The Bone Sialoprotein RGD Domain Modulates and Maintains Periodontal Development.

Bone sialoprotein (gene: Ibsp; protein: BSP) is a multifunctional extracellular matrix protein present in bone, cementum, and dentin. Accumulating evidence supports BSP as a key regulator of mineralized tissue formation via evolutionarily conserved functional domains, including a C-terminal integrin-binding Arg-Gly-Asp (RGD) domain implicated in extracellular matrix-cell signaling. Ablation of Ibsp in mice (Ibsp-/-) results in impaired bone growth and mineralization and defective osteoclastogenesis, with effects in the craniofacial region including reduced acellular cementum formation, detachment of the periodontal ligament (PDL), alveolar bone hypomineralization, and severe periodontal breakdown. We hypothesized that BSP-RGD plays an important role in cementum and alveolar bone formation and mineralization, as well as periodontal function. This hypothesis was tested by replacing the RGD motif with a nonfunctional Lys-Ala-Glu (KAE) sequence in (IbspKAE/KAE) mice and OCCM.30 murine (IbspKAE) cementoblasts. The RGD domain was not critical for acellular or cellular cementum formation in IbspKAE/KAE mice. However, PDL volume and thickness were increased, and significantly more tartrate-resistant acid phosphatase-positive osteoclasts were found on alveolar bone surfaces of IbspKAE/KAE mice versus wild type mice. PDL organization was disrupted as indicated by picrosirius red stain, second harmonic generation imaging, dynamic mechanical analysis, and decreased asporin proteoglycan localization. In vitro studies implicated RGD functions in cell migration, adhesion, and mineralization, and this was confirmed by an ossicle implant model where cells lacking BSP-RGD showed substantial defects as compared with controls. In total, the BSP-RGD domain is implicated in periodontal development, though the scale and scope of changes indicated by in vitro studies indicate that other factors may partially compensate for and reduce the phenotypic severity of mice lacking BSP-RGD in vivo.

Carbapenem-resistant Acinetobacter baumannii Bacteremia in Liver Transplant Recipients.

BACKGROUND: Acinetobacter baumannii has become an increasingly important nosocomial pathogen. Carbapenem is the preferred drug of choice for treatment of multidrug-resistant gram-negative bacilli, but carbapenem-resistant A baumannii (CRAB) has now emerged. The aim of this study was to determine the incidence, outcomes, and risk factors for CRAB bacteremia in liver transplant recipients. METHODS: The medical records of 393 subjects who underwent living donor liver transplant at Seoul St. Mary's Hospital from January 2008 to April 2015 were reviewed. RESULTS: A total of 92 (23.4%) bacteremic patients, comprising 156 episodes, were identified. Fourteen patients, totaling 18 episodes, had CRAB bacteremia. The median time of emergence of CRAB bacteremia was 55.5 (range, 2-829) days after transplantation, and 72.2% of episodes (n = 13) occurred within 6 months of transplant. The presumed sources of infection were intra-abdominal (n = 11, 61.1%), biliary tract (n = 3, 16.7%), lung (n = 2, 11.1%), catheter (n = 1, 5.6%), and wound (n = 1, 5.6%). By multivariate analysis, length of post-transplant intensive care unit (ICU) stay (odds ratio [OR], 1.1, 95% confidence interval [CI], 1.11-1.15; P = .04) was associated with CRAB bacteremia. Overall mortality in 14 recipients with CRAB bacteremia was 50% (n = 7), but only 10% (30 of 301) in non-bacteremic patients and 20.5% (16 of 78) in other bacteremic patients excluding CRAB (P < .001). CONCLUSION: In our study, patients with CRAB bacteremia after liver transplant showed an unfavorable outcome and, recently, CRAB has become an increasingly major pathogen at our center. Reducing the length of ICU stay could be a solution for preventing CRAB bacteremia.

Impact of Pretransplant Infections on Clinical Course in Liver Transplant Recipients.

