Analysis of the Efficacy of Universal Screening of Coronavirus Disease with Antigen-Detecting Rapid Diagnostic Tests at Point-or-Care Settings and Sharing the Experience of Admission Protocol-A Pilot Study.

AIMS: To introduce the admission protocol of a COVID-19 specialized hospital outlined by the government, including the assessment of reverse transcription polymerase chain reaction (RT-PCR), low dose chest computed tomography (CT) and antigen-detecting rapid diagnostic test (Ag-RDT) for patient screening. MATERIALS AND METHODS: This was a retrospective cohort study of 646 patients who were admitted between December 2020, and February 2021, during the third wave of COVID-19 in Korea. Ag-RDT and RT-PCR were routinely performed on all patients who required admission, and low-dose chest CT was performed on high-risk patients with associated symptoms. Any patients with high-risk COVID-19 infection according to the Ag-RDT test were quarantined alone in a negative pressured room, and those with low-risk COVID-19 infection remained in the preemptive quarantine room with or without negative pressure. The diagnostic values of the Ag-RDT test and associated cycle threshold (Ct) values of the RT-PCR test were subsequently evaluated. RESULTS: In terms of the diagnostic value, the Ag-RDT for COVID-19 had a sensitivity of 68.3%, specificity of 99.5%, positive predictive value (PPV) of 90.3%, and negative predictive value (NPV) of 97.9%. For the 355 symptomatic patients with low-dose chest CT, the diagnostic values of combined evaluations had a sensitivity of 90.2%, specificity of 99.0%, PPV of 86.1%, and NPV of 99.3%. The cut-off Ct value for positive Ag-RDT was ≤25.67 for the N gene (sensitivity: 89.3%, specificity: 100%), which was regarded as a high viable virus in cell culture. There were no patients or medical staff who had COVID-19 in the hospital. CONCLUSION: Appropriate patient care was possible by definitive triage of the area, according to the symptoms and using diagnostic tests. Screening protocols, including the Ag-RDT test and low-dose chest CT, could be helpful in emergency point-of-care settings.

Stem cell treatment for patients with autoimmune disease by systemic infusion of culture-expanded autologous adipose tissue derived mesenchymal stem cells.

Prolonged life expectancy, life style and environmental changes have caused a changing disease pattern in developed countries towards an increase of degenerative and autoimmune diseases. Stem cells have become a promising tool for their treatment by promoting tissue repair and protection from immune-attack associated damage. Patient-derived autologous stem cells present a safe option for this treatment since these will not induce immune rejection and thus multiple treatments are possible without any risk for allogenic sensitization, which may arise from allogenic stem cell transplantations. Here we report the outcome of treatments with culture expanded human adipose-derived mesenchymal stem cells (hAdMSCs) of 10 patients with autoimmune associated tissue damage and exhausted therapeutic options, including autoimmune hearing loss, multiple sclerosis, polymyotitis, atopic dermatitis and rheumatoid arthritis. For treatment, we developed a standardized culture-expansion protocol for hAdMSCs from minimal amounts of fat tissue, providing sufficient number of cells for repetitive injections. High expansion efficiencies were routinely achieved from autoimmune patients and from elderly donors without measurable loss in safety profile, genetic stability, vitality and differentiation potency, migration and homing characteristics. Although the conclusions that can be drawn from the compassionate use treatments in terms of therapeutic efficacy are only preliminary, the data provide convincing evidence for safety and therapeutic properties of systemically administered AdMSC in human patients with no other treatment options. The authors believe that ex-vivo-expanded autologous AdMSCs provide a promising alternative for treating autoimmune diseases. Further clinical studies are needed that take into account the results obtained from case studies as those presented here.

Genomic expression profiling in lymph nodes with lymphoid depletion from porcine circovirus 2-infected pigs.

