Selective Laser Melting of Maraging Steel Using Synchronized Three-Spot Scanning Strategies

The selective laser melting (SLM) process, a kind of metal additive manufacturing method, can produce parts with complex geometries that cannot be easily manufactured using material removal processes. With increasing industrial applications, there are still issues such as part quality and productivity that need to be resolved. In this study, maraging steel parts fabricated by synchronized three-spot scanning strategies, i.e., lateral spatial (LS) and spatial inline (SiL), are firstly presented. The LS and SiL represent the three-spot offset direction is perpendicular and parallel to the scanning direction, respectively. A laboratory SLM machine equipped with a fiber laser and three-spot module is used to fabricate the maraging steel parts with two scanning strategies, i.e., LS and SiL. The influence of these scanning strategies on the surface roughness, relative density, hardness, molten pool shapes, and microstructures are investigated. The relative density (~99.02%) and surface hardness (~34.0 HRC) are experimentally found to be higher than the SiL by the LS scanning strategy.     

Loss of cell invasiveness through PKC‐mediated syndecan‐1 downregulation in melanoma cells under anchorage independency

Anchorage‐independent survival is one of the key features for malignant tumor cells. Whether specific gene alterations contributed by anchorage independency would further affect metastatic phenotypes of melanoma cells was unclear. We adapted suspension culture of melanoma cells to establish anchorage independency. The suspended melanoma cells lost their invasive abilities in vitro. Specific loss of laminin‐binding ability in suspended melanoma cells was observed, which was correlated with downregulation of syndecan‐1 as revealed by microarray and validated by qPCR and Western blot. Modulation of syndecan‐1 expression level affected laminin binding, transwell migration and matrix metalloproteinase‐2 secretion in melanoma cells. SDC1 expression and transwell migration were correlated with activity or level of protein kinase Cδ as evidence by specific inhibitors and shRNA transfection. In this study, we compared metastatic phenotypes and gene expressions of adherent and suspended melanoma cells. The anchorage independency led to protein kinase Cδ‐mediated syndecan‐1 downregulation, which contributed to loss of laminin‐binding ability, reduced metalloproteinase‐2 secretion and loss of invasiveness.     

Vascular fibrinoid necrosis in the urinary bladder of ketamine abusers: A new finding that may provide a clue to the pathogenesis of ketamine‐induced vesicopathy

Two 31‐year‐old women who had abused ketamine, 1 for 8 years and 1 for 5 years, presented with ketamine‐induced vesicopathy with urinary frequency, decreased bladder capacity, and detrusor overactivity. An enterocystoplasty was performed in both cases. The pathology of the urinary bladders in both women showed ulcerative cystitis and fibrinoid necrosis of vessels; the latter was confirmed by Masson trichrome staining. Fibrinoid necrosis of vessels is a kind of immune complex‐mediated vasculitis that induces the release of inflammatory mediators, with subsequent thrombosis, ischemic injury, and eventual tissue necrosis in localized areas, the so‐called Arthus reaction. The new finding of fibrinoid necrosis in the urinary bladders of ketamine abusers may provide a new clue to the pathogenesis of ketamine‐induced vesicopathy.     

Heart transplantation in pediatric patients: twelve-year experience of the Asan Medical Center

Heart transplantation is a standard treatment for end-stage heart disease. Pediatric heart transplantation, however, is not frequently performed due to the shortage of pediatric heart donors. This is the first report of pediatric heart transplantation in Korea. Our retrospective study included 37 patients younger than 18 yr of age who underwent heart transplantation at Asan Medical Center between August 1997 and April 2009. Preoperative diagnosis was either cardiomyopathy (n = 29, 78.3%) or congenital heart disease (n = 8, 22.7%). Mean follow up period was 56.9 ± 44.6 months. There were no early death, but 7 late deaths (7/37, 18.9%) due to rejection after 11, 15, 41 months (n = 3), infection after 5, 8, 10 months (n = 3), suspicious ventricular arrhythmia after 50 months (n = 1). There was no significant risk factor for survival. There were 25 rejections (25/37, 67.6%); less than grade II occurred in 17 patients (17/25, 68%) and more than grade II occurred in 8 patients (8/25, 32%). Actuarial 1, 5, and 10 yr survival was 88.6%, 76.8%, and 76.8%. Our midterm survival of pediatric heart transplantation showed excellent results. We hope this result could be an encouraging message to do more pediatric heart transplantation in Korean society.     