BACKGROUND: Uncontrolled infections are known to be an absolute contraindication for liver transplantation; however, the posttransplant prognosis of recipients treated for pretransplant infection is unclear. The aim of this study was to analyze pretransplant infections among liver transplant recipients and to determine their impact on posttransplant clinical outcomes. METHODS: This study retrospectively analyzed 357 subjects who had undergone living-donor liver transplantation between January 2008 and May 2014. RESULTS: Among 357 recipients, 71 patients (19.8%) had 74 episodes of infectious complications before liver transplantation. These complications consisted of pneumonia (n = 13), spontaneous bacterial peritonitis (n = 12), catheter-related infection (n = 10), urinary tract infection (n = 12), biliary tract infection (n = 6), and skin and soft-tissue infection (n = 3). Twenty-six patients experienced 29 episodes of bacteremia, and the most common pathogens were coagulase-negative staphylococci (n = 8), followed by Klebsiella pneumoniae (n = 7), Staphylococcus aureus (n = 4), and Streptococcus species (n = 3). Twenty-one bacteremic episodes (70%) occurred within 1 month before transplantation (n = 4). Recipients with pretransplant infections had significantly more frequent posttransplant infections (71.8% [51 of 71] vs 47.2% [35 of 286]; P = .0001), posttransplant bacteremia (33.8% [24 of 71] vs 20.3% [58 of 286]; P = .015), and longer posttransplant intensive care unit stays (11.2 ± 10.7 days vs 7.3 ± 4.2 days; P = .0004) than those without pretransplant infections. However, episodes of rejection (P = .36), length of hospitalization (P = .10), 28-day mortality (P = .31), and 1-year mortality (P = .61) after transplantation were not significantly different between the 2 groups. CONCLUSIONS: Pretransplant infection had an impact on posttransplant morbidity, although not on rejection and mortality. Alertness for posttransplant infection and proper management (including effective antimicrobial coverage) would improve patient morbidity.

Exclusive radiotherapy for gliomatosis cerebri: long-term follow-up at a single institution

PURPOSE: To evaluate the efficacy of radiotherapy and factors affecting the prognosis of gliomatosis cerebri. METHODS: Twenty-eight patients with pathologically confirmed gliomatosis cerebri underwent radiotherapy between August 1988 and September 2003. The median age of the patients was 39 years (range 18-67). Performance status was good (ECOG score ≤2) in 23 patients (82 %). The extent of radiotherapy was partial brain in 17 patients, whole brain in 2 patients, and whole brain followed by partial brain in 9 patients. The median radiation dose was 55.8 Gy (range 46.8-70.4). The median duration of follow-up was 136 months for survivors (range 39-191). RESULTS: The median overall and progression-free survival times of all patients were 20 and 11 months, respectively. When initial response to radiotherapy was grouped as improved, stationary, and aggravated, the median overall survival times in patients with improved, stationary, and aggravated responses were 76, 20, and 7 months, respectively (p = 0.0129). However, radiation parameters such as dose and irradiation volume had no impact on overall survival. On multivariate analysis, both performance status and initial response to radiotherapy were significant prognostic factors affecting overall survival (p = 0.0249 and 0.0065, respectively). CONCLUSIONS: This study showed that gliomatosis cerebri could be effectively treated with radiotherapy and that initial response to radiotherapy was a significant prognostic factor affecting the survival (AU)

No disponible

Clinical significance of surveillance culture in liver transplant recipients.

