Cumulative incidence of femoral localized periosteal thickening (beaking) preceding atypical femoral fractures in patients with rheumatoid arthritis.

The incidence of localized periosteal thickening (LPT, also termed beaking) of the lateral cortex that often precedes an atypical femoral fracture (AFF) was not high in patients with rheumatoid arthritis (RA) but incomplete AFFs developed in two patients. Higher-dose prednisolone was a significant risk factor for LPT in patients with RA. INTRODUCTION: Atypical femoral fractures (AFFs) are stress fractures; bisphosphonate (BP) use is a major risk factor for the development of such fractures. Localized periosteal thickening (LPT, also termed beaking) of the lateral cortex often precedes a complete or incomplete AFF. We evaluated the incidence of latent LPT in patients with rheumatoid arthritis (RA), to evaluate LPT progression, and to define LPT risk factors. METHODS: A total of 254 patients with RA were included; all underwent annual X-ray evaluation, dual-energy X-ray absorptiometry, and analyses of serum and bone metabolic markers for 2-3 years. LPT of the lateral cortex was sought in femoral X-rays. RESULTS: The incidence of LPT was 2.4% (6/254). Among patients on both BP and prednisolone (PSL) at enrollment, the incidence was 2.3% (3/131). Two femurs of two patients with LPT developed incomplete AFFs; LPT was extensive and associated with endosteal thickening. One patient had been on BP and PSL and microscopic polyangiitis was comorbidity. The other was on a selective estrogen receptor modulator and PSL. A daily PSL dose >5 mg (OR 11.4; 95%CI 2.15-60.2; p = 0.004) and higher-dose methotrexate (OR 1.22; 95%CI 1.01-1.49; p = 0.043) were significant risk factors for LPT. CONCLUSIONS: The incidence of latent LPT was not high (2.4%) but incomplete AFFs developed in two RA patients. Higher-dose PSL because of a comorbid disease requiring glucocorticoid treatment other than RA or refractory RA were risk factors for LPT; X-ray screening for latent LPT would usefully prevent complete AFFs.

Estimating the Net Utility Gains Among Donors and Recipients of Adult Living Donor Kidney Transplant.

OBJECTIVES: Living donor kidney transplant relieves the disease burden of patients with end-stage renal disease but may shorten donor life expectancy; however, their quality of life (QOL) is preserved. Nevertheless, the magnitude of the net gain of this procedure is unknown. We evaluated the QOL of both donors and recipients concurrently and calculated the net utility gain. METHODS: We recruited 210 subjects who visited the kidney transplantation clinic of a university hospital. Subjects were asked to complete the 5-level EQ-5D-based questionnaire, and patient characteristics were extracted from their medical records. We performed multivariate tobit models analysis to evaluate the QOL change caused by transplant surgery and subsequently ran computational simulations to determine the net utility gains of donors and recipients. We also performed sensitivity analyses. RESULTS: After excluding 16 answers with missing data, we analyzed 203 answers in total. After the transplant surgery, recipients gained 0.07 in utility value while donors lost 0.04. In the net utility analysis, we found that the quality-adjusted life years gained ranged from 7.2 to 7.8 in the most favorable case observed in the combination of middle-aged recipients and elderly donors. Assuming no utility discount, the most favorable combination was that with older donors and younger recipients. CONCLUSIONS: These findings indicated that the QOL improvement in recipients was larger than the loss among donors. When calculating the net utilities, a combination of middle-aged recipients and elderly donors yielded the largest net utility, but this was likely derived from assumption in the discount of QOL.

Characterization of patients with systemic lupus erythematosus who meet the diagnostic criteria for TAFRO syndrome.

