[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.

[Impairments of gray matter in MRI-negative epileptic patients with different seizure types].

Objective: To investigate the damage of gray matter structure in MRI-negative epilepsy patients with different symptoms by voxel-based morphometry (VBM). Methods: From June, 2009 to October, 2016, ninety MRI-negative epilepsy patients and thirty-five healthy volunteers underwent the 3T magnetic resonance imaging scan in Nanjing General Hospital. The patients were divided into three groups, including idiopathic generalized tonic-clonic seizure (I-GTCS), secondarily generalized tonic-clonic seizure (S-GTCS), and partial seizure (PS) according to different symptoms. The three-dimensional high-resolution T1 structural MRI data was obtained for the voxel-based morphometry. Data of gray matter structure from four groups were compared using one-way analysis of variance (ANOVA). An independent-sample t test was performed in order to compare gray matter volume of the three patient groups with controls respectively. According the results of ANOVA, impaired brain regions were selected as regions of interest in order to carry out correlation analysis between gray matter volume and disease duration. Results: ANOVA showed significant differences in gray matter structure of bilateral thalamus and frontal lobe between four groups (alphasim correction, P<0.01). Independent-sample t test showed that the volume of bilateral thalamus and frontal lobe decreased in all three patients groups (alphasim correction, P<0.01) .The volume of bilateral thalamus showed significantly negatively correlation with disease duration in I-GTCS patients (r=-0.466, P<0.01). Conclusions: Generalized seizures and partial seizures all can cause damage to the gray matter structure, especially in thalamus and frontal lobe. The impairments of thalamus and frontal lobe in patients with different seizure types are different with the progression of disease, which suggests that influences of different epilepsy seizures on the thalamo-cortical network are different.

The transformer genes in the fig wasp Ceratosolen solmsi provide new evidence for duplications independent of complementary sex determination.

Transformer (tra) is the key gene that turns on the sex-determination cascade in Drosophila melanogaster and in some other insects. The honeybee Apis mellifera has two duplicates of tra, one of which (complementary sex determiner, csd) is the primary signal for complementary sex-determination (CSD), regulating the other duplicate (feminizer). Two tra duplicates have been found in some other hymenopteran species, resulting in the assumption that a single ancestral duplication of tra took place in the Hymenoptera. Here, we searched for tra homologues and pseudogenes in the Hymenoptera, focusing on five newly published hymenopteran genomes. We found three tra copies in the fig wasp Ceratosolen solmsi. Further evolutionary and expression analyses also showed that the two duplicates (Csoltra-B and Csoltra-C) are under positive selection, and have female-specific expression, suggesting possible sex-related functions. Moreover, Aculeata species exhibit many pseudogenes generated by lineage-specific duplications. We conclude that phylogenetic reconstruction and pseudogene screening provide novel evidence supporting the hypothesis of independent duplications rather an ancestral origin of multiple tra paralogues in the Hymenoptera. The case of C. solmsi is the first example of a non-CSD species with duplicated tra, contrary to the previous assumption that derived tra paralogues function as the CSD locus.

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.

Diversity and evolution of Ty1-copia retroelements within Chalcidoidea by reverse transcriptase domain analysis.

Ty1-copia retrotransposons are widespread and diverse in insects. Some features of their hosts, such as mating and genetic systems, are predicted to influence the spread of selfish genetic elements like Ty1-copia. Using part of the reverse transcriptase gene as a reference, we experimentally surveyed Ty1-copia elements in eight species of fig wasps (Hymenoptera: Chalcidoidea), and performed an in silico analysis of six available genomes of chalcid wasps. Contrary to initial expectations that selfish elements such as Ty1-copia would be purged from the genomes of these species because of inbreeding and haplodiploidy, almost all of these wasps harbour an abundance of diverse Ty1-copia elements. Phylogenetic analyses suggest that the families of Ty1-copia elements found in these species have had a long association with their chalcid hosts. These results suggest an evolutionary scenario in which there was ancestral polymorphism followed by some taxa-specific events including stochastic loss and further diversification. Furthermore, estimating natural selection within the internal and terminal portions of the Ty1-copia phylogenies demonstrated that the elements are under strong evolutionary constraints for their long-term survival, but evolve like pseudogenes in the short term, accompanied by the rise and fall of parasitic elements in the history of wasp lineage.

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.

Differentiation of tuberculosis from lymphomas in neck lymph nodes with multidetector-row computed tomography.

BACKGROUND: Tuberculosis (TB) of the cervical lymph nodes may mimic lymphoma. OBJECTIVE: To evaluate multidetector-row computed tomographic (MDCT) imaging criteria for differentiating between the two diseases. MATERIALS AND METHODS: We retrospectively reviewed the anatomical distribution and CT enhancement patterns of the nodes in 81 patients, 27 (33%) with untreated TB and 54 (67%) with untreated lymphomas involving cervical lymph nodes. Of the patients with lymphomas, 19 (35%) had Hodgkin's disease and 35 (65%) had non-Hodgkin's lymphoma. RESULTS: TB predominantly involved the upper cervical nodes. The supraclavicula fossa nodes on MDCT were involved more often in Hodgkin's disease (n = 15, 79%) and non-Hodgkin's lymphoma (n = 25, 71%) than in TB (n = 3, 11%). Tuberculous lymphadenopathy commonly showed peripheral enhancement, frequently with a multilocular appearance. Peripheral enhancement was significantly more frequent in TB (n = 19, 70%) than in Hodgkin's disease (n = 1, 5%) and non-Hodgkin's lymphoma (n = 1, 3%), but homogeneous enhancement was less common in the TB group. CONCLUSION: Our findings indicate that a specific enhancement pattern of lymphadenopathy seen on MDCT was useful in differentiating between untreated TB and lymphomas of the cervical lymph nodes.

