CircRRAS2 promotes myogenic differentiation of bovine MuSCs and is a novel regulatory molecule of muscle development

The proliferation and myogenic differentiation of muscle stem cells (MuSCs) are important factors affecting muscle development and beef quality. There is increasing evidence that circRNAs can regulate myogenesis. We found a novel circRNA, named circRRAS2 that is significantly upregulated in the differentiation phase of bovine MuSCs. Here, we aimed to determine its roles in the proliferation and myogenic differentiation of these cells. The results showed that circRRAS2 was expressed in several bovine tissues. CircRRAS2 inhibited MuSCs proliferation and promoted myoblast differentiation. In addition, chromatin isolation by using RNA purification and mass spectrometry in differentiated muscle cells identified 52 RNA-binding proteins that could potentially bind to circRRAS2, in order to regulate their differentiation. The results suggest that circRRAS2 could be a specific regulator of myogenesis in bovine muscle.HighlightsCircRRAS2 expression is higher in DM cells than in GM cells.CircRRAS2 could significantly inhibit the proliferation and apoptosis of bovine MuSCs.CircRRAS2 promotes the differentiation of bovine MuSCs into myotubes.CircRRAS2 may exert regulatory effects through multiple RNA binding proteins.

Dietary isoleucine supplementation enhances growth performance, modulates the expression of genes related to amino acid transporters and protein metabolism, and gut microbiota in yellow-feathered chickens

This study investigated the effects of dietary isoleucine (Ile) on growth performance, intestinal expression of amino acid transporters, protein metabolism-related genes and intestinal microbiota in starter phase Chinese yellow-feathered chickens. Female Xinguang yellow-feathered chickens (n = 1,080, aged 1 d) were randomly distributed to 6 treatments, each with 6 replicates of 30 birds. Chickens were fed diets with 6 levels of total Ile (6.8, 7.6, 8.4, 9.2, 10.0, and 10.8 g/kg) for 30 d. The average daily gain and feed conversion ratio were improved with dietary Ile levels (P < 0.05). Plasma uric acid content and glutamic-oxalacetic transaminase activity were linearly and quadratically decreased with increasing dietary Ile inclusion (P < 0.05). Dietary Ile level had a linear (P < 0.05) or quadratic (P < 0.05) effect on the jejunal expression of ribosomal protein S6 kinase B1 and eukaryotic translation initiation factor 4E binding protein 1. The relative expression of jejunal 20S proteasome subunit C2 and ileal muscle ring finger-containing protein 1 decreased linearly (P < 0.05) and quadratically (P < 0.05) with increasing dietary Ile levels. Dietary Ile level had a linear (P = 0.069) or quadratic (P < 0.05) effect on the gene expression of solute carrier family 15 member 1 in jejunum and solute carrier family 7 member 1 in ileum. In addition, bacterial 16S rDNA full-length sequencing showed that dietary Ile increased the cecal abundances of the Firmicutes phylum, and Blautia, Lactobacillus, and unclassified_Lachnospiraceae genera, while decreased that of Proteobacteria, Alistipes, and Shigella. Dietary Ile levels affected growth performance and modulated gut microbiota in yellow-feathered chickens. The appropriate level of dietary Ile can upregulate the expression of intestinal protein synthesis-related protein kinase genes and concomitantly inhibit the expression of proteolysis-related cathepsin genes.

CircUBE2Q2 promotes differentiation of cattle muscle stem cells and is a potential regulatory molecule of skeletal muscle development

Background

The growth and development of muscle stem cells (MuSCs) are significant events known to affect muscle plasticity, disease, meat production, and meat quality, which involves the types and functions of mRNA and non-coding RNA. Here, MuSCs were cultured from Guangxi fetal cattle. RNA sequencing was used to analyze the RNA expression of mRNA and non-coding RNAs during the cell proliferation and differentiation phases.