Purpose TAFRO syndrome is a novel disorder manifesting as fever, anasarca, thrombocytopenia, renal insufficiency and organomegaly, and its etiology has not been clarified. The aim of this study was to elucidate similarities and differences between systemic lupus erythematosus (SLE) and TAFRO syndrome. Methods We examined 46 consecutive patients diagnosed with SLE and determined whether they meet the proposed diagnostic criteria for TAFRO syndrome (2015 version). Results Of the 46 patients with SLE, four (8.7%) also met the TAFRO syndrome criteria (TAFRO-like group). All patients in the TAFRO-like group were males, and their mean age was significantly higher than that of the non-TAFRO group (67.5 ± 8.7 vs. 39.3 ± 18.1 years, p = 0.004). C-reactive protein and γ-glutamyl transpeptidase levels were significantly higher, and frequencies of anti-dsDNA and anti-Sm antibodies were significantly lower in the TAFRO-like than non-TAFRO group. Elder cases (onset age ≥ 50 years) met significantly more categories of the diagnostic criteria for TAFRO syndrome than did those with younger cases. Conclusions Several patients with SLE, especially elder cases, showed features similar to those of TAFRO syndrome. Although exclusion of SLE is needed in the diagnostic criteria for TAFRO syndrome, TAFRO syndrome-like SLE should be considered.

Isolated intestinal neuronal dysplasia Type B (IND-B) in Japan: results from a nationwide survey.

PURPOSE: Intestinal neuronal dysplasia Type B (IND-B) has been proposed to be an allied disorder of Hirschsprung's disease (ADHD). The original histological criteria included hyperganglionosis, giant ganglia, ectopic ganglion cells and an increased AChE activity in the lamina propria. The criteria for IND-B have been gradually revised. The present diagnostic criteria are [1] more than 20 % of the submucosal ganglia contain nine or more ganglion cells and [2] the patient is older than 1 year. To clarify the current status of IND-B in Japan, a nationwide retrospective cohort study was performed. METHODS: Questionnaires were sent to 161 major institutes of pediatric surgery and gastroenterology in Japan. RESULTS: A total of 355 cases of ADHD were collected, including 18 cases of IND-B (5 %). Based on original criteria, 13 out of 18 cases were diagnosed as IND-B. However, only four cases met the current criteria. Three of the four patients (75 %) required pull-through operation. All of the patients exhibited giant ganglia and ganglioneuromatosis-like hyperplasia of the myenteric plexus. CONCLUSIONS: IND-B cases matching the current criteria are thought to be quite rare and they are associated with marked hyperplasia of the myenteric plexus. "True" IND-B is a rare and intractable disease.

Postoperative Clostridium difficile infection with PCR ribotype 078 strain identified at necropsy in five Thoroughbred racehorses.

Clostridium difficile is an important cause of acute enterocolitis in horses. We describe five cases of C difficile infection occurring postoperatively in Thoroughbred racehorses. Following diarrhoea or colic accompanied by a marked increase in packed cell volume (to ≥60 per cent) and leucopenia (≤4000 cells/µl) within two to four days after surgery in all five horses, four of them died or were euthanased because of colitis or severe diarrhoea. In these four horses, necrotising entero-typhlo-colitis was revealed by postmortem examination, and C difficile was recovered from the contents of the small and/or large intestine. The remaining horse was euthanased because of marked decline in general condition and the presence of a lung abscess, from which C difficile was isolated. The horse had had severe postoperative diarrhoea before the onset of respiratory disorder; laboratory tests for C difficile were not performed on the faeces. All C difficile isolates were toxin-A-positive, toxin-B-positive and actin-specific ADP-ribosyltransferase (CDT)-positive. The isolates were indistinguishable by pulsed field gel electrophoresis analysis, PCR ribotyping, and slpA sequence typing, and the slpA sequences and PCR ribotype patterns were identical to those of known PCR type 078. This case sequence might have been healthcare-associated infection, although there was about a four-month interval between each disease onset.

Effect of Zr on microstructure of metallic glass coatings prepared by gas tunnel type plasma spraying.

