Background and Objectives
Survivors of pediatric hematopoietic stem cell transplantation (HSCT) are at risk for developing hypertension. The objectives of this study are to evaluate the prevalence and risk factors of early onset hypertension during the engraftment period after HSCT.
Subjects and Methods
This is a retrospective study of 157 consecutive patients (mean age at HSCT: 9.1±5.1 years) who underwent HSCT for acute myeloid leukemia (n=47), acute lymphoblastic leukemia (n=43), severe aplastic anemia (n=41), and other reasons (n=26). Blood pressure data were collected at five time points: 0, 7, 14, 21, and 28 days after HSCT. Hypertension was defined as having systolic and/or diastolic blood pressure ≥95th percentile according to age, gender, and height. To analyze the risk factors related to hypertension, data, including patients' demographic and transplant characteristics, were reviewed.
Hypertension developed in 59 patients (38%), among whom 12 (7.6%) required long term therapy. Thirty-two (54%) patients had systolic and diastolic, 8 (14%) had only systolic, and 19 (32%) had only diastolic hypertension. Younger age, acute graft-versus-host disease, sinusoidal obstruction syndrome, treatment with antifungal agent, and greater increase in serum creatinine (Cr) levels were associated with hypertension. Multivariate analysis showed that younger age at HSCT and greater increase in serum Cr level were independent risk factors for hypertension.
Prevalence of hypertension during immediate post-HSCT period is high, especially in younger children. A greater increase in Cr after HSCT was significantly associated with hypertension. Further study is needed to elucidate long-term cardiovascular complications in pediatric HSCT survivors.
Hematopoletic stem cell transplantation; Child; Incidence; Blood pressure; Hypertension
Acinetobacter baumannii, an opportunistic nosocomial pathogen that can cause significant morbidity and mortality, has emerged as a worldwide problem. The aim of this study was to evaluate the risk factors for mortality in patients with A. baumannii bacteremia.
Materials and Methods
We retrospectively evaluated 118 patients who had A. baumannii bacteremia between July 2003 and December 2011. The aim of this study was to identify the 30-day mortality in patients with A. baumannii bacteremia and relevant risk factors.
The bacteremia-related 30-day mortality rate was 34.1%. Univariate analysis revealed that the risk factors for mortality included malignancy, longer hospital stay before bacteremia, intensive care unit (ICU) stay at the time of bacteremia, mechanical ventilation, use of a central venous catheter, unknown origin of bacteremia, bacteremia due to pneumonia, antimicrobial resistance to carbapenems, and elevated Acute Physiology and Chronic Health Evaluation II and Pitt bacteremia scores. Multivariate logistic regression analysis revealed that resistance to carbapenems (odds ratio [OR]: 4.01, 95% confidence interval [CI]: 1.51 to 0.68, P = 0.005), need for mechanical ventilation (OR: 3.97, 95% CI: 1.41 to 11.13, P = 0.005), and presence of malignancy (OR: 4.40, 95% CI: 1.60 to 12.08, P = 0.004) were significantly related to mortality risk.
Risk factors such as resistance to carbapenems, mechanical ventilation, and presence of malignancy were found to be associated with high mortality rates in the patients with A. baumannii bacteremia.
Acinetobacter baumannii; Bacteremia; Mortality
Acinic cell carcinoma (ACC) of the breast is extremely rare and is characterized by widespread acinar cell-like differentiation. We report of a 39-year-old woman presented with a palpable breast mass with significant morphological, immunohistochemical and ultrastructural findings. Histologically, ACC showed a diffuse glandular infiltrative pattern, with small acinar or glandular structures mixed with solid nests. Neoplastic cells were monotonous proliferation of cells with a granular or clear cytoplasm, resembling acinar cells of the salivary glands or Paneth cells. Both glandular and solid tumor cell populations were strongly positive for lysozyme and α-1-antitrypsin.
