Real-world efficacy of letermovir prophylaxis for cytomegalovirus infection after allogeneic hematopoietic stem cell transplantation: A single-center retrospective analysis.

INTRODUCTION: Cytomegalovirus (CMV) infection is a common complication following allogeneic hematopoietic stem cell transplantation (aHSCT) and is associated with increased mortality. Letermovir (LET) is a novel antiviral drug used to prevent CMV infection. METHODS: We analyzed 111 consecutive patients who underwent aHSCT, retrospectively, to evaluate the efficacy of LET prophylaxis for clinically significant CMV infection (csCMVi) in real-world situations. In addition, we analyzed the influence of LET on transplant outcomes. Thirty-eight patients who were administered LET prophylactically were compared with 73 patients without LET prophylaxis after aHSCT. RESULTS: On day 180, the cumulative incidence of csCMVi in patients who received LET prophylaxis was significantly lower than that in patients without LET prophylaxis (29.7% vs. 56.2%, P < 0.001). Among the patients who developed csCMVi, the interval from aHSCT to the initiation of preemptive therapy was significantly longer in patients who received LET prophylaxis than in those who did not (129.5 days vs. 42 days, P < 0.001). The six-month overall survival was 86.1% in patients who received LET prophylaxis and 66.8% in the non-LET group (P = 0.035). CONCLUSION: LET prophylaxis was highly effective in preventing csCMVi and could potentially improve transplant outcomes, particularly when initiated early after transplantations.

Contribution of Coiled-Coil Assembly to Ca2+/Calmodulin-Dependent Inactivation of TRPC6 Channel and its Impacts on FSGS-Associated Phenotypes.

BACKGROUND: TRPC6 is a nonselective cation channel, and mutations of this gene are associated with FSGS. These mutations are associated with TRPC6 current amplitude amplification and/or delay of the channel inactivation (gain-of-function phenotype). However, the mechanism of the gain-of-function in TRPC6 activity has not yet been clearly solved. METHODS: We performed electrophysiologic, biochemical, and biophysical experiments to elucidate the molecular mechanism underlying calmodulin (CaM)-mediated Ca2+-dependent inactivation (CDI) of TRPC6. To address the pathophysiologic contribution of CDI, we assessed the actin filament organization in cultured mouse podocytes. RESULTS: Both lobes of CaM helped induce CDI. Moreover, CaM binding to the TRPC6 CaM-binding domain (CBD) was Ca2+-dependent and exhibited a 1:2 (CaM/CBD) stoichiometry. The TRPC6 coiled-coil assembly, which brought two CBDs into adequate proximity, was essential for CDI. Deletion of the coiled-coil slowed CDI of TRPC6, indicating that the coiled-coil assembly configures both lobes of CaM binding on two CBDs to induce normal CDI. The FSGS-associated TRPC6 mutations within the coiled-coil severely delayed CDI and often increased TRPC6 current amplitudes. In cultured mouse podocytes, FSGS-associated channels and CaM mutations led to sustained Ca2+ elevations and a disorganized cytoskeleton. CONCLUSIONS: The gain-of-function mechanism found in FSGS-causing mutations in TRPC6 can be explained by impairments of the CDI, caused by disruptions of TRPC's coiled-coil assembly which is essential for CaM binding. The resulting excess Ca2+ may contribute to structural damage in the podocytes.

[A Resected Case of Leiomyosarcoma Originating from the Ovarian Vein].

We present a 46-year-old female patient who underwent resection of a retroperitoneal tumor, which was found by medical check-up. The tumor which was elastic hard and had good mobility displaced the duodenum to her abdominal wall. Since her right ovarian vein adhered to the tumor, we removed the tumor with the ligated vein. Pathological findings showed the tumor consisted of spindle-shaped cells with pleomorphic nucleus and it presented the fascicular growth pattern. Additional immunostaining showed positive for HHF35, h-caldesmon. Because the leiomyosarcoma connected with the smooth muscle of the right ovarian vein, we considered the vascular smooth muscle was the origin of the tumor. It is 2 years after the operation, there has been no local recurrence or metastasis.

[A Case of Advanced Rectal Cancer Successfully Treated with Preoperative Radiochemotherapy].