BACKGROUND: Routine microbiologic surveillance is a method of infection control, but its clinical significance in transplant recipients is not known. We analyzed microbiologic data to evaluate the influence of cultured microorganisms between the point of surveillance and infectious episodes in liver transplant recipients. METHODS: We performed surveillance culture for sputum and peritoneal fluid in liver transplant recipients from January 2009 to December 2011, at the time of transplantation (T1), 5 days (T2), and 10 days (T3) postoperatively. RESULTS: Of the 179 recipients, 32.9% had a positive sputum culture result and 37.4% had a positive peritoneal culture result during surveillance. In the culture surveillance of sputum, 37 organisms were isolated from 35 recipients at T1, and the most common organism was Staphylococcus aureus (n = 13). At T2, 45 organisms were isolated from 39 recipients, including Klebsiella pneumoniae (n = 10), S aureus (n = 8), and Acinetobacter baumannii (n = 6). At T3, 18 organisms were isolated from 15 patients, including Stenotrophomonas maltophilia (n = 5) and K pneumonia (n = 4). In the peritoneal fluid, 11 organisms were isolated from 10 recipients at T1, including Pseudomonas aeruginosa (n = 2) and Enterococcus species (n = 2). At T2, 39 organisms were isolated from 36 recipients, including coagulase-negative Staphylococcus species (CNS; n = 8) and Enterococcus species (n = 7). At T3, 54 organisms were isolated from 51 recipients, including CNS (n = 17) and Candida species (n = 8). Among the 59 patients with positive culture results for sputum surveillance, 16.9% developed pneumonia caused by the same organisms. Among the 67 patients with positive peritoneal fluid culture, 16.4% developed an intra-abdominal infection caused by the same organisms cultured. The recipients with positive surveillance culture had a higher risk of pneumonia (20.3% [12/59] vs 1.6% [2/120]; P < .001) and intra-abdominal infection (31.3% [21/67] vs 18.7% [21/112]; P = .05). CONCLUSIONS: Periodic microbiologic surveillance may be useful in the prediction of post-transplantation pneumonia and intra-abdominal infection and could offer a potential target for empirical antimicrobial therapy in cases of infection.

Chest CT findings of toxocariasis: correlation with laboratory results.

AIM: To assess the relationship between chest computed tomography (CT) findings of patients with toxocariasis and levels of serological markers. MATERIALS AND METHODS: A total of 38 cases of patients diagnosed with toxocariasis by enzyme-linked immunosorbent assay (ELISA), CT, and serological markers were retrospectively reviewed. The presence of nodule with or without ground-glass opacity (GGO) halo, consolidation, focal GGO, pleural effusion, and lymphadenopathy at chest CT were evaluated. Statistical analysis was performed with the Fisher's exact test. RESULTS: The most common chest CT findings were nodule (n = 12, 31.6%) and focal GGO (n = 12, 31.6%). In patients with normal eosinophil levels, focal GGO (n = 9, 37.5%) was the most common finding. In contrast, nodule with a GGO halo (n = 7, 50%) was the most common finding in the eosinophilia group. Nodule with a GGO halo was more common in the eosinophilia group, with a statistically significant difference (p = 0.017). Nodule was more common in the eosinophilia group, and focal GGO was more common in the normal eosinophil group. CONCLUSION: The most common chest CT findings in toxocariasis were nodule with or without GGO halo, and focal GGO. In the eosinophilia group, nodule with a GGO halo was significantly more frequent. Other CT findings did not show a statistically significant relationship with serological markers.

Physiologic load-bearing characteristics of autografts, allografts, and polymer-based scaffolds in a critical sized segmental defect of long bone: an experimental study.

BACKGROUND: To address the challenge of treating critical sized intercalary defects, we hypothesized that under physiologic cyclic loading, autografts, allografts, and scaffolds loaded with and without human mesenchymal stem cells (hMSCs) would have different biomechanical characteristics. METHODS: Using a rat femoral defect model, 46 rats were assigned to four groups, ie, autograft (n = 12), allograft (n = 10), scaffold (n = 13), and scaffold with hMSCs (n = 11). The scaffold groups used a 5 mm segment of scaffold composed of 80% poly-ε-caprolactone and 20% hydroxyapatite. Rats were sacrificed 4 months postoperatively, and the repairs were assessed radiographically and biomechanically. RESULTS: Autograft and allograft groups exhibited the most bridging callus, while the scaffold/hMSCs group had more callus than the scaffold repairs. Although signs of radiographic healing did not accurately reflect restoration of mechanical properties, addition of hMSCs on the scaffold enhanced bone formation. The scaffold alone group had significantly lower elastic and viscous stiffness and higher phase angles than other repairs and the contralateral controls. Addition of hMSCs increased the elastic and viscous stiffness of the repair, while decreasing the phase angle. CONCLUSION: Further comparative analysis is needed to optimize clinical use of scaffolds and hMSCs for critical sized defect repairs. However, our results suggest that addition of hMSCs to scaffolds enhances mechanical simulation of native host bone.

Comparison of micro-CT and cone beam CT-based assessments for relative difference of grey level distribution in a human mandible.

