mutualistic system

The interaction between figs and their pollinating wasps is regarded as a model system for studying specialized co-evolved mutualism. Chemoreception of fig wasps plays an important role in this interaction, and odorant-binding proteins (OBP) function in the first step of odorant detection. The OBP repertoire of the fig wasp Ceratosolen solmsi is reported to be one of the smallest among insects; however, it is unknown how these OBPs are related to the complicated mating process occurring within the fig cavity and the extreme host specificity of the species. In the present study, we combined a structural analysis of the conserved cysteine pattern and motif order, a phylogenetic analysis, and previous studies on ligand-binding assays to deduce the function of OBPs. We also quantified the expression of OBP genes in different life stages of female and male fig wasps by using real-time quantitative PCR, which can help to predict the function of these genes. The results indicated that CsolOBP1 and CsolOBP2 (or CsolOBP5) in males may bind to pheromones and play important roles in mate choice, whereas CsolOBP4 and CsolOBP5 may primarily function in host localization by females through binding of volatile compounds emitted by receptive figs.

Diversity of bacterial symbionts in populations of Sitobion miscanthi (Hemiptera: Aphididae) in China

Aphids are a group of insects frequently associated with bacterial symbionts. Although Chinese aphids harbor a high level of species diversity, the associations between Chinese aphids and bacterial symbionts are less known. In this study, we uncovered the diversity of bacterial symbionts in a Chinese widespread aphid, Sitobion miscanthi (Takahashi). In this study, we detected the aphid obligate symbiont Buchnera aphidicola, and two secondary symbionts, Hamiltonella defensa and Regiella insecticola, with the diagnostic polymerase chain reaction method in S. miscanthi samples. In addition, symbiotic species of Acinetobacter, Aeromonas, Enterobacter, Pantoea, and Pseudomonas, and the family Enterobacteriaceae were also found. Geographically, sporadic occurrences were detected for H. defensa and R. insecticola. Moreover, the infection rates of them vary widely among the infected populations: H. defensa (5.26-95.2%) and R. insecticola (5.26-46.7%). Phylogenetic analyses indicated that the strain of B. aphidicola mirrored the history and divergence of S. miscanthi; however, the H. defensa and R. insecticola strains were probably experienced horizontal transmission among S. miscanthi and its distantly related species.

Multiple ancient horizontal gene transfers and duplications in lepidopteran species

Eukaryotic horizontal gene transfer (HGT) events are increasingly being discovered yet few reports have summarized multiple occurrences in a wide range of species. We systematically investigated HGT events in the order Lepidoptera by employing a series of filters. Bombyx mori, Danaus plexippus and Heliconius melpomene had 13, 12 and 12 HGTs, respectively, from bacteria and fungi. These HGTs contributed a total of 64 predicted genes: 22 to B. mori, 22 to D. plexippus and 20 to H. melpomene. Several new genes were generated by post-transfer duplications. Post-transfer duplication of a suite of functional HGTs has rarely been reported in higher organisms. The distributional patterns of paralogues for certain genes differed in the three species, indicating potential independent duplication or loss events. All of these HGTs had homologues expressed in some other lepidopterans, indicating ancient transfer events. Most HGTs were involved in the metabolism of sugar and amino acids. These HGTs appeared to have experienced amelioration, purifying selection and accelerated evolution to adapt to the background genome of the recipient. The discovery of ancient, massive HGTs and duplications in lepidopterans and their adaptive evolution provides further insights into the evolutionary significance of the events from donors to multicellular host recipients.

Apis mellifera has two isoforms of cytoplasmic HSP90

Unlike most other insects, annotated genomic data suggest that Apis mellifera has two homologous copies of the cytoplasmic gene HSP90. In this study, we did a phylogenetic analysis on these two copies with some other insects HSP90 genes, and we also manipulated a reverse transcript (RT)-PCR to find all the putative transcripts for both copies. Phylogenetic analysis indicates that A. mellifera possesses two isoforms of cytoplasmic HSP90: The 'traditional' isoform clusters with cytoplasmic HSP90 of other insects. The other isoform, which occurs phylogenetically as the sister group of all insects, may be a new gene and specific to A. mellifera. The results of RT-PCR indicate that this new isoform contains at least eight transcripts derived from the same genomic locus by complicated alternative splicing (GenBank accession numbers: FJ713701, FJ713702, FJ713703, FJ713704, FJ713705, FJ713706, FJ713707 and FJ713708, respectively). The existence of this specific HSP90 might be related to the caste differentiation of bees.

Effects on superconductivity of transition-metal doping in FeSe(0.5)Te(0.5)

We investigate superconductivity in the compound FeSe(0.5)Te(0.5) and in its transition-metal-substituted derivatives Fe(1-x)TM(x)Se(0.5)Te(0.5), where x = 5% and the substituent ions studied were Mn, Co, Ni, Cu and Zn. Electronic and magnetic measurements indicate that doping with Mn or by Co acts respectively to cause a slight enhancement or suppression of the transition temperature. However, doping with this concentration of Ni or Cu destroys the superconductivity completely, and leads to semiconducting behaviour. Zn ions cannot be incorporated properly into the parent compound. The reasons for these contrasting effects are associated with the differing magnetic properties of the substituent ions, which determine their local impurity moments and the net carrier concentrations in the doped 11 system. The effects of magnetic ion substitution on superconductivity suggest that the pairing symmetry may not be either pure s wave or pure d wave.