Acinic cell carcinoma; Breast neoplasms; Electron microscopy; Immunohistochemistry
Necrotizing fasciitis is a life-threatening infectious disease with rapidly progressive involvement of the affected site. Because of the high mortality rate of this disease, early diagnosis, surgical exploration, and administration of appropriate antibiotics are necessary. The present study aimed to further review the changes in the clinical and microbiological characteristics of necrotizing fasciitis using patients' medical records from consecutive databases of 3 hospitals in Korea.
Materials and Methods
In this study, we retrospectively reviewed the medical records of patients with necrotizing fasciitis who were clinically diagnosed between May 2001 and February 2012 in 3 university hospitals in Korea. In total, the data of 83 patients were analyzed, including those of 20 patients from our previous study in 2006. An organism found in a blood culture or surgical specimen was regarded as a causative organism.
Of the 83 patients, 68(81.9%) had community-acquired infections. Ninety microorganism species were indentifed by culture. Streptococcus was the most commonly identified pathogen. Non-fermentative gram-negative bacteria and Candida species have recently emerged, especially in immunocompromised hosts.
Gram-positive organisms are still the most common pathogens of necrotizing fasciitis. However in our study, various gram-negative bacteria with different levels of susceptibility to antibiotics, as well as Candida species, were responsible for the necrotizing fasciitis. Initial empirical antimicrobial agents for necrotizing fasciitis should be considered depending on the individual patient's condition.
Necrotizing fasciitis; Skin and soft tissue infection
Recently, claim-data-based comorbidity-adjusted methods such as the Charlson index and the Elixhauser comorbidity measures have been widely used among researchers. At the same time, there have been an increasing number of attempts to improve the predictability of comorbidity-adjusted models. We tried to improve the predictability of models using the Charlson and Elixhauser indices by using medication data; specifically, we used medication data to estimate omitted comorbidities in the claim data.
We selected twelve major diseases (other than malignancies) that caused large numbers of in-hospital mortalities during 2008 in hospitals with 700 or more beds in South Korea. Then, we constructed prediction models for in-hospital mortality using the Charlson index and Elixhauser comorbidity measures, respectively. Inferring missed comorbidities using medication data, we built enhanced Charlson and Elixhauser comorbidity-measures-based prediction models, which included comorbidities inferred from medication data. We then compared the c-statistics of each model.
247,712 admission cases were enrolled. 55 generic drugs were used to infer 8 out of 17 Charlson comorbidities, and 106 generic drugs were used to infer 14 out of 31 Elixhauser comorbidities. Before the inclusion of comorbidities inferred from medication data, the c-statistics of models using the Charlson index were 0.633-0.882 and those of the Elixhauser index were 0.699-0.917. After the inclusion of comorbidities inferred from medication data, 9 of 12 models using the Charlson index and all of the models using the Elixhauser comorbidity measures were improved in predictability but, the differences were relatively small.
Prediction models using Charlson index or Elixhauser comorbidity measures might be improved by including comorbidities inferred from medication data.
Severity-of-illness index; Comorbidity; Prescriptions; Drug; Risk-adjustment; Outcome assessment
The bark of Ulmus davidiana var. japonica Nakai (Ulmaceae) has been used in traditional Korean medicine for chronic inflammation in the gastrointestinal tract. Here we investigated the frequency and cytokine profile of the major immune cells in the small intestinal lamina propria (SI LP), spleen, and mesenteric lymph nodes (MLNs) of mice treated orally with Ulmus davidiana var. japonica Nakai bark water extract (UDE) to address the immunomodulatory role of this herb in intestinal homeostasis. B6 mice were given 5g/kg UDE once daily for 14 days. They were then sacrificed, and cells were isolated from the spleen, MLNs, and SI LP. The proportion of B versus T lymphocytes, CD4+ versus CD8+ T lymphocytes, Th1 and Th17 cells, and Foxp3+ regulatory T cells in the spleen, MLNs, and SI LP were analyzed. The frequency of antigen-presenting cells (APCs), including dendritic cells, macrophages, and eosinophils in the SI LP and the expression of costimulatory molecules on APCs were also evaluated. The numbers and frequencies of Th1 and Th17 cells in the SI LP were significantly reduced in the UDE-treated mice compared with PBS controls. In addition, the proportion of IL-4-producing eosinophils in the SI LP was significantly elevated in the UDE-treated mice compared with controls. Taken together, these data indicate that UDE up-regulates the number and frequency of SI LP eosinophils, which can down-regulate the Th1 and Th17 responses via IL-4 secretion and contribute to intestinal homeostasis.
