A comparative effectiveness pilot study of teriparatide for medication-related osteonecrosis of the jaw: daily versus weekly administration

We studied the effectiveness of teriparatide (TPTD) for treating medication-related osteonecrosis of the jaw (MRONJ) in patients with osteoporosis and examined differences in the clinical outcomes following daily versus weekly TPTD. The outcomes were significantly improved in the entire patient series and the daily group.

PURPOSE

Teriparatide (TPTD) treatment for Stage II-III medication-related osteonecrosis of the jaw (MRONJ) in osteoporotic patients has yielded promising results in uncontrolled studies. The daily administration and the weekly administration of TPTD have been reported to improve outcomes in MRONJ. Herein, we sought to identify differences in the clinical outcomes of MRONJ patients treated with daily TPTD versus weekly TPTD.

METHODS

We enrolled 13 patients and randomly assigned them to receive either of two treatments: 1×/week 56.5-μg TPTD injection for 6 months (weekly group; n = 6 patients after 1 dropout), or 20-μg TPTD injection daily for 6 months (daily group; n = 6 patients). Patients in both groups received conventional therapy plus intensive antibiotic therapy as necessary. We compared the changes in the patients' clinical stage of MRONJ, bone metabolism, percentage of bone formation, and bone turnover markers between the weekly and daily groups.

RESULTS

TPTD treatment with MRONJ led to partial remission or complete remission in 5 daily-group patients and 3 weekly-group patients. The MRONJ stage was significantly improved from baseline to 6 months of treatment in the entire series of 12 patients (p = 0.008); the weekly group did not show significant improvement, but the daily group did (p = 0.01).

CONCLUSIONS

This study provides the first comparison of clinical outcomes between MRONJ patients who received daily or weekly TPTD injections. Six months of treatment with TPTD realized a significant improvement of MRONJ stage in both the entire patient series and the daily group.

P1444 Occurrence and predictors of right ventricular dysfunction after pericardiocentesis

Background—The changes in cardiac function that occur after pericardiocentesis are unclear.Purpose—This study was performed to assess right ventricular (RV) and left ventricular (LV) function with echocardiography before and after pericardiocentesis.

Method and Results—In total, 19 consecutive patients who underwent pericardiocentesis for more than moderate pericardial effusion were prospectively enrolled from August 2015 to October 2017. Comprehensive transthoracic echocardiography was performed before, immediately after (within 3 hours), and 1 day after pericardiocentesis to investigate the changes in RV and LV function. RV dysfunction is defined as meeting three of the four criteria: a TAPSE of <17 mm, an S’ of <9.5 cm, an FAC of <35%, and an RV free wall longitudinal strain >−20%. The mean age of all patients was 72.6 ± 12.2 years. The changes of echocardiographic parameters related to RV function are shown in Table. After pericardiocentesis, RV inflow and outflow diameters increased and the parameters of RV function significantly decreased. These abnormal values or RV dysfunction remained at 1 day after pericardiocentesis. Conversely, no parameters of LV function parameters changed after pericardiocentesis. Of 19 patients, 13 patients showed RV dysfunction immediately after pericardiocentesis and 6 patients did not. RV free wall longitudinal strain before pericardiocentesis was higher in patients with post-procedural RV dysfunction (−18.9 ± 3.6%) than in those without (−28.4 ± 6.3%). ROC analysis revealed that a RV free wall longitudinal strain cut-off value of −23.0% had a sensitivity of 100% and a specificity of 83.3% for predicting the occurrence of RV dysfunction after pericardiocentesis (AUC = 0.910).

Conclusions—The occurrence of RV dysfunction after pericardiocentesis should be given more attention. Pre-existing RV dysfunction maybe related to the occurrence of RV dysfunction after pericardiocentesis.

