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The presence of protein inclusions, called Lewy bodies (LBs) and Lewy neurites (LNs), in the brain is the main feature of Parkinson’s disease (PD). Recent evidence that the prion-like propagation of α-synuclein (α-syn), as a major component of LBs and LNs, plays an important role in the progression of PD has gained much attention, although the molecular mechanism remains unclear. In this study, we evaluated whether neuronal ApoE regulates the cell-to-cell transmission of α-syn and explored its molecular mechanism using in vitro and in vivo model systems. We demonstrate that neuronal ApoE deficiency attenuates both α-syn uptake and release by downregulating LRP-1 and LDLR expression and enhancing chaperone-mediated autophagy activity, respectively, thereby contributing to α-syn propagation. In addition, we observed that α-syn propagation was attenuated in ApoE knockout mice injected with pre-formed mouse α-syn fibrils. This study will help our understanding of the molecular mechanisms underlying α-syn propagation.

The purpose of this study is to analyze the effects of collaborative leadership on organizational effectiveness (job satisfaction, organizational commitment) in naval organizations and to analyze empirically the factors affecting organizational effectiveness. The subordinate factors of collaborative leadership were identified as procedural cooperation, cognitive cooperation, and structural cooperation. The surveys were conducted among the naval officers in C City. As a result of the reliability analysis, validity analysis and stepwise multiple regression analysis of the data obtained through the questionnaire, it was confirmed that collaborative leadership had a positive effect on organizational effectiveness. This study suggests that the findings of this research should be reflected in further research and education on naval leadership. This study contributes to the literature by confirming not just a concept but also the components of the cooperative leadership and analyzing empirically the cooperative leadership suitable for naval applications in South Korea.

To overcome unpredictable fat graft resorption, cell-assisted lipotransfer using stromal vascular fraction (SVF) has been introduced. However, its effect on cancer growth stimulation and its oncological safety are debatable. We investigated the effect of SVF on adjacent breast cancer and transplanted fat in a mouse model. A breast cancer xenograft model was constructed by injecting 2 × 106 MDA-MB-231-luc breast cancer cells into the right lower back of 40 NOD/SCID mice. Two weeks later, cancer size was sorted according to signal density using an in vivo optical imaging system, and 36 mice were included. Human fat was extracted from the abdomen, and SVFs were isolated using a component isolator. The mice were divided into four groups: A, controls; B, injected with 30 μl SVF; C, injected with 0.5 ml fat and 30 μl saline; group D, injected with 0.5 ml fat and 30 μl SVF. Magnetic resonance imaging and three-dimensional micro-computed tomography volumetric analysis were performed at 4 and 8 weeks. Tumor volume was 43.6, 42.3, 48.7, and 42.4 mm3 at the initial time point and 6780, 5940, 6080, and 5570 mm3 at 8 weeks in groups A, B, C, and D, respectively. Fat graft survival volume after 8 weeks was 49.32% and 62.03% in groups C and D, respectively. At 2-month follow-up after fat grafting in the xenograft model, SVF injection showed an increased fat survival rate and did not increase the adjacent tumor growth significantly. Fat grafting with SVF yields satisfactory outcome in patients who undergo breast reconstruction surgery. This journal requires that authors assign a level of evidence to each article. For a full description of these Evidence-Based Medicine ratings, please refer to the Table of Contents or the online Instructions to Authors www.springer.com/00266.

This paper investigates the concrete breakout shear capacity of a single cast-in headed anchor embedded in steel fiber-reinforced concrete (SFRC). Experiments were carried out for anchors with a diameter of 30 mm, embedment depth of 240 mm, and edge distance of 150 mm. Fiber volume fractions of 0.33, 0.67, and 1.00% were examined. In addition to shear tests, four-point bending tests were carried out to evaluate the relationship between the material properties of SFRC and the shear capacity of anchors. The experimental results show that the current design formulas are valid for anchors in conventional plain concrete but not appropriate for the shear capacity of anchors in SFRC. Using the equivalent flexural strength ratio, a revised design equation is proposed to incorporate the effect of the steel fiber content on the concrete breakout shear capacity and provide reasonably similar safety for anchors in both un-reinforced and SFRC.