Since graphene, a single sheet of graphite, has all of its carbon atoms on the surface, its property is very sensitive to materials contacting the surface. Herein, we report novel Raman peaks observed in annealed graphene and elucidate their chemical origins by Raman spectroscopy and atomic force microscopy (AFM). Graphene annealed in oxygen-free atmosphere revealed very broad additional Raman peaks overlapping the D, G and 2D peaks of graphene itself. Based on the topographic confirmation by AFM, the new Raman peaks were attributed to amorphous carbon formed on the surface of graphene by carbonization of environmental hydrocarbons. While the carbonaceous layers were formed for a wide range of annealing temperature and time, they could be effectively removed by prolonged annealing in vacuum. This study underlines that spectral features of graphene and presumably other 2-dimensional materials are highly vulnerable to interference by foreign materials of molecular thickness.
Phylogeographic studies of animals with low vagility and restricted to patchy habitats of the supralittoral zone, can uncover unknown diversity and shed light on processes that shaped evolution along a continent’s edge. The Pacific coast between southern California and central Mexico, including the megadiverse Gulf of California, offers a remarkable setting to study biological diversification in the supralittoral. A complex geological history coupled with cyclical fluctuations in temperature and sea level provided ample opportunities for diversification of supralittoral organisms. Indeed, a previous phylogeographic study of Ligia, a supralittoral isopod that has limited dispersal abilities and is restricted to rocky patches, revealed high levels of morphologically cryptic diversity. Herein, we examined phylogeographic patterns of Tylos, another supralittoral isopod with limited dispersal potential, but whose habitat (i.e., sandy shores) appears to be more extensive and connected than that of Ligia. We conducted Maximum Likelihood and Bayesian phylogenetic analyses on mitochondrial and nuclear DNA sequences. These analyses revealed multiple highly divergent lineages with discrete regional distributions, despite the recognition of a single valid species for this region. A traditional species-diagnostic morphological trait distinguished several of these lineages. The phylogeographic patterns of Tylos inside the Gulf of California show a deep and complex history. In contrast, patterns along the Pacific region between southern California and the Baja Peninsula indicate a recent range expansion, probably postglacial and related to changes in sea surface temperature (SST). In general, the phylogeographic patterns of Tylos differed from those of Ligia. Differences in the extension and connectivity of the habitats occupied by Tylos and Ligia may account for the different degrees of population isolation experienced by these two isopods and their contrasting phylogeographic patterns. Identification of divergent lineages of Tylos in the study area is important for conservation, as some populations are threatened by human activities.
Interdigitating dendritic cell sarcoma (IDCS) is an extremely rare neoplasm that mainly arises from the lymphoid tissues of the immune system. Although this neoplasm typically occurs anywhere along the lymph nodes, it can also be found at extranodal sites, especially in the head and neck. We experienced a rare case of extranodal IDCS in the nasal cavity, a location that has not been previously reported. A 73-year-old woman presented with a polyp-like mass in the nasal cavity and underwent endoscopic sinus surgery. A histologic study confirmed the mass as IDCS by immunohistochemistry with S-100 antibody, and postoperative adjuvant radiotherapy was administered. Although the incidence is extremely rare, this case suggests that extranodal IDCS should be considered in the differential diagnosis of nasal cavity masses.
