Effect of mindfulness-based mind-body therapies in patients with non-specific low back pain-A network meta-analysis of randomized controlled trials.

Background/objectives: Although mindfulness-based mind-body therapy (MBMBT) is an effective non-surgical treatment for patients with non-specific low back pain (NLBP), the best MBMBT mode of treatment for NLBP patients has not been identified. Therefore, a network meta-analysis (NMA) was conducted to compare the effects of different MBMBTs in the treatment of NLBP patients. Methods: PubMed, EMBASE, Cochrane Central Register of Controlled Trials, and Web of Science databases were searched for randomized controlled trials (RCTs) applying MBMBT for the treatment of NLBP patients, with all of the searches ranging from the time of database creation to January 2023. After 2 researchers independently screened the literature, extracted information, and evaluated the risks of biases in the included studies, the data were analyzed by using Stata 16.0 software. Results: A total of 46 RCTs were included, including 3,886 NLBP patients and 9 MBMBT (Yoga, Ayurvedic Massage, Pilates, Craniosacral Therapy, Meditation, Meditation + Yoga, Qigong, Tai Chi, and Dance). The results of the NMA showed that Craniosacral Therapy [surface under the cumulative ranking (SUCRA): 99.2 and 99.5%] ranked the highest in terms of improving pain and disability, followed by Other Manipulations (SUCRA: 80.6 and 90.8%) and Pilates (SUCRA: 54.5 and 71.2%). In terms of improving physical health, Craniosacral Therapy (SUCRA: 100%) ranked the highest, followed by Pilates (SUCRA: 72.3%) and Meditation (SUCRA: 55.9%). In terms of improving mental health, Craniosacral Therapy (SUCRA: 100%) ranked the highest, followed by Meditation (SUCRA: 70.7%) and Pilates (SUCRA: 63.2%). However, in terms of improving pain, physical health, and mental health, Usual Care (SUCRA: 7.0, 14.2, and 11.8%, respectively) ranked lowest. Moreover, in terms of improving disability, Dance (SUCRA: 11.3%) ranked lowest. Conclusion: This NMA shows that Craniosacral Therapy may be the most effective MBMBT in treating NLBP patients and deserves to be promoted for clinical use. Systematic review registration: https://www.crd.york.ac.uk/PROSPERO/, PROSPERO [CRD42023389369].

Root acid phosphatases and rhizobacteria synergistically enhance white lupin and rice phosphorus acquisition.

The rhizosheath is a belowground area that acts as a communication hub at the root-soil interface to promote water and nutrient acquisition. Certain crops, such as white lupin (Lupinus albus), acquire large amounts of phosphorus (P), owing partially to exudation of acid phosphatases (APases). Plant growth-promoting rhizobacteria also increase soil P availability. However, potential synergistic effects of root APases and rhizosheath-associated microbiota on P acquisition require further research. In this study, we investigated the roles of root purple APases (PAPs) and plant growth-promoting rhizobacteria in rhizosheath formation and P acquisition under conditions of soil drying (SD) and P treatment (+P: soil with P fertilizer; -P: soil without fertilizer). We expressed purple acid phosphatase12 (LaPAP12) in white lupin and rice (Oryza sativa) plants and analyzed the rhizosheath-associated microbiome. Increased or heterologous LaPAP12 expression promoted APase activity and rhizosheath formation, resulting in increased P acquisition mainly under SD-P conditions. It also increased the abundance of members of the genus Bacillus in the rhizosheath-associated microbial communities of white lupin and rice. We isolated a phosphate-solubilizing, auxin-producing Bacillus megaterium strain from the rhizosheath of white lupin and used this to inoculate white lupin and rice plants. Inoculation promoted rhizosheath formation and P acquisition, especially in plants with increased LaPAP12 expression and under SD-P conditions, suggesting a functional role of the bacteria in alleviating P deficit stress via rhizosheath formation. Together, our results suggest a synergistic enhancing effect of LaPAP12 and plant growth-promoting rhizobacteria on rhizosheath formation and P acquisition under SD-P conditions.