Porcine circovirus type 2 (PCV2) is the main causative agent of porcine circovirus-associated disease, such as post-weaning multisystemic wasting syndrome, which involves lymphocyte depletion. However, little is known about the molecular mechanisms of lymphoid depletion. To gain insight into the interaction between virus and host cells, microarrays were used to analyse changes in genomic expression in lymph nodes following PCV2 infection of pigs, together with negative controls. Total RNA was subjected to microarray analysis with an Affymetrix Porcine Genome Array GeneChip. Of the 23,256 pig genes arrayed on a chip, 160 genes showed altered expression after infection (upregulated, 64; downregulated, 96). The altered genomic expression of 18 selected genes was confirmed by quantitative real-time PCR. The expression changes of numerous genes involved in innate immune defence (TLR1, CD14 and CD180), immunosuppressed responses (FGL2 and GPNMB), pro-inflammatory signals (galectin-3) and fasting processes (ANGPTL-4) indicate that PCV2 has developed an intricate mechanism to cause immunosuppression, inflammatory cell infiltration and weight loss in pigs. The results of this study provide a basis for understanding the molecular pathogenesis of PCV2 infection.

Elevated serum levels of S100 calcium binding protein A8 (S100A8) reflect disease severity in canine atopic dermatitis.

A monoclonal antibody to canine S100 calcium binding protein A8 (S100A8) was developed to determine the association between S100A8 and the disease severity of canine atopic dermatitis. Serum S100A8 concentrations were studied in dogs with canine atopic dermatitis (n=213) and healthy dogs (n=213). Statistical correlations between these indices and atopic dermatitis activity were established, and dermatitis severity was assessed according to the CADESI score. Serum S100A8 concentrations were measured with an enzyme-linked immunosorbent assay (ELISA). S100A8 serum levels were significantly higher in canine atopic dermatitis patients than in healthy dogs. A strong positive correlation was identified between S100A8 levels and canine atopic dermatitis patients. Our findings suggested that S100A8 is actively involved in the pathogenesis and clinical picture of canine atopic dermatitis.

bFGF enhances the IGFs-mediated pluripotent and differentiation potentials in multipotent stem cells.

It has widely been reported that basic fibroblast growth factor (bFGF) promotes proliferation of human stem cells and contributes to the maintenance of their self-renewal capability through repeated replications. In contrast to embryonic stem cells (ESCs), the effects of growth factors on adult stem cells are poorly understood. In human umbilical cord blood-derived multipotent stem cells (hUCB-MSCs), bFGF is associated with an increased number of proliferating cells. Furthermore, expression levels of ESC markers were increased after treatment with bFGF. bFGF also increased the expression of FGFR, which in turn increased expression of insulin-like growth factor (IGFs). Since IGFs exert autocrine and paracrine effects on stem cells, bFGF-mediated release of IGFs from hUCB-MSCs might enhance FGFR1 and IGF1R expression in neighboring cells. These receptors could subsequently regulate the effects of bFGF and IGFs in adult stem cells. These results suggest that positive feedback regulation of bFGF and IGFs leads to proliferation of hUCB-MSCs.

OCT4A contributes to the stemness and multi-potency of human umbilical cord blood-derived multipotent stem cells (hUCB-MSCs).

The OCT4A gene, a POU homeodomain transcription factor, has been shown to be expressed in embryonic stem cells (ESC) as well as hUCB-MSCs. In this study, the roles played by OCT4A in hUCB-MSCs were determined by stably inhibiting OCT4A with lenti-viral vector-based small hairpin RNA (shRNA). A decreased rate of cell proliferation was observed in OCT4-inhibited hUCB-MSCs. Down-regulation of CCNA2 expression in OCT4-inhibited hUCB-MSCs was confirmed by RT-PCR and real-time RT-PCR analysis in three genetically independent hUCB-MSC clones. Adipogenic differentiation was also suppressed in OCT4-inhibited hUCB-MSCs. The up-regulation of DTX1 and down-regulation of HDAC1, 2, and 4 expressions may be related to this differentiation deformity. The expression of other transcription factors, including SOX2, REX1 and c-MYC, was also affected by OCT4 inhibition in hUCB-MSCs. In conclusion, these finding suggest that OCT4A performs functionally conserved roles in hUCB-MSCs, making its expression biologically important for ex vivo culture of hUCB-MSCs.