Isolation and expression of GA 2-oxidase2 in tomato

GA 2-oxidases, a key enzyme involves GA biosynthesis, catalyze the degradation of active C(19)-Gibberellins (GAs) through 2-hydroxylation yields inactive GA product. Searching public tomato database, the putative GA2ox2 sequences were assembled. We isolated a full-length GA2ox2 cDNA with primers designed from the assembled sequence. This gene was designed as SlGA2ox2 (GenBank accession No. EF017805). The full-length GA2ox2 gene contained a complete open reading frame (ORF) of 1203 bp, which encoded 322 amino acid residues. Amino acid sequence homology analysis of SlGA2ox2 showed an 88% identity with NtGA2ox2 in tobacco. And alignments of SlGA2ox2 with other known GA2ox from Arabidopsis, Pea, Adzuki Bean, Winter Squash etc indicate low similarity of 47-70%. Semi-quantitative RT-PCR analysis showed a specific expression profile of SlGA2ox2 in different tissues, which mainly expressed in flowers and traces were detected in roots, stems, leaves and immature fruits.

Optimization of submerged culture requirements for the production of mycelial growth and exopolysaccharide by Cordyceps jiangxiensis JXPJ 0109

AIMS

The objective of the present study was to investigate the optimal culture requirements for mycelial growth and exopolysaccharide production by Cordyceps jiangxiensis JXPJ 0109 in submerged culture.

METHODS AND RESULTS

The effects of medium ingredients (i.e. carbon and nitrogen sources, and growth factor) and other culture requirements (i.e. initial pH, temperature, etc.) on the production of mycelia and exopolysaccharide were observed using a one-factor-at-a-time method. More suitable culture requirements for mycelial growth and exopolysaccharide production were proved to be maltose, glycerol, tryptone, soya bean steep powder, yeast extract, medium capacity 200 ml in a 500-ml flask, agitation rate 180 rev min(-1), seed age 4-8 days, inoculum size 2.5-7.5% (v/v), etc. The optimal temperatures and initial pHs for mycelial growth and exopolysaccharide production were at 26 degrees C and pH 5 and at 28 degrees C and pH 7, respectively, and corresponding optimal culture age were observed to be 8 and 10 days respectively. According to the primary results of the one-factor-at-a-time experiments, the optimal medium for the mycelial growth and exopolysaccharide production were obtained using an orthogonal layout method to optimize further. Herein the effects of medium ingredients on the mycelial growth of C. jiangxiensis JXPJ 0109 were in the order of yeast extract > tryptone > maltose > CaCl2 > glycerol > MgSO4 > KH2PO4 and the optimal concentration of each composition was 15 g maltose (food-grade), 10 g glycerol, 10 g tryptone, 10 g yeast extract, 1 g KH2PO4, 0.2 g MgSO4, and 0.5 g CaCl2 in 1 l of distilled water, while the order of effects of those components on exopolysaccharide production was yeast extract > maltose > tryptone > glycerol > KH2PO4 > CaCl2 > MgSO4, corresponding to the optimal concentration of medium was as follows: 20 g maltose (food-grade), 8 g glycerol, 5 g tryptone, 10 g yeast extract, 1 g KH2PO4, and 0.5 g CaCl2 in 1 l of distilled water.

CONCLUSIONS

Under the optimal culture requirements, the maximum exopolysaccharide production reached 3.5 g l(-1) after 10 days of fermentation, while the maximum production of mycelial growth achieved 14.5 g l(-1) after 8 days of fermentation.

SIGNIFICANCE AND IMPACT OF THE STUDY

This is the first report on the submerged culture requirements for mycelial growth and exopolysaccharide in C. jiangxiensis, and this two-step optimization strategy in this study can be widely applied to other microbial fermentation processes.

Effects of regenerator geometry on pulse tube refrigerator performance

This paper gives results of the cooling performance of a double-inlet pulse tube refrigerator using various regenerators. The same pulse tube was used for all the experiments and measured 4.76 mm in diameter and 46.2 mm in length. A commercial linear compressor with a swept volume of 4 cm3 was used in these experiments. The operating conditions were held constant at a mean pressure of 2.0 MPa and a frequency of 54 Hz. Using finite difference software called REGEN3.1, developed at NIST, and recent experiment results, we optimized a series of regenerators based on dimensions, materials and screen packing. The values used for calculating the thermal conduction through stacked screens by REGEN3.1 were based on recent experimental results from NIST. The regenerator tubes were designed using 316 stainless steel and titanium materials. The regenerator matrices investigated were 400-mesh and 500-mesh stainless steel screen. The valve settings for both orifices were adjusted to minimize the no-load temperature for all regenerators. A cooling capacity curve from 0 to 3 W was also determined. The performance of the pulse tube refrigerator using the different regenerators is discussed. The experimental results from the various regenerators are evaluated and compared with their corresponding numerically calculated coefficient of performance (COP) and regenerator design as determined by REGEN3.1.