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.

Porphyrin with amino acid moieties: a tumor photosensitizer.

A porphyrin with amino acid moieties was synthesized in this work, which may be a latent photosensitizer for photodynamic therapy (PDT). Adler's strategy was used to synthesize meso-tetra (4-nitrophenyl) porphyrin (TNPP) through cyclolization of 4-nitrobenzaldhyde and pyrrole in refluxed nitrobenzene. Reduction of TNPP yielded meso-tetra(4-aminophenyl) porphyrin (TAPP). The synthesis was improved by employing lactic acid as a catalyst. Based on TAPP, porphyrin with valine (TAPP-4Val) was obtained. The application of the resultant TAPP-4Val as tumor photosensitizer on human breast tumor cells for photodynamic therapy (PDT) was preliminarily explored. Dark-toxicity evaluations showed that, under a concentration at up to 6 x 10(-6) M, the survival of MCF-7 cells was larger than 90%, which means TAPP-4Val is almost of non-cytotoxicity. However, TAPP-4Val showed remarkable phototoxicity after visible light irradiation. Effects of irradiation time on the survival of cells under typical concentrations of TAPP-4Val were also studied. The new porphyrin with amino acid moieties, TAPP-4Val, is of high phototoxicity but minimal or no dark-toxicity, which can be used as an effective photosensitizer for PDT.

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.

Inhibitory effects of 2,3,5,4'-tetrahydroxystilbene-2-O-beta-D-glucoside on experimental inflammation and cyclooxygenase 2 activity.

The inhibitory effects of 2,3,5,4'-tetrahydroxystilbene-2-O-beta-d-glucoside (THSG), extracted from the roots of Polygonum multiflorum Thunb, on inflammatory activity in animal models and cyclooxygenase-2 (COX-2) activity in lipopolysaccharide (LPS)-induced mouse RAW264.7 macrophage cells were investigated. The carrageenin (CGN)-induced rat paw oedema model and dimethylbenzene-induced mouse ear oedema model were prepared; MTT assay, semi-quantitative RT-PCR, Western blot and ELISA were adopted. THSG 2.3, 4.6 and 9.2 mg kg(- 1) by oral administration inhibited mouse ear oedema and the percentage of inhibition of THSG 9.2 mg kg(- 1) is 87%. THSG 3.2, 6.4 and 12.8 mg kg(- 1) by oral administration dose-dependently inhibited rat paw oedema and the percentage of inhibition of THSG 12.8 mg kg(- 1) is 56% at 6 h. Indomethacin 13 and 9 mg kg(- 1) showed 90% and 57% inhibition in the same animal models, respectively. LPS 1 microg ml(- 1) significantly up-regulated prostaglandin E(2) (PGE(2)) production (inducing COX-2 activity) by 35% (exogenous arachidonic acid, AA), which was dose-dependently decreased by THSG 1, 10, and 100 micromol L(- 1) and the percentage of inhibition of THSG 10 micromol L(- 1) was 40%. NS-398 10 micromol L(- 1) decreased PGE(2) production by 42%. THSG 1, 10, 100 micromol L(- 1) was shown to markedly inhibit the LPS-induced COX-2 protein and mRNA expression in RAW264.7 cells (P < 0.05) but had no effect on COX-1 protein and mRNA (P>0.05). In summary, the data showed that THSG possessed an anti-inflammatory effect, which was perhaps related to the inhibition of COX-2 enzyme activity and expression in RAW264.7 macrophage cells.

Effects of isoliensinine on angiotensin II-induced proliferation of porcine coronary arterial smooth muscle cells.

The inhibitory effects of isoliensinine (IL), a bisbenzylisoquinoline alkaloid extracted from the seed embryo of the traditional chinese medicinal herb Nelumbo nucifera Gaertn, on the proliferation of porcine coronary arterial smooth muscle cells (CASMCs) induced by angiotensin II(Ang II) and its mechanisms of action were investigated. Counting cultured cell number, MTT assay, immunohistochemical method and Western blot were adopted. Ang II 0.1 micromol l (-1) significantly evoked CASMC proliferation by 42%, which could be dose-dependently inhibited by IL 0.01-3 micromol l (-1) and the percentage of inhibition of IL 0.1 micromol l (-1) was 25%. Irbesartan (Irb) 0.1 micromol l (-1) inhibited CASMC proliferation by 22%. IL or Irb 0.1 micromol l (-1) decreased Ang II-induced overexpression of Platelet-derived growth factor (PDGF)-beta and basic fibroblast growth factor (bFGF), respectively. Both of them also declined c-fos, c-myc and hsp70 overexpression, respectively. At the same concentration, the inhibitory effects of IL on PDGF-beta were even stronger than those of Irb (P < 0.05). In summary, the data showed that IL possesses an anti-proliferative effect, which is related to the decrease of the overexpression of growth factors PDGF-beta, bFGF, proto-oncogene c-fos, c-myc and hsp70.

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.

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.