p53 protein overexpression and allele loss of p53 gene in gastric adenocarcinoma.

Gene alterations of p53 tumor suppressor gene such as point mutations, deletions or insertions occur in various human cancers. p53 protein overexpression was studied immunohistochemically in 80 gastric adenocarcinomas using an anti-human p53 antibody (Pab 1801) and the avidin-biotin-peroxidase technique. We have also analyzed allele loss of the human p53 gene in 54 cases of gastric adenocarcinoma using polymerase chain reaction and restriction fragment length polymorphism. p53 immunostaining was also demonstrated in 48 of 80 carcinomas (60%). Normal mucosa was always negative. No relation could be found between p53 immunostaining and the degree of differentiation. 21 of the 54 patients(39%) were informative for the p53 exon 4. In ten of these informative cases(47.6%), tumor DNAs showed allele loss when compared with nonmetastatic lymph node DNAs. Seven of the ten(70%) showed p53 immunoreactivity. These findings suggest that mutations of the p53 gene may play a role in the development of gastric adenocarcinoma and that allele loss of p53 frequently occurs in p53 immunoreactive gastric adenocarcinoma.     

Association between Second-hand Smoke Exposure and Urinary NNAL Level in Korean Adolescents

BackgroundThe 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanol (NNAL) is a metabolite of tobacco-specific lung carcinogen that can be found in both smokers and non-smokers. Particularly, NNAL levels of children with a history of exposure to second-hand smoke (SHS) are higher than those of adults. Thus, we aimed to investigate the association between SHS exposure and urine NNAL levels in Korean adolescents.MethodsThis cross-sectional study used data from the Korea National Health and Nutrition Examination Survey VII. Overall, 648 never-smoking adolescents (425 boys and 223 girls) aged 12 to 18 were included in this study. Logistic regression analyses identified the relationship between SHS exposure and elevated urine NNAL levels.ResultsThe mean urine NNAL levels of the no exposure and exposure group in boys were 1.39 and 2.26 ng/mL, respectively, whereas they were 1.01 and 2.45 ng/mL in girls, respectively (P < 0.001). Among the adolescents exposed to SHS, the confounder-adjusted odds ratio (95% confidence intervals) for elevated urine NNAL levels according to exposure area as overall, home, and public area were 2.68 (1.58–4.53), 31.02 (9.46–101.74), and 1.89 (1.12–3.17) in boys; and 6.50 (3.22–13.11), 20.09 (7.08–57.04), and 3.94 (1.98–7.77) in girls, respectively.ConclusionSHS exposure was significantly associated with elevated urine NNAL levels in Korean adolescents, particularly in female adolescents and in those with home exposure. These findings remind us of the need to protect adolescents from SHS.     

Transduced PEP-1-FK506BP ameliorates atopic dermatitis in NC/Nga mice

Immunophilin, FK506-binding protein 12 (FK506BP), is a receptor protein for the immunosuppressive drug FK506 by the FK506BP/FK506 complex. However, the precise function of FK506BP in inflammatory diseases remains unclear. Therefore, we examined the protective effects of FK506BP on atopic dermatitis (AD) in tumor necrosis factor-α (TNF-α)/interferon-γ (IFN-γ)-induced HaCaT cells and 2,4-dinitrofluorobenzene-induced AD-like dermatitis in Nishiki-nezumi Cinnamon/Nagoya (NC/Nga) mice using a cell-permeable PEP-1-FK506BP. Transduced PEP-1-FK506BP significantly inhibited the expression of cytokines, as well as the activation of NF-κB and mitogen-activated protein kinase (MAPK) in TNF-α/IFN-γ-induced HaCaT cells. Furthermore, topical application of PEP-1-FK506BP to NC/Nga mice markedly inhibited AD-like dermatitis as determined by a histological examination and assessment of serum IgE levels, as well as cytokines and chemokines. These results indicate that PEP-1-FK506BP inhibits NF-κB and MAPK activation in cells and AD-like skin lesions by reducing the expression levels of cytokines and chemokines, thus suggesting that PEP-1-FK506BP may be a potential therapeutic agent for AD.     

Concentration-dependent effects of muscimol to enhance pulsatile GnRH release from GT1–7 neurons in vitro

Immortalized GT1–7 neurons were used to characterize the effect of muscimol, a GABA_A receptor agonist, to enhance pulsatile gonadotropin-releasing hormone (GnRH) release. GT1–7 neurons were grown on Cytodex-3 beads and placed in special superfusion microchambers. The cells were superfused at a rate of 6.2 ml·h⁻¹ with Media 199 (pH 7.35) using a commercially available perfusion system. After a pre-muscimol period of 120 min, the cells were exposed for 5 min to 0.35, 1, 5 or 10 μM muscimol or 5 μM muscimol+20 μM of the GABA_A receptor antagonist, bicuculline. Following removal of the muscimol (and bicuculline, in the case of the latter experiment), the superfusion was continued for another 115 min. Sample fractions were collected at 5 min intervals throughout the perfusion. Basal GnRH release from the GT1–7 neurons was pulsatile with an average interpulse interval of 45.4±0.5 min and an average pulse amplitude of 191.5±22.6 pg·min·ml⁻¹. Our results also demonstrated that the GABA_A receptor agonist, muscimol, enhances pulsatile GnRH release from GT1–7 neurons in culture. The response to muscimol was saturable and concentration-dependent with an EC₅₀ of 0.47 μM. The effects of 5 μM muscimol to increase GnRH pulsatility were blocked by co-exposure to the GABA_A receptor antagonist, bicuculline. The average GnRH interpulse intervals were 41.7±1.8 min, 32.5±2.9 min, 30.6±0.7 min and 25.5±0.4 min in the period following exposure to 0.35, 1, 5 and 10 μM of muscimol, respectively (post-muscimol period). GnRH pulse amplitude (mean-area for each pulse) was increased during exposure to muscimol but not during the pre- or post-muscimol periods. The GABA_A receptor antagonist, bicuculline, itself had no effect on pulsatile GnRH release. These results are consistent with previously published reports suggesting that activation of the GABA_A receptor stimulates hypothalamic GnRH release in embryonic and neonatal animals.     