Temporally-controlled site-specific mutagenesis in the basal layer of the epidermis: comparison of the recombinase activity of the tamoxifen-inducible Cre-ER(T) and Cre-ER(T2) recombinases

Conditional DNA excision between two LoxP sites can be achieved in the mouse using Cre-ER(T), a fusion protein between a mutated ligand binding domain of the human estrogen receptor (ER) and the Cre recombinase, the activity of which can be induced by 4-hydroxy-tamoxifen (OHT), but not natural ER ligands. We have recently characterized a new ligand-dependent recombinase, Cre-ER(T2), which was approximately 4-fold more efficiently induced by OHT than Cre-ER(T) in cultured cells. In order to compare the in vivo efficiency of these two ligand-inducible recombinases to generate temporally-controlled somatic mutations, we have engineered transgenic mice expressing a LoxP-flanked (floxed) transgene reporter and either Cre-ER(T) or Cre-ER(T2) under the control of the bovine keratin 5 promoter that is specifically active in the epidermis basal cell layer. No background recombinase activity could be detected, while recombination was induced in basal keratinocytes upon OHT administration. Interestingly, a dose-response study showed that Cre-ER(T2) was approximately 10-fold more sensitive to OHT induction than Cre-ER(T).

1,25-Dihydroxyvitamin D3 increases nuclear vitamin D3 receptors by blocking ubiquitin/proteasome-mediated degradation in human skin

1,25-Dihydroxyvitamin D3 (D3) exerts its effects by binding to and activating nuclear vitamin D3 receptors (VDRs) that regulate transcription of target genes. We have investigated regulation of VDR levels in human skin in vivo and in cultured human keratinocytes. Quantitative ligand-binding analysis revealed that human skin expressed approximately 220 VDRs per cell, which bound D3 with high affinity [(dissociation constant (Kd) = 0.22 nM]. In human skin nuclear extracts, VDR exclusively bound to DNA containing vitamin D3 response elements as heterodimers with retinoid X receptors. Topical application of D3 to human skin elevated VDR protein levels 2-fold, as measured by both ligand-binding and DNA-binding assays. In contrast, the D3 analog calcipotriene had no effect on VDR levels. Topical D3 had no effect on VDR mRNA, indicating that D3 either stimulated synthesis and/or inhibited degradation of VDRs. To investigate this latter possibility, recombinant VDRs were incubated with skin lysates in the presence or absence of D3. The presence of D3 substantially protected VDRs against degradation by human skin lysates. VDR degradation was inhibited by proteasome inhibitors, but not lysosome or serine protease inhibitors. In cultured keratinocytes, D3 or proteasome inhibitors increased VDR protein without affecting VDR mRNA levels. In cells, VDR was ubiquitinated and this ubiquitination was inhibited by D3. Proteasome inhibitors in combination with D3 enhanced VDR-mediated gene expression, as measured by induction of vitamin D3 24-hydroxylase mRNA in cultured keratinocytes. Taken together, our findings indicate that low VDR levels are maintained, in part, through ubiquitin/proteasome-mediated degradation and that low VDR levels limit D3 signaling. D3 exerts dual positive influences on its nuclear receptor, simultaneously stimulating VDR transactivation activity and retarding VDR degradation.

Identification of heparin-binding EGF-like growth factor as a target in intercellular regulation of epidermal basal cell growth by suprabasal retinoic acid receptors

The role of retinoic acid receptors (RARs) in intercellular regulation of cell growth was assessed by targeting a dominant-negative RARalpha mutant (dnRARalpha) to differentiated suprabasal cells of mouse epidermis. dnRARalpha lacks transcriptional activation but not DNA-binding and receptor dimerization functions. Analysis of transgenic mice revealed that dnRARalpha dose-dependently impaired induction of basal cell proliferation and epidermal hyperplasia by all-trans RA (tRA). dnRARalpha formed heterodimers with endogenous retinoid X receptor-alpha (RXRalpha) over RA response elements in competition with remaining endogenous RARgamma-RXRalpha heterodimers, and dose-dependently impaired retinoid-dependent gene transcription. To identify genes regulated by retinoid receptors and involved in cell growth control, we analyzed the retinoid effects on expression of the epidermal growth factor (EGF) receptor, EGF, transforming growth factor-alpha, heparin-binding EGF-like growth factor (HB-EGF) and amphiregulin genes. In normal epidermis, tRA rapidly and selectively induced expression of HB-EGF but not the others. This induction occurred exclusively in suprabasal cells. In transgenic epidermis, dnRARalpha dose-dependently inhibited tRA induction of suprabasal HB-EGF and subsequent basal cell hyperproliferation. Together, our observations suggest that retinoid receptor heterodimers located in differentiated suprabasal cells mediate retinoid induction of HB-EGF, which in turn stimulates basal cell growth via intercellular signaling. These events may underlie retinoid action in epidermal regeneration during wound healing.

Keratinocyte-specific retinoid regulation of human cellular retinoic acid binding protein-II (hCRABPII) gene promoter requires an evolutionarily conserved DR1 retinoic acid-responsive element

Transcription of the hCRABPII gene is retinoid inducible in human skin keratinocytes (KC) but, surprisingly, not in cultured cells. The promoter for the gene harbors three putative nuclear receptor binding sites: DR5, upstream of the transcription start site; DR1 (DR1d), distal to the site; and DR1 (DR1p), a proximal variant. DR1d, but not DR1p, is conserved between human and mouse. Although DR5 has been found to be a retinoid receptor target in COS-1 cells, the function of DR1 remains unknown. We examined the functions of these DR in retinoid regulation of the hCRABPII promoter in human KC. In reporter gene assays, no significant retinoid response was observed in the promoter in cultured KC; however, overexpression of retinoid receptor heterodimers RARgamma x RXRalpha restored the response. Gel supershift assays showed that endogenous RARgamma x RXRalpha levels are much lower in cultured KC than in skin in vivo. Ligand-binding assays showed that cultured KC contain only one-third of the level of retinoic acid receptor (RAR) and one-eighth of the level of retinoid X receptor found in KC in skin. Deletion of the DR1d or DR5 sites reduced retinoid-induced promoter activity by 63% and 27%, respectively. Isolated DR1d and DR5 sites, but not DR1p, efficiently bound RARgamma-RXRalpha and conferred RAR-selective retinoid responsiveness on a heterologous promoter. These data indicate that: (i) the previously reported lack of retinoid regulation of endogenous hCRABPII gene transcription in cultured KC is likely due to insufficient levels of RARgamma x RXRalpha, but not their cofactors; (ii) the conserved DR1d site is the major functional target in RARgamma x RXRalpha regulation of hCRABPII in KC; (iii) the DR1p site is nonfunctional due to its lack of affinity for RARgamma x RXRalpha, although its half-sites share high sequence homology with the consensus retinoid receptor-binding half-site.