OBJECTIVES: The purpose of this study was to examine the ability of CT to assess the relative difference of degree of bone mineralization (grey level) parameters in a human mandible. METHODS: Ten mandibular sections from cadavers (81.5 ± 12.1 years) were scanned using micro-CT with 27.2 µm voxel size and cone beam CT (CBCT) with 200 µm, 300 µm, and 400 µm voxel sizes. In addition, 15 clinical CBCT images from young patients (mean age 18.9 ± 3.3 years) were identified. After segmentation of bone voxels, alveolar bone and basal cortical bone regions were digitally isolated. A histogram of grey level, which is equivalent to degree of bone mineralization, was obtained from each region of the CT images. Mean, standard deviation (SD), coefficient of variation (COV), fifth percentile low (Low(5)) and high (High(5)) of alveolar bone and basal cortical bone regions were obtained. Percentage differences of grey level parameters between alveolar and basal cortical bones were computed. RESULTS: The alveolar bone region had significantly lower Mean, Low(5) and High(5) values but significantly higher SD and COV than the basal cortical bone region for all CT images (p < 0.05). All parameters were significantly lower for the old cadaver group than for the young patient group (p < 0.05). CONCLUSIONS: CBCT and micro-CT provide comparable results in the assessment of relative difference in grey level distribution between alveolar and basal cortical bone regions in the human mandible. The percentage difference relative to an internal reference (basal cortical bone) can be a reliable method when assessing the degree of bone mineralization using CBCT images for both cross-sectional and longitudinal comparisons.

Quantification of reductions in ammonia emissions from fertiliser urea and animal urine in grazed pastures with urease inhibitors for agriculture inventory: New Zealand as a case study.

Urea is the key nitrogen (N) fertiliser for grazed pastures, and is also present in excreted animal urine. In soil, urea hydrolyses rapidly to ammonium (NH4(+)) and may be lost as ammonia (NH3) gas. Unlike nitrous oxide (N2O), however, NH3 is not a greenhouse gas although it can act as a secondary source of N2O, and hence contribute indirectly to global warming and stratospheric ozone depletion. Various urease inhibitors (UIs) have been used over the last 30 years to reduce NH3 losses. Among these, N-(n-butyl) thiophosphoric triamide (nBTPT), sold under the trade name Agrotain®, is currently the most promising and effective when applied with urea or urine. Here we conduct a critical analysis of the published and non-published data on the effectiveness of nBTPT in reducing NH3 emission, from which adjusted values for FracGASF (fraction of total N fertiliser emitted as NH3) and FracGASM (fraction of total N from, animal manure and urine emitted as NH3) for the national agriculture greenhouse gas (GHG) inventory are recommended in order to provide accurate data for the inventory. We use New Zealand as a case study to assess and quantify the overall reduction in NH3 emission from urea and animal urine with the application of UI nBTPT. The available literature indicates that an application rate of 0.025% w/w (nBTPT per unit of N) is optimum for reducing NH3 emissions from temperate grasslands. UI-treated urine studies gave highly variable reductions (11-93%) with an average of 53% and a 95% confidence interval of 33-73%. New Zealand studies, using UI-treated urea, suggest that nBTPT (0.025% w/w) reduces NH3 emissions by 44.7%, on average, with a confidence interval of 39-50%. On this basis, a New Zealand specific value of 0.055 for FracGASF FNUI (fraction of urease inhibitor treated total fertiliser N emitted as NH3) is recommended for adoption where urea containing UI are applied as nBTPT at a rate of 0.025% w/w. Only a limited number of published data sets are available on the effectiveness of UI for reducing NH3 losses from animal urine-N deposited during grazing in a grazed pasture system. The same can be said about mixing UI with urine, rather than spraying UI before or after urine application. Since it was not possible to accurately measure the efficacy of UI in reducing NH3 emissions from animal urine-N deposited during grazing, we currently cannot recommend the adoption of a FracGASM value adjusted for the inclusion of UI.

Development of a groEL gene-based species-specific multiplex polymerase chain reaction assay for simultaneous detection of Vibrio cholerae, Vibrio parahaemolyticus and Vibrio vulnificus.