A porcine skin model was developed to characterize the dose-dependent response to high-dose radiation. The dorsal skin of a mini pig was divided into four paraspinal sections, with 11 small irradiation fields (2 cm × 2 cm) in each section, and a single fraction of 15, 30, 50 or 75 Gy was delivered to each section using a 6 MeV electron beam. A spectrophotometer measured gross skin changes, and a biopsy for each radiation dose was performed in the 1st, 2nd, 4th, 6th and 9th weeks for histology, immunostaining with anti-CD31, and western blotting with IL-6 and TGF-β1 to determine the degree of skin damage. After a 4-week latency period, erythema and dry desquamation, moist desquamation, and ulceration appeared at 4, 6 and 9 weeks, respectively. Gross skin toxicity was more pronounced, occurred early and continued to progress with irradiation >50 Gy, whereas complete healing was observed 12 weeks after 15 Gy. Spectrophotometry showed erythema indices rapidly increased during the first 4 weeks after irradiation. The number of eosinophils began rising sharply at 4 weeks and normalized after reaching peaks at 7–8 weeks. Microvessel density showed a biphasic pattern with a transient peak at 1 week, a nadir at 4–6 weeks, and maximum recovery at 9 weeks. Increase in the levels of IL-6 and TGF-β1 was detected soon after irradiation. Most of these parameters indicated complete healing of the skin 12 weeks after 15 Gy. Our porcine skin model provides an effective platform for studying high-dose radiation-induced skin injury, in particular histologic and molecular changes, during the early latency period.
radiation skin injury; porcine skin model; high-dose radiation
Laryngeal amyloidosis is uncommon and poorly understood, with limited long-term studies. Although primary localized laryngeal amyloidosis is extremely rare, it frequently involves the ventricles and the false and true vocal cords. We present a 58-year-old woman with localized laryngeal amyloidosis who presented no symptoms. On indirect laryngoscopic examination, the mass involved both arytenoids only, and had a likeness to a "boxer glove." She was treated surgically by microlaryngoscopy under general anesthesia and the mass was excised using a carbon dioxide laser. We present this case and a review of literature.
The indications and optimal surgical treatments for intracranial cysts are controversial. In the present study, we describe long-term clinical and neuroimaging results of surgically treated intracranial cysts in children. The goal of this study is to contribute to the discussion of the debate.
This study included 110 pediatric patients that underwent surgeries to treat intracranial cysts. Endoscopic cyst fenestrations were performed in 71 cases, while craniotomies and cyst excisions (with or without fenestrations) were performed in 30 patients. Cystoperitoneal shunts were necessary for nine patients. Long-term results were retrospectively assessed with medical and neuroimaging records.
Clinical and radiological improvement was reported in 87.3% and 92.8% of cases, respectively, after endoscopic neurosurgery, and in 93.3% and 100% using open microsurgery whereas 88.9% and 85.7% after shunt operation. There were no statistical differences in clinical outcomes (p=0.710) or volume reductions (p=0.177) among the different surgeries. There were no mortalities or permanent morbidities, but complications such as shunt malfunctions, infections, and subdural hematomas were observed in 56% of the patients that had shunt operations. A total of 13 patients (11.8%) underwent additional surgeries due to recurrences or treatment failures. The type of surgery performed did not influence the recurrence rate (p=0.662) or the failure rate (p=0.247).
Endoscopic neurosurgeries are less invasive than microsurgeries and are at least as effective as open surgeries. Thus, given the advantages and complications of these surgical techniques, we suggest that endoscopic fenestration should be the first treatment attempted in children with intracranial cysts.
Arachnoid cysts; Central nervous system cysts; Congenital; Neuroendoscopy; Child
The common characteristics of metabolic syndrome (MetS) and Cushing's syndrome suggest that excess cortisol may be involved in the pathogenesis of MetS. Salivary cortisol measurements are simple and can be surrogates for plasma free cortisol, which is the most biologically active form. We evaluated the association between levels of midnight salivary cortisol and MetS in Korean adults.