Retinoid X receptor-specific ligands synergistically upregulate 1, 25-dihydroxyvitamin D3-dependent transcription in epidermal keratinocytes in vitro and in vivo

We have examined the mechanism by which endogenous retinoid X receptor (RXR), vitamin D3 receptor (VDR), and cognate ligands regulate nuclear 1,25-dihydroxyvitamin D3 (D3) signaling in epidermal keratinocytes from skin, a physiologic D3 target. In vitro, RXR and VDR-specific antibodies identified endogenous RXR and VDR bound to a vitamin D3-responsive element (DR3) as heterodimers (VDR-RXR). In cultured keratinocytes, 9-cis retinoic acid (9cRA), a panagonist for RXR and retinoic acid receptor (RAR), and an RXR-selective agonist, SR11237, synergized with D3 to activate DR3 via endogenous as well as overexpressed VDR-RXR, whereas both of these RXR agonists alone were ineffective. In contrast, SR11237 did not synergize with but antagonized an RAR-selective ligand activation of a retinoic acid-responsive element (DR5) via endogenous RAR-RXR. Furthermore, expression of RXR mutated in transactivation domain AF-2 inhibited endogenous VDR-RXR activity over DR3. This mutant efficiently bound to DR3 as VDR-RXR but showed reduced capacity to transactivate DR3 in response to D3 and SR11237. In vivo, D3 and SR11237 synergistically induced the naturally occurring D3-responsive 24-hydroxylase gene in epidermis of mouse skin, whereas SR11237 alone was ineffective. Our data suggest that allosteric changes caused by VDR in DR3-bound VDR-RXR do not block access of ligands to RXR. RXR ligand-induced conformational changes permit VDR-RXR, via both VDR and RXR activation function domains, to mediate maximal D3 signaling in keratinocytes.

Suprabasal expression of a dominant-negative RXR alpha mutant in transgenic mouse epidermis impairs regulation of gene transcription and basal keratinocyte proliferation by RAR-selective retinoids

To determine whether 9-cis retinoic acid receptors (RXRs) regulate the biological activity of all-trans retinoic acid (tRA) and its receptors (RARs) in skin, we have targeted a dominant-negative RXR alpha (dnRXR alpha) lacking transactivation function AF-2 to differentiated suprabasal keratinocytes in the epidermis of transgenic mice. Driven by the suprabasal-specific keratin-10 gene promoter, expression of dnRXR alpha severely reduced the ability of RAR-selective ligands tRA and CD367 to induce epidermal mRNA levels of the CRABPII, CRBPI, and CRBPII genes, which contain RA-responsive elements (RAREs) DR1 and/or DR2. It also reduced gene-specific, synergistic induction of CRBPI mRNA by a combination of CD367 and RXR-selective SR11237. Like endogenous RXR alpha, dnRXR alpha in epidermal nuclear extracts from the transgenic mice competitively formed heterodimers with endogenous RAR gamma on RAREs, suggesting that dnRXR alpha impairs retinoid signaling by competing with endogenous RAR gamma-RXR alpha heterodimers. Histologically, the epidermis of dnRXR alpha mice showed no detectable developmental abnormalities. Surprisingly, in adult animals, the suprabasal expression of dnRXR alpha significantly reduced the ability of topically applied tRA to stimulate proliferation of undifferentiated keratinocytes in the basal layer of epidermis. RXR-selective ligands alone had no detectable effects on both normal and transgenic mouse epidermis. Accordingly, we suggest that in vivo: (1) in suprabasal keratinocytes, retinoids regulate gene transcription via RAR-RXR heterodimers in which RAR confers a predominant ligand response, whereas RXR AF-2 is required for liganded RAR AF-2 to efficiently trans-activate target genes, and (2) this suprabasal RXR-assisted mechanism indirectly regulates proliferation of basal keratinocytes likely via intercellular signaling.