Therapeutic potential of mesenchymal stromal cells in a mouse breast cancer metastasis model.

BACKGROUND AIMS: Mesenchymal stromal cells (MSC) have been studied intensively in regenerative medicine. However, their therapeutic potential against tumor formation and cancer metastasis is still unclear. The effects of transplantation of MSCs in early-stage of carcinogenesis, should be evaluated. METHODS: MSC isolated from human umbilical cord blood (UCB) and adipose tissue (AD) were transplanted in a mouse cancer metastasis model. The effects of MSC on tumor growth and metastasis were analyzed. The effects of transplantation of MSC into the mouse model at very early stage carcinogenesis were also evaluated. RESULTS: Human MSC reduced lung metastasis and inhibited the growth of human breast cancer cells by inducing apoptosis. In addition, transplantation of both UCB and AD MSC into a cancer model with no detectable clinical symptoms did not appear to promote tumor growth or metastasis. CONCLUSIONS: We evaluated the effect of MSC derived from human UCB and AD tissue in a tumor model. Our findings may help to elucidate the interaction between cancer cells and MSC, as well as the application of MSC to clinical trials.

Quercetin prevents cardiac hypertrophy induced by pressure overload in rats.

Inhibition of cardiac hypertrophy leads to a significant reduction in cardiovascular mortality and morbidity. Quercetin is by far the most abundant flavonoid and believed to ameliorate cardiovascular disease. Therefore, we investigated whether quercetin supplementation could attenuate the development of cardiac hypertrophy induced by pressure overload. Three weeks after suprarenal transverse abdominal aortic constriction, heart to body weight (HW/BW) ratio increased compared to the sham group (3.40 +/- 0.06 mg/g versus 2.83 +/- 0.02 mg/g, P<0.001). The quercetin administered group showed complete inhibition of cardiac hypertrophy (2.85 +/- 0.01 mg/g, P<0.001). Malonyldialdehyde production induced by pressure overload was suppressed by quercetin. The activities of extracellular signal-regulated kinase (ERK1/2), p38 MAP kinase, Akt and GSK-3beta were significantly increased with pressure overload and attenuated by quercetin treatment. We conclude that quercetin appears to block the development of cardiac hypertrophy induced by pressure overload in rats and that these effects may be mediated through reduced oxidant status and inhibition of ERK1/2, p38 MAP kinase, Akt and GSK-3beta activities.

Expression analysis of early response-related genes in rat liver epithelial cells exposed to thioacetamide in vitro.

Thioacetamide (TA) is a potent hepatotoxicant known to affect liver metabolism, inhibit mRNA transport and induce immune suppression. The genetic mechanism underlining this biological toxic compound is well understood using microarray technology. Thus, we used high-throughput rat genome oligonucleotide microarrays containing approximately 22,000 genes to investigate the genetic components of TA-related cytotoxicity in WB-F344 rat liver epithelial (WB-F344) cells. We treated cells with TA (two concentrations over five time periods, ranging from 1 to 24 hr), isolated total RNA at 1, 3, 6, 12 and 24 hr following TA treatment and hybridized the RNA to microarrays. Clustering analysis distinguished two groups of genes, early (1 and 3 hr) and late (6, 12 and 24 hr) phase genes. In total, 2,129 and 2,348 differentially-expressed genes were identified following treatment with low and high concentrations of TA, respectively. A common set of 1,229 genes that were differentially expressed following treatment with both low (1,000 muM) and high (10,000 muM) concentrations of TA had similar expression patterns. Interestingly, 1,410 genes at the low concentration and 1,858 genes at the high concentration were differentially expressed in the early phases, suggesting that these genes associated with the early response to TA may be useful as early markers of hepatotoxicity.

Indole-3-carbinol prevents H(2)O(2)-induced inhibition of gap junctional intercellular communication by inactivation of PKB/Akt.