A System Pharmacology Model for Decoding the Synergistic Mechanisms of Compound Kushen Injection in Treating Breast Cancer.

Breast cancer (BC) is one of the most common malignant tumors among women worldwide and can be treated using various methods; however, side effects of these treatments cannot be ignored. Increasing evidence indicates that compound kushen injection (CKI) can be used to treat BC. However, traditional Chinese medicine (TCM) is characterized by "multi-components" and "multi-targets", which make it challenging to clarify the potential therapeutic mechanisms of CKI on BC. Herein, we designed a novel system pharmacology strategy using differentially expressed gene analysis, pharmacokinetics synthesis screening, target identification, network analysis, and docking validation to construct the synergy contribution degree (SCD) and therapeutic response index (TRI) model to capture the critical components responding to synergistic mechanisms of CKI in BC. Through our designed mathematical models, we defined 24 components as a high contribution group of synergistic components (HCGSC) from 113 potentially active components of CKI based on ADME parameters. Pathway enrichment analysis of HCGSC targets indicated that Rhizoma Heterosmilacis and Radix Sophorae Flavescentis could synergistically target the PI3K-Akt signaling pathway and the cAMP signaling pathway to treat BC. Additionally, TRI analysis showed that the average affinity of HCGSC and targets involved in the key pathways reached -6.47 kcal/mmol, while in vitro experiments proved that two of the three high TRI-scored components in the HCGSC showed significant inhibitory effects on breast cancer cell proliferation and migration. These results demonstrate the accuracy and reliability of the proposed strategy.

Metabolite profiling of the hyphal exudates of Rhizophagus clarus and Rhizophagus irregularis under phosphorus deficiency.

Arbuscular mycorrhizal (AM) fungal extraradical hyphae exude their metabolites into the soil. Root exudate metabolites are affected by plant species and P status. However, the effect of P status on AM hyphal exudate metabolites has been unknown. This study aimed to examine hyphal exudate metabolite composition of two AM fungal species and their response to P deficiency through metabolite profiling. Rhizophagus clarus and R. irregularis were grown in a two-compartment in vitro culture system of Linum usitatissimum roots on solid modified Strullu-Romand medium in combination with two P levels (3 µM (P3) and 30 µM (P30)). Hyphal exudates were collected from the hyphal compartment at 118 days after inoculation (DAI). The metabolite composition of the hyphal exudates was determined by capillary electrophoresis/time-of-flight mass spectrometry, resulting in the identification of a total of 141 metabolites at 118 DAI. In the hyphal exudates of R. clarus, the concentrations of 18 metabolites, including sugars, amino acids, and organic acids, were significantly higher (p < 0.05) under P3 than under P30 conditions. In contrast, the concentrations of 10 metabolites, including sugar and amino acids, in the hyphal exudates of R. irregularis were significantly lower (p < 0.05) under P3 than under P30 conditions. These findings suggest that the extraradical hyphae of AM fungi exude diverse metabolites of which concentrations are affected by P conditions and differ between AM fungal species.

Chinese medicine GeGen-DanShen extract protects from myocardial ischemic injury through promoting angiogenesis via up-regulation of VEGF/VEGFR2 signaling pathway.