Endogenous retinoic acid receptor (RAR)-retinoid X receptor (RXR) heterodimers are the major functional forms regulating retinoid-responsive elements in adult human keratinocytes. Binding of ligands to RAR only is sufficient for RAR-RXR heterodimers to confer ligand-dependent activation of hRAR beta 2/RARE (DR5)

We have examined how retinoic acid receptors (RARs) and retinoid X receptors (RXRs) at physiological concentrations regulate distinct retinoid-responsive elements, hRAR beta 2/beta RARE (DR5) and rCRBPII/RXRE (DR1), in keratinocytes from human skin, a major retinoid target. In vitro, endogenous RAR gamma and RXRs bound to these elements as heterodimers (RAR.RXR) but not homodimers (RAR.RAR or RXR.RXR). In cultured keratinocytes, all-trans retinoic acid, 9-cis retinoic acid, and CD367 activated beta RARE but not RXRE via endogenous RAR.RXR (ED50 = 2.3, 3.8, and 0.3 nM, respectively) whereas SR11237 showed no significant effect. All-trans retinoic acid, 9-cis retinoic acid, and SR11237 activated RXRE via overexpressed RXR.RXR (ED50 = 110, 120, and 11 nM, respectively), indicating interconversion between retinoic acid isomers, whereas co-overexpression of RAR alpha or RAR gamma suppressed this activation. Unlike 9cRA, CD367 neither induced formation of nor activated RXR.RXR. Overexpression of RAR or RXR mutated in transactivation domain AF-2 suppressed endogenous receptor activity over beta RARE. Our data suggest that 1) in keratinocytes, RAR.RXR-mediated pathway dominates over that mediated by RXR.RXR; 2) RAR-selective CD367 and RXR-selective SR11237 can be used to identify these two distinct pathways, respectively; 3) beta RARE is mainly regulated by RAR.RXR, in which RAR alone confers ligand inducibility whereas AF-2 of unliganded RXR is required for transactivation by liganded RAR AF-2; 4) lack of RXRE activity in keratinocytes is due to low endogenous levels of RXR.RXR and inhibition by RAR.RXR; and 5) interaction among RXRs is much lower than that between RAR and RXR.

Biological activity of all-trans retinol requires metabolic conversion to all-trans retinoic acid and is mediated through activation of nuclear retinoid receptors in human keratinocytes

The biological activity of all-trans retinol, in human keratinocytes, was investigated through metabolic and functional analyses that assessed the capacity for retinol uptake and metabolism and the mechanism of retinol-induced activation of gene transcription. Human keratinocytes converted all-trans retinol predominantly to retinyl esters, which accounted for 60 and 90% of cell-associated radiolabel after a 90-min pulse and a 48-h chase, respectively. Human keratinocytes also metabolized all-trans retinol to low levels of all-trans retinoic acid (11.47-131.3 ng/mg of protein) in a dose-dependent manner, between 0.3 and 10 microM added retinol. Small amounts of 13-cis retinoic acid (5.47-8.62 ng/mg of protein) were detected, but 9-cis retinoic acid was detected only when keratinocytes were incubated with radiolabeled retinol. There was no accumulation of the oxidized catabolic metabolites 4-hydroxy- or 4-oxoretinoic acid; however, 5,6-epoxy retinoic acid was detected at pharmacological levels (10 and 30 microM) of added retinol. Biological activity of retinol was assessed through analysis of two known retinoic acid-mediated responses: 1) reduction of type I epidermal transglutaminase and 2) activation of a retinoic acid receptor-dependent reporter gene, beta RARE3-tk-CAT. Both all-trans retinol and all-trans retinoic acid reduced type I epidermal transglutaminase in a dose-dependent manner; however, the ED50 for all-trans retinol (10 nM) was 10 times greater than for all-trans retinoic acid (1 nM). All-trans retinol also stimulated beta RARE3-tk-CAT reporter gene activity in a dose-dependent manner. Half-maximal induction was observed at 30 nM retinol, which was again 10-fold greater than observed with all-trans retinoic acid. Cotransfection of human keratinocytes with expression vectors for dominant negative mutant retinoic acid and retinoid X receptors reduced retinol-induced beta RARE3-tk-CAT reporter gene activation by 80%. Inhibition of conversion of all-trans retinol or all-trans retinaldehyde to all-trans retinoic acid by citral reduced beta RARE3-tk-CAT activity 98 and 86%, respectively. These data demonstrate that retinol-induced responses in human keratinocytes are mediated by its tightly regulated conversion to retinoic acid, which functions as a ligand to activate nuclear retinoic acid receptors.

Immunological identification and functional quantitation of retinoic acid and retinoid X receptor proteins in human skin

We have determined protein levels of total and individual nuclear retinoic acid (RAR-alpha, -beta, -gamma) and retinoid X (RXR-alpha, -beta, -gamma) receptors by ligand binding, Western analysis, and gel shift assays, in adult human skin, a major retinoid-responsive tissue. Total RARs and RXRs, measured by direct binding of specific ligands, were 0.24 +/- 0.01 fmol/micrograms (n = 13) and 1.26 +/- 0.08 fmol/micrograms (n = 7), respectively. These values calculated on an average per cell basis were 1790 RARs/cell and 9400 RXRs/cell. Similar results were obtained with competitive ligand binding assays. RAR-alpha, -beta, and -gamma were each specifically immunoprecipitated, and their levels determined by ligand binding assays of supernatants and Western analysis of precipitates. RAR-gamma was the most abundant, representing 87% of RAR protein. The remaining 12-14% of RAR protein was RAR-alpha. No RAR-beta was detected. Similar immunoprecipitation studies revealed that RXR-alpha represented 90% of RXR protein expressed in human skin. No RXR-beta or RXR-gamma proteins were detected by Western blot. Supershift gel retardation with antibodies to RARs detected probe-RAR-alpha and probe-RAR-gamma complexes in a 1 to 4 ratio. No probe-RAR-beta complex was detected. With antibodies to both RAR-gamma and RXR, a double supershifted complex was formed, indicating that RAR-gamma/RXR heterodimers bound to the probe. These data demonstrate 1) protein levels of RXRs are five times greater than RARs, 2) relative protein levels of RAR and RXR family members are compatible with their previously described relative mRNA levels, and 3) RXR-alpha/RAR-gamma heterodimers are the major retinoid receptors that have the potential to regulate transcription of target genes, in adult human skin.