Indole-3-carbinol (I3C) is a phytochemical found in cruciferous vegetables and possesses a variety of biological and biochemical effects. Despite a wealth of data about the chemopreventive properties of I3C, its effects on gap junctional intercellular communication (GJIC), which is associated with the promotion and progression phases of the multi-stage process of carcinogenesis, has not been studied. In this study, we examined the ability of I3C to prevent H(2)O(2)-induced inhibition of GJIC in WB-F344 rat liver epithelial cells (WB cells). The cells were preincubated with I3C for 48 hr, and then treated with 1 mM H(2)O(2) for 1 hr. We found that I3C could prevent the H(2)O(2)-induced inhibition of GJIC through prevention of the phosphorylated state of gap junction protein connexin 43 (Cx43) phosphorylation. Prevention of GJIC by I3C was dependent upon inactivation of Akt, but not MAPK, although inhibition of GJIC by H(2)O(2) leads to activation of both. Similar to I3C, modulation of Akt activation through the phosphoinositide-3 kinase inhibitor, LY294002, could also prevent H(2)O(2)-induced inhibition of GJIC and phosphorylation of Cx43. Our results suggest that I3C might exert its dietary chemopreventive effects by interfering with the Akt signaling pathway, which appears to be linked to modulating GJIC, a cellular mechanisms regulating cell proliferation, differentiation and apoptosis.

The penile erection efficacy of a new phosphodiesterase type 5 inhibitor, mirodenafil (SK3530), in rabbits with acute spinal cord injury.

Mirodenafil (SK3530) is a new potent and selective inhibitor of cGMP-specific phosphodiesterase type 5 (PDE5). Recent clinical trials have demonstrated that mirodenafil is an effective treatment for erectile dysfunction. Its mechanism of action is enhancement of nitric oxide (NO) induced cGMP formation resulting in significant relaxation of the corpus cavernosum (CC). The aim of this study was to investigate the oral efficacy of mirodenafil in an acute spinal cord-injured rabbit model. Mirodenafil or sildenafil citrate was given orally to male rabbits with a surgical transection of the spinal cord at the L2-L4 lumbar vertebra or ischemic-reperfusion spinal cord injury (SCI). Erections were evaluated in a time-course manner by measuring the length of the uncovered penile mucosa. In the transection SCI model, penile erections were induced at 0.3, 1 and 3 mg/kg of mirodenafil but sildenafil only showed an erectile response at 3 mg/kg. The effects of 1 and 3 mg/kg of mirodenafil were significantly increased by intravenous injection of sodium nitroprusside (SNP), a nitric oxide donor. In the ischemic-reperfusion injury model, 3 mg/kg of either mirodenafil or sildenafil produced a penile erection response. After injection of SNP, the lengths of immediate penile erections were significantly increased in the 1 and 3 mg/kg mirodenafil and 3 mg/kg sildenafil groups. The onset of erectile activity was faster with mirodenafil than with sildenafil citrate. These results demonstrate that mirodenafil may be useful for treating erectile dysfunction in patients with a spinal cord injury.

Induction of apoptosis in MCF-7 and MDA-MB-231 breast cancer cells by Oligonol is mediated by Bcl-2 family regulation and MEK/ERK signaling.

Oligonol is a novel catechin-rich biotechnology product. The role of oligonol in modulating intracellular signaling mechanisms was investigated with the view of demonstrating its potential chemopreventive effect and the ability to inhibit cell proliferation using the estrogen-responsive MCF-7 and the estrogen-unresponsive MDA-MB-231 human breast cancer cell lines. Cell survival assay indicated that Oligonol was cytotoxic to both cells. Oligonol triggered apoptosis as revealed by the morphological features typical of nucleus staining and the accumulation of sub-G1 peak. Treatment with 25 microg/ml Oligonol resulted in an activation of caspase-7 and up-regulation of Bad on MCF-7 cells, while the Oligonol (20 microg/ml) induced up-regulation of Bcl-2 protein in a time-response manner on MDA-MB-231 cells. ERK1/2 in both cells were inactivated after Oligonol treatment in a time-dependent manner, and also inactivated upstream MEK1/2. Oligonol triggers apoptosis in MCF-7 and MDA-MB-231 cells through the modulation of pro-apoptotic Bcl-2 family proteins and MEK/ERK signaling pathway.