Metallic glass is one of the most attractive advanced materials, and many researchers have conducted various developmental research works. Metallic glass is expected to be used as a functional material because of its excellent physical and chemical functions such as high strength and high corrosion resistance. However, the application for small size parts has been carried out only in some industrial fields. In order to widen the industrial application fields, a composite material is preferred for the cost performance. In the coating processes of metallic glass with the conventional deposition techniques, there is a difficulty to form thick coatings due to their low deposition rate. Thermal spraying method is one of the potential candidates to produce metallic glass composites. Metallic glass coatings can be applied to the longer parts and therefore the application field can be widened. The gas tunnel plasma spraying is one of the most important technologies for high quality ceramic coating and synthesizing functional materials. As the gas tunnel type plasma jet is superior to the properties of other conventional type plasma jets, this plasma has great possibilities for various applications in thermal processing. In this study, the gas tunnel type plasma spraying was used to form the metallic glass coatings on the stainless-steel substrate. The microstructure and surface morphology of the metallic glass coatings were examined using Fe-based metallic glass powder and Zr-based metallic glass powder as coating material. For the mechanical properties the Vickers hardness was measured on the cross section of both the coatings and the difference between the powders was compared.

An unusual case of subclinical diffuse glucagonoma coexisting with two nodules in the pancreas: characteristic features on computed tomography.

A lesion was discovered in the tail of the pancreas by ultrasonography performed during a health checkup for a 59-year-old Japanese man. Abdominal contrast-enhanced computed tomography (CE-CT) revealed strong enhancement in a 4-cm tumor in the pancreatic tail and in a 1-cm tumor in the pancreatic body. Serum glucagon levels were elevated to 54,405 pg/mL and a preoperative diagnosis of glucagonoma was made. The pancreatic tail and spleen were resected en bloc, along with a protruding tumor in the pancreatic body. However, histopathological evaluation revealed diffuse glucagonoma throughout the pancreas. When we retrospectively reviewed abdominal CE-CT after the operation, the entire pancreas was seen to be enlarged and diffusely enhanced by strong spots. Immunohistochemical examination using anti-CD31 demonstrated rich microvessels in two solid glucagonomas as well as microglucagonoma throughout the entire pancreas, indicating hypervascularity. Enlarged pancreas and diffuse enhancement of the pancreas by strong spots may be characteristic features of diffuse glucagonoma on abdominal CE-CT.

Oncolytic herpes simplex virus expressing yeast cytosine deaminase: relationship between viral replication, transgene expression, prodrug bioactivation.

Yeast cytosine deaminase (yCD) is a well-characterized prodrug/enzyme system that converts 5-fluorocytosine (5-FC) to 5-fluorouracil (5-FU), and has been combined with oncolytic viruses. However, in vivo studies of the interactions between 5-FC bioactivation and viral replication have not been previously reported, nor have the kinetics of transgene expression and the pharmacokinetics of 5-FC and 5-FU. We constructed a replication-conditional Herpes simplex virus 1 (HSV-1) expressing yCD and examined cytotoxicity when 5-FC was initiated at different times after viral infection, and observed that earlier 5-FC administration led to greater cytotoxicity than later 5-FC administration in vitro and in vivo. In animal models, 12 days of 5-FC administration was superior to 6 days, but dosing beyond 12 days did not further enhance efficacy. Consistent with the dosing-schedule results, both viral genomic DNA copy number and viral titers were observed to peak on Day 3 after viral injection and gradually decrease thereafter. The virus is replication-conditional and was detected in tumors for as long as 2 weeks after viral injection. The maximum relative extent of yCD conversion of 5-FC to 5-FU in tumors was observed on Day 6 after viral injection and it decreased progressively thereafter. The observation that 5-FU generation within tumors did not lead to appreciable levels of systemic 5-FU (<10 ng ml⁻¹) is important and has not been previously reported. The approaches used in these studies of the relationship between the viral replication kinetics, transgene expression, prodrug administration and anti-tumor efficacy are useful in the design of clinical trials of armed, oncolytic viruses.

Tubulointerstitial nephritis with IgM-positive plasmacytoid large lymphocyte infiltration in a patient with primary biliary cirrhosis and Sjögren's syndrome.