Changes in RV function before and after Before Immediately after One day after P−value Basal right ventricular linear dimension (mm) 32.8 ± 5.0 37.1 ± 4.4† 33.6 ± 5.4 0.028 Mid-cavity right ventricular linear dimension (mm) 34.5 ± 4.6 38.8 ± 5.3† 37.0 ± 5.6 0.0504 Proximal right ventricular outflow diameter (mm) 30.2 ± 4.0 33.9 ± 3.5† 31.4 ± 3.9 0.014 TAPSE (mm) 20.0 ± 4.2 13.6 ± 4.3* 14.7 ± 3.9 <0.001 S" (cm/s) 12.6 ± 3.3 8.7 ± 2.4* 9.1 ± 2.4 <0.001 Fractional area change (%) 48.3 ± 5.9 37.8 ± 8.0* 40.0 ± 9.0 <0.001 Right ventricular free wall strain (%) −21.3 ± 6.3 −15.8 ± 6.7* −16.9 ± 5.2 0.036 Tricuspid regurgitation velocity peak (m/s) 2.41 ± 0.29 2.43 ± 0.25 2.34 ± 0.32 0.37

Angiogenin promotes tumoral growth and angiogenesis by regulating matrix metallopeptidase-2 expression via the ERK1/2 pathway

Tumor angiogenesis is essential for tumor growth and metastasis and is dependent on key angiogenic factors. Angiogenin (ANG), a 14.2-kDa polypeptide member of the RNase A superfamily, is an angiogenic protein that has been reported to be upregulated and associated with poor prognosis in some human cancers. The mechanisms through which aberrant ANG levels promote specific steps in tumor progression are unknown. Here, we show that ANG expression in human tissues is strongly correlated with an invasive cancer phenotype. We also show that ANG induces cellular survival, proliferation, endothelial tube formation and xenograft angiogenesis and growth. Novel mechanistic investigations revealed that ANG expression stimulated matrix metallopeptidase-2 (MMP2) expression through the phosphorylation of ERK1/2. Targeting ANG in vivo with N65828, a small-molecule inhibitor of the ribonucleolytic activity of human ANG, resulted in the diminution of xenograft tumoral growth through the inhibition of angiogenesis. Our findings support an unrecognized interplay between ANG, ERK1/2 and MMP2 that can impact tumor growth and progression. The targeting of ANG and associated factors could provide a novel strategy to inhibit tumor establishment and growth.

Myostatin alters glucose transporter-4 (GLUT4) expression in bovine skeletal muscles and myoblasts isolated from double-muscled (DM) and normal-muscled (NM) Japanese shorthorn cattle

The purpose of this study was to determine whether myostatin alters glucose transporter-4 (GLUT4) expression in bovine skeletal muscles and myoblasts isolated from double-muscled (DM) and normal-muscled (NM) Japanese Shorthorn cattle. Plasma concentrations of glucose were lower in DM cattle than in NM cattle (P < 0.01). The expression of GLUT4 messenger RNA (mRNA) in the skeletal muscle ex vivo and in myoblasts at 72 h after differentiation in vitro was higher in DM cattle than in NM cattle (P < 0.01). In contrast, the NM and DM cattle did not differ with respect to skeletal muscle expression of GLUT1 and myocyte enhancer factor-2c (MEF2c), a transcription factor of GLUT4. In differentiated myoblasts, the expression of GLUT1, GLUT4, and MEF2c mRNAs was greater in DM cattle than in NM cattle (P < 0.01). In the presence and absence of insulin, glucose uptake in myoblasts was increased in DM cattle relative to that of NM cattle (P < 0.01). The addition of myostatin decreased the expression of GLUT4 and MEF2c mRNAs in DM myoblasts (P < 0.05). Results of the present study suggest that myostatin inhibits the expression of GLUT4 mRNA possibly via MEF2c and that the greater ability of the DM cattle to produce muscle relative to the NM cattle may be due to their greater sensitivity to insulin and greater use of glucose.