Efficacy of sulforaphane is mediated by p38 MAP kinase and caspase-7 activations in ER-positive and COX-2-expressed human breast cancer cells.

Sulforaphane is an antioxidant and a potent stimulator of natural detoxifying enzyme and associated with lowered risk of cancer that is associated with the consumption of cruciferous vegetables. The chemopreventive effects of SFN was investigated using the MCF-7 human breast cancer cells and the M13SV1-immortalized human breast luminal epithelial cells. Sulforaphane reduced proliferation in MCF-7 cells and inhibited cyclooxygenase-2 expression in M13SV1 cells treated with 12-O-tetradecanoylphorbol-13-acetate (TPA). The chemopreventive effects of sulforaphane were associated with p38 mitogen-activated protein kinase suggest its important role in cell survival/apoptosis regulation and stabilization of cyclooxygenase-2. Sulforaphane upregulates p38 in MCF-7 cells and prevented TPA-reduced phosphorylation of p38 in M13SV1 cells, but activated caspase-7 associated with apoptosis in MCF-7 cells. These results suggest that sulforaphane may be an alternative candidate for targeted prevention of ER-positive and cyclooxygenase-2-induced phenotypes and breast cancer.

Gold thread implantation promotes hair growth in human and mice.

Thread-embedding therapy has been widely applied for cosmetic purposes such as wrinkle reduction and skin tightening. Particularly, gold thread was reported to support connective tissue regeneration, but, its role in hair biology remains largely unknown due to lack of investigation. When we implanted gold thread and Happy Lift™ in human patient for facial lifting, we unexpectedly found an increase of hair regrowth in spite of no use of hair growth medications. When embedded into the depilated dorsal skin of mice, gold thread or polyglycolic acid (PGA) thread, similarly to 5% minoxidil, significantly increased the number of hair follicles on day 14 after implantation. And, hair re-growth promotion in the gold threadimplanted mice were significantly higher than that in PGA thread group on day 11 after depilation. In particular, the skin tissue of gold thread-implanted mice showed stronger PCNA staining and higher collagen density compared with control mice. These results indicate that gold thread implantation can be an effective way to promote hair re-growth although further confirmatory study is needed for more information on therapeutic mechanisms and long-term safety.

Effects of the histone deacetylases inhibitors sodium butyrate and trichostatin A on the inhibition of gap junctional intercellular communication by H2O2- and 12-O-tetradecanoylphorbol-13-acetate in rat liver epithelial cells.

The histone deacetylase (HDAC) inhibitors, trichostatin A (TSA) and sodium butyrate (NaBu) are considered as potent therapeutic agents for cancer treatment presenting therapeutic benefits with less risk of side effects. The microbial metabolite, TSA is a potent reversible and highly specific inhibitor of mammalian histone deacetylases. NaBu causes hyperacetylation of core histones with effects similar to TSA but it is not a specific inhibitor of HDACs. The gap junction is a channel in the plasma membrane of most cell types which allows direct communication (gap junctional intercellular communication; GJIC) of small molecules and ions. Modulation of GJIC is a known cellular event associated with tumor promotion. The effects of NaBu and TSA on the H(2)O(2)- and 12-O-tetradecanoylphorbol-13-acetate (TPA)-induced GJIC inhibition of WB cells and the mechanisms involved in the process were assessed. TSA and NaBu exerted differential preventive effects on the H(2)O(2) and TPA-induced inhibition of GJIC as well as hyperphosphorylation of connexin43 (Cx43) in WB-F344 rat liver epithelial cells (WB cells). NaBu prevented the TPA-induced GJIC inhibition via ERK1/2 inactivation whilst TSA restored the H(2)O(2)-induced GJIC inhibition and Cx43 hyperphosphorylation by preventing p38 MAP kinase. The inhibition of tyrosine phosphorylation and down-regulation of src protein observed may also contribute to Connexin 43 dephosphorylation and GJIC restoration by TSA and NaBu partly through depletion of src protein pool. Thus, TSA and NaBu exert differential effects on chemically induced GJIC inhibition via modulation of MAP kinases and partly, tyrosine kinases.

