Induction of thoracic aortic dissection: a mini-review of β-aminopropionitrile-related mouse models / 浙江大学学报（英文版）（B辑：生物医学和生物技术）

Thoracic aortic dissection (TAD) is one of the most lethal aortic diseases due to its acute onset, rapid progress, and high rate of aortic rupture. The pathogenesis of TAD is not completely understood. In this mini-review, we introduce three emerging experimental mouse TAD models using β-aminopropionitrile (BAPN) alone, BAPN for a prolonged duration (four weeks) and then with added infusion of angiotensin II (AngII), or co-administration of BAPN and AngII chronically. We aim to provide insights into appropriate application of these three mouse models, thereby enhancing the understanding of the molecular mechanisms of TAD.

Manipulation of a quasi-natural cell block for high-efficiency transplantation of adherent somatic cells

Recent advances have raised hope that transplantation of adherent somatic cells could provide dramatic new therapies for various diseases. However, current methods for transplanting adherent somatic cells are not efficient enough for therapeutic applications. Here, we report the development of a novel method to generate quasi-natural cell blocks for high-efficiency transplantation of adherent somatic cells. The blocks were created by providing a unique environment in which cultured cells generated their own extracellular matrix. Initially, stromal cells isolated from mice were expanded in vitro in liquid cell culture medium followed by transferring the cells into a hydrogel shell. After incubation for 1 day with mechanical agitation, the encapsulated cell mass was perforated with a thin needle and then incubated for an additional 6 days to form a quasi-natural cell block. Allograft transplantation of the cell block into C57BL/6 mice resulted in perfect adaptation of the allograft and complete integration into the tissue of the recipient. This method could be widely applied for repairing damaged cells or tissues, stem cell transplantation, ex vivo gene therapy, or plastic surgery.

Retinal protective effects of topically administered agmatine on ischemic ocular injury caused by transient occlusion of the ophthalmic artery

Agmatine, an endogenous polyamine and putative neuromodulator, is known to have neuroprotective effects on various neurons in the central nervous system. We determined whether or not topically administered agmatine could reduce ischemic retinal injury. Transient ocular ischemia was achieved by intraluminal occlusion of the middle cerebral artery of ddY mice (30-35 g) for 2 h, which is known to also induce occlusion of the ophthalmic artery. In the agmatine group (N = 6), a 1.0 mM agmatine-containing ophthalmic solution was administered four times daily for 2 weeks before occlusion. In the control group (N = 6), a 0.1 percent hyaluronic acid ophthalmic solution was instilled at the same times. At 22 h after reperfusion, the eyeballs were enucleated and the retinal sections were stained by terminal deoxynucleotidyl transferase dUTP nick-end labeling (TUNEL). Transient ocular ischemia induced apoptosis of retinal cells in the entire retinal layer, and topically administered agmatine can significantly reduce this ischemic retinal injury. The proportion of apoptotic cells was definitely decreased (P < 0.001; Kruskal-Wallis test). Overall, we determined that topical agmatine application effectively decreases retinal damage in an in vivo ocular ischemic injury model. This implies that agmatine is a good candidate as a direct neuroprotective agent for eyes with ocular ischemic diseases.

Impacto da maturação esquelética em biomarcadores do metabolismo ósseo e na densidade mineral óssea em adolescentes brasileiros saudáveis / Impact of skeletal maturation on bone metabolism biomarkers and bone mineral density in healthy Brazilian male adolescents