Database for exchangeable gene trap clones: pathway and gene ontology analysis of exchangeable gene trap clone mouse lines

Gene trapping in embryonic stem (ES) cells is a proven method for large-scale random insertional mutagenesis in the mouse genome. We have established an exchangeable gene trap system, in which a reporter gene can be exchanged for any other DNA of interest through Cre/mutant lox-mediated recombination. We isolated trap clones, analyzed trapped genes, and constructed the database for Exchangeable Gene Trap Clones (EGTC) [http://egtc.jp]. The number of registered ES cell lines was 1162 on 31 August 2013. We also established 454 mouse lines from trap ES clones and deposited them in the mouse embryo bank at the Center for Animal Resources and Development, Kumamoto University, Japan. The EGTC database is the most extensive academic resource for gene-trap mouse lines. Because we used a promoter-trap strategy, all trapped genes were expressed in ES cells. To understand the general characteristics of the trapped genes in the EGTC library, we used Kyoto Encyclopedia of Genes and Genomes (KEGG) for pathway analysis and found that the EGTC ES clones covered a broad range of pathways. We also used Gene Ontology (GO) classification data provided by Mouse Genome Informatics (MGI) to compare the functional distribution of genes in each GO term between trapped genes in the EGTC mouse lines and total genes annotated in MGI. We found the functional distributions for the trapped genes in the EGTC mouse lines and for the RefSeq genes for the whole mouse genome were similar, indicating that the EGTC mouse lines had trapped a wide range of mouse genes.

An in vitro chemosensitivity test for solid human tumors using collagen gel droplet embedded cultures

In vitro chemosensitivity testing using a collagen gel droplet embedded culture drug sensitivity test (CD-DST), was conducted with several types of solid cancer. The overall evaluable rate was 80% (443/554), including 76% for lung (n=243), 78% for breast (n=110), 87% for gastric (n=62), 83% for colorectal (n=107) cancers and 88% for 32 metastatic brain tumors. The in vitro sensitivity of breast, gastric and colorectal cancers to mitomycin C (MMC), cisplatin (CDDP), 5-fluorouracil (5-FU) and doxorubicin (DXR) was similar to the efficacy rates reported for each drug. This was also observed with lung cancer, the sensitivity of which to MMC, CDDP, vindesine (VDS) and etoposide (VP-16) was similar to the clinical efficacy. The clinical response to chemotherapy was compared with the results of in vitro chemosensitivity testing in Il patients: the clinical correlation was 91%, with a 80% true positive and 100% true negative rate. These results suggest that the CD-DST may be clinically useful by allowing the prediction of clinical response in various solid cancers.

A circulating heat-resistant mucin-like antigen in patients with lung-cancer detected by a new murine monoclonal-antibody

We discovered a circulating mucin-like antigen designated as CAM-14 detected by a new murine monoclonal antibody KL-14 (IgM). We found different heat resistant properties between serum CAM- 14 from normal individuals and from lung cancer patients. Heat treatment had less effect on the levels of CAM-14 in sera from lung cancer patients, whereas CAM-14 levels in sera from normal individuals were markedly decreased after heat treatment at tempratures > 65-degrees-C. As a serum tumor marker, CAM- 14 had only very low levels of false-positive values with a high specificity and effectively increased the positive rate for lung cancer patients when used together with carcinoembryonic antigen.