As the availability of breast reconstruction using implants is becoming widespread and many implant recipients undergo radiation therapy, there is an increasing interest in understanding the potential complications associated with capsule-tissue interactions in response to irradiation. Accordingly, our medical institution designed an animal experiment to investigate the effects of irradiation on capsular contracture. A total of 40 mice (C57BL6) were divided into four groups according to whether or not they received irradiation and the time from implantation to irradiation. After each mouse received a specially-fabricated, 1.5 cm semi-spherical silicone implant inserted into the area below the panniculus carnosus, half of the mice were irradiated using singe administration of a 10 Gy dose of radiation (6 MeV). Subsequently, data from gross inspection, histological analysis and immunohistochemical analysis were obtained at one and three months postoperatively and analyzed. Changes that occurred near the capsule led to the phenomenon of contracture subsequent to encapsulation. Our findings suggest that the inflammation reaction occurring near the implant becomes aggravated by 'radiation toxicity' and creates an environment conducive to capsular contracture. The present study demonstrated the process by which the complication of capsular contracture may occur during the treatment of human breast cancer via radiotherapy. These findings may serve as the basis for research and development of future treatments of capsular contracture.

This study aimed to apply fluoride formulations to enamel with cold atmospheric plasma (CAP) and analyze the fluoride uptake, retention, and acid resistance quantitatively. Human enamel specimens were divided randomly into 2 groups: group APF1, 1.23% acidulated phosphate fluoride (APF) gel; group APF2, 1.23% APF gel with CAP. Fluoride and CAP were applied to the samples 4 times at 1-wk intervals. The specimens were also stored in artificial saliva for 4 wk to evaluate the retention of fluoride. The fluoride content on the fluoride-treated enamel was measured by an electron probe microanalyzer. To detect the resistance to demineralization, the calcium-to-phosphate ratio of the enamel samples was measured after the application of APF gel with or without CAP, followed by soaking in the demineralization solution. In groups APF1 and APF2, the amount of fluoride detected increased depending on the application frequency, and more fluoride was detected in group APF2 than in group APF1. In the experiment examining the maintenance effect, fluoride was not detected in group APF1, whereas fluoride was detected in group APF2 up to the fourth week. As for the resistance to demineralization, the calcium-to-phosphate ratio of the enamel treated with APF and CAP was higher than that treated with APF alone, and it increased with the frequency of treatment. This study suggests that the combination treatment of CAP and fluoride improves retention of fluoride on the enamel and resistance to demineralization when compared with treatment with fluoride alone.

Tests of the lateral and torsional stability are quite sensitive to the experimental conditions, such as support conditions and loading system. Controlling all of these conditions in a full-size test is a very challenging task. Therefore, in this paper, an experimental measurement method that can control the experimental conditions using a small-scale model was proposed to evaluate the lateral and torsional stability of beams. For this, a loading system was provided to maintain the vertical direction of the load applied to the beam, and a support frame was produced to satisfy the in-plane and out-of-plane support conditions. The experimental method using a small-scale model was applied successively to the lateral and torsional behavior and stability of I-shaped beams. The proposed experimental methods, which effectively accommodate the changes in the geometry and length of the beam, could contribute to further experimental studies regarding the lateral and torsional stability of flexural members.

Among autologous breast reconstruction techniques, breast reconstruction using the latissimus dorsi musculocutaneous flap is widely used, offering advantages including the relative simplicity of the procedure and the reliable and consistent vascularity of the flap. Accordingly, more than 500 cases have been performed in the past 8 years at Kyungpook National University Medical Center. This study reports on a rare case involving a radial nerve neuropathy complication which was experienced for the first time at the medical center. The current case demonstrates that in addition to common complications, such as seroma of the donor site and scarring, additional intraoperative complications in areas unrelated to the surgical site can occur, including radial nerve neuropathy in the opposite arm.

Pseudoangiomatous stromal hyperplasia (PASH) is a benign proliferative mesenchymal lesion of the breast. PASH presents as a palpable or mammographically detectable mass or is an incidental microscopic finding in up to 23% of breast biopsies. Its pathogenesis is unclear but may involve hormonal factors, as recently postulated. Its clinical, cytological, and radiological characteristics resemble those of other benign tumors, including low-grade angiosarcomas and phyllodes tumors. Because of its uncertain pathogenesis, PASH is usually treated via surgical excision, with post-excision recurrence rates ranging from 7% to 22% [1]. Although several cases of PASH have been recently reported, cases of PASH involving large, rapidly growing lesions refractory to surgical incision are rare [2]. In this study, we report our experience with a case of PASH that presented as rapidly growing bilateral breast enlargement refractory to surgical excision. We also review the pertinent literature, including the clinical and histopathological features, pathogenesis, imaging findings, treatment, and prognosis of PASH.