OBJETIVO: Avaliar o comportamento de biomarcadores de formação e reabsorção óssea em adolescentes brasileiros em função da sua maturação biológica. MÉTODOS: Oitenta e sete voluntários foram divididos em grupos segundo a idade óssea (IO): 10-12 anos (n = 25), 13-15 anos (n = 36) e 16-18 anos (n = 26). Foram analisados peso (kg), estatura (m), índice de massa corporal (kg/m2), ingestão de cálcio de 3 dias (mg/dia), avaliação dos eventos pubertários pelos critérios de Tanner, níveis dos biomarcadores [osteocalcina (OC) (ng/mL), fosfatase alcalina óssea (FAO) (U/L), telopeptídeo carboxiterminal sérico (S-CTx) (ng/mL)] e sua correlação com a densidade mineral óssea (DMO) (g/cm2) por atenuação de raios X de dupla energia da coluna lombar, do fêmur proximal e de corpo total. RESULTADOS: Os biomarcadores mostraram comportamento semelhante, apresentando medianas elevadas dos 13 aos 15 anos (FAO = 154,71 U/L, OC = 43,0 ng/mL, S-CTx = 2,09 ng/mL; p < 0,01) e no estágio puberal G4. As medianas decresceram com o avançar da IO e da maturação sexual. Os níveis dos biomarcadores mostraram paralelismo com pico de velocidade em estatura, e, curiosamente, os biomarcadores de formação indicaram correlação negativa com a DMO, isto é, valores de DMO elevados se correlacionaram com valores baixos dos biomarcadores. CONCLUSÕES: Este é o primeiro estudo em adolescentes brasileiros com critérios de inclusão e exclusão rígidos e cuidadosos a avaliar a correlação entre marcadores ósseos e DMO frente a indicadores da maturação biológica. Os resultados ajudam a compreender o turnover ósseo e o monitoramento do metabolismo ósseo.

OBJECTIVE: To evaluate the behavior of biomarkers of bone formation and resorption in healthy male Brazilian adolescents according to their biological maturation. METHODS: Eighty-seven volunteers were divided into age groups according to bone age (BA): 10-12 years (n = 25), 13-15 years (n = 36), and 16-18 years (n = 26). Weight (kg), height (m), body mass index (kg/m2), calcium intake from 3 days assessed by 24-h food recall (mg/day), pubertal event evaluation by Tanner criteria, and serum biomarker levels (osteocalcin [OC] [ng/mL], bone alkaline phosphatase [BAP] [U/L], and serum carboxyterminal telopeptide [S-CTx] [ng/mL]) were recorded and correlated to bone mineral density (BMD) (g/cm2) measured by dual energy X-ray absorptiometry of the lumbar spine, proximal femur, and whole body. RESULTS: Biomarkers showed similar behaviors, presenting higher median values in the 13-15 year group (BAP = 154.71 U/L, OC = 43.0 ng/mL, S-CTx = 2.09 ng/mL; p < 0.01) and when adolescents were in the pubertal stage G4. Median biomarker values decreased with advancing BA and sexual maturation. Biomarker values showed parallelism with peak height velocity, and, interestingly, bone formation biomarkers indicated significant negative correlation with BMD in the different evaluated locations, i.e., higher BMD values correlated with lower bone biomarker values. CONCLUSIONS: This is the first study of healthy Brazilian adolescents with rigid and careful inclusion and exclusion criteria to assess the correlation of bone markers and BMD with biological maturation indicators. Our results can help understand bone turnover and monitor bone metabolism.

Protective mechanism of agmatine pretreatment on RGC-5 cells injured by oxidative stress

Agmatine has neuroprotective effects on retinal ganglion cells (RGCs) as well as cortical and spinal neurons. It protects RGCs from oxidative stress even when it is not present at the time of injury. As agmatine has high affinity for various cellular receptors, we assessed protective mechanisms of agmatine using transformed RGCs (RGC-5 cell line). Differentiated RGC-5 cells were pretreated with 100 ìM agmatine and consecutively exposed to 1.0 mM hydrogen peroxide (H2O2). Cell viability was determined by measuring lactate dehydrogenase (LDH), and the effects of selective alpha 2-adrenergic receptor antagonist yohimbine (0-500 nM) and N-methyl-D-aspartic acid (NMDA) receptor agonist NMDA (0-100 µM) were evaluated. Agmatine’s protective effect was compared to a selective NMDA receptor antagonist MK-801. After a 16-h exposure to H2O2, the LDH assay showed cell loss greater than 50 percent, which was reduced to about 30 percent when agmatine was pretreated before injury. Yohimbine almost completely inhibited agmatine’s protective effect, but NMDA did not. In addition, MK-801 (0-100 µM) did not significantly attenuate the H2O2-induced cytotoxicity. Our results suggest that neuroprotective effects of agmatine on RGCs under oxidative stress may be mainly attributed to the alpha 2-adrenergic receptor signaling pathway.