Results

Two thousand one hundred forty-eight mRNAs and 888 non-coding RNAs were differentially expressed between cell proliferation and differentiation phases, including 113 miRNAs, 662 lncRNAs, and 113 circRNAs. RT-qPCR verified the differential expression levels of mRNAs and non-coding RNAs, and the differentially expressed circUBE2Q2 was subsequently characterized. Expression profile analysis revealed that circUBE2Q2 was abundant in muscle tissues and intramuscular fat. The expression of cricUBE2Q2 was also significantly upregulated during MuSCs myogenic differentiation and SVFs adipogenic differentiation and decreased with age in cattle muscle tissue. Finally, the molecular mechanism of circUBE2Q2 regulating MuSCs function that affects skeletal muscle development was investigated. The results showed that circUBE2Q2 could serve as a sponge for miR-133a, significantly promoting differentiation and apoptosis of cultured MuSCs, and inhibiting proliferation of MuSCs.

Conclusions

CircUBE2Q2 is associated with muscle growth and development and induces MuSCs myogenic differentiation through sponging miR-133a. This study will provide new clues for the mechanisms by which mRNAs and non-coding RNAs regulate skeletal muscle growth and development, affecting muscle quality and diseases.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12864-022-08518-4.

Dietary L-arginine supplementation enhances growth performance, intestinal antioxidative capacity, immunity and modulates gut microbiota in yellow-feathered chickens

This study investigated the effects of dietary Arginine (Arg) on performance, intestinal antioxidative capacity, immunity, and gut microbiota in Chinese yellow-feathered chickens. One thousand two hundred 1-day-old female Qingyuan partridge chickens were randomly assigned to 5 groups with 6 replicates of 40 birds each. Chickens were fed diets with 5 levels of total Arg (8.5, 9.7, 10.9, 12.1, and 13.3 g/kg) without antibiotics for 30 d. The ADFI, ADG, and feed conversion ratio were improved with dietary Arg levels (P < 0.05). The proportions of CD3⁺ and CD4⁺/CD8⁺ lymphocytes responded in a linear (P < 0.05) manner and those of CD4⁺ in a linear or quadratic (P < 0.05) manner as dietary Arg levels increased. Dietary Arg level had a linear (P < 0.05) or quadratic (P < 0.05) effect on the gene expression of glutathione peroxidase 1, heme oxygenase 1, nuclear factor erythroid 2-related factor 2, and the activities of glutathione peroxidase and total antioxidative capacity in the jejunum and ileum. The relative expression of IL-1β, myeloid differentiation primary response 88, and Toll-like receptor 4 decreased linearly (P < 0.05) in the ileum with increasing dietary Arg levels; secretory IgA contents were increased. In addition, sequencing data of 16S rRNA indicated that dietary Arg increased the relative abundance of Firmicutes phylum, Romboutsia and Candidatus Arthromitus genera, while decreased that of Clostridium sensu stricto 1. A diet containing 12.1 g Arg/kg promoted growth performance, intestinal antioxidation, and innate immunity and modulated gut microbiota in yellow-feathered chickens.

CircRNAs: potency of protein translation and feasibility of novel biomarkers and therapeutic targets for head and neck cancers

Circular RNAs (circRNAs), a new star noncoding RNA (ncRNA), show stability, conservation, abundance, and tissue and stage specificity. They act as key regulators of biological processes. They target the mRNAs of many other different genes or signaling pathways, and closely link associated genes into regulatory networks. Growing evidence has demonstrated that circRNAs may play an important role in the carcinogenesis, progression and chemoradiation resistance of many cancers including head and neck cancers (HNC). CircRNA, like other ncRNA, such as miRNA, lncRNA, usually is considered to be non-protein coding transcript. However, recent studies indicated that abnormal translation of circRNAs may be involved in human diseases. In this review, we collected the origin, classification, characteristics, function of circRNAs, exosmal circRNAs, and then synthesize current study results to highlight aberration of circRNAs in various types of HNC, and try to clarify the molecular mechanisms of circRNAs affecting the pathogenesis and progression of HNC, as well as pay particular attention to provide a new avenue to the diagnosis and treatment strategy for HNC.