HEADINGS ETHNOPHARMACOLOGICAL RELEVANCE: Coronary heart disease (CHD) usually refers to myocardial ischemia or myocardial necrosis caused by coronary artery stenosis. GeGen and DanShen (GD) are popular Chinese herbs for the treatment of angina pectoris and myocardial infarction (MI). This sentence needs to be a separate paragraph. AIM OF THE STUDY: This study was to investigate the role of GD extract in promoting ischemic myocardial angiogenesis, and to explore its signaling mechanism, so as to provide a more reliable scientific basis for the clinical treatment of ischemic cardiovascular disease. MATERIALS AND METHODS: GD extract was initially analyzed by HPLC-Q-TOF MS. In vitro, migration assay and tube formation assay were subsequently used to detect the angiogenesis activity of GD extract in human umbilical vein endothelial cells (HUVECs). Following the in vitro study, an MI rat model was established by ligating the left anterior descending coronary artery (LAD), immediately followed by a 4-week daily GD extract treatment by intragastric administration. After the animal sacrifice, hematoxylin-eosin (HE) staining was conducted to observe the pathological changes of the infarct margin. Besides, the MI area was measured by 2,3,5-triphenyltetrazoliumchloride (TTC) staining. The microvascular density (MVD) was also quantified through CD31 immunohistochemistry. Moreover, the levels of VEGF, TXB2 and 6-keto-PGF1α in serum were detected by enzyme-linked immunosorbent assay. The expression of VEGFR2 and ERK were detected by immunohistochemistry as well. RESULTS: In vitro study, GD extract was found to induce significant angiogenesis in HUVECs. In vivo, smaller infarct size was found in treatment groups than that of the model group, and the protein expression of VEGFR2 as well as ERK in the marginal zone of MI in treatment groups were significantly increased. The morphological changes of myocardium were observed with a significant growth in the number of new blood vessels. Regarding the effect of GD extract, the serum levels of CK, LDH and TXB2 were consequently reduced, whereas the levels of VEGF, 6-keto-PGF1α were significantly increased. CONCLUSIONS: Based on the findings of this study, GD extract had a protective effect against MI in rats. The possible mechanism is to promote angiogenesis by regulating the VEGF/VEGFR2 signaling pathway after MI occurrence.

NIR Stimulus-Responsive PdPt Bimetallic Nanoparticles for Drug Delivery and Chemo-Photothermal Therapy.

The combination of chemotherapy and phototherapy has attracted increasing attention for cancer treatment in recent years. In the current study, porous PdPt bimetallic nanoparticles (NPs) were synthesized and used as delivery carriers for the anti-cancer drug doxorubicin (DOX). DOX@PdPt NPs were modified with thiol functionalized hyaluronic acid (HA-SH) to generate DOX@PdPt@HA NPs with an average size of 105.2 ± 6.7 nm. Characterization and in vivo and in vitro assessment of anti-tumor effects of DOX@PdPt@HA NPs were further performed. The prepared DOX@PdPt@HA NPs presented a high photothermal conversion efficiency of 49.1% under the irradiation of a single 808 nm near-infrared (NIR) laser. Moreover, NIR laser irradiation-induced photothermal effect triggered the release of DOX from DOX@PdPt@HA NPs. The combined chemo-photothermal treatment of NIR-irradiated DOX@PdPt@HA NPs exerted a stronger inhibitory effect on cell viability than that of DOX or NIR-irradiated PdPt@HA NPs in mouse mammary carcinoma 4T1 cells in vitro. Further, the in vivo combination therapy, which used NIR-irradiated DOX@PdPt@HA NPs in a mouse tumor model established by subcutaneous inoculation of 4T1 cells, was demonstrated to achieve a remarkable tumor-growth inhibition in comparison with chemotherapy or photothermal therapy alone. Results of immunohistochemical staining for caspase-3 and Ki-67 indicated the increased apoptosis and decreased proliferation of tumor cells contributed to the anti-tumor effect of chemo-photothermal treatment. In addition, DOX@PdPt@HA NPs induced negligible toxicity in vivo. Hence, the developed nanoplatform demonstrates great potential for applications in photothermal therapy, drug delivery and controlled release.

Effects of dietary yeast nucleotides supplementation on intestinal barrier function, intestinal microbiota, and humoral immunity in specific pathogen-free chickens.