A total of 46 subjects, aged 20 to 70 years, who visited the Health Care Center at Konkuk University Hospital from August 2008 to August 2009 were enrolled. We compared the levels of midnight salivary cortisol in subjects with MetS with those in subjects without MetS. We analyzed the associations between midnight salivary cortisol levels and components of MetS.
Midnight salivary cortisol levels were higher in the MetS group (70±42.4 ng/dL, n=12) than that in the group without MetS (48.1±36.8 ng/dL, n=34) (P=0.001). Positive correlations were observed between midnight salivary cortisol levels and waist circumference, fasting blood glucose, and homeostasis model assessment of insulin resistance. The risk for MetS was significantly higher in subjects with midnight salivary cortisol levels ≥100 ng/dL than in those with levels <50 ng/dL (odds ratio, 5.9; 95% confidence interval, 2.35 to 36.4).
The results showed a positive correlation between midnight salivary cortisol levels and MetS, suggesting that hypercortisolism may be related to MetS.
Corticosteroid; Insulin resistance; Metabolic syndrome
This study investigated the epidemiology of Kawasaki disease (KD) in infants ≤3-month-old.
To study the epidemiology of KD in Korea, data for 27,851 KD patients were collected on a 3-year basis between 2000 and 2008 in a retrospective survey. From this, data for 609 KD patients ≤3-month-old were analyzed and compared with the data for KD patients >3-month-old.
The 609 KD patients ≤3-month-old (385 males and 224 females) constituted 2.2% of the KD patients. They included 25 infants <1-month-old, 198 infants ≤1- to 2-month-old, and 386 infants >2- and 3-months-old. The ratio of males to females was 1.72:1. The incidence of coronary artery (CA) dilatation (19.9% vs. 18.7%) and CA aneurysms (3.4% vs. 2.6%) detected by echocardiography did not differ significantly between patients with KD younger and older than 3-month-old.
Compared with the data for the KD patients >3-month-old, the data for the 609 patients ≤3-month-old did not show a significantly higher incidence of CA dilatation or CA aneurysms.
Kawasaki disease; Coronary artery dilatation; Coronary aneurysm; Epidemiology; Infant
Colon cancer is a common epithelial malignancies worldwide. Epidemiologic evidence has shown that nutrition and dietary components are important environmental factors involved in the development of this disease. We investigated the biological activity of 6,7,4′-trihydroxyisoflavone (6,7,4′-THIF, a metabolite of daidzein) in in vitro and in vivo models of human colon cancer. 6,7,4′-THIF suppressed anchorage-dependent and -independent growth of HCT-116 and DLD1 human colon cancer cells more effectively than daidzein. In addition, 6,7,4′-THIF induced cell cycle arrest at the S and G2/M phases in HCT-116 human colon cancer cells. Western blot analysis revealed that 6,7,4′-THIF effectively suppressed the expression of cyclin-dependent kinase (CDK) 2, but had no effect on other S- or G2/M-phase regulatory proteins such as cyclin A, cyclin B1 or CDK1. Daidzein did not affect the expression of any of these proteins. In kinase and pull-down assays, 6,7,4′-THIF, but not daidzein, inhibited CDK1 and CDK2 activities in HCT-116 cells by directly interacting with CDK1 and CDK2. In a xenograft mouse model, 6,7,4′-THIF significantly decreased tumor growth, volume and weight of HCT-116 xenografts. 6,7,4′-THIF bound directly to CDK1 and CDK2 in vivo, resulting in the suppression of CDK1 and CDK2 activity in tumors corresponding with our in vitro results. Collectively, these results suggest that CDK1 and CDK2 are potential molecular targets of 6,7,4′-THIF to suppress HCT-116 cell proliferation in vitro and in vivo. These findings provide insight into the biological actions of 6,7,4′-THIF and might establish a molecular basis for the development of new cancer therapeutic agents.