Integrated analysis of transcriptome profiling predicts potential lncRNA and circRNA targets in human nasopharyngeal carcinoma

Non-coding RNAs (ncRNAs) regulate numerous genes and influence the progression of various human diseases, including cancer. The role of regulatory ncRNAs implicated in nasopharyngeal carcinoma (NPC), as well as their target genes, remains unclear. The present study aimed to investigate specific long non-coding (lnc)RNAs, circular RNAs (circRNAs) and mRNAs associated with the molecular pathogenesis of NPC, and to predict the underlying target genes of specific lncRNAs and circRNAs. The expression levels of lncRNAs, circRNAs and mRNAs in NPC and chronic nasopharyngitis tissues were detected and analyzed using microarray and bioinformatics techniques. A total of 2.80% lncRNAs (425 upregulated and 431 downregulated) were significantly differentially expressed (DE) between the two tissue types. Additionally, 0.96% circRNAs (18 upregulated and 13 downregulated) were significantly DE, while 2.94% mRNAs (426 upregulated and 341 downregulated) were significantly DE between the two tissue types. In total, 420 NPC-associated nearby encoding genes (196 up- and 224 downregulated) of the DE lncRNAs were identified. Overlap analysis identified 23 DE circRNAs and their corresponding target genes, with 37 microRNAs and 50 mRNAs, from which 14 interaction networks were constructed. Subsequent pathway analysis revealed 221 DE target genes corresponding to 31 key signaling pathways associated with NPC, 14 of which may represent hub genes associated with NPC pathophysiology. Thus, certain lncRNAs, circRNAs and mRNAs are aberrantly expressed in NPC tissues, and partially specific lncRNAs, circRNAs and their target genes may influence the tumorigenesis and progression of NPC. Target prediction and regulatory network identification may help to determine the pathogenic mechanisms of NPC.

[Expression of myocyte enhancer factor 2B in mantle cell lymphoma and its clinical significance]

Objective: To investigate the expression of myocyte enhancer factor 2B (MEF2B) in mantle cell lymphomas (MCL), and to analyze the correlation between the expression of MEF2B and pathological subtypes, structural subtypes, SOX11 expression and its clinical significance. Methods: Paraffin-embedded tissues were stained with HE, immunohistochemistry (EnVision method) and fluorescence in situ hybridization (FISH) , in addition, the clinical and pathological data of 60 cases of MCL were collected at Sun Yat-sen University Foshan Hospital and Sun Yat-sen University Cancer Center from January,2002 to May, 2019 for analysis. Results: Of the 60 MCLs, males is predominant (M∶F=3∶1). Histologically, the typical MCL is the majority (classical MCL: variant type MCL=48 cases:12 cases) . Fifty cases were classified into non-complete FDC meshwork type MCL, and the remaining 10 cases were classified into the complete-FDC meshwork type MCL group. Patients with classical MCL were more than 60 years old. The coexistent lesion sites both node and extranode in pathological subtype or structural subtype was the most common lesion sites. SOX11(+) MCL was common in classical MCL (P=0.040) and tended to be complete-FDC meshwork type MCL (P=0.086). The expression rate of MEF2B in MCL was 60.0%(36/60). This rate of MEF2B in classical type, complete-FDC meshwork type and SOX11(+) MCL was significantly higher than that variant type, no complete-FDC meshwork type, SOX11(-)MCL (P<0.05), respectively. There was no difference in clinical characteristics of MCL between MEF2B positive and negative groups. Compared with SOX11(-)MCL, the percentage of MEF2B expressed in tumor cells of SOX11(+)MCL was significantly higher (P=0.027). The expression of MEF2B was not related to the proliferation of tumor cells (P=0.341). There was no significant difference in the survival rate between different expression groups of MEF2B and SOX11 (P=0.304 and P=0.819, respectively). Only the mortality of variant type (blastoid/pleomorphic) MCL within 2 years was significantly higher than that of classical type MCL (P<0.05). Conclusions: The expression of MEF2B in MCL is related to the pathological subtypes, structural subtypes and the expression of SOX11, but not to the proliferation and prognosis. The high mortality rate within 2 years is only found in variant MCL. However, the role of MEF2B in MCL needs to be further studied.

Research Status of New Designer Drug Methcathinone in Forensic Toxicology

Methcathinone, a new cathinone designer drug, which is structurally similar to amphetamine analogs, is a central nervous stimulant. Recently, there has been a worldwide rise in its popularity and abuse, and a growing number of cases with disability or even death is reported in several countries, resulting in public concern. The typical symptoms include accelerated heartbeat, high temperature, anxiety, depression, etc. Forensic studies on its toxicity mechanism are rare. This article reviews its toxicological effects, poisoning symptoms, poisoning and addiction mechanisms, and detection methods, to provide theoretical reference for future studies and guidance for related forensic identification.