Yeast nucleotides are a fine functional additive in human and animals. The effects of dietary yeast nucleotides supplementation on intestinal development, expression of intestinal barrier-related genes, intestinal microbiota, and infectious bronchitis virus (IBV) antibody titer of specific pathogen-free (SPF) chickens were investigated. A total of 60 1-d-old chickens were divided into 4 groups, each of which included 3 replicates of 5 chickens. Group 1 served as a control that was fed a basal diet. Groups 2 to 4 were fed the basal diet supplemented with 0.1%, 0.3% and 0.5% yeast nucleotides, respectively. All chickens were inoculated intranasally with inactivated IBV vaccine at day 1 and day 10. At day 17, the intestinal development, expression of intestinal barrier-related genes and microbiota were evaluated. There was a significant increased ileal villus height and villus height to crypt depth ratio in group 2 (P < 0.05). Moreover, group 4 exhibited higher expression of zonula occludens-1 (ZO-1) and Occludin gene in ileum (P < 0.05), whereas groups 2 and 3 exhibited higher expression of Mucin 2 (MUC2) and trefoil factor 2 (TFF2) gene (P < 0.05), group 2 showed lower expression of IFN-α gene (P < 0.05). Dietary yeast nucleotides increased intestinal bacterial diversity (P < 0.05), and the abundance of Lactobacillus (P < 0.05). At day 10, 17, 24, 31, 38, and 45, the serum IBV antibody titers were tested. Group 2 exhibited higher IBV antibody titer at day 17 (P < 0.05), furthermore, groups 2 to 4 reached the effective levels 1 wk earlier than control group. In conclusion, dietary yeast nucleotides supplementation can help birds to mount a faster and stronger antibody response to IBV vaccine. In addition, dietary yeast nucleotides supplementation can also promote the intestinal development and barrier-related genes expression, and diversity and richness of intestinal microbiota.

Danggui Buxue Decoction, a Classical Formula of Traditional Chinese Medicine, Fails to Prevent Myelosuppression in Breast Cancer Patients Treated With Adjuvant Chemotherapy: A Prospective Study.

Danggui Buxue Decoction (DBD), a classical formula of traditional Chinese medicine (TCM), has an impact on promoting hematopoiesis. The aim of our study was to determine whether DBD can prevent myelosuppression in breast cancer patients treated with adjuvant chemotherapy. We conducted a phase II randomized prospective controlled clinical study. From December 2013 to February 2015, 106 patients were enrolled and randomly assigned (1:1) to the TCM group and control group. The primary end point was incidence of grade 3-4 neutropenia. The secondary end points included incidence of grade 3-4 neutropenia in each cycle, incidence of anemia, and incidence of thrombopenia during 4 cycles. Seventeen patients withdrew from this study, and 89 patients were included in the final analysis. Incidences of grade 3-4 neutropenia during 4 cycles were 57.1% in the TCM group and 59.6% in the control group, and there was no significant difference ( P = .816). Similarly, no significant differences were observed between the 2 groups for incidence of grade 3-4 neutropenia in each cycle. While incidences of anemia were 54.8% and 66.6% for the TCM group and control group, respectively ( P = .280), incidences of thrombopenia were 11.9% for the TCM group and 4.3% for the control group ( P = .248). No significant differences were observed for the incidence of other nonhematological toxicities between the 2 groups. DBD failed to prevent myelosuppression in breast cancer patients treated with adjuvant chemotherapy. Further studies are warranted to validate the efficacy of DBD in selected patients.

Three-dimensional ionic liquid functionalized magnetic graphene oxide nanocomposite for the magnetic dispersive solid phase extraction of 16 polycyclic aromatic hydrocarbons in vegetable oils.