Background Palatoplasty is aimed to achieve normal speech, improve food intake, and ensure successful maxillary growth. However, the velopharyngeal function is harder to control than other functions. Therefore, many studies on the prognostic factor of velopharyngeal insufficiency have been conducted. This study aimed to evaluate the relationships between speech outcomes and multimodality based on intraoral and preoperative three-dimensional computerized tomographic (CT) findings. Methods Among 73 children with cleft palate who underwent palatoplasty between April 2011 and August 2014 at Kyungpook National University Hospital (KNUH), 27 were retrospectively evaluated. The 27 cases were non-syndromic, for which successful speech evaluation was conducted by a single speech-language pathologist ( Table 1 ). Successful speech evaluation was defined as performing the test three times in 6-month intervals. Three intraoral parameters were measured before and immediately after operation ( Fig. 1 ). On axial- and coronal-view preoperative facial CT, 5 and 2 different parameters were analyzed, respectively ( Fig. 2 , Fig. 3 ). Regression analysis (SPSS IBM 22.0) was used in the statistical analysis. Results Two-flap palatoplasty and Furlow's double opposing Z-plasty were performed in 15 and 12 patients, respectively. The operation was performed 11 months after birth on average. Children with a higher palatal arch and wider maxillary tuberosity distance showed hypernasality (p Table 2 ). Conclusions The useful prognostic factors of velopharyngeal function after palatoplasty were palate width and height, rather than initial diagnosis, treatment method, or palate length. Therefore, a more active intervention is needed, such as orthopedic appliance, posterior pharyngeal wall augmentation, or early speech training.

Background The emergence of breast-conserving surgery combined with radiotherapy as the treatment of choice for early stage breast cancer has resulted in greater focus on oncoplastic breast surgery. The use of perforator flaps has particularly gained in reputation for its effectiveness in the reconstruction of partial breast defects in Korean women. Herein, we present our experience with the use of thoracodorsal artery perforator (TDAP) and lateral intercostal artery perforator (LICAP) flaps. Methods This study included 33 patients who underwent breast reconstruction using TDAP or LICAP flaps at our hospital from January 2011 to December 2014. Data from patient medical records, and patient satisfaction surveys, which were conducted 12 months postoperatively, were retrospectively evaluated. Results TDAP and LICAP flap-based reconstructions were performed in 14 and 19 patients, respectively. Five patients developed complications that required additional intervention. Overall patient satisfaction was observed to be excellent in 15 (46%) patients, and good in 12 (36%). Conclusions Based on our experience, oncoplastic breast surgery using TDAP or LICAP flap is an effective remodeling technique for small-to-moderate breast defects in Korean women with smaller breasts.

Summary: Recent evidence of prion-like propagation of α-synuclein (α-syn) into neighboring neurons set up a paradigm to elucidate the mechanism of progression of Parkinson’s disease (PD) and to develop therapeutic strategies. Here, we show that FcγRIIB expressed in neurons functions as a receptor for α-syn fibrils and mediates cell-to-cell transmission of α-syn. SHP-1 and 2 are activated downstream by α-syn fibrils through FcγRIIB and play an important role in cell-to-cell transmission of α-syn. Also, taking advantage of a co-culture system, we show that cell-to-cell transmission of α-syn induces intracellular Lewy body-like inclusion body formation and that the FcγRIIB/SHP-1/2 signaling pathway is involved in it. Therefore, the FcγRIIB-SHP-1/-2 signaling pathway may be a therapeutic target for the progression of PD. The in vitro system is an efficient tool for further high-throughput screening that can be used for developing a therapeutic intervention in PD. : Prion-like propagation of α-synuclein (α-syn) may contribute to the progression of Parkinson’s disease. Choi et al. demonstrate that FcγRIIB functions as a receptor for α-syn fibrils and that the FcγRIIB-SHP-1/2 signaling pathway mediates cell-to-cell transmission of α-syn. Blocking this signaling pathway attenuates transmission, suppressing Lewy body-like inclusion body formation. Keywords: α-synuclein, cell-to-cell transmission, FcγRIIB, SHP-1, SHP-2