AIMS: To develop an effective multiplex polymerase chain reaction (PCR) for the simultaneous detection of three important Vibrio species, Vibrio cholerae (Vc), V. parahaemolyticus (Vp) and V. vulnificus (Vv) using the groEL gene, a potential phylogenetic marker. METHODS AND RESULTS: Three species-specific primer sets were designed to target Vc, Vp and Vv. A total of 131 Vibrio and non-Vibrio strains were used to determine the specificity and sensitivity of primers. The primers produced specific PCR fragments from all target species strains and did not cross-react with other Vibrio and non-Vibrio species. This PCR method showed good efficiency in detecting coexisting target species in the same sample with a detection limit of 100 pg of Vc, Vp and Vv from mixed purified DNA. Detection of three target species was also possible from artificially inoculated shellfish, flounder and sea water. CONCLUSIONS: The groEL gene is a potential marker for accurate simultaneous detection of Vc, Vp and Vv and could be used to detect these species in environmental and clinical samples. SIGNIFICANCE AND IMPACT OF THE STUDY: This newly developed multiplex PCR is a useful and cost-effective method that is applicable in a disease-outbreak prediction system and may provide an effective tool for both the epidemiologist and ecologist.

Denitrification and N2O:N2 production in temperate grasslands: processes, measurements, modelling and mitigating negative impacts.

In this review we explore the biotic transformations of nitrogenous compounds that occur during denitrification, and the factors that influence denitrifier populations and enzyme activities, and hence, affect the production of nitrous oxide (N2O) and dinitrogen (N2) in soils. Characteristics of the genes related to denitrification are also presented. Denitrification is discussed with particular emphasis on nitrogen (N) inputs and dynamics within grasslands, and their impacts on the key soil variables and processes regulating denitrification and related gaseous N2O and N2 emissions. Factors affecting denitrification include soil N, carbon (C), pH, temperature, oxygen supply and water content. We understand that the N2O:N2 production ratio responds to the changes in these factors. Increased soil N supply, decreased soil pH, C availability and water content generally increase N2O:N2 ratio. The review also covers approaches to identify and quantify denitrification, including acetylene inhibition, (15)N tracer and direct N2 quantification techniques. We also outline the importance of emerging molecular techniques to assess gene diversity and reveal enzymes that consume N2O during denitrification and the factors affecting their activities and consider a process-based approach that can be used to quantify the N2O:N2 product ratio and N2O emissions with known levels of uncertainty in soils. Finally, we explore strategies to reduce the N2O:N2 product ratio during denitrification to mitigate N2O emissions. Future research needs to focus on evaluating the N2O-reducing ability of the denitrifiers to accelerate the conversion of N2O to N2 and the reduction of N2O:N2 ratio during denitrification.

Altered dynamics of ubiquitin hybrid proteins during tumor cell apoptosis.

The ubiquitin hybrid genes Uba80 and Uba52 encode ubiquitin (Ub), which is fused to the ribosomal proteins S27a (RPS27a) and L40 (RPL40), respectively. Here, we show that these genes are preferentially over-expressed during hepatoma cell apoptosis. Experiments using the tet-inducible transgenic system revealed that over-expression of the ubiquitin hybrid genes sensitized the cells to apoptosis. Further analysis suggested that Ub, and not RPS27a or RPL40, was associated with apoptotic cell death. Cleavage-resistant mutation analysis revealed that the N-terminal portion and the last two amino acids (GG) of Ub are critical for cleavage at the junction between the two protein moieties. An apoptogenic stimulus enhances the nuclear targeting and aggregation of Ub in the nucleus, resulting in histone H2A deubiquitylation followed by abnormal ubiquitylation of the nuclear envelope and the lamina. These events accompany the apoptotic nuclear morphology in the late stage of apoptosis. Each fused RP is localized in the nucleoli. These results suggest a role for Ub hybrid proteins in the altered nuclear dynamics of Ub during tumor cell apoptosis induced by apoptogenic stimuli.

Application of groEL gene for the species-specific detection of Vibrio parahaemolyticus by PCR.