Influence of dairy by-product waste milk on the microbiomes of different gastrointestinal tract components in pre-weaned dairy calves

The community structure of colonised bacteria in the gastrointestinal tracts (GITs) of pre-weaned calves is affected by extrinsic factors, such as the genetics and diet of the calves; however, the dietary impact is not fully understood and warrants further research. Our study revealed that a total of 6, 5, 2 and 10 bacterial genera showed biologically significant differences in the GITs of pre-weaned calves fed four waste-milk diets: acidified waste milk, pasteurised waste milk, untreated bulk milk, and untreated waste milk, respectively. Specifically, generic biomarkers were observed in the rumen (e.g., Bifidobacterium, Parabacteroides, Fibrobacter, Clostridium, etc.), caecum (e.g., Faecalibacterium, Oxalobacter, Odoribacter, etc.) and colon (e.g., Megamonas, Comamonas, Stenotrophomonas, etc.) but not in the faeces. In addition, the predicted metabolic pathways showed that the expression of genes related to metabolic diseases was increased in the calves fed untreated waste milk, which indicated that untreated waste milk is not a suitable liquid diet for pre-weaned calves. This is the first study to demonstrate how different types of waste milk fed to pre-weaned calves affect the community structure of colonised bacteria, and the results may provide insights for the intentional adjustment of diets and gastrointestinal bacterial communities.

Head and neck rhabdomyosarcoma: follow-up results of four cases and review of the literature

Head and neck rhabdomyosarcoma (HNRMS) is exceedingly rare and poorly documented. The difficult diagnosis often causes a poor prognosis and high mortality. Hence, we report 4 cases of HNRMS and their follow-up outcomes, and review the clinicopathological features of this rare tumor. The 4 patients ranged in age from 5 to 29 years. Among them, 3 patients had a good prognosis after combination of radiotherapy and chemotherapy or surgery alone. Another patient survived for only 3 months after diagnosis without therapy. Deeply insight into HNRMS might improve the ability of diagnosis and treatment for this disease.

Genome-wide analysis of long non-coding RNA in primary nasopharyngeal carcinoma by microarray

AIMS

Alterations in the expression of several long non-coding RNAs (lncRNAs) have been found in primary nasopharyngeal carcinoma (NPC). However, the effect of lncRNA expression on primary NPC as well as the molecular mechanism of lncRNA remains vague. This study was to identify differentially expressed lncRNAs involved in NPC on a genome-wide scale and predict their potential functions.

METHODS AND RESULTS

Using high-throughput microarray with 30,586 lncRNA and 26,109 mRNA probes, 856 lncRNAs and 767 mRNAs were expressed differentially between NPC and chronic nasopharyngitis tissues. Bioinformatic analysis (clustering analysis, gene ontology analysis and pathway analysis) was used for further research. Differentially expressed lncRNAs were subgrouped into three types and differentially expressed mRNAs were clustered into 28 pathways. The first coexpression network analysis revealed that 46 lncRNAs interacting with three mRNAs involved the Janus kinase-signal transducer and activator of transcription (JAK-STAT) signalling pathway. Quantitative real-time polymerase chain reaction (PCR) verified 11 up- and down-regulated lncRNAs and eight mRNAs in NPC. The second coexpression network analysis showed that 23 significantly aberrantly expressed mRNAs interacted with three validated lncRNAs.

CONCLUSIONS

This study could provide new insight into the molecular mechanisms of lncRNAs and their potential role in NPC for further study. These differentially expressed lncRNAs may act as novel biomarkers and therapeutic targets for NPC.

Concurrent alterations of RAGE, RECK, and MMP9 protein expression are relevant to Epstein-Barr virus infection, metastasis, and survival in nasopharyngeal carcinoma

This study aimed to concurrently investigate the expressions of receptor for advanced glycation end products (RAGE), reversion inducing cysteine-rich protein with Kazal motifs (RECK) and matrix metalloproteinase 9 (MMP9) in nasopharyngeal carcinoma (NPC) and their correlations with clinicopathological properties. Using immunohistochemistry, we found that RECK expression was downregulated in NPC tissues compared with chronic nasopharyngitis (CNT) tissues, while RAGE and MMP9 expressions were upregulated. We further found that RECK expression level was inversely correlated with MMP9 expression level in NPC, whereas RAGE expression level was positively correlated with MMP9 expression level. Moreover, aberrant expressions of these proteins had a positive correlation with the titers of EBVCA-IgA, lymphatic metastasis, recurrence and survival. Together, these findings suggest that dysregulations of RECK and RAGE expressions may be collectively involved in tumor progression of NPC by regulating MMP9 expression and that they may be a good prognostic predictors for NPC.