MRP-1/CD9 and KAI1/CD82 expression in normal and various cancer tissues

As part of our evaluation of MRP-1/CD9 and KAI1/CD82 as prognostic predictors among patients with cancer, we have extended our studies to solid tumors of a variety of anatomical sites. Normal tissues were included for comparison. Immunohistochemical techniques were used throughout. Our results indicate that MRP-1/CD9 was strongly expressed by many normal tissues, including the epithelium of the gastrointestinal tract, alveolar epithelium of the lung, urothelium and smooth muscle. Expression was weak in the pituitary gland, spleen and hepatocytes, and absent in testes and spinal cord. KAI1/CD82 was also expressed by many normal tissues, but was absent in some MRP-1/CD9-positive tissues (e.g., smooth muscle, adrenal cortex, urothelium, myelin of peripheral nerves, epithelium of amnion). On the other hand, KAI1/CD82 was strongly expressed in spinal cord gray matter, which was MRP-1/CD9-negative. Expression of these glycoproteins was detected in almost all types of tumors examined. In certain cancers, MRP-1/CD9 and KAI1/CD82 positivity was inversely related to lymph node involvement. Whereas lymph node metastases were present in 22.2% of lung cancer patients whose tumors were MRP-1/CD9 and KAI1/CD82-positive, 65.5% of patients with MRP-1/CD9 and KAI1/CD82-reduced/negative tumors had lymph node metastases. A similar inverse relationship was seen in colon cancer and breast cancer patients with respect to MRP-1/CD9 expression. The present data, together with our previous results suggest that evaluating the MRP1/CD9 and KAI1/CD82 status of cancers of the lung, breast and colon may provide useful information on the metastatic potential of the tumors.

[Lung cancer accompanied by active pulmonary tuberculosis]

We report 2 patients with lung cancer accompanied by active pulmonary tuberculosis. Case1 was a 82-year-old woman with stage I A bronchioloalveolar carcinoma and tuberculosis in right upper lobe. Right upper lobectomy was performed after the histological diagnosis of lung cancer by intraoperative frozen section. Case2 was a 69-year-old man with papillary adenocarcinoma in right lower lobe and tuberculosis in bilateral upper lobe. Partial resection in right lower lobe was performed for diagnosis of lung cancer. Smear-positive tuberculosis was diagnosed by sputum examination after the operation. Post-operative anti-tuberculosis chemotherapy was added in both patients.

Heterogeneity of colorectal cancers and extraction of discriminator gene signatures for personalized prediction of prognosis

Dissected specimens of colorectal cancer (CRC) have been intensively studied using molecular sketches (gene signatures) to obtain a set of discriminator gene signatures for accurate prognosis prediction in individual patients. The discriminators obtained so far are not universally applicable, as the gene sets reflect the method and site of the study. In this study, we show that dissected stage II and III CRC samples are significantly heterogeneous in molecular sketches, and are not appropriate sources for discriminator extraction unless handled individually. To search for an accurate discriminator gene set for prediction of metastases, we need to start with less heterogeneous stage II CRC. We examined 198 (92 stage II and 106 stage III) CRC dissected samples for the predictability of discriminator gene signatures by analyzing stage II CRC alone, stage III alone, or in combination. The best predictive power of discriminator genes was obtained only when these genes were extracted and validated with stage II CRC samples. An accurate discriminator gene set for the prediction of CRC metastases can be obtained by focusing on stage II CRC samples.

New analysis of the hypertension mechanism in bevacizumab-treated patients using 3-tesla dynamic contrast-enhanced magnetic resonance imaging

450

Background: Vascular endothelial growth factor (VEGF) signaling inhibitors, such as bevacizumab (BV), leads to endothelial dysfunction and microvascular rarefaction in noncancer tissue. Angiotensin II has been reported to induce VEGF production by inhibiting VEGF, but the reasons for activation of angiotensin II are unclear. We conducted a study to examine the relationship between renin-angiotensin axis and renal blood perfusion using dynamic contrast magnetic resonance imaging (DCE-MRI) in colorectal cancer patients.

Methods: Sixteen patients with colorectal cancer were enrolled. They received BV+FOLFIRI regimen as second line. DCE-MRI was performed before the treatment and after 12th courses. Renin, angiotensin I, angiotensin II and aldosterone were examined before treatment and at 3, 5, 8, 12th courses. DCE-MRI parameters, Area under the time-intensity curve over the first 90 seconds after injection of contrast material (AUC90) and volume transfer constant of contrast material (Ktrans, Kep) were calculated in the normal kidney and examine the correlation with renin-angiotensin axis.