An 80-year-old woman who visited our hospital with chief complaints of decreased appetite and diarrhea. Lower gastrointestinal endoscopy showed a type 2 tumor in the rectal Ra, and biopsy revealed a well-differentiated adenocarcinoma. The patient had locally advanced rectal cancer with widespread contact with the sacrum, and preoperative radiochemotherapy (S-1 100 mg/day plus radiotherapy 50 Gy/25 Fr)was performed. After the treatment was completed, the tumor was remarkably reduced, but the surgery was strongly rejected, and therefore chemotherapy became the policy. XELOX plus bevacizumab therapy was started, but in the second course was performed, obstructive symptoms appeared, so a semi-urgent lower anterior resection and ileostomy were performed. Postoperative pathological findings showed only a small amount of tumor cells in the mucosa, suggesting that preoperative treatment was effective.

[A Clinical Study of Seven Cases of LECS for Gastric Submucosal Tumors].

Laparoscopy and endoscopy cooperative surgery(LECS)is a surgical technique to resect a tumor with minimal invasion, using both a laparoscope and endoscope. Twenty-eight surgeries for gastric submucosal tumors(SMT)were performed between 2009 and 2019. Seven of those cases were performed using LECS. Two male and 5 female patients underwent LECS; their mean age was 53 years. The tumors were located at the anterior wall of the fornix in 1 case, anterior wall of the subcardia in 2 cases, anterior wall of the upper gastric body in 3 cases, and anterior wall of the lower gastric body in 1 case. Two cases were intraductal growing types, and 5 cases were intramural growing types. No postoperative complications have occurred. The mean size of the tumors was 21.1 mm. In pathological findings, 5 cases were gastrointestinal stromal tumor (GIST); 1 case was high risk, 2 cases were low risk, and 1 case was very low risk as classified using the modified-Fletcher's classification. Imatinib was administered to the high risk case, and there have been no recurrences in any cases.

[A Case of Small Cell Carcinoma of the Pancreas].

A 55-year-old man was admitted to our hospital for jaundice. Magnetic resonance cholangiopancreatography showed a mass in the pancreatic head as well as biliary obstruction. We strongly suspected invasive ductal carcinoma of the pancreas. We performed pancreaticoduodenectomy with partial resection of the portal vein. The histopathological diagnosis was small cell carcinoma of the pancreas. We detected metastasis of the right hilar lymph node in PET-CT scan performed 2 months after the surgery and started chemotherapy with cisplatin(CDDP)plus irinotecan(CPT-11). However, we observed recurrent metastasis of the right hilar lymph node 12 months after the surgery. We started second-line chemotherapy with amrubicin( AMR)and radiotherapy. Unfortunately, the patient died from multiple metastases of the left adrenal gland and brain 26 months after the surgery. The prognosis of small cell carcinoma of the pancreas is extremely poor. Multimodal treatment such as chemotherapy, radiotherapy, and curative operation are required for long-term survival.

[Radical Surgery Following Chemotherapy in a Patient with Mesenteric Recurrence Associated with Hematoma upon ESD for Rectal Cancer Three Years Six months Later].

A63 -year-old man complaining of anal pain visited our hospital. Three years 6 months previously, the patient underwent endoscopic submucosal dissection(ESD)for early-stage rectal cancer. Based on the pathological findings, adenocarcinoma with invasion to the submucosal layer(2,000 mm)and lymphovascular invasion were diagnosed. Abdominal computed tomography( CT)revealed a solid tumor 50mm in diameter and hematoma measuring approximately 90mm in length adjoining the tumor in the mesorectum. We performed exploratory laparoscopy. Ahematoma was confirmed in the mesentery from the sigmoid colon and rectum. After the surgery, endoscopic ultrasound-guided fine needle aspiration(EUS-FNA)revealed well-differentiated adenocarcinoma. We diagnosed a hematoma associated with mesenteric recurrence following ESD for rectal cancer. The patient received chemotherapy first because of the large size of the recurrent cancer. Four courses of mFOLFOX6(5-FU: bolus 400mg/m / / / 2,2,400mg/m2,oxaliplatin 85 mg/m2) and panitumumab(6 mg/kg)were administered. Based on the CT findings following chemotherapy, the hematoma had disappeared, and the size of the recurrent cancer in the mesorectum reduced to 28 mm. The patient underwent laparoscopic lower anterior resection with D3 lymph node dissection and ileostomy. The postoperative course was uneventful. Currently, the patient has no recurrence.