Aberrant SATB1 expression is associated with Epstein-Barr virus infection, metastasis and survival in human nasopharyngeal cells and endemic nasopharyngeal carcinoma

Special AT-rich sequence-binding protein 1 (SATB1) has been identified as a key factor in the progression of some cancers, functioning as a global genome organizer and chromatin regulator. We examined the levels of SATB1 mRNA expression in NPC cell lines 5-8F (high metastasis) and 6-10B (low metastasis) and immortalized human nasopharyngeal epithelial cells NP69-SV40T by quantitative real-time PCR. We also examined the protein expression levels of SATB1 in 72 cases of nasopharyngeal carcinoma (NPC) tissues and 30 cases of normal nasopharyngeal (NNP) tissues by immunohistochemistry, and then assessed the correlations between SATB1 expression and clinicopathological factors. The expression level of SATB1 mRNA in 5-8F was much higher than those in 6-10B and NP69-SV40T (P<0.05). The expression level of SATB1 mRNA in 6-10B was higher than in NP69-SV40T, but the difference was not statistically significant (P>0.05). The positive expression rates of SATB1 protein in NPC (38/72, 52.8%) were significantly higher than in NNP (4/30, 13.3%) (P<0.05). SATB1 protein levels in NPC were not associated with gender, age, and T stage (P>0.05), but positively correlated with the titers of EBVCA-IgA, metastasis (N and M stage), recurrence, and survival (P<0.05). Multivariate analysis showed that the overexpression of SATB1 protein is an independent prognostic factor for NPC. The expression levels of SATB1 were obviously upregulated in primary NPC tissues and human NPC cell lines. Therefore, SATB1 may be a valuable predictor in assessing the metastasis, recurrence, and prognosis of NPC.

Long non-coding RNAs as novel biomarkers and therapeutic targets in head and neck cancers

Long non-coding RNAs (lncRNAs) are generally defined as RNA molecules greater than 200 nt in length and without protein-coding property that different from housekeeping RNAs such as tRNAs, rRNAs, and snRNAs, and independent from small RNAs with specific molecular processing machinery such as micro- or piwi-RNAs. LncRNAs are a novel class of mRNA-like transcripts which contribute to cancer development and progression and accelerate cancer cells proliferation, invasion, metastasis, and apoptosis. These research results indicate the potential of lncRNAs as prospective novel biomarkers for diagnosis, therapeutic targets and prognosis for cancers. In this review, we synthesize present study results to highlight aberration of lncRNAs in various types of head and neck cancers, and try to clarify the molecular mechanisms of lncRNAs affecting the oncogenesis and progression of head and neck cancer, as well as pay particular attention to provide a new avenue to the diagnosis and treatment strategy.

Silencing SATB1 influences cell invasion, migration, proliferation, and drug resistance in nasopharyngeal carcinoma

Special AT rich sequence binding protein 1 (SATB1) play an important role in many cancers, but the role of SATB1 in nasopharyngeal carcinoma (NPC) is still not full understand. Immunofluorescence staining showed that SATB1 was mainly localized in the nuclei in CNE-2 cell. After successful down-regulation of SABT1 in NPC cell line CNE-2 by shRNA, compared to parental CNE-2 and control shRNA group, the capacity of the proliferation, migration, invasion and drug resistance of CNE-2 cell was reduced, which indicated that SATB1 may be involved in NPC development and progression. SATB1 may be a promising therapeutic target for nasopharyngeal carcinoma.