Reduced expression of 1-cys peroxiredoxin in oxidative stress-induced cataracts

1-cys peroxiredoxin (1-cysPrx), a member of the peroxiredoxin family with a single conserved cysteine residue, reduces a broad spectrum of hydroperoxides. This study was undertaken to examine changes in 1-cysPrx expression in human cataract samples, human lens epithelial (HLE B3) cell line, and rat organ-cultured lenses in response to oxidative insult induced by H2O2 or transforming growth factor-beta1 (TGF-beta1). Expression of 1-cysPrx mRNA and protein in HLE B3 cells increased in response to 2-8 ng ml(-1) TGF-beta1 and 50-75 microm H2O2 and then decreased below the control level at high doses (10 ng ml(-1) TGF-beta1 and 100-150 microm H2O2), as determined by Northern blot and immunoblot analysis. This reduction coincided with the decrease of cell viability. Immunoreactive 1-cysPrx protein was measured in capsulorrhexis specimens obtained from patients with anterior subcapsular cataract (ASC), nuclear sclerosis (NS), cortical spokes (CS), posterior subcapsular cataract (PSC), or white mature cataract (WC) at the time of cataract surgery. Significant reduction of 1-cysPrx protein was observed in ASC, PSC, and WC samples, but there was no statistical difference in CS and NS samples relative to normal control. Also, rat lens explants were cultured with 10 ng ml(-1) TGF-beta1 for approximately 5 days or 500 microm H2O2 for approximately 2 days. Subsequently, expression of 1-cysPrx mRNA and protein in the lens capsules was evaluated. Rat lens explants treated with TGF-beta1 or H2O2 developed a cataract similar to human ASC or WC, respectively, which resulted in a markedly decreased expression of 1-cysPrx mRNA and protein. Collectively, these findings show that expression patterns of 1-cysPrx gene in the lens are changed in response to oxidative stress, a major factor in the etiology of cataract.     

2型糖尿病患者血糖控制对种植体龈沟牙周致病菌的影响

目的: 观察2型糖尿病患者的血糖控制对种植体龈沟牙周致病菌的影响。方法: 收集接受种植牙手术的106例2型糖尿病伴牙周炎的患者,按糖化血红蛋白（HbA1c）值分为HbA1c<8%组（48例）和HbA1c≥8%组（58例）。比较两组患者的年龄、HbA1c比例、菌斑指数、牙周探诊深度。采集入选牙位的龈下菌斑,采用聚合酶链式反应（PCR）检测6种可疑牙周致病菌数量并统计检出率;分析龈下病菌感染与HbA1c的相关性。结果： HbA1c≥8%组患者龈沟出血指数、探诊深度、福塞坦氏菌、中间普氏菌和具核梭杆菌数量和检出率均明显高于HbA1c<8%组（P均<0.05）;牙龈卟啉单胞菌、福塞坦氏菌和具核梭杆菌与患者HbA1c呈正相关（P<0.05）,中间普氏菌与HbA1c呈负相关（P<0.05）。 结论： 糖尿病患者的血糖水平与种植体龈下牙周致病菌菌群的繁殖有相关性。     

Progenitor cell expansion: an important source of hepatocyte regeneration in chronic hepatitis

BACKGROUND/AIMS: Progenitor cell activation with subsequent maturation to hepatocytes and cells of the biliary lineage has been demonstrated in a variety of chronic liver diseases but the kinetics and magnitude of the progenitor cell response has not been adequately studied in detail in chronic hepatitis. We undertook this study to evaluate factors responsible for the progenitor cell/ductular response and further dissect the role of disease grade and stage as determinants of hepatocellular differentiation of bipotential progenitor cells in chronic hepatitis. METHODS: Cytokeratin 7 (and 19) stained biopsies from patients with chronic hepatitis C (n = 47), hepatitis B (n = 20), and autoimmune hepatitis (n = 20) were studied. Ploidy analysis and proliferation indices were evaluated in a subset of cases. RESULTS: Ductular reactions were present in the majority of cases (97%), appeared early in disease, and correlated with disease activity, while progenitor cell derived hepatocyes appeared later in disease and their extent correlated with disease stage. Proliferation indices of all cell types correlated with disease activity. CONCLUSIONS: Progenitor cell derived hepatocytes accrue in chronic hepatitis, possibly related to native hepatocellular dysfunction. However, the fate of these hepatocytes is unclear.     

Cytotoxic diarylheptanoids from the roots of Juglans mandshurica

A new (2) and three known diarylheptanoids (1, 3, and 4), along with one known sesquiterpenoid (5), were isolated from the roots of Juglans mandshurica, and their structures were elucidated on the basis of spectroscopic studies. Four of these compounds (2-5) exhibited moderate cytotoxicities against human colon carcinoma and human lung carcinoma cell lines with IC(50)'s ranging from 2 to 25 microg/mL.     

民族中草医李小艺大通大补法治疗癌症经验

广西民族医药协会李小艺提出癌症与其它慢性病一样本质皆为寒凝诸症，只是堵塞程度更严重，已危及生命，不可误认为热毒，妄用清热解毒药，也不可一味温平，贻误治疗时机。癌症治疗之急在于疏通，治疗之本在于“扶补阳火，驱除阴邪”，治疗之要则在于辨证施用大通大补之法。     

Extracorporeal membrane oxygenation support in a patient with status asthmaticus

Status asthmaticus is a rare, fatal condition, especially in children. Sometimes respiratory support is insufficient with a mechanical ventilator or medical therapy for patients with status asthmaticus. In such situations, early extracorporeal membrane oxygenation application is a useful method for treating refractory respiratory failure. We report on a case of a six-year-old, male child who underwent venovenous extracorporeal membrane oxygenation support for refractory status asthmaticus.