In this paper, a novel three-dimensional ionic liquid functionalized magnetic graphene oxide nanocomposite (3D-IL@mGO) was prepared, and used as an effective adsorbent for the magnetic dispersive solid phase extraction (MSPE) of 16 polycyclic aromatic hydrocarbons (PAHs) in vegetable oil prior to gas chromatography-mass spectrometry (GC-MS). The properties of 3D-IL@mGO were characterized by scanning electron micrographs (SEM), X-ray photoelectron spectroscopy (XPS), vibrating sample magnetometer (VSM). The 3D-IL@mGO, functionalized by ionic liquid, exhibited high adsorption toward PAHs. Compared to molecularly imprinted solid phase extraction (MISPE), the MSPE method based on 3D-IL@mGO had less solvent consumption and low cost, and was more efficent to light PAHs in quantitative analysis. Furthermore, the rapid and accurate GC-MS method coupled with 3D-IL@mGO MSPE procedure was successfully applied for the analysis of 16 PAHs in eleven vegetable oil samples from supermarket in Zhejiang Province. The results showed that the concentrations of BaP in 3 out of 11 samples were higher than the legal limit (2.0µg/kg, Commission Regulation 835/2011a), the sum of 8 heavy PAHs (BaA, CHR, BbF, BkF, BaP, IcP, DaA, BgP) in 11 samples was between 3.03µg/kg and 229.5µg/kg. Validation results on linearity, specificity, accuracy, precision and stability, as well as on application to the analysis of PAHs in oil samples demonstrated the applicability to food safety risk monitoring in China.

The treatment effects of flaxseed-derived secoisolariciresinol diglycoside and its metabolite enterolactone on benign prostatic hyperplasia involve the G protein-coupled estrogen receptor 1.

Secoisolariciresinol diglucoside (SDG), a lignan extracted from flaxseed, has been shown to suppress benign prostatic hyperplasia (BPH). However, little is known about the mechanistic basis for its anti-BPH activity. The present study showed that enterolactone (ENL), the mammalian metabolite of SDG, shared the similar binding site of G1 on a new type of membranous estrogen receptor, G-protein-coupled estrogen eceptor 1 (GPER), by docking simulations method. ENL and G1 (the specific agonist of GPER) inhibited the proliferation of human prostate stromal cell line WPMY-1 as shown by MTT assay and arrested cell cycle at the G0/G1 phase, which was displayed by propidium iodide staining following flow cytometer examination. Silencing GPER by short interfering RNA attenuated the inhibitory effect of ENL on WPMY-1 cells. The therapeutic potential of SDG in the treatment of BPH was confirmed in a testosterone propionate-induced BPH rat model. SDG significantly reduced the enlargement of the rat prostate and the number of papillary projections of prostatic alveolus and thickness of the pseudostratified epithelial and stromal cells when comparing with the model group. Mechanistic studies showed that SDG and ENL increased the expression of GPER both in vitro and in vivo. Furthermore, ENL-induced cell cycle arrest may be mediated by the activation of GPER/ERK pathway and subsequent upregulation of p53 and p21 and downregulation of cyclin D1. This work, in tandem with previous studies, will enhance our knowledge regarding the mechanism(s) of dietary phytochemicals on BPH prevention and ultimately expand the scope of adopting alternative approaches in BPH treatment.

Effect of Flaxseed Intervention on Inflammatory Marker C-Reactive Protein: A Systematic Review and Meta-Analysis of Randomized Controlled Trials.

Functional food-flaxseed and its derivatives (flaxseed oil or lignans) are beneficial for human health, possibly because of their anti-inflammatory effects. C-reactive protein (CRP), a sensitive marker of inflammation was chosen to evaluate the anti-inflammatory effects of flaxseed. We searched randomized controlled trials from PubMed and the Cochrane Library in October 2015 and conducted a meta-analysis to evaluate the effectiveness of flaxseed and its derivatives on CRP. The mean differences (net change) in CRP (mg/L) concentrations were pooled with a random- or a fixed-effects model depending on the results of heterogeneity tests. Overall, flaxseed interventions had no effects on reduction of CRP (p = 0.428). The null effects were consistent in the subgroup analysis with multiple studies and population characteristics. Significant heterogeneity was observed in most of the analyses. Meta-regression identified baseline body mass index (BMI) as a significant source of heterogeneity (P-interaction = 0.032), with a significant reduction in CRP of 0.83 mg/L (95% confidence interval -1.34 to -0.31; p = 0.002) among subjects with a BMI of ≥30 kg/m². In conclusion, our meta-analysis did not find sufficient evidence that flaxseed and its derivatives have a beneficial effect on reducing circulating CRP. However, they may significantly reduce CRP in obese populations.