Critical role of the c-JunNH2-terminal kinase and p38 mitogen-activated protein kinase pathways on sodium butyrate-induced apoptosis in DU145 human prostate cancer cells.

Sodium butyrate (NaBu) is known to exhibit anti-cancer effects via the differentiation and apoptosis of various carcinoma cells. However, the mechanism by which NaBu induces apoptosis and the involvement of protein kinases during apoptosis is not completely understood. To investigate the underlying pathways, we performed cell culture experiments in androgen-independent human prostate cancer (DU145 cells) focusing on various protein kinases. NaBu causes concentration-dependent cell detachment and growth inhibition. Exposure of DU145 cells to NaBu for 24 h caused a strong apoptotic effect with 26% nuclear fragmentation and condensation. In addition, NaBu induced caspase-3 and poly-ADP ribose polymerase cleavage and up-regulation of bax, suggesting that mitochondrial damage is involved in NaBu-induced caspase-dependent apoptosis. Interestingly, NaBu stimulated p38 mitogen-activated protein kinase (MAPK) and c-Jun NH2-terminal kinase (JNK) activation, but not extracellular signal-regulated kinase 1/2 activation during apoptosis. Furthermore, NaBu up-regulated total protein levels and phospho forms of MAPK kinase 3 (MKK3) and MAPK kinase 4 (MKK4) as the upstream kinases of p38 MAPK and JNK independently of oxidative stress. Taken together, it is suggested that NaBu can be a promising chemopreventive agent for prostate cancer and the p38 MAPK and JNK pathways have critical roles in NaBu-induced apoptosis in DU145 cells.

Use of PCR-restriction fragment length polymorphism for the identification of zoonotic mycobacteriosis in zebrafish caused by Mycobacterium abscessus and Mycobacterium chelonae.

Skin ulcers, scoliosis, and dropsy-like scale edema were observed in laboratory-maintained zebrafish. Affected fish had multifocal granulomas not only in internal organs such as the liver, intestine, genital organs, kidney, muscle, and spleen but also in the fin, epithelium, gills, and sclera of the eyes. Large numbers of acid-fast-rod-shaped bacteria were observed within the necrotic centers of well-demarcated, multifocal granulomas with Gram's stain and Ziehl-Neelson's stain. The size of the Mycobacterium spp. was 1-2 microm x 2-3 microm with a double-layered cell wall, based upon electron-microscopical features. Definitive diagnosis of these outbreaks was obtained by culture on selective media followed by PCR-restriction fragment length polymorphism analysis (PRA) of the rpoB gene for species identification. The amplified 360-bp products of the rpoB gene of mycobacteria isolated from zebrafish were digested with MspI restriction enzyme, which revealed unique band patterns matching those of Mycobacterium abscessus and Mycobacterium chelonae which are responsible for skin and soft tissue infection caused by rapidly growing mycobacteria in humans. This is the first documentation of the precise identification of zoonotic non-tuberculous mycobacteria isolated from laboratory-maintained zebrafish by the PRA of the rpoB gene; this study thus provides a great deal of useful epidemiological information and reduces the likelihood that epizootics will occur.

Reversal of the TPA-induced inhibition of gap junctional intercellular communication by Chaga mushroom (Inonotus obliquus) extracts: effects on MAP kinases.