The survival rate for childhood acute lymphoblastic leukemia (ALL) has improved significantly. However, overall prognosis for the 20 to 25% of patients who relapse is poor, and allogeneic hematopoietic stem cell transplantation (HSCT) offers the best chance for cure. In this study, we identified significant prognostic variables by analyzing the outcomes of allogeneic HSCT in ALL patients in second complete remission (CR).
Fifty-three ALL patients (42 men, 79%) who received HSCT in second CR from August 1991 to February 2009 were included (26 sibling donor HSCTs, 49%; 42 bone marrow transplantations, 79%). Study endpoints included cumulative incidence of acute and chronic graft-versus-host disease (GVHD), relapse, 1-year transplant-related mortality (TRM), disease-free survival (DFS), and overall survival (OS).
Cumulative incidences of acute GVHD (grade 2 or above) and chronic GVHD were 45.3% and 28.5%, respectively. The estimated 5-year DFS and OS for the cohort was 45.2±6.8% and 48.3±7%, respectively. Only donor type, i.e., sibling versus unrelated, showed significant correlation with DFS in multivariate analysis (P=0.010). The rates of relapse and 1 year TRM were 28.9±6.4% and 26.4±6.1%, respectively, and unrelated donor HSCT (P=0.002) and HLA mismatch (P=0.022) were significantly correlated with increased TRM in univariate analysis.
In this single institution study spanning more than 17 years, sibling donor HSCT was the only factor predicting a favorable result in multivariate analysis, possibly due to increased TRM resulting from unrelated donor HSCT.
Acute lymphoblastic leukemia; Child; Second complete remission; Transplantation
Ultraviolet (UV) radiation is the primary environmental risk factor in the development of nonmelanoma skin cancer, and UVB in particular promotes tumor growth through various signaling pathways. Kaempferol, a flavonoid with anti-inflammatory and anti-oxidative properties, has been studied as a chemopreventive agent; however, little is known regarding its effects on UVB-induced photo-carcinogenesis. Here, we examined the effect of kaempferol on UVB-induced skin inflammation. We found that kaempferol suppressed UVB-induced cyclooxygenase-2 (COX-2) protein expression in mouse skin epidermal JB6 P+ cells and attenuated the UVB-induced transcriptional activities of cox-2 and activator protein-1 (AP-1). Kaempferol attenuated the UVB-induced phosphorylation of several mitogen-activated protein kinases (MAPKs), including ERKs, p38, and JNKs, but had no effect on the phosphorylation of the upstream MAPK regulator Src. However, in vitro and ex vivo kinase assays demonstrated that kaempferol suppressed Src kinase activity. Furthermore, in vivo data from mouse skin support the idea that kaempferol suppresses UVB-induced COX-2 expression by blocking Src kinase activity. A pull-down assay revealed that kaempferol competes with ATP for direct binding to Src. Docking data suggest that kaempferol docks easily into the ATP-binding site of Src, which is located between the N and C lobes of the kinase domain. Taken together, these results suggest that kaempferol is a potent chemopreventive agent against skin cancer through its inhibitory interaction with Src.
flavonoid; photo-carcinogenesis; skin cancer
Norovirus (NV) has caused large outbreaks of gastroenteritis in schools. Studies of NV epidemiology in schools related to NV outbreaks have been frequently reported. However, reports of that in schools without outbreaks are not found. Presently, NV molecular epidemiology surveillance was carried out in asymptomatic food handlers working at nonoutbreak elementary schools in Incheon, Korea, in March, April and December, 2009. NV prevalence was examined by real-time reverse transcription-PCR (RT-PCR) and the positive products were re-evaluated by conventional RT-PCR for sequencing. Fecal samples (n = 776) were collected from 776 food handlers in 60 schools. NV was detected in 26 of them (3.4%). Of these, 17 (65%) were positive for NV GII and 10 (38%) were positive for NV GI. Of the 26 samples, 19 were positive by conventional RT-PCR. Sequencing of these 19 strains revealed GII/4 (n = 5), GI/6 (n = 3), GI/14 (n = 2), GII/8 (n = 2), GI/2 (n = 2), GI/10 (n = 1), GII/1 (n = 1), GII/3 (n = 1), GII/7 (n = 1), and GII/16 (n = 1). In this survey, the food handler population unrelated to NV outbreaks was found to normally contain asymptomatic carriers of NV. The excretion of NV from asymptomatic food handlers should be an infection source of NV outbreaks.