[Determination of chlorfenapyr and indoxacarb in tea by gas chromatography-mass spectrometry with solid phase extraction].

OBJECTIVE: To establish a method for simultaneous determination of chlorfenapyr and indoxacarb in tea by gas chromatography-mass spectrometry. METHODS: The tea samples were homogenized and extracted with acetonitrile. Extracts obtained through centrifugation were cleaned up by CARB / NH2 cartridges, and further purified with SLH cartridges. After separated by DB-5MS capillary column( 30 m × 0. 25 mm × 0. 25µm), the analytes were measured by gas chromatography-mass spectrometry in selective ion monitoring( SIM) mode and quantified by external standard method. RESULTS: The linear range was 0. 10- 10 µg / m L for both of the two pesticides. The detection limits of chlorfenapyr and indoxacarb in tea samples were 0. 01 and 0. 008 mg / kg, and the quantitation limits were 0. 03 and 0. 025 mg / kg, respectively. The recoveries were from75. 6% to 92. 7%, and the relative standarddeviations( RSDs) were 3. 6%- 11. 4%( n =6). CONCLUSION: The proposed method has good purification effect and high accuracy, which is capable for simultaneously detecting the chlorfenapyr and indoxacarb in tea samples.

Two novel saponins of 20, 26-epoxy derivatives of pseudojujubogenin from the seeds of Hovenia trichocarpa.

Two new saponins of 20, 26-epoxy derivatives of pseudojujubogenin, hoduloside XI (1) and hoduloside XII (2) were isolated from the seeds of Hovenia trichocarpa. The structures of the new compounds were established by extensive NMR experiments and chemical methods. Hoduloside XI was confirmed to be 3-O-{ß-D-glucopyranosyl(1→3)-[ß-D-xylopyranosyl(1→2)]-α-L-arabinopyranosyl}-20, 26-epoxypseudojujubogenin. Hoduloside XII was identified as 3-O-{ß-D-xylopyranose(1→2)glucopyranosyl(1→3)[rhamnopyranose(1→2)]ß-D-glucopyranosyl}-20, 26-epoxypseudojujubogenin. The in vitro cytotoxic activity of compounds 1 and 2 was assayed. They displayed inhibitive activities against human cancer cell lines HL60 and K562.

Prof. ZHANG Yi's experience in treating severe arrhythmia.

The prescription of Zhi Gan Cao Tang (? Decoction of prepared Licorice) is made for the syndrome of both yin and yang deficiency of the Heart, with the effects of tonifying yin and nourishing blood, activating yang and restoring normal pulse, and evenly tonifying yin and yang. However, in clinical practice, the symptoms may vary greatly. The heart rate may be slow or fast; and the symptoms may belong to the cold or heat, excess or deficiency syndrome. Therefore, the treatment should be based on syndrome-differentiation. We can learn from the above sample cases. The two patients with bradycardia needed to carry pacemaker. Their TCM differentiations were different, one due to insufficiency of yang-qi should be treated based on the principle of restoring yang from collapse; while the other due to obstruction of collaterals by phlegm and blood stasis should be treated based on the principle of resolving phlegm, promoting circulation of blood and dredging the collaterals. However, they used the same prescription of Zhi Gan Cao Tang (? Decoction of prepared Licorice) with different modifications, and both of them got quite good therapeutic effects. We can also learn from the other three cases of tachycardia. Based on western medical analyses, the 3 patients had different etiology, clinical manifestations, and ECG findings. However, they were treated with the same prescription of Zhi Gan Cao Tang (? Decoction of prepared Licorice), with modifications made according to the different accompanying symptoms. As a result, all of the three patients got marked therapeutic effects.