Transcriptional activation by simian virus 40 large T antigen: interactions with multiple components of the transcription complex

Simian virus 40 (SV40) large T antigen is a potent transcriptional activator of both viral and cellular promoters. Within the SV40 late promoter, a specific upstream element necessary for T-antigen transcriptional activation is the binding site for transcription-enhancing factor 1 (TEF-1). The promoter structure necessary for T-antigen-mediated transcriptional activation appears to be simple. For example, a promoter consisting of upstream TEF-1 binding sites (or other factor-binding sites) and a downstream TATA or initiator element is efficiently activated. It has been demonstrated that transcriptional activation by T antigen does not require direct binding to the DNA; thus, the most direct effect that T antigen could have on these simple promoters would be through protein-protein interactions with either upstream-bound transcription factors, the basal transcription complex, or both. To determine whether such interactions occur, full-length T antigen or segments of it was fused to the glutathione-binding site (GST fusions) or to the Gal4 DNA-binding domain (amino acids 1 to 147) (Gal4 fusions). With the GST fusions, it was found that TEF-1 and the TATA-binding protein (TBP) bound different regions of T antigen. A GST fusion containing amino acids 5 to 172 (region T1) efficiently bound TBP. TEF-1 bound neither region T1 nor a region between amino acids 168 and 373 (region T2); however, it bound efficiently to the combined region (T5) containing amino acids 5 to 383.(ABSTRACT TRUNCATED AT 250 WORDS)

Transcriptional enhancer factor (TEF)-1 and its cell-specific co-activator activate human papillomavirus-16 E6 and E7 oncogene transcription in keratinocytes and cervical carcinoma cells

The human papillomavirus (HPV)-16 oncogenes, E6 and E7, are transcribed preferentially in keratinocytes and cervical carcinoma cells due to a 5' enhancer. An abundant peptide binding to a 37 nt enhancer element was purified from human keratinocytes by sequence-specific DNA chromatography. This protein was identified as transcriptional enhancer factor (TEF)-1 by complex mobility, binding to wild-type and mutant SV40 and HPV-16 enhansons and antigenic reactivity with two anti-TEF-1 antibodies. TEF-1 is cell-specific, but its transactivation also depends on a limiting, cell-specific TEF-1 'co-activator'. We show that both TEF-1 and the TEF-1 co-activator are active in human keratinocytes and essential for HPV-16 transcription. TEF-1 binding in vivo was necessary for HPV-16 P97 promoter activity. Excess TEF-1 and chimeric GAL4-TEF-1 specifically inhibited the P97 promoter by 'squelching', indicating that HPV-16 transcription also requires a limiting TEF-1 co-activator. TEF-1 and the TEF-1 co-activator functions mirrored HPV-16 transcription by their presence in keratinocytes and cervical carcinoma cells and their absence from lymphoid B-cells, but also functioned in liver cells where the HPV-16 promoter is inactive. TEF-1 and its associated co-activator are thus part of a complex mechanism which determines the restricted cell range of the HPV-16 E6 and E7 oncogene promoter.

Cloning, expression, and transcriptional properties of the human enhancer factor TEF-1

We describe the cDNA encoding the SV40 transcriptional enhancer factor 1 (TEF-1) and show that its translation initiates exclusively at an AUU codon in vivo. Cloned TEF-1, which is unrelated to other known transcription factors, specifically binds the SV40 GT-IIC and Sph enhansons. Cloned TEF-1 does not activate these enhansons in lymphoid MPC11 cells where they are known to be inactive, but represses the endogenous HeLa TEF-1 activity in vivo and in vitro. Repression is also observed with chimeras where the DNA-binding domain of the GAL4 activator replaces that of TEF-1, showing that repression results from interference/squelching. Such chimeras stimulate transcription in HeLa, but not in MPC11, cells in vivo and in HeLa cell extracts in vitro. However, high concentrations result in self-interference/squelching. These results strongly suggest that the trans-activation function of TEF-1 is mediated by a highly limiting, possible cell-specific, titratable transcriptional intermediary factor(s).

[Accidental methyl alcohol poisoning]

An accidental poisoning due to drinking methyl alcohol in Chaoyang county is reported, analysing the accident. The poison came from the "retail white spirit" which was contaminated with methyl alcohol. Twenty-nine persons drank the wine, fourteen of them died, two of them became blind. After drinking this "retail white spirit" the drinkers showed symptoms of vertigo, headache, weakness, vomiting, night sweat, dyspnea and blurring of vision etc. within 6-120 hours. On examining the remaining spirit, we found the content of methyl alcohol to be between 16.6 and 40.69 g/100 ml. Some of the patients' urine and blood also contained methyl alcohol. We reckoned that each one of the twenty patients had taken more than 27 g of methyl alcohol and each of the ten dead drank more than 40 ml of the alcohol.