[A Case of Mesenteric Malignant Lymphoma Treated Using Single-Port Surgery and an Umbilical ZigZag Incision].

A 73 -year-old man was found to have a mesenteric tumor on abdominal ultrasonography and computed tomography (CT). Single-port laparoscopic surgery using an umbilical ZigZag incision was performed. Operative findings revealed that the tumor involved the mesentery. The tumor and a section of small intestines were resected. Pathological examination diagnosed follicular lymphoma. Single-port laparoscopic surgery using an umbilical ZigZag incision is superior for manipulation of forceps and evisceration. This operative method may be useful for resection or biopsy of mesenteric tumors.

Collective In-Plane Molecular Rotator Based on Dibromoiodomesitylene π-Stacks.

Interest in artificial solid-state molecular rotator systems is growing as they enable systems to be designed for achieving specific physical functions. The phase transition behavior of four halomesitylene crystals indicated dynamic in-plane molecular rotator characteristics in dibromoiodomesitylene, tribromomesitylene, and dibromomesitylene crystals. Such molecular rotation in diiodomesitylene crystals was suppressed by effective I···I intermolecular interactions. The in-plane molecular rotation accompanied by a change in dipole moment resulted in dielectric phase transitions in polar dibromoiodomesitylene and dibromomesitylene crystals. No dielectric anomaly was observed for the in-plane molecular rotation of tribromomesitylene in the absence of this dipole moment change. Typical antiferroelectric-paraelectric phase transitions were observed in the dibromomesitylene crystal, whereas the dielectric anomaly of dibromoiodomesitylene crystals was associated with the collective in-plane molecular rotation of polar π-molecules in the π-stack. We found that the single-rope-like collective in-plane molecular rotator was dominated by intermolecular I···I interactions along the π-stacking column of polar dibromoiodomesitylene.

Molecular determinants for cardiovascular TRPC6 channel regulation by Ca2+/calmodulin-dependent kinase II.

The molecular mechanism underlying Ca(2+)/calmodulin (CaM)-dependent kinase II (CaMKII)-mediated regulation of the mouse transient receptor potential channel TRPC6 was explored by chimera, deletion and site-directed mutagenesis approaches. Induction of currents (ICCh) in TRPC6-expressing HEK293 cells by a muscarinic agonist carbachol (CCh; 100 µm) was strongly attenuated by a CaMKII-specific peptide, autocamtide-2-related inhibitory peptide (AIP; 10 µm). TRPC6/C7 chimera experiments showed that the TRPC6 C-terminal sequence is indispensable for ICCh to be sensitive to AIP-induced CaMKII inhibition. Further, deletion of a distal region (Gln(855)-Glu(877)) of the C-terminal CaM/inositol-1,4,5-trisphosphate receptor binding domain (CIRB) of TRPC6 was sufficient to abolish ICCh. Systematic alanine scanning for potential CaMKII phosphorylation sites revealed that Thr(487) was solely responsible for the activation of the TRPC6 channel by receptor stimulation. The abrogating effect of the alanine mutation of Thr(487) (T487A) was reproduced with other non-polar amino acids, namely glutamine or asparagine, while being partially rescued by phosphomimetic mutations with glutamate or aspartate. The cellular expression and distribution of TRPC6 channels did not significantly change with these mutations. Electrophysiological and immunocytochemical data with the Myc-tagged TRPC6 channel indicated that Thr(487) is most likely located at the intracellular side of the cell membrane. Overexpression of T487A caused significant reduction of endogenous TRPC6-like current induced by Arg(8)-vasopressin in A7r5 aortic myocytes. Based on these results, we propose that the optimal spatial arrangement of a C-terminal domain (presumably the distal CIRB region) around a single CaMKII phosphorylation site Thr(487) may be essential for CaMKII-mediated regulation of TRPC6 channels. This mechanism may be of physiological significance in a native environment such as in vascular smooth muscle cells.

Advanced pancreatic cancer with long-term recurrence-free survival after radical pancreatic resection and subsequent resection of lung metastases twice: A case report.