Agmatine pretreatment protects retinal ganglion cells (RGC-5 cell line) from oxidative stress in vitro

Agmatine, 2-(4-aminobutyl)guanidine, has been reported to have neuroprotective effects against various neuronal damages. In this study it was investigated whether agmatine pretreatment rescues the retinal ganglion cells from oxidative injury in vitro. Alter differentiation of transformed rat retinal ganglion cells (RGC-5 cell line) with staurosporine, agmatine (0.0 to 100.0 microM) pretreatment was performed for 2 hours. Subsequently, they were exposed to hydrogen peroxide (0.0 to 2.5 mM) as an oxidative stress. Cell viability was monitored for up to 48 hours with the lactate dehydrogenase (LDH) assay and apoptosis was examined by the Terminal deoxynucleotide transferase-mediated terminal uridine deoxynucleotidyl transferase nick end-labeling (TUNEL) method. As a result, differentiated RGC-5 cells were found to have decreased viability after addition of hydrogen peroxide in a dose-dependent manner. This hydrogen peroxide induced cytotoxicity caused apoptosis characterized by DNA fragmentation. Agmatine pretreatment not only increased cell viability but also attenuated DNA fragmentation. In conclusion, agmatine pretreatment demonstrated neuroprotective effects against oxidative stress induced by hydrogen peroxide in differentiated RGC-5 cells in vitro. This suggests a novel therapeutic strategy rescuing retinal ganglion cells from death caused by oxidative injury.

Agmatine inhibits hypoxia-induced TNF-alpha release from cultured retinal ganglion cells

The effect of hypoxia on the release of tumor necrosis factor-alpha (TNF-alpha) in transformed rat retinal ganglion cells (RGCs) and the effect of agmatine on the hypoxia-induced production of TNF-alpha in RGCs were evaluated. RGCs were cultured under hypoxic conditions with 5% oxygen, with or without 100 microM agmatine. The expression levels of TNF-alpha and its receptor-1 (TNF-R1) were investigated by Western blot analysis. After 6 hours of hypoxia, we noted an increase in TNF-alpha production in RGCs. Agmatine significantly reduced TNF-alpha level after 12 hours of hypoxic treatment. The expression of TNF-R1 was not affected by the hypoxia or agmatine treatment. Our results show that agmatine inhibits the TNF-alpha production of RGCs in hypoxic condition. These results demonstrate a possible neuroprotective mechanism for agmatine against hypoxic damage in RGCs.

Standardization of anti-lethal toxin potency test of antivenoms prepared from two different Agkistrodon halys venoms

In Korea, antivenoms for the treatment of patients bitten by venomous snakes have been imported from Japan or China. Although there is cross-reactivity between these antibodies and venoms from snakes indigenous to Korea (e.g. Agkistrodon genus), protection is not optimal. Antivenoms specifically prepared to neutralize Korean snake venoms could be more effective, with fewer side effects. To this end, we established an infrastructure to develop national standards and created a standardized method to evaluate the efficacy of two horse-derived antivenoms using mouse lethal toxin test. Additionally, we determined the antivenoms neutralizing activity against lethal doses (LD50) of Agkistrodon halys (from Japan) and Jiangzhe Agkistrodon halys (from China) venoms. We also performed cross-neutralization tests using probit analysis on each pairing of venom and antivenom in order to check the possibility of using Jiangzhe A. halys venom as a substitute for A. halys venom, the current standard. Slope of A. halys venom with A. halys antivenom was 10.2 and that of A. halys venom with Jiangzhe A. halys antivenom was 9.6. However, Slope of Jiangzhe A. halys venom with A. halys antivenom was 4.7 while that of Jiangzhe A. halys venom with Jiangzhe A. halys antivenom was 11.5. Therefore, the significant difference in slope patterns suggests that Jiangzhe A. halys venom cannot be used as a substitute for the standard venom to test the anti-lethal toxin activity of antivenoms (p<0.05).(AU)

Standardization of an antihemorrhagic potency test of antivenoms prepared from two different Agkistrodon halys venoms