The SV40 TC-II(kappa B) enhanson binds ubiquitous and cell type specifically inducible nuclear proteins from lymphoid and non-lymphoid cell lines

We have characterized the complexes resulting from the specific binding in vitro of proteins present in nuclear extracts of several lymphoid and non-lymphoid cell lines to the TC-I and TC-II sequences of the simian virus 40 (SV40) enhancer. No proteins could be detected, binding selectively to the TC-I sequence, but two proteins TC-IIA and TC-IIB were identified interacting specifically with both the TC-II/kappa B enhanson, 5'-GGAAAGTCCCC-3' (important for the activity of the SV40 enhancer in vivo), and with the related H-2Kb enhanson, 5'-TGGGGATTCCCCA-3'. The binding of these two proteins to mutated TC-II enhansons correlates with the effect of these mutations in vivo, suggesting that both proteins may be important for SV40 enhancer activity. The TC-IIA binding activity was present in nuclear extracts of mature lymphoid B cells and was increased in pre-B cell nuclear extracts by lipopolysaccharide (LPS) and cycloheximide treatment. Furthermore, complex formation between the TC-IIA protein and the TC-II enhanson was efficiently competed by the kappa B motif from the kappa chain enhancer, indicating that TC-IIA is the NF-kappa B factor or a closely related protein. However, in contrast to previous reports, a TC-IIA/NF-kappa B-like protein whose properties could not be distinguished from those of the TC-IIA protein present in lymphoid B cells, was found in nuclear extracts of several untreated non-lymphoid cell lines, notably of HeLa cells, but not of undifferentiated F9 embryonal carcinoma (EC) cells [F9(ND)]. The TC-IIA binding activity which was moderately increased in HeLa cell nuclear extracts by 12-O-tetradecanoylphorbol-13-acetate (TPA) and/or cycloheximide treatment could be induced in nuclear extracts of F9(ND) cells by cycloheximide, but not by TPA. Moreover, the TC-IIA binding activity could be induced in cytosolic fractions from F9(ND) cells by treatment with deoxycholate, indicating that these cells contain an inhibitor protein similar to the previously described NF-kappa B inhibitor, I kappa B. The second TC-II enhanson binding protein, TC-IIB, which could be clearly distinguished from the TC-IIA/NF-kappa B-like protein, by a number of differential properties, resembles the previously described KBF1/H2TF1 protein as it binds with a higher affinity to the H-2Kb enhanson than to the TC-II/kappa B enhanson, and its pattern of methylation interference on the H-2Kb and TC-II/kappa B enhansons is identical to that reported for the KBF1/H2TF1 protein.(ABSTRACT TRUNCATED AT 400 WORDS)

[Postoperative computed tomography: study of 10 cases on reactive ring-enhancement in brain]

This paper presents 10 cases with CT appearances of postoperative reactive ring-enhancement in the brain, which were not reported in our country. The mechanisms and differential diagnosis of postoperative ring-enhancement are discussed with reports in the literature. The ring-enhancement at surgical margin is the reactive change of the brain traumatized by operation and related to postoperative pathological processes such as breakdown of blood-brain barrier, vascular granulation and luxury perfusion. This paper demonstrates that reactive ring-enhancement appears as early as 2-4 wk and may last as long as 7 wk after operation. It disappears gradually in 7 wk and cannot exist over 3 mon after operation. In the first 3 mon after operation, peripheral enhancement around the surgical site may be operative reaction, or residual tumor and cerebral abscess. The presence of ring-enhancement beyond 3 mon should be viewed as evidence of pathological process other than postoperative change. This paper emphasizes that ring-enhancement at margin of the surgical site with fine clinical manifestations in the early postoperative period is probably normal postoperative reaction. Close follow-up enhanced CT scan proves to be an effective measure to avoid misdiagnosis and unnecessary reexploration.

Avian retroviral vectors derived from avian defective leukemia virus: role of the translational context of the inserted gene on efficiency of the vectors

We have constructed retroviral vectors derived from the genome of avian erythroblastosis virus ES4 (AEV ES4). The neo selectable gene was substituted for the original v-erbA or v-erbB oncogenes of AEV, either in the same or in a different reading frames. Recombinant retrovirus were rescued and used to infect chicken embryo fibroblasts or quail QT6 cells. When the neo gene was inserted in the same reading frame as the original oncogene, we obtained (1) a high level of expression of the neo gene, (2) a balanced ration of both genomic and subgenomic RNAs, and (3) high titer recombinant viruses. Conversely, when the neo gene was inserted in a reading frame different from that of the original oncogene, we observed (1) a very low level of expression of the neo protein, (2) a predominance of the viral transcript used as translational template for the neo protein synthesis, and (3) low titer recombinant viruses. One of the vectors was used to transfer a human delta-globin gene into avian cells in culture without detectable rearrangement of this gene, but exhibited a deletion within the conserved noncoding region located between the two original oncogenes. Our data provide information for further construction of double expression vectors. Furthermore, three of the vectors would provide helpful tools to identify genetic elements of the virus genome involved in splicing regulation.

The HeLa cell protein TEF-1 binds specifically and cooperatively to two SV40 enhancer motifs of unrelated sequence

We have purified a protein (TEF-1) that specifically binds to two sequence unrelated motifs (GT-IIC and Sph) of the simian virus 40 (SV40) enhancer. TEF-1 binds cooperatively to templates containing tandem but not inverted or spaced repeats of its cognate motifs. This cooperative binding correlates with the ability of the tandem repeats to generate enhancer activity in vivo. In contrast, TEF-1 and a second SV40 enhancer binding protein, TEF-2, bind independently to templates containing the cognate motifs of both proteins (GT-I and either GT-IIC or Sph motifs) even though these motifs cooperate in enhancer activity in vivo. These results allow us to distinguish different classes of enhancer factors.