Identification of a mouse short-chain dehydrogenase/reductase gene, retinol dehydrogenase-similar. Function of non-catalytic amino acid residues in enzyme activity.

We report a mouse short-chain dehydrogenase/reductase (SDR), retinol dehydrogenase-similar (RDH-S), with intense mRNA expression in liver and kidney. The RDH-S gene localizes to chromosome 10D3 with the SDR subfamily that catalyzes metabolism of retinoids and 3 alpha-hydroxysteroids. RDH-S has no activity with prototypical retinoid/steroid substrates, despite 92% amino acid similarity to mouse RDH1. This afforded the opportunity to analyze for functions of non-catalytic SDR residues. We produced RDH-S Delta 3 by mutating RDH-S to remove an "additional" Asn residue relative to RDH1 in its center, to convert three residues into RDH1 residues (L121P, S122N, and Q123E), and to substitute RDH1 sequence G208FKTCVTSSD for RDH-S sequence F208-FLTGMASSA. RDH-S Delta 3 catalyzed all-trans-retinol and 5 alpha-androstane-3 alpha,17 alpha-diol (3 alpha-adiol) metabolism 60-70% as efficiently (Vm/Km) as RDH1. Conversely, substituting RDH-S sequence F208FLTGMASSA into RDH1 produced a chimera (viz. C3) that was inactive with all-trans-retinol, but was 4-fold more efficient with 3 alpha-adiol. A single RDH1 mutation in the C3 region (K210L) reduced efficiency for all-trans-retinol by >1250-fold. In contrast, the C3 area mutation C212G enhanced efficiency with all-trans-retinol by approximately 2.4-fold. This represents a >6000-fold difference in catalytic efficiency for two enzymes that differ by a single non-catalytic amino acid residue. Another chimera (viz. C5) retained efficiency with all-trans-retinol, but was not saturated and was weakly active with 3 alpha-adiol, stemming from three residue differences (K224Q, K229Q, and A230T). The residues studied contribute to the substrate-binding pocket: molecular modeling indicated that they would affect orientation of substrates with the catalytic residues. These data report a new member of the SDR gene family, provide insight into the function of non-catalytic SDR residues, and illustrate that limited changes in the multifunctional SDR yield major alterations in substrate specificity and/or catalytic efficiency.

SDR-O: an orphan short-chain dehydrogenase/reductase localized at mouse chromosome 10/human chromosome 12.

We report cloning a cDNA that encodes a novel short-chain dehydrogenase/reductase, SDR-O, conserved in mouse, human and rat. Human and mouse liver express SDR-O (short-chain dehydrogenase/reductase-orphan) mRNA intensely. The mouse embryo expresses SDR-O mRNA as early as day seven. Human SDR-O localizes on chromosome 12; mouse SDR-O localizes on chromosome 10 with CRAD1, CRAD2 and RDH4. SDR-O shares highest amino acid similarity with rat RoDH1 and mouse RDH1 (69-70%), but does not have the retinol and 3alpha-hydroxysteroid dehydrogenase activity of either, nor is it active as a 17beta- or 11beta-hydroxysteroid dehydrogenase. Short-chain dehydrogenase/reductases catalyse the metabolism of ligands that bind with nuclear receptors: the occurrence of 'orphan' nuclear receptors may imply existence of 'orphan' SDR, suggesting that SDR-O may catalyse the metabolism of another class of nuclear receptor ligand. Alternatively, SDR-O may not have a catalytic function, but may regulate metabolism by binding substrates/products and/or by serving as a regulatory factor.