AIMS: Vibrio parahaemolyticus is a significant cause of human gastrointestinal disorders and is transmitted through ingestion of raw or undercooked contaminated seafood. We used the groEL gene for the species-specific detection of V. parahaemolyticus from artificially inoculated shellfish, fish and seawater. METHODS AND RESULTS: The nucleotide sequences of 24 Vibrio and seven non-Vibrio spp. were compared, and less conserved regions were selected for the designing of primer sets. To detect V. parahaemolyticus specifically, PCR conditions were standardized and tested to evaluate the specificity of primers. A 510-bp band was appeared only from V. parahaemolyticus by PCR. Notably, the detection was shown to be functional at high annealing temperature above 68°C. The groEL primers detected 100 pg and 1 ng of DNA purified from V. parahaemolyticus culture and artificially infected oyster tissue, respectively. CONCLUSIONS: The groEL gene is a potential marker for the species-specific detection of V. parahaemolyticus and could be used to detect this bacterium in contaminated food by PCR. SIGNIFICANCE AND IMPACT OF THE STUDY: PCR using primers designed from groEL gene provide an efficient method for the accurate identification of V. parahaemolyticus from contaminated samples.

Application of the rpoS gene for the detection of Vibrio anguillarum in flounder and prawn by polymerase chain reaction.

Vibrio anguillarum, an opportunistic fish pathogen, is the main species responsible for vibriosis, a disease that affects feral and farmed fish and shellfish, and causes considerable economic losses in marine aquaculture. In this study, we used polymerase chain reaction (PCR) to detect V. anguillarum. PCR specificity was evaluated by amplifying the rpoS gene, a general stress regulator, in six strains of V. anguillarum and 36 other bacterial species. PCR amplified a species-specific fragment (689 bp) from V. anguillarum. Furthermore, the PCR assay was sensitive enough to detect rpoS expression from 3 pg of genomic DNA, or from six colony-forming units (CFU) mL(-1) of cultured V. anguillarum. However, the assay was less sensitive when genomic DNA from the infected flounder and prawn was used (limit of detection, 50 ng and 10 ng g(-1) tissue, respectively). These data demonstrate that PCR amplification of the rpoS gene is a sensitive and species-specific method to detect V. anguillarum in practical situations.

Evaluation of pre- and posttransplantation serum interferon-gamma and soluble CD30 for predicting liver allograft rejection.

The aim of the present study was to identify whether the serum interferon-gamma (IFNgamma), a Th1 cytokine, or soluble CD30 (sCD30), a marker for activation of Th2 cytokine-producing T cells, predict acute cellular rejection episodes among liver graft patients. Pretransplant and posttransplant sera from 32 living donor liver transplant recipients obtained on days 1, 3, and 7 after surgery were tested for serum IFNgamma and sCD30 concentrations using commercial enzyme-linked immunosorbent assay kits. Recipients with an acute rejection episode (ARE) (n=14) displayed significantly higher IFNgamma concentrations pretransplant than did the patients with no ARE (n=18) (P<.05). The pretransplant serum levels of sCD30 were not different between the non-ARE and ARE groups. However, in comparison with the non-ARE group, who showed steadily decreasing serum sCD30 levels after transplantation, 12 among the 14 patients in the ARE group showed increasing sCD30 levels from day 1 to day 3 after transplantation (P<.05). These results suggest that the sCD30 increment during the early period after liver transplantation affects the immune response of rejection. This observation emphasizes the clinical relevance of serum sCD30, in addition to serum IFNgamma, as predictive markers for acute liver graft rejection.

Volume variation of mastoid pneumatization in different age groups: a study by three-dimensional reconstruction based on computed tomography images.

Although there have been some reports that measured the size of mastoid pneumatization, only a few studies have reported the age-related variations in the mastoid air cell system using three-dimensional (3D) reconstruction techniques of computed tomography (CT) images. We performed a retrospective, cross-sectional study. A 3D reconstruction based on CT images was performed on 199 ears of 102 patients (age range 6-84 years) without otologic disease by a surface-rendering algorithm. The results showed that mastoid pneumatization continued to grow until the third decade. Thereafter, it declined slowly, and then rapidly after the seventh decade. No statistically significant difference was found between male and female or between right and left sides. There was a significant difference between the larger and smaller sides of individuals. The volume measurement technique based on the 3D reconstruction technique reported here is widely available, highly accurate and easy to perform.