Background Arteriovenous malformation (AVM) of the head and neck regions show low incidence; hence, studies regarding the causative factors of onset, diagnostic criteria, clinical aspects, treatment methods, and outcomes remain lacking. Objective To share the diagnostic and treatment experiences at the center and to understand the treatments' effect through a retrospective analysis of cases in the past 15 years. Materials and methods The authors included 60 patients with AVM in the head and neck area between January 1999 and September 2014 to investigate diagnostic methods, distributions and locations of lesions, clinical stage, and treatment methods by retrospective evaluation. Results In all, 3.7% were diagnosed with AVMs of the head and neck. No sex-related differences were observed, and the mean age at diagnosis was 27.6 ± 14.24 years. The left (26 patients, 43%) and V2 sections (33 patients, 55%) of the head and neck were the most frequent locations. Stage II (28 patients, 47%) had the largest distribution. Forty-four patients (73%) showed improvement after sclerotherapy, embolization, and surgical resection. Conclusion The diagnosis and treatment of AVMs should be approached on a case-by-case basis by gathering opinions from specialists in each department using medical history, physical examination, and imaging results.

*Department of Biochemistry, Hallym University Medical School, Chuncheon 200-702, Korea.**Institute of Natural Medicine, Hallym University Medical School, Chuncheon 200-702, Korea.***Department of Food and Nutrition, College of Natural Sciences, Hallym University, Chuncheon 200-702, Korea.****Institute of Cell Differentiation and Aging, Hallym University Medical School, Chuncheon 200-702, Korea.ABSTRACT : Chelidonium majus (CM) contains several isoquinoline alkaloids that have been reported to have various bio-logical activities such as anti-inflammatory, antimicrobial, antioxidant, immune-modulatory, and antitumoral. It has beenreported that the extract of CM had an antioxidant potential, however the mechanism has not been verified. In this study,we found that CM extract activated FOXO3a. FOXO3a is a transcription factor that involved in various biological processessuch as cell cycle arrest, apoptosis, DNA repair, and ROS detoxification. Transcriptional activities of FOXO3a were regu-lated by post-translational modifications including phosphorylation, acetylation, and ubiquitination. Protein level ofFOXO3a was increased by CM extract. Promoter activities of FOXO-transcriptional target genes such as MnSOD, p27 andGADD45 were activated by CM extract in a dose dependent manner. In addition, protein level of MnSOD, major antioxi-dant enzyme, was increased by CM extract. Thereby ROS level was decreased by CM in old HEF cells. These results suggestthat CM extract has an antioxidant activity through FOXO activation. Key Words : Chelidonium majus, FOXO3a, Antioxidant

The load carrying capacities of railway bridges should be periodically evaluated due to its social significance. Especially, load carrying capacity evaluation for a high speed railway bridge is more needed because of nasty accident. Numerical analysis can be a good tool for evaluating load carrying capacity instead of field test which has limitations such as traffic control, weather conditions, and economic problem. For reasonable evaluating load carrying capacity, numerical model should be reliably updated with accurate measured data. In this study, combined phase model updating technique based on univariate search method was used for model updating. And measuring point roaming method was used for meticulous measurement with limited number of sensor. As a result, it was possible to get similar response from numerical experiment with ambient vibration response from existing bridge. The updated model could be used for estimating load carrying capacity of a bridge.

The purpose of this study is to review and suggest coastal shipping policies for introduction of WIG craft into domenstic passenger shipping market. Two Korean companies are leading in the development of WIG craft as an innovative sea transportation vehicle, and it is awaiting for commercialization. WIG craft is expected to be commercialized from coastal passenger market and we used AHP method to investigate the major factors and its` priority for smooth market entry. The results shows that priorities are on the WIG craft legislation, dock installation and operation, port state control, and pilot hiring and training, craft maintenance, and ship`s certification in order.

Logistics in a supply chain network has become an important operational strategy in a competitive market. A number of internal and external risks involved in the logistics operations in a company tend to create problems in fulfilling customer orders. This research presents how ERM (enterprise risk management) can be used to identify, assess, and control logistics risks. An electronic company's logistics activities were used as an industry case to demonstrate a way to identify and assess risks surrounding global logistics function. This paper has further presented action plans to mitigate the impact of the risks that occur.