To establish Korea National Standards for venoms and antivenoms, it is necessary to have standardized assay methods. In this study, we standardized a method to evaluate the antihemorrhagic potency of two horse-derived antivenoms using rabbit intracutaneous injection. We expressed the capability of these antivenoms to neutralize the hemorrhagic activities triggered by the venoms of Agkistrodon halys from Japan and Jiangzhe Agkistrodon halys from China as Minimum Hemorrhagic Dose (MHD). We also performed cross-neutralization tests employing the parallel line assay on different pairings of venoms and antivenoms to check the possibility of using Jiangzhe Agkistrodon halys venom as a substitute for the standard Agkistrodon halys venom in measurements of the antihemorrhagic activity, since A. halys venom is not easily available. Slope function ratio (S.R.) was 0.957 for Agkistrodon halys venom either with Agkistrodon halys antivenom or with Jiangzhe Agkistrodon halys antivenom (p>0.05). Similarly, S.R. was 0.348 for Jiangzhe Agkistrodon halys venom either with Agkistrodon halys antivenom or with Jiangzhe Agkistrodon halys antivenom (p>0.05). Thus, in this study we established antihemorrhagic potency test methods for both Agkistrodon halys and Jiangzhe Agkistrodon halys antivenoms and we could also show it is possible to use Jiangzhe Agkistrodon halys venom as a standard.

Increasing prevalence of antimicrobial resistance among organisms isolated from blood culture in a Singapore hospital.

The blood culture isolates obtained over the period 1985-1990 in a general teaching hospital were reviewed to determine trends in the prevalence of resistance to antimicrobial drugs. The percentages of Staphylococcus aureus isolates resistant to methicillin increased each year. Resistance among coagulase negative staphylococci also increased in prevalence: by 1990 approximately 50% of such isolates were resistant to methicillin, erythromycin, co-trimoxazole and gentamicin, 24% were resistant to clindamycin, 20% to fucidic acid but only 0.5% to vancomycin. Isolates of Enterobacteriaceae, excluding community-acquired salmonellae, showed increasing prevalence of resistance to beta-lactams, as did Acinetobacter spp isolates to gentamicin, co-trimoxazole and ceftriaxone. The isolates of Pseudomonas aeruginosa were exceptional, having no evident increase in the prevalence of resistance during the period. The rapid increases observed in relation to the other pathogens indicate the need for an antibiotic policy based on continuous surveillance of susceptibility patterns in the hospital.

Clinical Report of 46 Intracranial Tumors with LINAC Based Stereotactic Radiosurgery / 대한치료방사선과학회지

Between July 1988 and December 1992, we treated 45 patients who had deep seated inoperable or residual and/or recurrent intracranial tumors using LINAC based stereotactic radiosurgery at the Department of Therapeutic Radiology, Kangnam St. Mary's Hospital, Catholic University Medical College. Treated intracranial tumors included pituitary tumors(n=15), acoustic neurinomas(n=8), meningiomas(n=7), gliomas(n=6), craniopharyngiomas(n=4), pinealomas(n=3), hemangioblastomas(n=2), and solitary metastatic tumor from lung cancer (n=1). The dimension of treatment field varied from 0.23 to 42.88 cm3(mean ; 7.26 cm3). The maximum tumor doses ranging from 5 to 35.5 Gy (mean; 29.9 Gy) were given, and depended on patients' age, target volume, location of lesion and previous history of irradiation. There were 22 male and 23 female patients. The age was varied from 5 to 74 years of age(a median age; 43 years). The mean duration of follow-up was 35 months (2~55 months). To date, 18(35.1%) of 46 intracranial tumors treated with SRS showed absent or decrease of the tumor by serial follow-up CT and/or MRI and 16(34.8%) were stationary, e.g. growth arrest. From the view point of the clinical aspects, 34(73.9%) of 46 tumors were considered improved status, that is, alive with no evidence of active tumor and 8(17.4%) of them were stable, alive with disease but no deterioration as compared with before SRS. Although there showed slight increase of the tumor in size according to follow-up imagings of 4 cases(pituitary tumor 1, acoustic neurinomas 2, pinealoma 1), they still represented clinically stable status. Clinically, two(4.4%) patients who were anaplastic astrocytoma(n=1) and metastatic brain tumor(n=1) were worsened following SRS treatment. So far, no serious complications were found after treatment. The minor degree headache which could be relieved by steroid or analgesics and transient focal hair loss were observed in a few cases. There should be meticulous long term follow-up in all cases.