We report a 38-year-old woman diagnosed with tubulointerstitial nephritis (TIN) on renal biopsy, followed by being diagnosed with primary biliary cirrhosis (PBC) and Sjögren's syndrome (SS). Immunohistochemically, the cellular infiltrates in TIN were mainly composed of small lymphocytes and IgM-positive plasmacytoid large lymphocytes. IgM-positive plasmacytoid large lymphocytes were not identical with, but colocalized with CD3- or CD20-positive lymphocytes. TIN in patients with PBC is very rare and little is known about immunohistochemical characteristics of infiltrating cells in this setting. To our knowledge, this is the first report demonstrating predominant infiltrating of IgM-positive plasmacytoid large lymphocytes in TIN due to PBC and SS.

Cystatin C is a sensitive marker for detecting a reduced glomerular filtration rate when assessing chronic kidney disease in patients with rheumatoid arthritis and secondary amyloidosis.

OBJECTIVE: Chronic kidney disease is a predictor of end-stage renal disease, and evaluating the glomerular filtration rate (GFR) is necessary to make a definite diagnosis. We assessed the utility of serum cystatin C (cysC) for identifying a reduced GFR in patients who have rheumatoid arthritis (RA) with secondary amyloidosis. METHODS: Fifty patients with RA and secondary amyloidosis (mean age 60.9+/-11.2 years; 45 women) were evaluated. The revised 24-h creatinine clearance (r24-hC(Cr)), which was determined by multiplying the original value by 0.719, was used as a reference for the GFR. The screening potential of the serum cysC and some estimates of the GFR calculated from the serum cysC (cysC-eGFR: eGFR(Hoek) and eGFR(Rule)) for detecting a reduced GFR (r24-hC(Cr)<60 mL/min/1.73 m(2)) were analysed. RESULTS: Both cysC-eGFRs were strongly correlated with the r24-hC(Cr) (eGFR(Hoek), r=0.846, p<0.001; eGFR(Rule), r=0.820, p<0.001). The difference between the average eGFR(Rule) (37.1+/-31.2 mL/min/1.73m(2)) and average r24-hC(Cr) (35.3+/-30.9 mL/min/1.73 m(2)) was small, whereas eGFR(Hoek) and sCr-eGFR were higher than eGFR(Rule) and r24-hC(Cr). In receiver operating characteristic (ROC) curve analyses of a reduced GFR, serum cysC gave a greater area under the curve (AUC=0.958) than the sCr-eGFR (0.939-0.942). The specificity and positive predictive value (PPV) reached 100% when serum cysC >1.365 mg/L was used. CONCLUSIONS: Serum cysC can identify a reduced GFR more accurately than sCr-eGFRs. Serum cysC >1.09 mg/L (i.e. eGFR(Rule)<60 mL/min/1.73 m(2)) could be a marker of a reduced GFR, and serum cysC >1.365 mg/L would strongly suggest a reduced GFR in patients who have RA with secondary amyloidosis.

Comparison of intravenous versus intraperitoneal administration of oncolytic herpes simplex virus 1 for peritoneal carcinomatosis in mice.

hrR3 is an oncolytic herpes simplex virus 1 (HSV-1) mutant that replicates preferentially in tumors compared with normal tissues. Portal venous administration of hrR3 in mice bearing diffuse colorectal carcinoma liver metastases significantly reduces tumor burden and prolongs animal survival. In this study, we compared survival benefit and biodistribution of hrR3 following intravenous (i.v.) administration versus intraperitoneal (i.p.) administration in immunocompetent mice bearing colon carcinoma peritoneal metastases. Mice bearing peritoneal metastases received 1 x 10(8) plaque-forming units hrR3 or mock-infected media every other day for three doses and were randomized to have the viruses administered by either an i.p. or i.v. route. Biodistribution was assessed by PCR amplification of HSV-1-specific sequences from tumor and normal tissues including the small bowel, liver, spleen, kidney, lung, heart and brain. LD(50) for i.p. administration was compared with the LD(50) for i.v. administration. In subsequent experiments, animals were monitored for survival. The frequency of HSV-1 detection in peritoneal tumors was similar in mice randomized to either i.p. or i.v. administration. However, i.p. administration resulted in a more restricted systemic biodistribution, with a reduced frequency of virus detected in the kidney, lung and heart. The LD(50) associated with i.p. administration was higher than that with i.v. administration. Tumor burden was more effectively reduced with i.p. compared with i.v. administration. Median survival following i.p. administration was approximately twice that observed with i.v. administration. I.p. administration of an HSV-1 oncolytic mutant is associated with a more restricted biodistribution, less toxicity and greater efficacy against peritoneal metastases compared with i.v. administration.