Epidemiology; Norovirus; School
Myricetin is one of the principal phytochemicals in onions, berries and red wine. Previous studies showed that myricetin exhibits potent anticancer and chemopreventive effects. The present study examined the effect of myricetin on ultraviolet (UV) B-induced angiogenesis in an SKH-1 hairless mouse skin tumorigenesis model. Topical treatment with myricetin inhibited repetitive UVB-induced neovascularization in SKH-1 hairless mouse skin. The induction of vascular endothelial growth factor, matrix metalloproteinase (MMP)-9 and MMP-13 expression by chronic UVB irradiation was significantly suppressed by myricetin treatment. Immunohistochemical and western blot analyses revealed that myricetin inhibited UVB-induced hypoxia inducible factor-1α expression in mouse skin. Western blot analysis and kinase assay data revealed that myricetin suppressed UVB-induced phosphatidylinositol-3 (PI-3) kinase activity and subsequently attenuated the UVB-induced phosphorylation of Akt/p70S6K in mouse skin lysates. A pull-down assay revealed the direct binding of PI-3 kinase and myricetin in mouse skin lysates. Our results indicate that myricetin suppresses UVB-induced angiogenesis by regulating PI-3 kinase activity in vivo in mouse skin.
Gagamjungjihwan (GJ), a decoction consisting of five herbs including ginseng, Acori Graminei Rhizoma, Uncariae Ramulus et Uncus, Polygalae Radic and Frustus Euodiae (FE), has been widely used as herbal treatment for ischemia. In order to investigate the neuroprotective action of this novel prescription, we examined the influence of GJ and FE on learning and memory using the Morris water maze and studied their affects on the central cholinergic system in the hippocampus with neuronal and cognitive impairment. After middle cerebral artery occlusion was applied for 2 h, rats were administered GJ (200 mg kg−1, p.o.) or FE (200 mg kg−1, p.o.) daily for 2 weeks, followed by training and performance of the Morris water maze tasks. Rats with ischemic insults showed impaired learning and memory of the tasks. Pre-treatment with GJ and FE produced improvement in the escape latency to find the platform. Pre-treatments with GJ and FE also reduced the loss of cholinergic immunoreactivity in the hippocampus. The results demonstrated that GJ and FE have a protective effect against ischemia-induced neuronal and cognitive impairment. Our results suggest that GJ and FE might be useful in the treatment of vascular dementia.
The requirements for engineering clinically sized cardiac constructs include medium perfusion (to maintain cell viability throughout the construct volume) and the protection of cardiac myocytes from hydrodynamic shear. To reconcile these conflicting requirements, we proposed the use of porous elastomeric scaffolds with an array of channels providing conduits for medium perfusion, and sized to provide efficient transport of oxygen to the cells, by a combination of convective flow and molecular diffusion over short distances between the channels. In this study, we investigate the conditions for perfusion seeding of channeled constructs with myocytes and endothelial cells without the gel carrier we previously used to lock the cells within the scaffold pores. We first established the flow parameters for perfusion seeding of porous elastomer scaffolds using the C2C12 myoblast line, and determined that a linear perfusion velocity of 1.0 mm/s resulted in seeding efficiency of 87 ± 26% within 2 hours. When applied to seeding of channeled scaffolds with neonatal rat cardiac myocytes, these conditions also resulted in high efficiency (77.2 ± 23.7%) of cell seeding. Uniform spatial cell distributions were obtained when scaffolds were stacked on top of one another in perfusion cartridges, effectively closing off the channels during perfusion seeding. Perfusion seeding of single scaffolds resulted in preferential cell attachment at the channel surfaces, and was employed for seeding scaffolds with rat aortic endothelial cells. We thus propose that these techniques can be utilized to engineer thick and compact cardiac constructs with parallel channels lined with endothelial cells.