Cell-specific activity of the constituent elements of the simian virus 40 enhancer

We have compared the activation of transcription from the early promoter of simian virus 40 brought about by the enhancer during transient expression in several cell lines. The enhancer stimulated RNA synthesis approximately 400-, 100-, 100-, and 300-fold in human HeLa cells, the mouse plasmacytoma B cells MPC11, and the nondifferentiated and retinoic acid-differentiated mouse embryonal carcinoma F9 cells, respectively. The contribution to enhancer activity of its multiple constituent motifs has been investigated in the different cell types using the pA series of recombinants mutated throughout the enhancer. A comparison of the activity of these recombinants in the four cell lines indicates that the activity of the various enhancer motifs is cell specific. The activity of a given motif in a given cell line correlates well with the known presence in this cell line of a protein(s) that binds specifically to that motif in vitro.

One cell-specific and three ubiquitous nuclear proteins bind in vitro to overlapping motifs in the domain B1 of the SV40 enhancer

We have used the gel retardation assay to investigate the binding of nuclear proteins to the domain B1 of the SV40 enhancer, which contains the GT-II motif. Four proteins (GT-IIA, GT-IIB alpha, GT-IIB beta and GT-IIC) were detected, three of which were present in nuclear extracts from several cell lines. The fourth protein (GT-IIC) showed a clear cell-specificity, being absent from the lymphoid cell extracts tested. The results of methylation interference assays and of the binding of the proteins to mutated templates indicate that the domain B1 contains three distinct, but overlapping, protein-binding motifs (GT-IIA, B and C). The cell-specific binding of protein GT-IIC in vitro correlates with the in vivo enhancer activity of its cognate motif, strongly suggesting that this protein acts as a positive trans-acting enhancer factor. Two of the proteins also recognize other enhancer motifs; protein GT-IIB alpha binds to the microE3 motif present in the immunoglobulin heavy chain enhancer; protein GT-IIC binds to an enhancer motif of the polyomavirus mutant PyEC9.1 adapted to growth in F9 embryonal carcinoma cells, but not to the corresponding wild-type sequence.

In vitro binding of several cell-specific and ubiquitous nuclear proteins to the GT-I motif of the SV40 enhancer

We have investigated the specific in vitro binding of nuclear proteins from several cell lines to the GT-I motif of the SV40 enhancer which overlaps with the canonical enhancer "core" homology. The binding of three proteins (GT-IA, GT-IB, and GT-IC), one of which (GT-IC) exhibits cell specificity, was detected. Competition and direct binding experiments demonstrated that the two ubiquitous proteins also bind to the GC-rich motif III from the 21-bp repeat upstream element of the SV40 early promoter and that protein GT-IA is most probably the transcription factor Sp1. The third, cell-specific protein GT-IC exhibited a high affinity for both the GT-I motif and an upstream element in the promoter of the mouse beta-major-globin gene, suggesting that this protein can act both as an enhancer and an upstream element trans-acting factor. The good correlation between the known cell-specific in vivo activity of the wild-type and mutated GT-I motif and the cell-specific binding of protein GT-IC in vitro strongly supports the conclusion that this protein is an enhancer factor. Interestingly, its cognate recognition sequence does not coincide with the core homology.

In vitro binding of cell-specific and ubiquitous nuclear proteins to the octamer motif of the SV40 enhancer and related motifs present in other promoters and enhancers

We have used the gel retardation and DNase I footprinting assays to investigate the in vitro binding of nuclear proteins to the octamer motif present in domain A of the SV40 enhancer and in other enhancer and promoter elements. Three apparently cell-specific (oct-B1A, oct-B1B and oct-B2) and one ubiquitous (oct-B3) proteins were detected in various lymphoid and non-lymphoid cell extracts. We show that the previously described 'ubiquitous' NF-A1 factor may correspond in fact to two proteins, oct-B1A in HeLa cells and oct-B1B in lymphoid cells. Interestingly, the HeLa cell protein oct-B1A formed a complex with the SV40 octamer, which could be detected in gel retardation, but not in DNase I footprinting assays. This absence of protection from DNase I digestion correlates with the inactivity of the SV40 octamer in HeLa cells in vivo. We have also found that the in vitro interaction between the SV40 octamer motif and the lymphoid cell-specific protein oct-B2 was negatively modulated by a component present in the nuclear extracts from several lymphoid cell lines. The interactions between the multiple octamer-binding proteins and the related octamer motifs present in other promoter and enhancer elements were systematically compared and the possible role of these proteins in the control of transcription is discussed.

Expression of the v-erbA oncogene in chicken embryo fibroblasts stimulates their proliferation in vitro and enhances tumor growth in vivo

In contrast to uninfected chicken embryo fibroblasts (CEFs), CEFs infected with a retroviral vector that carries the v-erbA gene of avian erythroblastosis virus displayed new properties. These included limited anchorage-independent growth in soft agar, growth without latency in serum-supplemented medium, ability to overcome quiescence induced by serum deprivation, growth at low cell density, and an extended life span in vitro. Furthermore, when explanted in vivo onto the chorioallantoic membrane of chicken embryo, the transformed CEFs expressing v-erbA in addition to v-erbB exhibited a high proliferative rate, giving rise to fibrosarcoma tumors that were ten times larger than those developed from transformed CEFs expressing v-erbB alone. All these data show that CEFs expressing the v-erbA oncogene display activated growth and suggest that the v-erbA product interferes with the mechanisms regulating the growth and/or differentiation of primary CEFs.