Development of hepatocellular carcinoma in patients with chronic hepatitis C who had a sustained virological response to interferon therapy: a multicenter, retrospective cohort study of 1124 patients.

BACKGROUND: Interferon (IFN) improves hepatic inflammation/fibrosis and reduces the risk of hepatocellular carcinoma (HCC) in patients with chronic hepatitis C (CH-C). However, HCC develops in some patients who have a sustained virological response (SVR) to IFN therapy. We designed this study to establish a follow-up protocol for patients with CH-C who have SVR to IFN therapy. METHODS: We retrospectively studied 1124 patients with CH-C who received IFN. RESULTS: HCC developed in 3.5% of patients with SVR to IFN. As compared with SVR patients without HCC, SVR patients with HCC were predominantly male (P=0.003), older at the initiation of IFN therapy (P=0.002), and at a more advanced histologic stage of disease (P<0.001). However, three of the 13 SVR HCC patients had mild fibrosis. The mean interval from IFN therapy to the detection of HCC in SVR HCC patients was 5.8 years and did not differ significantly from that in non-SVR HCC patients (P=0.304). Although most patients with HCC received curative therapy, the prognosis of some SVR HCC patients was poor, probably because of insufficient follow-up, resulting in delayed detection of HCC. CONCLUSIONS: SVR patients with CH-C who are elderly, male, or have an advanced histologic stage are at a high risk for the development of HCC after IFN therapy. We recommend that SVR patients should be observed carefully for more than 10 years after the completion of IFN therapy, even if they only have early fibrosis.

Combined fibrolamellar carcinoma and cholangiocarcinoma exhibiting biphenotypic antigen expression: a case report.

Fibrolamellar carcinoma (FLC), a variant of hepatocellular carcinoma (HCC), very rarely occurs in association with cholangiocarcinoma (CC). This report describes the first case of FLC coexisting with CC (FLC-CC) from Japan. Although the major part of the tumour located in the right lobe of the liver showed the typical features of FLC, CC was admixed with the FLC, not only in the primary hepatic tumour, but also in the lymph node metastases. Immunohistochemical analysis revealed that, although carcinoembryonic antigen (CEA), which can be detected with monoclonal antibodies in the cytoplasm and the cell surface of CC cells but not HCC cells, was expressed in only the CC cells in the primary tumour, it was expressed extensively in the cytoplasm of both CC and FLC cells in the metastatic and recurrent tumours. Furthermore, Hep Par 1, a hepatocyte specific antigen, was also expressed in both the FLC and CC cells. These findings suggest that, in this case, both FLC and CC were possibly derived from the same cancer stem cell with the capacity to differentiate into both hepatocytes and bile duct epithelium, and that both the cellular components, therefore, exhibited biphenotypic antigen expression.

Hydrodynamics-based delivery of the viral interleukin-10 gene suppresses experimental crescentic glomerulonephritis in Wistar-Kyoto rats.

Gene therapy is expected to revolutionize the treatment of kidney diseases. Viral interleukin (vIL)-10 has a variety of immunomodulatory properties. We examined the applicability of vIL-10 gene transfer to the treatment of rats with crescentic glomerulonephritis, a T helper 1 (Th 1) predominant disease. To produce the disease, Wistar-Kyoto rats were injected with a rabbit polyclonal anti-rat glomerular basement membrane antibody. After 3 h, a large volume of plasmid DNA expressing vIL-10 (pCAGGS-vIL-10) solution was rapidly injected into the tail vein. pCAGGS solution was similarly injected into control rats (pCAGGS rats). We confirmed the presence of vector-derived vIL-10 mainly in the liver and observed high serum vIL-10 levels in pCAGGS-vIL-10-injected rats. Compared with the pCAGGS rats, the pCAGGS-vIL-10 rats showed significant therapeutic effects: reduced frequency of crescent formation, decrease in the number of total cells, macrophages, and CD4+ T cells in the glomeruli, decrease in urine protein, and attenuation of kidney dysfunction. Using quantitative real-time polymerase chain reaction, we also observed that this model was Th1-predominant in the glomeruli and that the ratio of the transcripts of CD4, interferon-gamma, tumor necrosis factor-alpha, and monocyte chemotactic protein-1 to the transcripts of glucose-6-phosphate dehydrogenase in the glomeruli were all significantly lower in the pCAGGS-vIL-10 rats than in the pCAGGS rats. These results demonstrate that pCAGGS-vIL-10 gene transfer by hydrodynamics-based transfection suppresses crescentic glomerulonephritis.