INTRODUCTION AND IMPORTANCE: Reports on lung resection for recurrence with lung metastases after the surgical treatment of pancreatic cancer have been sporadic, and limited information is currently available on the long-term postoperative course. Furthermore, the significance of the surgical resection of recurrent/metastatic lesions after the resection of pancreatic cancer has not been sufficiently established. We herein present a long-term recurrence-free survivor after perioperative chemotherapy and pancreatic resection for primary pancreatic body cancer who underwent resection for isolated lung metastases twice. CASE PRESENTATION: A 66-year-old woman with locally advanced pancreatic cancer accompanied by invasion of the splenic artery underwent distal pancreatectomy with celiac axis resection following preoperative S1 + gemcitabine therapy. Recurrence with lung metastasis was detected 42 and 62 months after resection of the primary lesion, and lung resection was performed both times. As postoperative adjuvant therapies, S1 + gemcitabine therapy was performed after lung resection. The patient has survived free of recurrence for 11 years after resection of the primary lesion and 5 years and 9 months after the second lung resection. CLINICAL DISCUSSION: A long interval from resection of the primary lesion to the occurrence of lung metastases and the high responsiveness of the patient to chemotherapy may have contributed to her long-term survival. CONCLUSION: This case suggests that if lung metastasis occurring after radical resection of the primary lesion is resected without remnants, aggressive multidisciplinary treatment, including surgical resection with the appropriate selection of cases, may contribute to improvements in patient outcomes.

A case of mesenteric venous thrombosis complicating appendiceal diverticulitis.

BACKGROUND: Mesenteric venous thrombosis (MVT) and appendiceal diverticulitis are rare diseases. There has been no previous report on MVT complicating appendiceal diverticulitis. Herein, we report the first case of MVT complicating appendiceal diverticulitis. CASE PRESENTATION: A 70-year-old male patient with right lower abdominal pain presented to our hospital. Abdominal contrast-enhanced computed tomography (CT) suggested MVT complicating appendiceal diverticulitis. Initially, we started conservative treatment with antibacterial drugs, but on the 2nd hospital day his general condition deteriorated due to sepsis that seemed to be caused by appendiceal diverticulitis. Therefore, we performed laparoscopic appendectomy. Histopathological findings of the specimen showed appendiceal diverticulitis. After the operation, he gradually improved. He was discharged on the 30th hospital day. CONCLUSIONS: We report a successfully treated case of MVT complicating appendiceal diverticulitis by surgical intervention. This is the first case of MVT complicating appendiceal diverticulitis.

Association of High Mobility Group Box-Protein 1 and Platelet Microparticles in Patients After Hematopoietic Stem Cell Transplantation.

Thrombotic complications after allogeneic hematopoietic stem cell transplantation (allo-HSCT) significantly impact transplant outcomes. We focused on high mobility group box-protein (HMGB)1, one causative agent of thrombotic lesions in allo-HSCT, and investigated its association with platelets. We statistically analyzed available data from 172 patients with hematopoietic malignancies receiving allo-HSCT. A significant enhancement of monocyte-chemotactant protein-1, HMGB1, and platelet-derived microparticle (PDMP) levels was observed at day 0 after transplantation as compared to pre-transplantation. Multivariate analysis of the association among HMGB1 and 16 factors on day 0 revealed a significant correlation of HMGB1 levels with thrombin-antithrombin complex, interleukin-6, and PDMPs. High mobility group box-protein 1-induced procoagulant platelet induction and PDMP generation were performed in vitro using healthy platelets. High mobility group box-protein 1-induced PDMP generation was suppressed by toll-like receptor inhibitors and recombinant thrombomodulin. These results suggest that HMGB1 contributes to platelet activation in patients after allo-HSCT and is associated with PDMP-related thrombotic complications.

Analysis of group behavior based on sharing heterogeneous roles in a triad using a coordinated drawing task.

Humans often share roles and aim to achieve a group goal based on sociality, which is the tendency to spontaneously involve oneself with others. Cognitive science, psychology, and neuroscience studies suggest that in such planned coordination, adjusting one's own actions based on other roles is crucial for high task performance. However, the mechanisms of complex and dynamically planned coordination, such as non-verbal group behavior with three or more members, remain to be fully investigated. This study introduced a coordinated drawing task in a triad, quantitatively analyzed non-verbal group behavior based on sharing heterogeneous roles, and investigated an important role. Participant triads engaged in the task repeatedly by operating reels to change thread tensions and moving a pen connected to the three threads to draw an equilateral triangle. Then, the three roles (pulling, relaxing, and adjusting) had to be shared. The pulling and relaxing roles served to move the pen as if an operator pulled it closer to the hand and to support the pen's movement, respectively. However, these roles alone could not draw a side considering the task specification. The adjusting role needed to change the tension flexibly and maintain an overall balance. In the experiment, we measured the pen positions and tensions, and established statistical models to fit the analyzed data. The results estimated that the action in the adjusting role was related to the improved performance of faster drawing on a side. This role may moderately intervene in the actions by the other roles and fine-tune without disturbing the pen's smooth movement while avoiding great pen deviation. Our findings may suggest the crucial role as a facilitator that handles resiliently in non-verbal coordinated behavior of a triad, and contribute to our understanding of social interactions.