Results: All DCE-MRI parameters decreased significantly after 12th courses compared with before treatment (Variables median: Ktrans -1.51, Kep -2.30, AUC90 -26.0, P < 0.001, all). A decrease in Kep correlated with higher renin, angiotensin I and angiotensin II (renin: P =0.001, angiotensin I: P =0.003, angiotensin II: P =0.002, respectively). A decrease in AUC90 correlated with higher aldosterone (P =0.005). Blood pressure did not correlate with each DCE-MRI parameters.

Conclusions: VEGF inhibition decreases vessel permeability and raises interstitial pressure in normal kidney. Our data suggest that renin-angiotensin axis is also one mechanism of hypertension caused by BV.

No significant financial relationships to disclose.

Morphological study of cationic polymer-anionic surfactant complex precipitated in solution during the dilution process

We investigated the phase diagrams and the morphology of the complexes that were formed by cationic polymers, cationic cellulose (CC) and cationic dextran (CD), and by anionic surfactant-based sodium poly(oxyethylene) lauryl ether sulfate (LES). The anionic charge of the LES-based surfactants was changed by adding an amphoteric surfactant, lauryl amidopropyl betaine acetate (LPB), or a nonionic surfactant, polyoxyethylene stearyl ether (C18EO25). We discuss the relationship between the complex aggregation process and the morphology of the precipitated complexes. The morphologies of CC complex aggregates, which precipitated during the dilution process in a model shampoo solution, changed from membranous forms to mesh-like forms by decreasing the charges of both the CC and the surfactant. Their touch on hair in the rinsing process changed from sticky to smooth and velvety, corresponding to their rheological properties. In contrast, CD complex aggregates had a membranous form and a smooth touch independently of the charges on the polymer and surfactant. These results suggested that the control of the charges of both the polymer and surfactant and the choice of polymer structure are important for excellent conditioning effects upon rinsing with shampoo.

Application of positron emission tomography in physical medicine

Positron emission tomography (PET) is widely used in the fields of clinical and basic medicine. The PET device utilizes coincidence logic to detect annihilation photons emitted from positrons and estimates physiological functions of human organs in vivo. Radiopharmaceutical 18F- fluorodeoxyglucose (FDG), an analogue of glucose, is trapped metabolically in cells after being administered into the body, and can be substantially used for evaluating physiological and biochemical functions in vivo. Here, we attempted to describe the basics of PET as well as to apply the technique together with 18F-FDG as a tracer for evaluating organ glucose metabolism induced by exercise. Three-dimensional (3D) FDG-PET was applied to normal volunteers who performed exercise to evaluate whole-body glucose metabolism. Regions of interest analysis were drawn on visually defined regions (i.e., lower limbs, thigh, liver, intestine, brain, heart, etc.) to determine radioactivity distribution. FDG-PET clearly showed the recruitment of energy resources from abdominal organs to lower limb skeletal muscles to balance energy expenditures. The results suggested that 3D FDG-PET can be applied as an imaging tool to physical medicine.

Early morphological events of in vitro fertilized bovine oocytes with frozen-thawed spermatozoa

Bovine follicular oocytes were matured and inseminated in vitro with spermatozoa capacitated in vitro. The first evidence of sperm penetration was observed at 3 h after insemination. The penetration rate increased until 5 h, and reached a maximum rate (92%) at 5 h. Decondensation of the sperm head and pronuclear formation were observed 4 h and 7 h after insemination, respectively. Female chromatins of all penetrated oocytes were activated at 3 h, and female pronuclei were formed at 7 h after insemination. Percentages of oocytes with male and female pronuclei at 9 h were 88 and 94%. Polyspermy (4, 7, 19 and 29% at 4, 5, 7 and 9 h after insemination, respectively) and abnormal development of male pronuclei (6 and 7% at 7 and 9 h after insemination, respectively) were also seen.