In the central Busan area from Haeundae to Saha, fishing villages are vanished actually in the progress of urbanization, and 17 fishing ports surrounded by urbanized area are left alone and isolated. But, we think these urbanized fishing ports are the very resource which grant the identity as the marine city and they have considerable potentials to enhance the value of neighboring community depending on the proper development of it. In this study, we defined the fishing ports in central Busan area as the representatives of `urban fishing port`, and tried to find the way of coexistence and harmony between `city` and `fishing port`. For this purpose, we investigated the fishery potentials, physical environments and development demands of 17 fishing ports in central Busan area, and composed opinions from fishing communities and neighboring inhabitants to set up the long term directions of urban fishing ports development for harmonious coexistence of city and fishing port.

Background: Stathmin1 is a microtubule-regulating protein that has an important role in the assembly and disassembly of the mitotic spindle. The roles of stathmin1 in carcinogenesis of various cancers, including prostate and breast cancer, have been explored. However, its expression and roles in gastric cancer have not yet been described. Methods: Stathmin1 expression in paraffin-embedded tissue sections from 226 patients was analysed by immunohistochemistry. Roles of stathmin1 were studied using a specific small interfering RNA (siRNA). Results: The expression of stathmin1 was positively correlated with lymph node metastasis, TNM stages and vascular invasion, and negatively with recurrence-free survival, in the diffuse type of gastric cancer. The median recurrence-free survival in patients with a negative and positive expression of stathmin1 was 17.0 and 7.0 months, respectively (P=0.009). When the expression of stathmin1 was knocked down using siRNA, the proliferation, migration and invasion of poorly differentiated gastric cancer cells in vitro were significantly inhibited. Moreover, stathmin1 siRNA transfection significantly slowed the growth of xenografts in nude mice. Conclusion: These results suggest that stathmin1 can be a good prognostic factor for recurrence-free survival rate and is a therapeutic target in diffuse-type gastric cancer.

The current study explored if alpha-iso-cubebene, a novel cubebene sesquiterpene compound purified from Schisandra chinensis, could attenuate the activities of adhesion molecules in tumor necrosis factor-alpha (TNF-alpha)-stimulated human umbilical vein endothelial cells (HUVECs). The study was performed on HUVECs that were pretreated with 25 microg/ml of alpha-iso-cubebene before TNF-alpha treatment. Treatment of HUVECs with alpha-iso-cubebene for 6 h significantly inhibited TNF-alpha-induced reactive oxygen species (ROS) formation. HUVECs treated with alpha-iso-cubebene showed markedly suppressed TNF-alpha-induced mRNA expression of VCAM-1 and E-selectin, but little alteration in ICAM-1 mRNA expression. alpha-iso-Cubebene treatment also significantly decreased the TNF-alpha-induced cell surface and total protein expression of VCAM-1 and E-selectin without affecting ICAM-1 expression. In addition, treatment of HUVECs with alpha-iso-cubebene markedly reduced U937 monocyte adhesion to TNF-alpha-stimulated HUVECs. alpha-iso-Cubebene treatment did not affect translocation of NF-kappaB transcription factor from the cytosol into the nucleus. However, alpha-iso-cubebene significantly inhibited NF-kappaB transcription factor activation in TNF-alpha-stimulated HUVECs. The new anti-inflammatory agent alpha-iso-cubebene attenuates TNF-alpha-stimulated endothelial adhesion to monocytes by inhibiting intracellular ROS production, the activation of redox-sensitive NF-kappaB transcription factor and expression of VCAM-1 and E-selectin. Based on these findings, alpha-iso-cubebene is proposed as an effective new anti-inflammatory agent that may have a potential therapeutic use for the prevention and treatment of vascular diseases.

Hedgehog (Hh) signaling is an essential pathway in embryonic development of prostate. Hh also plays roles in the proliferation of progenitor cells and cancer cells of adult prostate. However, how Hh signaling contributes to carcinogenesis of prostate is poorly understood. Stathmin1 is a microtubule-regulating protein that plays an important role in the assembly and disassembly of the mitotic spindle. Stathmin1 is expressed in normal developing mouse prostate and in prostate cancer. The expression pattern of stathmin1 is similar to that of Shh in prostate development and cancer, suggesting a connection between these two proteins. In this study, we examined the relationship between stathmin1 and Hh signaling. Here, we show that stathmin1 expression is regulated by Hh signaling in prostate cancer cells. Cyclopamine, a specific inhibitor of Hh signaling, reduced the expression of stathmin1 in prostate cancer cells. However, the Shh peptide induced stathmin1 expression. Overexpression of Gli1 further confirmed the relationship. Co-expression of stathmin1 and Patched 1, a receptor for Hh signaling was observed in prostate cancer tissues. Cyclopamine and stathmin1 siRNA both decreased proliferation of prostate cancer cells but did not produce an additive effect, suggesting a common pathway. These results suggest that Hh signaling regulates proliferation of prostate cancer cells by controlling stathmin1 expression.