Robot-assisted laparoscopic low anterior resection for rectal cancer with persistent descending mesocolon: A case report.

INTRODUCTION: Persistent descending mesocolon (PDM) is a fixed abnormality in which the descending to sigmoid colon adheres to the small intestinal mesentery or right pelvic wall through right displacement. Surgery for colorectal cancer with PDM is difficult. Therefore, in addition to the anatomical characteristics of PDM, the extent of adhesion and characteristics of vascular courses need to be assessed in individual patients. The number of patients now undergoing laparoscopic or robot-assisted surgery for colorectal cancer has rapidly increased. We herein report a rectal cancer patient with PDM who safely underwent robot-assisted laparoscopic low anterior resection (RLAR). PRESENTATION OF CASE: A 71-year-old male was referred to our hospital for a detailed examination following a fecal occult blood-positive reaction. Lower gastrointestinal endoscopy revealed a type 2 lesion of the rectum. Moderately differentiated adenocarcinoma was diagnosed based on the results of a histopathological examination. Preoperative contrast-enhanced thoracoabdominal computed tomography showed abnormalities in the colonic course and characteristic vascular courses, suggesting rectal cancer with PDM. RLAR was performed. DISCUSSION: In surgery, it is important to initially perform adhesiolysis accurately in order to reconstruct the original shape of the colonic mesentery and confirm/dissect vascular bifurcations due to the risk of marginal arterial injury. CONCLUSION: In the present case, a detailed anatomical understanding of the site of intestinal adhesion and vascular courses, as well as surgical procedures, facilitated safe RLAR. We described this case and reviewed the anatomical characteristics of PDM and cautions for surgery.

[Kidney stone formation during space flight and long-term bed rest].

Microgravity environment like space flight or a condition requiring long-term bed-rest increase bone resorption and decrease bone formation, inducing the rapid decrease of bone minerals to osteoporosis. Bone mineral loss increases urinary calcium excretion and the risk of urinary stone formation. To clarify the influence of the conditions on renal stone formation, a 90-day bed rest test was performed to analyze the mechanism of microgravity or bed rest-induced stone formation and prevention by bisphosphonate medication and bed-rest exercise. As the results, renal stone formation was observed in control and exercise groups and no stone was seen in the medication group. In the medication group, urinary calcium excretion and relative supersaturation of calcium oxalate were lower than in the control group throughout the bed-rest and recovery period. Bisphosphonate is useful for the prevention of renal stone formation during space flight and long-term bed-rest.

Quantitative analysis of spontaneous sociality in children's group behavior during nursery activity.

Sociality is the tendency to spontaneously interact with others to establish and maintain relationships. Some approaches, including questionnaires, tests, controlled experiments, and qualitative field research, cannot capture complex social interactions, such as in children during nursery activities, because of problems with ecological validity and the labor cost of analysis. Here, we introduced a new methodology for the quantitative analysis of spontaneous social movement and investigated children's group behavior using position data. We periodically visited a nursery and recorded videos of eurhythmics, in which children move in tune with music, in different classes. The results revealed that children in the six-year-old class approached others in a short period of time (within one second) and established group behavior like that in a game of tag. It can be interpreted that such social behavior may include actions related to the cognition of anticipating others' behaviors in a complex situation. Although only a small amount of data could be acquired, this study suggests one of the characteristics of social behaviors in the classroom considering an ecological approach.

Serum-free medium with osteogenic supplements induces adipogenesis in rat bone marrow stromal cells.