Bovine oocytes from early antral follicles grow to meiotic competence in vitro: effect of FSH and hypoxanthine

A large number of oocytes are contained in the mammalian ovary. A very small number of these oocytes grow to the final size, mature, and are ovulated. In the ovary there are more early antral follicles than late antral or preovulatory follicles, offering a large pool of oocytes for IVM and IVF if appropriate culture conditions could be devised. In the present study, early antral follicles containing oocytes 90 to 99 microm in diameter were isolated from bovine ovaries. Cumulus-oocyte complexes (COC) with pieces of parietal granulosa (COCG) were then dissected from the follicles. The COCGs were embedded in collagen gels and cultured in Medium 199 with 10% fetal calf serum (FCS) for 8 d. In Experiment 1, the effect of hypoxanthine and FSH on the growth of bovine oocytes was examined. When hypoxanthine (2 and 4 mM) and FSH (10 ng/ml) were added to the culture medium, the number of granulosa cell-enclosed oocytes increased significantly (P < 0.05). All of the oocytes surrounded by granulosa cells showed a normal morphology and were at the germinal vesicle stage, while 75 to 94% of the denuded oocytes were degenerated and had resumed meiosis. The mean diameter of the oocytes showing normal morphology was significantly higher than that measured before culture (P < 0.05). In Experiment 2, the maturational competence of in vitro-grown bovine oocytes was examined. Oocytes which were 90 to 99 microm in diameter before culture did not have meiotic competence. After being in a growth culture of 4 mM hypoxanthine- and 10 ng/ml FSH-supplemented medium for 7 or 11 d, granulosa cell-enclosed oocytes were recovered from the COCGs. No significant difference (P < 0.05) in the diameters of the oocytes was observed between 7 and 11 d of culture (7 d: 107.5 +/- 6.1 microm, n = 30; 11 d: 108.0 +/- 5.3 microm, n = 35). After a subsequent 24 h in a maturation free of hypoxanthine and FSH medium, only 17% of the oocytes cultured for 7 d underwent germinal vesicle breakdown. On the other hand, 89% of the oocytes cultured for 11 d underwent germinal vesicle breakdown, and 11% of the oocytes emitted the first polar body and reached metaphase II. These results demonstrate for the first time that bovine oocytes harvested from early antral follicles can grow, and acquire meiotic competence in vitro.

303 FERTILIZATION-RELATED PARAMETERS OF FROZEN - THAWED SPERMATOZOA FROM SUBFERTILE JAPANESE BLACK CATTLE

The subfertility derived from male factors is a problem of concern in domestic animals, because it could cause a disintegration of the breeding system and large economic losses, particularly when the subfertility affects genetically superior male animals. Therefore, it is urgent that causal factors of male subfertility be determined. Recently, an increasing number of subfertile bulls have been found among Japanese Black cattle, which is a representative breed of Japanese beef cattle. The purpose of the present study was to elucidate causal factors of male subfertility in Japanese Black cattle. Frozen–thawed spermatozoa from 8 subfertile (S1-S8) and 7 fertile (F1–F7, control) bulls were used for the assessment of fertilization-related parameters. The data obtained from each subfertile bull in the following experiments were individually compared with the mean values of the fertile bull group. In Experiment 1, sperm motility was observed in samples that were frozen-thawed and subsequently washed in PBS. Many spermatozoa (higher than 65%) exhibited flagellar movement in all samples from fertile and subfertile bulls. However, the percentages of progressively motile spermatozoa from 2 subfertile bulls were significantly lower (S2: 6%; S7: 7%; P &lt; 0.05, ANOVA and Tukey&apos;s multiple range tests) than those from fertile bulls (average: 37&percnt;). Moreover, rapidly progressive movement was not observed in the spermatozoa from 4 subfertile bulls (S1, S2, S6, and S7). These data suggest abnormality in the motility system of sperm flagella in these 4 subfertile bulls. In Experiment 2, the capacitation&ndash;acrosome reaction state of frozen&ndash;thawed spermatozoa was examined by the CTC-staining assay. More than 50&percnt; of the frozen&ndash;thawed spermatozoa from 4 subfertile bulls (S5&ndash;S8) were prematurely progressing in the capacitation state immediately after washing and resuspension in the medium lacking CaCl2. Moreover, the addition of CaCl2 to the medium induced acrosomal loss in these sperm samples (percentages of spermatozoa without the acrosome: 36&ndash;49&percnt;). These findings indicate the occurrence of premature capacitation and a spontaneous acrosome reaction in spermatozoa from these 4 subfertile bulls. In Experiment 3, the in vitro fertilizing ability of frozen&ndash;thawed spermatozoa was evaluated by the IVF test. The percentages of fertilized eggs with both male and female pronuclei or developmental rates of fertilized eggs to the 2-cell or 4-cell stage were significantly lower in the spermatozoa from S6 to S8 bulls than in those from fertile bulls (P &lt; 0.05, chi-squared tests). This may suggest that spermatozoa from these 3 subfertile bulls hardly accomplish the normal fertilization process. In summary, low progressive motility and low in vitro fertilizing ability because of premature capacitation were found in the spermatozoa from subfertile bulls. It is therefore possible that these are causal factors for the subfertility of male Japanese Black cattle.