Expression of TRPV6 and CaBP-D28k in the egg shell gland (uterus) during the oviposition cycle of the laying hen

1. The aim of this study was to investigate the localisation of the transient receptor potential vanilloid channel type 6 (TRPV6) in egg shell gland (ESG) and examine the dynamic expression of TRPV6 and Calbindin-d28k (CaBP-D28k), as well as the changes in concentration of total calcium (Ca), total inorganic phosphorus (P), alkaline phosphatase (ALP), parathyroid hormone (PTH) and calcitonin (CT) in plasma during the oviposition cycle. 2. The plasma ALP activity was notably increased at 8 h. In addition, plasma CT was highest at 0 h and significantly lower at 8 h. The change of plasma PTH concentration increased slightly post-oviposition and reached a maximum at 16 h. 3. Immunohistochemical analysis indicated that TRPV6 was strongly localised to the apical luminal epithelium of the mucosa. The mRNA levels of TRPV6 and CaBP-D28k in the ESG remained very low from 0 to 4.5 h, but were significantly increased at 16 h. Furthermore, Western blotting analysis showed that the expression of TRPV6 and CaBP-D28k also reached a maximum at 16 h and was different from the concentration of CaBP-D28k. 4. In conclusion, the epithelial Ca(2+) channel TRPV6 is strongly expressed in the epithelial cells of the eggshell gland, and the increase of TRPV6 and CaBP-D28k mRNA and protein expression during eggshell formation suggests that active Ca(2+) transcellular transport exerts significant effects in delivering active calcium in the ESG.

Potential implication of activating killer cell immunoglobulin-like receptor and HLA in onset of pulmonary tuberculosis

Killer cell immunoglobulin-like receptor (KIR) and human leucocyte antigen (HLA) play crucial role in maintaining immune homoeostasis and controlling immune responses. To investigate the influence of KIR and HLA-C ligands on the risk of pulmonary tuberculosis (PTB), we studied 200 patients who were confirmed to have PTB and 200 healthy controls on the different frequencies of KIR and HLA-C ligands. Genotyping of these genes was conducted by sequence-specific primer polymerase chain reaction (SSP-PCR) method. Gene frequencies were compared between PTB group and the control group by χ(2) test, and P < 0.05 was regarded as statistically significant. As a result, the frequency of KIR genotype A/B was increased in PTB than controls but A/A was decreased. Moreover, striking differences were observed in the frequencies of HLA-Cw*08 between the two groups. Besides, the frequencies of '2DL2/3 with C1' in PTB were increased compared with control group. In addition, individuals with no KIR2DS3 and no Cw*08 were higher in controls than in PTB. KIR2DS1 was increased in PTB when HLA-C group 2 alleles were missing. In conclusion, KIR and HLA-C gene polymorphisms were related to susceptibility to PTB.

Inhibitory activities of baicalin against renin and angiotensin-converting enzyme

CONTEXT

Baicalin has been characterized as the active compound and quality control marker in Scutellaria baicalensis Georgi, traditionally used as a hypotensive herb.

OBJECTIVES

To investigate the inhibitory activities of baicalin against renin and angiotensin-I converting enzyme (ACE) and their molecule mechanism of interactions.

METHODS

The fluorescence method using renin substrate 1(R-2932) and the spectroscopy method by Cushman were used to determine renin and ACE activities, respectively. The fluorescence quench techniques were used to characterize their interactions.

RESULTS

The results showed that baicalin inhibited renin activity with an IC(50) value of 120.36 µM and inhibited ACE activity with an IC(50) value of 2.24 mM in vitro. The fluorescence emission of both renin and ACE were efficiently quenched by baicalin and a complete quenching was achieved at a high concentration of baicalin. Furthermore, baicalin was more effective in quenching the fluorescence of renin (K(SV) = 60 × 10(3) M(-1)) than ACE (K(SV) = 17.1 × 10(3) M(-1)). The quenching of fluorescence of renin and ACE involved static interactions, which was characterized by the formation of quencher-enzyme complex. The baicalin-renin complex formed through three-sites binding including the active site with a binding constant of 796.15 × 10(13) M(-1), but there was only one binding site for the baicalin-ACE complex with a much smaller binding constant of 6.8 × 10(5) M(-1).

CONCLUSION

The inhibition activity of baicalin against renin was a result of the formation of stable complex through multisites binding including the active site, which could explain the higher inhibitory efficiency.