A case of dermatomyositis complicated with pneumomediastinum successfully treated with cyclosporin A.

We describe a rare case of a 46-year-old Japanese man with dermatomyositis (DM) and interstitial lung disease who developed spontaneous pneumomediastinum and subcutaneous emphysema. Relatively mild myositis, mild elevation of CK values and the absence of anti-Jo-1 antibody were observed and the case was similar to amyopathic DM. Treatment of this patient with oral prednisolone and cyclosporin A (CsA) was effective for the myositis and interstitial lung disease. The administration of CsA enabled rapid tapering of the dose of prednisolone without aggravating the disease. Pneumomediastinum and subcutaneous emphysema disappeared 5 months later without recurrence. The serum levels of KL-6 were monitored every 2 weeks to help determine whether this may have contributed to the recurrence of interstitial pneumonitis. This is a rare case of pneumomediastinum in a patient with DM.

Comparison of gastroduodenal, renal and abdominal fat biopsies for diagnosing amyloidosis in rheumatoid arthritis.

The aim of the study was to determine the frequency of amyloidosis detected by gastroduodenal biopsy in rheumatoid arthritis (RA) patients, and to investigate correlations between the results of gastroduodenal biopsy and abdominal fat and renal biopsies. A total of consecutive 1006 RA patients underwent gastroduodenal biopsy. The 71 patients who tested positive for gastrointestinal (GI) amyloidosis were asked to undergo renal and abdominal fat biopsies, and 21 did so. Renal biopsies were also performed on 12 patients with no amyloidosis but indicators of drug-induced renal damage, and abdominal fat biopsies were performed on 50 RA patients with no indication of amyloidosis. The prevalence of GI amyloidosis was 7.1%. Urinary abnormalities and GI symptoms were common in GI amyloidisis, and inflammatory markers were elevated. Sixty-one (86%) had either depressed creatinine clearance or urinary symptoms. Nineteen of the 21 patients (91%) with GI amyloidosis who underwent renal biopsies also had renal amyloid deposits. Eleven of the 21 (52%) had amyloidosis on abdominal fat biopsy. None of the 12 patients without GI amyloidosis had renal amyloidosis on renal biopsy, and none of the 50 patients without GI amyloidosis had amyloidosis on abdominal fat biopsy. Gastroduodenal biopsy reveals a high prevalence of amyloidosis in RA patients. Amyloidosis is often associated with signs of renal impairment. Results of GI biopsy are highly correlated with those of renal biopsy, but the results of fat biopsy are not. We recommend GI biopsy for RA patients for the screening of systemic amyloidosis.

Interleukin-2 levels are elevated in the bone marrow serum of patients with mutilans-type rheumatoid arthritis.