Chaga mushroom (Inonotus obliquus) has continued to receive attention as a folk medicine with indications for the treatment of cancers and digestive diseases. The anticarcinogenic effect of Chaga mushroom extract was investigated using a model system of gap junctional intercellular communication (GJIC) in WB-F344 normal rat liver epithelial cells. The cells were pre-incubated with Chaga mushroom extracts (5, 10, 20 microg/ml) for 24 h and this was followed by co-treatment with Chaga mushroom extracts and TPA (12-O-tetradecanoylphorbol-13-acetate, 10 ng/ml) for 1 h. The inhibition of GJIC by TPA (12-O-tetradecanoylphorbol-13-acetate), promoter of cancer, was prevented with treatment of Chaga mushroom extracts. Similarly, the increased phosphorylated ERK1/2 and p38 protein kinases were markedly reduced in Chaga mushroom extracts-treated cells. There was no change in the JNK kinase protein level, suggesting that Chaga mushroom extracts could only block the activation of ERK1/2 and p38 MAP kinase. The Chaga mushroom extracts further prevented the inhibition of GJIC through the blocking of Cx43 phosphorylation. Indeed cell-to-cell communication through gap junctional channels is a critical factor in the life and death balance of cells because GJIC has an important function in maintaining tissue homeostasis through the regulation of cell growth, differentiation, apoptosis and adaptive functions of differentiated cells. Thus Chaga mushroom may act as a natural anticancer product by preventing the inhibition of GJIC through the inactivation of ERK1/2 and p38 MAP kinase.

Expression of MAP kinases and connexins in the differentiation of rat mammary epithelial cells.

Gap junctional intercellular communication (GJIC) is involved in the regulation of many cellular processes. MAP kinases are known to affect GJIC and phosphorylation of connexin (Cx). MAP kinases can also be a regulator of cell proliferation and growth. This study was undertaken to show the relevance between expression patterns of Cxs and MAP kinases in rat mammary epithelial cells (RMECs). In order to characterize the RMECs, they were stained with Peanut lectin, which indicates most alveolar epithelial cells, and Thy-1.1 was used as a marker of luminal epithelial cells or myoepithelial cells, respectively. We studied the expression patterns of major gap junction proteins, Cx26, 32, and 43 in RMECs. Western blot analysis demonstrated that Cx26 gradually decreased from day 2, while Cx32 was expressed constantly from day 1 to 14. Cx43 dramatically increased on day 5 and decreased thereafter. The expression patterns and phosphorylation of ERK1/2 and JNK were similar to Cx43, but expression of p38 was like that of Cx32. These results showed that the MAP kinases that comprise ERK1/2, p38, and JNK were involved in regulation of Cxs. Our data suggests that GJIC plays an important role during rat mammary differentiation and that MAP kinases may be closely related functionally to regulate the gap junction.

Gene expression profile by 2,3,7,8-tetrachlorodibenzo-p-dioxin in the liver of wild-type (AhR+/+) and aryl hydrocarbon receptor-deficient (AhR-/-) mice.

2,3,7,8-Tetrachlorodibenzo-p-dioxin (TCDD) is one of the most toxic environmental pollutants that cause various biological effects on mammals. The purpose of our study was to identify the genes involved in hepatotoxicity and hepatocarcinogenesis caused by TCDD. C57BL/6 (AhR+/+, wild type) and B6.129-AhR/J (AhR-/-, knock out) mice were injected i.p. with a single treatment of TCDD at the dose of 100 microg/kg body weight. Relative liver weight was significantly increased at 72 hr after TCDD treatment without an apparent histopathological change in AhR+/+ mice (p<0.05). TCDD treatment also significantly increased activity of serum alanine aminotransferase in AhR-/- mice (p<0.05). The liver was analyzed for gene expression profiles 72 hr later. As compared with AhR-/- mice, the expression of 51 genes (>3-fold) was changed in AhR+/+ mice; 28 genes were induced, while 23 genes were repressed. Most of the genes were associated with chemotaxis, inflammation, carcinogenesis, acute-phase response, immune responses, cell metabolism, cell proliferation, signal transduction, and tumor suppression. This study suggests that the microarray analysis of genes in the liver of AhR+/+ and AhR-/- mice may help to clarify the mechanism of AhR-mediated hepatotoxicity and hepatocarcinogenesis by TCDD.