Hedgehog signaling plays critical roles during embryonic development. It is also involved in tissue regeneration and carcinogenesis in various adult tissues. Moreover, it regulates the maintenance of cancer stem cells and adult stem cells. Although hedgehog signaling is important in gastric carcinogenesis, its role in gastric regeneration has not been previously examined. In the present study, we evaluated the expression and roles of hedgehog signaling during gastric regeneration.Gastric ulcers were induced by serosal application of an acetic acid solution in mice. Sham-operated mice served as controls. The proliferation of gastric progenitor cells was studied using bromodeoxyuridine (BrdU). The expression of hedgehog signaling molecules and the differentiation of gastric progenitor cells were examined by immunohistochemical staining and Western blotting.One day after the induction of gastric ulcer, the proliferation of gastric progenitor cells increased; however, the expression of hedgehog signaling molecules, including sonic hedgehog (Shh), Indian hedgehog (Ihh), desert hedgehog (Dhh), and patched (Ptch1) decreased at the ulcer margin. From 5 days after the induction of gastric ulcer, newly generated gastric glands and their differentiation were observed at the ulcer margin. The expression of hedgehog signaling molecules gradually increased in the newly generated gastric glands of the ulcer margin. Cyclopamine, a specific inhibitor of hedgehog signaling, significantly inhibited the differentiation of mucous cells and parietal cells during the gastric regeneration process.The above results suggest that hedgehog signaling is involved in the differentiation of gastric progenitor cells during the gastric ulcer repair process.

Ischemia-induced cerebral injury evolves over a longer period than previously believed through post-ischemic inflammation. Retinoic acid (RA) has been shown to exert cytoprotective effects on several cells, but its effects on ischemia-induced cerebral injury have been poorly characterized. The aim of the present study was to examine the effects of all-trans-RA on ischemia-induced cerebral injury and elucidate the underlying mechanism. All-trans-RA treatment reduced the size of the ischemia-induced cerebral infarct. To elucidate the underlying mechanism, ischemia-induced cerebral inflammation was studied by examination of expressions of interleukin 1beta (IL-1beta) and ED-1. RA treatment significantly reduced the cerebral inflammation. Moreover, cerebral ischemic induction of cyclooxygenase-2 (COX-2) and CCAAT/enhancer binding protein beta (C/EBPbeta), which binds to the COX-2 promoter, was also inhibited by RA. These results suggest that RA can reduce ischemia-induced cerebral injury by an anti-inflammatory action, which may be effected via inhibition of C/EBPbeta-mediated COX-2 induction.

Thymus can regenerate to its normal mass within 14 days after acute involution induced by cyclophosphamide (CY) in adult rat. Despite the established role of Wnt pathways in the process of thymus development, they have not yet been associated with the regeneration of adult thymus. The purpose of this study was to investigate whether Wnt7b, which is expressed in developing thymic epithelial cells rather than in thymocytes, is modulated during thymic regeneration in adult rat. Here, we show that Wnt7b expression was up-regulated in the regenerating thymus. Cells immunolabeled for the Wnt7b were identified as macrophages. Furthermore, Wnt7b gene expression was decreased by the treatment of receptor activator of NF-kappaB ligand (RANKL). Taken together, our results demonstrate that Wnt7b gene expression was increased in macrophages during thymic regeneration and negatively regulated by RANKL.

Neuroimmune networks in the thymic microenvironment are thought to be involved in the regulation of T cell development. Nerve growth factor (NGF) is increasingly recognized as a potent immunomodulator, promoting "cross-talk" between various types of immune system cells. The present study describes the expression of NGF during thymus regeneration following acute involution induced by cyclophosphamide in the rat. Immunohistochemical stain demonstrated not only the presence of NGF but also its upregulated expression mainly in the subcapsular, paraseptal, and perivascular epithelial cells, and medullary epithelial cells including Hassall's corpuscles in both the normal and regenerating thymus. Biochemical data obtained using Western blot and RT-PCR supported these results and showed that thymic extracts contain NGF protein and mRNA, at higher levels during thymus regeneration. Thus, our results suggest that NGF expressed in these thymic epithelial cells plays a role in the T lymphopoiesis associated with thymus regeneration during recovery from acute thymic involution.