Localisation and expression of TRPV6 in all intestinal segments and kidney of laying hens

1. The aim of this study was to investigate the localisation and expression of the epithelial Ca2+ channel TRPV6 (transient receptor potential vanilloid channel type 6) in different intestinal segments and kidney of laying hens during peak lay. 2. Immunohistochemical analysis of the intestine indicated that TRPV6 was localised to the brush-border membranes of the duodenum, jejunum, ileum, caecum, and rectum. Expression was weaker in the rectum, and little or no expression was found in crypt and goblet cells. In addition, TRPV6 mRNA was quantified amongst different intestinal segments, and expression was highest in the duodenum and jejunum. Furthermore, Western blotting indicated that the duodenum expressed the greatest amount of TRPV6 and the rectum the least with the other segments expressing intermediate levels. 3. In the kidney, distinct immunopositive staining for TRPV6 was detected at the apical domain of the distal convoluted tubules (DCT) and medullary connecting tubules (CNT). Interestingly, distribution of TRPV6 extended to the proximal convoluted tubules (PCT). Furthermore, the kidney expressed lower TRPV6 mRNA and protein levels compared with that in the duodenum. 4. In conclusion, the epithelial Ca2+ channel TRPV6 is strongly expressed in the apical cells of the entire intestine and the renal tubules, suggesting that active Ca2+ transcellular transport plays a crucial role in dietary calcium (re)absorption in laying hens.

Frequent allelic loss at the FRA3B site in endemic nasopharyngeal carcinoma: association with clinical features and Epstein-Barr virus infection

In this study, we aimed to precisely define the patterns of allelic loss at the FRA3B site in endemic nasopharyngeal carcinoma and to determine whether an association exists between allelic loss, clinicopathological features and Epstein-Barr virus infection. We examined the loss of heterozygosity in 40 cases of nasopharyngeal carcinoma from an endemic area in southern China, using eight high dense, polymorphic, microsatellite markers within or flanking the FRA3B site. Loss of heterozygosity at the FRA3B region was shown in 31 (77.5 per cent) primary tumours. Loss of heterozygosity was found most frequently at the D3S1300 (55.6 per cent) and D3S2757 (50.0 per cent) loci. The common area of deletion was located between the D3S4103 and D3S4260 loci. In nasopharyngeal carcinoma, loss of heterozygosity at the FRA3B/fragile histidine triad locus correlated with the following clinicopathological parameters: tumour T-stage, lymph node status, clinical stage, tumour differentiation and serum antibody titres of immunoglobulin (Ig) A against Epstein-Barr virus capsid antigen. Significantly frequent loss of heterozygosity was observed in nasopharyngeal carcinoma with tumour stages T3 and T4, lymph node metastasis and advanced tumour-node-metastasis staging (III and IV). Very frequent loss of heterozygosity was also observed to correlate with World Health Organization type III nasopharyngeal carcinoma histopathology. We also found that nasopharyngeal carcinoma patients with high titres of IgA against Epstein-Barr virus capsid antigen showed very frequent loss of heterozygosity. Allelic loss at the FRA3B site occurs significantly more commonly in endemic nasopharyngeal carcinoma patients. This suggests that the region between D3S4103 and D3S4260 may represent a preferential molecular target in nasopharyngeal carcinogenesis.

HRTEM analysis of nanocrystallization during uniaxial compression of a bulk metallic glass at room temperature

Nanocrystallization during deformation of metallic glass at room temperature has significant implications to understand its deformation mechanism. We present here direct high-resolution transmission electron microscopy (HRTEM) observations of nanocrystallization in a Zr(55)AI(10)Ni(5)Cu(30) bulk metallic glass (BMG) fractured by uniaxial compression at room temperature. The formed nanocrystallites are Zr(2)Cu, with the average diameter of less than 10nm, and are distributed within the round-like regions of localized plastic deformation. We also show direct evidence of atomic neighbor distance increases associated with the shrinkage and broadening of diffused ring pattern from local deformed areas, which may enhance atomic mobility so that nanocrystallization occurred. Our results demonstrate that the origin of the room-temperature deformation of BMG can be attributed to the local atomic spacing increases induced by localization of plastic flow under uniaxial compression test.