In order to investigate the pathogenesis of mutilans-type rheumatoid arthritis (RA), we measured cytokine levels in the bone marrow serum of patients with RA. We studied 35 patients with non-mutilans RA, 19 with mutilans RA, and 20 patients with osteoarthritis (OA) undergoing joint surgery. At the time of surgery, iliac bone marrow and peripheral blood were sampled from all 74 patients and cytokine levels measured. The serum levels of five cytokines (IL-1beta, IL-2, IL-3, IL-6 and GM-CSF) were measured by ELISA. Haematologic and inflammatory factors were also measured. Levels of IL-2, IL-6 and GM-CSF in bone marrow serum were significantly higher in all RA patients than in those with OA. Mean (+/-SD) IL-2 levels were significantly higher in patients with mutilans-type RA (309.8+/-686.3 pg/ml) than in patients with other types of RA (66.5+/-173.1 pg/ml; P<0.01). IL-2 was detected significantly more often in patients with mutilans-type RA than in patients with other types of RA (P < 0.01). Inflammatory factors were higher in all RA groups than in OA patients. However, the haematologic and immunologic variables were no different between mutilans RA and other types of RA. No correlations were observed between IL-1beta, IL-2, IL-3, IL-6 and GM-CSF levels and these laboratory variables. In patients with mutilans-type RA, IL-2 levels in the bone marrow serum were significantly higher than in patients with other types of RA or with OA. This elevation does not appear to be related to systemic inflammation, as there was no correlation with other inflammatory factors.

Disturbed tooth development in parathyroid hormone-related protein (PTHrP)-gene knockout mice.

Parathyroid hormone-related protein (PTHrP) is involved in epithelial-mesenchymal cell interactions during development of various tissues and organs. Tooth germ development is a classical model for this interaction. In tooth germs, PTHrP is expressed in the enamel organ (epithelial component), whereas its major receptor, the type I PTH/PTHrP receptor is expressed in cells of the alveolar bone and dental follicle (mesenchymal components). To clarify the role of PTHrP during fetal tooth germ development, PTHrP gene-knockout mice were used for histochemical and ultrastructural analysis. In wild-type mice, osteoclastic cells were aligned predominantly in the inner aspects of the alveolar bone surrounding the developing tooth germs throughout the late embryonic (after embryonic, 17.5 days) and neonatal animals examined. In contrast, osteoblasts were predominant in corresponding areas of fetal homozygous PTHrP-gene knockout mice with only occasional osteoclasts. In such areas, cell-free surfaces showing cement line-like tartrate-resistant acid phosphatase (TRAP) reactions were frequently observed. In neonatal homozygous mice, bone spicules were often shown to penetrate and/or compress the enamel organ and caused partial destruction of the tooth germs. Osteoclasts were few in number in the inner aspects of the alveolar bone, and had poorly developed ruffled border. No morphological abnormality was noted in cells of the tooth germs proper. On bone surfaces away from developing tooth germs, functional osteoclasts with structural features similar to those in wild-type mice were observed in homozygous mice. These observations suggest that PTHrP is required to maintain an appropriate spatiotemporal arrangement of bone cells and osteoclast function, which are necessary for the normal development of tooth germ and alveolar bone encasing the tooth germ. The observation also demonstrates that PTHrP deficiency affects the structure and function of osteoclasts exclusively those located in the vicinity of the growing tooth germ.

Gas6 rescues cortical neurons from amyloid beta protein-induced apoptosis.

Gas6, a product of the growth-arrest-specific gene 6, protects neurons from serum deprivation-induced apoptosis. Neuronal apoptosis is also caused by amyloid beta protein (Abeta), whose accumulation in the brain is a characteristic feature of Alzheimer's disease. Abeta induces Ca(2+) influx via L-type voltage-dependent calcium channels (L-VSCCs), leading to its neurotoxicity. In the present study, we investigated effects of Gas6 on Abeta-induced cell death in primary cultures of rat cortical neurons. Abeta caused neuronal cell death in a concentration- and time-dependent manner. Gas6 significantly prevented neurons from Abeta-induced cell death. Gas6 ameliorated Abeta-induced apoptotic features such as the condensation of chromatin and the fragmentation of DNA. Prior to cell death, Abeta increased influx of Ca(2+) into neurons through L-VSCCs. Gas6 significantly inhibited the Abeta-induced Ca(2+) influx. The inhibitor of L-VSCCs also suppressed Abeta-induced neuronal cell death. The present cortical cultures contained few non-neuronal cells, indicating that Gas6 affected the survival of neurons directly, but not indirectly via non-neuronal cells. In conclusion, we demonstrate that Gas6 rescues cortical neurons from Abeta-induced apoptosis. Furthermore, the present study indicates that inhibition of L-VSCC contributes to the neuroprotective effect of Gas6.