Bioreactor; scaffold; perfusion; cell seeding; cardiac tissue engineering
Of 63 patients with Staphylococcus lugdunensis bacteremia, 15 (23.8%) had clinically significant bacteremia, with an incidence of 1.3 cases per 100,000 admissions. Of the five patients with community-acquired S. lugdunensis bacteremia, three had endocarditis. Catheters were the most common portal of entry for health-care-associated or hospital-acquired bacteremia. Only one patient died of bacteremia-related causes.
Structural and mechanical anisotropy are critical to the function of many engineered tissues. This study examined the ability of anisotropic tissue constructs to overcome contact guidance cues and remodel in response to altered mechanical loading conditions. Square tissues engineered from dermal fibroblasts and type-I collagen were uniaxially loaded to induce cell and matrix alignment. After an initial time, t*, of 5 to 72 hrs, loading was switched from the x-axis to the y-axis. Cell alignment was examined throughout the experiment until a steady state was reached. Before t*, cells spontaneously aligned in the x-direction. After t*, the strength of alignment transiently decreased then increased, and mean cell orientation transitioned from the x- to the y-direction following an exponential time course with a time constant that increased with t*. Collagen fiber orientation exhibited similar trends that could not be explained by passive kinematics alone. Structural realignment resulted in concomitant changes in biaxial tissue mechanical properties. The findings suggest that even highly aligned engineered tissue constructs retain the capacity to remodel in response to altered mechanical stimuli. This may have important functional consequences when an anisotropic engineered tissue designed in vitro is surgically implanted into a mechanically complex graft site.
biaxial; biomechanics; collagen; contact guidance; fibroblast
Engineering solid tissues, including cardiac muscle, requires the inclusion of a microvasculature. Prevascularization in vitro will likely be dependent upon coculturing parenchymal cells with vascular cells, on a matrix that is sufficiently porous to allow microvessel formation. In this study, we examined the behavior and function of endothelial cells on a highly porous elastomeric 3D poly(glycerol sebacate) (PGS) scaffold, to provide a flexible and biocompatible endothelial cell delivery system for developing cardiac engineered tissues with neovascularization potential. Both static and perfusion cell seeding methods were used, and the effects of surface treatment of the scaffold with various extracellular matrix components were examined. Endothelial cell adhesion and phenotype on the PGS scaffold under various flow conditions were also determined. Surface coating with laminin markedly improved the endothelial cell adhesion, survival, and proliferation. The anticoagulant phenotype of adhered endothelial cells was further regulated by the application of flow through regulation of nitric oxide expression. By providing a highly porous scaffolding that contains endothelium with anticoagulant properties, the endothelial cell-seeded PGS scaffold could provide a new basis for subsequent coculture studies with various cell types to develop complex engineered tissue constructs with vascularization capacity.
Endothelial cell function; Flow; Vascular tissue engineering; PGS scaffold
Although the importance of fluid flow for proper vascular development and function in vivo is well recognized, microvascular formation in response to flow has not been well evaluated in a three-dimensional (3D) environment in vitro. In this study, we developed a novel 3D in vitro perfusion system that allows direct investigation of the effects of shear stress on the development of microvasculature in vitro. This system utilizes a 3D collagen gel for suspension of vascular cells and mesenchymal stem cells, through which flow is directly perfused. We characterized the flow conditions and demonstrate the impact of flow on the development of microvasculature using a coculture of endothelial cells and mesenchymal stem cells. With the unique ability to apply bulk flow through the collagen gels, and to estimate shear stress within the constructs, this perfusion system provides a flexible platform for developing a controllable biomimetic environment that can be adapted for a variety of investigations of microvascularization.