159 LOCALIZATION OF CLAUDIN FAMILY PROTEINS IN PIG EMBRYOS DURING PRE-IMPLANTATION DEVELOPMENT

Tight junctions (TJ) are critical for blastocoel formation in mammalian pre-implantation embryos. Claudin family proteins, which are TJ proteins, are generally important for the barrier function of TJ. However, the expression and localization of claudin proteins are not clarified in mammalian pre-implantation embryos. The present study was designed to examine changes in the localization of claudin isoforms, claudin-1, -2, and -4, in pig parthenogenetic diploids through pre-implantation development. Oocyte–cumulus–granulosa cell complexes were collected from the follicles 4–6 mm in diameter, and then maturation-cultured. Only oocytes with a prominent first polar body were subjected to electro-stimulation after maturation, and they were treated with cytochalasin B to produce parthenogenetic diploids. Presumptive diploids were then cultured for 168 h and observed every 24 h. Embryos of each developmental stage from 2-cell to blastocyst were subjected to immunofluorescence staining of the anti-TJ proteins. Zona-free embryos were fixed and treated with rabbit anti-claudin-1 and -2 polyclonal antibodies or mouse anti-claudin-4 monoclonal antibody, followed by treatment with Alexa fluor 488-labeled goat anti-rabbit IgG antibody or goat anti-mouse IgG antibody. Some embryos were treated with rabbit anti-occludin antibody or anti-ZO-1 antibody for the detection of the TJ-net work. All embryos were counterstained with Hoechst 33342 and observed under an epifluorescence microscope after whole-mounting. The specific fluorescence for all TJ proteins examined was observed in embryos at all pre-implantation stages. Occludin and ZO-1 were detected in the cytoplasm before the morula stage (96 h), and localized toward the boundary region among cells from the morula and early blastocyst stages, reflecting the distribution of the tight junction in embryos. Claudin-1 and -2 localized in the cytoplasm at early-cleaving stages. They were detected in the nucleus after compaction, and the distribution of these proteins in the nucleus was dominant at the blastocyst stage. The distribution of the 2 claudin proteins in the nucleus was quite different; claudin-1 distributed rather homogeneously, but claudin-2 formed several bright spots in the nucleus. Claudin-4 also showed a unique distribution pattern in embryos; it was detected in the cytoplasm with strong fluorescence at the periphery of the nucleus of the 2- and 4-cell embryos. Claudin-4 changed its localization toward the boundary region of cells around the early blastocyst stage (120 h), and then the distribution of claudin-4 was restricted to the boundary region later in the blastocyst stage (144 h). These results indicate that claudin-4, but not claudin-1 and -2, is responsible for the formation of TJ in the pre-implantation embryos, although the function of these claudin proteins in the nucleus is unknown.