Mutation and abnormal expression of the fragile histidine triad gene in nasopharyngeal carcinoma

OBJECTIVE

To determine alterations of fragile histidine triad (FHIT) gene in nasopharyngeal carcinoma and the correlation of FHIT gene with nasopharyngeal carcinogenesis.

STUDY DESIGN

Prospective study.

METHODS

A total of 28 nasopharyngeal carcinoma and 16 normal nasopharyngeal epithelium specimens were examined for abnormalities of FHIT gene by nested reverse-transcriptase-polymerase chain reaction and DNA sequencing.

RESULTS

The deletion of FHIT gene was not observed in 16 normal nasopharyngeal epithelium specimens. In 28 cases of nasopharyngeal carcinoma tissues, 12 (42.9%) exhibited FHIT aberrant transcripts. Complementary DNA sequencing revealed exonic deletion, small DNA insertion, synonymous mutation in exon 8, or frameshift mutation in exon 5.

CONCLUSIONS

The present results suggest that the FHIT gene may play an important role in the pathogenesis of nasopharyngeal carcinoma and may be one of the candidate tumor suppressor genes in nasopharyngeal carcinoma.

The chromosomal effect of birchen dust as determined by the micronucleus test

In a wood processing factory, the measured air concentration of birchen dust was 1.26 +/- 0.41 mg/m3, and the micronucleus frequency of peripheral blood lymphocytes in 83 workers exposed to wood dust was 1.13 +/- 2.83/1000, which was significantly higher (P < 0.01) than that of control group (0.51 +/- 1.41/1000). The number of exposed workers with positive micronucleus test was 9.6%, which was higher than that of control group (4.5%), but the difference was not significant (P > 0.05). The micronucleus test in mice treated with water extracts of unsteamed and unbaked birchen dust showed that the micronucleus frequencies in all treated groups were significantly higher than that of control group (P < 0.01) and there was also a dose response correlation (r = 0.96, P < 0.0005). The results of steamed and baked birchen dust extracts were significantly lower than those of the unsteamed and unbaked ones at the same doses (P < 0.001). This suggests that when the birchen dust is steamed at the temperature of 100 degrees C for 24 h or baked at the temperature of 80 degrees C, its inducing effect in micronucleus test could be lowered.

Effect of anisodine on acute forebrain ischemia-reperfusion damage in rats

AIM

To study the protective effect of anisodine (Ani) on acute forebrain ischemia-reperfusion injury in rats.

METHODS

Both vertebral arteries were occluded by electrocautery. Severe, but transient bilateral cerebral ischemia was produced by clamping both common carotid arteries in rats. Atomic absorption spectrophotometric and spectrophotometric methods were used to determine the contents of calcium and extravasated Evans blue (EB), respectively, remained in forebrain at 60-min recirculation after 30-min ischemia.

RESULTS

At 60-min recirculation, the brain calcium contents were increased from 112 +/- 6 micrograms/g brain dry weight in control (sham operation) group to 165 +/- 7 micrograms/g brain dry weight with marked increase of EB extravasation. Ani (2.5 mg.kg-1, i.p.), and scopolamine (Sco, 0.25 mg.kg-1, i.p.) decreased the elevated calcium and extravasated EB contents.

CONCLUSION

Ani prevented the brain from ischemia insults through reducing intracellular calcium accumulation resulted from ischemia and reperfusion.

Study on micronucleus frequency in peripheral lymphocytes in workers of match factories

This paper reports the results of the study of micronucleus frequency in peripheral lymphocytes in workers exposed to soft wood dust (poplar and linden wood) in match factories. 298 workers exposed to soft wood dust in three match factories were defined as exposure group and 45 waiters in a restaurant as control group. The frequency of micronucleus in peripheral lymphocytes was examined and the control's 95% confidential upper limit >, 4/1000 was defined as the standard to determine the positivity. The positive rate in the exposure group was 36.2% while that in the control group was only 4.4%; the difference is significant (P < 0.01). As the coefficient of correlation between length of work and positive rate was 0.86 (P < 0.01), a dose/time-response is in existence. Meanwhile, the analysis of relation between quantity of smoking and positive rate eliminated the effect of smoking on variation of positive rates. In this paper, we also discussed the relation between positive rates and wood dust concentrations in different worksites and we think that the volatile and unsteady substances in soft wood dust are micronucleus-inducing matters.