Adult BMSCs (bone marrow stromal cells) contain MSCs (mesenchymal stem cells). MSCs can differentiate into osteoblasts, chondrocytes, adipocytes and myoblasts and are thus considered useful in tissue engineering for therapeutic and clinical purposes. FCS (fetal calf serum) is usually included in the differentiation medium, but the clinical application of FCS may pose a problem for some patients. To improve the efficiency and safety of BMSC cultivation, the effect of SF (serum-free) conditions on the osteogenic differentiation of rat BMSCs was examined. In the presence of 10% FCS and osteogenic supplements, the cells formed mineralized von Kossa-positive deposits. Under SF conditions with osteogenic supplementation, however, the cells possessed cytosolic lipid vacuoles that could be stained with Oil Red O. The mRNA expression of PPARgamma (peroxisome proliferator-activated receptor gamma), an adipogenic marker, increased under the SF condition with osteogenic supplements. These data indicate that rat BMSCs differentiate into adipocytes under SF conditions even with osteogenic supplementation and that FCS is needed to induce proper osteogenic differentiation in rat BMSCs.

Subtotal gastrectomy for gastric tube cancer using intraoperative indocyanine green fluorescence method.

INTRODUCTION: Currently, the frequency of evaluating the flow of a reconstructed gastric tube using indocyanine green (ICG) fluorescence has been increasing. However, it has been difficult to decide on the operation method for patients with gastric tube cancer (GTC). We herein report a case in which ICG was effective in a patient with resection of GTC. PRESENTATION OF CASE: An 83-year-old man underwent subtotal esophagectomy with gastric tube reconstruction via the retrosternal route for esophageal cancer and right hemicolectomy for ascending colon cancer 16 years earlier. Postoperatively, the proximal part of the gastric tube had poor blood flow. Therefore, the patient underwent proximal-side resection of the gastric tube. Thereafter, free jejunal graft reconstruction was performed. The patient had not developed recurrence at that point. Recently, the patient visited the hospital complaining of nausea and chest discomfort. Upper gastrointestinal endoscopy revealed a type 0-IIa + IIc lesion located around the pylorus. A biopsy showed adenocarcinoma. Based on these findings, the patient was diagnosed with gastric tube cancer (cT1bN0M0StageI). The invasion depth of the cancer was predicted to be widespread submucosal invasion. Therefore, the patient underwent surgery. Intraoperatively, we evaluated the flow of the gastric tube after clamping the right gastroepiploic artery using ICG fluorescence. As a result, the flow of the gastric tube was deemed insufficient. Consequently, subtotal gastrectomy was performed with preservation of the right gastroepiploic artery via Roux-en-Y reconstruction. DISCUSSION: ICG fluorescence is useful for evaluating the flow of the gastric tube helping to decide the operating method. CONCLUSION: We herein report a case of subtotal gastrectomy for GTC using intraoperative ICG fluorescence.

Cell density-dependent changes in intracellular Ca2+ mobilization via the P2Y2 receptor in rat bone marrow stromal cells.

Bone marrow stromal cells (BMSCs) are an interesting subject of research because they have characteristics of mesenchymal stem cells. We investigated intracellular Ca(2+) signaling in rat BMSCs. Agonists for purinergic receptors increased intracellular Ca(2+) levels ([Ca(2+)](i)). The order of potency followed ATP = UTP > ADP = UDP. ATP-induced rise in [Ca(2+)](i) was suppressed by U73122 and suramin, but not by pyridoxalphosphate-6-azophenyl-2',4'-disulfonic acid (PPADS), suggesting the functional expression of G protein-coupled P2Y(2) receptors. RT-PCR and immunohistochemical studies also showed the expression of P2Y(2) receptors. [Ca(2+)](i) response to UTP changed with cell density. The UTP-induced rise in [Ca(2+)](i) was greatest at high density. V(max) (maximum Ca(2+) response) and EC(50) (agonist concentration that evokes 50% of V(max)) suggest that the amount and property of P2Y(2) receptors were changed by cell density. Note that UTP induced Ca(2+) oscillation at only medium cell density. Pharmacological studies indicated that UTP-induced Ca(2+) oscillation required Ca(2+) influx by store-operated Ca(2+) entry. Carbenoxolone, a gap junction blocker, enhanced Ca(2+) oscillation. Immunohistochemical and quantitative real-time PCR studies revealed that proliferating cell nuclear antigen (PCNA)-positive cells declined but the mRNA expression level of the P2Y(2) receptor increased as cell density increased. Co-application of fetal calf serum with UTP induced Ca(2+) oscillation at high cell density. These results suggest that the different patterns observed for [Ca(2+)](i) mobilization with respect to cell density may be associated with cell cycle progression.