Progesterone increases mRNA levels of pituitary adenylate cyclase-activating polypeptide (PACAP) and type I PACAP receptor (PAC(1)) in the rat hypothalamus

Pituitary adenylate cyclase-activating polypeptide (PACAP) regulates pituitary hormone biosynthesis and secretion through its cognate receptors. PACAP also plays an important role in the regulation of ovarian steroid biosynthesis. If so, there might be a feedback regulation of hypothalamic PACAP synthesis by the pituitary and by ovarian steroids. In the present study, we used RNase protection assays to determine changes in mRNA levels of PACAP and type I PACAP receptor (PAC(1)) under the conditions of ovariectomy and replacement with ovarian steroids. Progesterone (P) alone or in combination with estradiol (E) induced significant increases in PACAP mRNA level in the medial basal hypothalamus (MBH) and PAC(1) mRNA levels in MBH and the preoptic area (POA). This finding suggests that feedback regulation takes place between the ovary and hypothalamic PACAP neurons. P is known to be a major regulatory feedback factor for hypothalamic luteinizing hormone-releasing hormone (LHRH) neurons, but P receptor is not present in these neurons. Therefore, we examined a possible involvement of PACAP in the feedback regulatory pathway of P to LHRH neurons. After an antisense PAC(1) oligodeoxynucleotide (ODN) was i.c.v.-injected into the third ventricle of E and P-treated rats, LHRH mRNA levels were determined. The ODN markedly decreased the P-induced increase in the LHRH mRNA level. Taken together, the present data suggest that PACAP may play a role as a mediator in the regulation of LHRH synthetic machinery by stimulatory feedback of P.     

Added Value of Arterial Spin-Labeling MR Imaging for the Differentiation of Cerebellar Hemangioblastoma from Metastasis

BACKGROUND AND PURPOSE:In adults with only cerebellar masses, hemangioblastoma and metastasis are the 2 most important differential diagnoses. Our aim was to investigate the added value of arterial spin-labeling MR imaging for differentiating hemangioblastoma from metastasis in patients with only cerebellar masses.MATERIALS AND METHODS:This retrospective study included a homogeneous cohort comprising patients with only cerebellar masses, including 16 hemangioblastomas and 14 metastases. All patients underwent enhanced MR imaging, including arterial spin-labeling. First, the presence or absence of a hyperperfused mass was determined. Next, in the hyperperfused mass, relative tumor blood flow (mean blood flow in the tumor divided by blood flow measured in normal-appearing cerebellar tissue) and the size ratio (size in the arterial spin-labeling images divided by size in the postcontrast T1WI) were measured. To validate the arterial spin-labeling findings, 2 observers independently evaluated the conventional MR images and the combined set of arterial spin-labeling images.RESULTS:All patients with hemangioblastomas and half of the patients with metastases presented with a hyperperfused mass (P < .001). The size ratio and relative tumor blood flow were significantly larger for hemangioblastomas than for metastases (P < .001 and P = .039, respectively). The size ratio revealed excellent diagnostic power (area under the curve = 0.991), and the relative tumor blood flow demonstrated moderate diagnostic power (area under the curve = 0.777). The diagnostic accuracy of both observers was significantly improved after the addition of arterial spin-labeling; the area under the curve improved from 0.574 to 0.969 (P < .001) for observer 2 and from 0.683 to 1 (P < .001) for observer 2.CONCLUSIONS:Arterial spin-labeling imaging can aid in distinguishing hemangioblastoma from metastasis in patients with only cerebellar masses.

Hemangioblastoma and metastasis are the 2 most important differential diagnoses of cerebellar masses in adults. Hemangioblastomas are benign tumors of vascular origin and are the second most common infratentorial parenchymal tumor, accounting for 7% of posterior fossa tumors in adults.¹ Metastases are the most common type of brain tumor, and posterior fossa metastases represent approximately 8.7%–10.9% of all brain metastases.^2,3 Discriminating between hemangioblastoma and brain metastasis is important because their therapeutic approaches and prognoses are quite different. The standard treatment for hemangioblastoma is complete surgical resection. However, patients with a brain metastasis usually undergo surgery, stereotactic surgery, whole-brain radiation therapy, chemotherapy, or a combination of these. Furthermore, hemangioblastomas are associated with longer patient survival times,⁴ whereas brain metastases are associated with a poor prognosis.⁵ Because the frequency of metastasis increases with time, patient age is often helpful in distinguishing between these tumors but is not always reliable. In addition, although one-third of patients with cerebellar hemangioblastomas also have von Hippel-Lindau disease,⁶ a clinical history of von Hippel-Lindau disease may not be available at the time of initial presentation.Hemangioblastoma is characterized by markedly increased vascularity⁷; therefore, angiographically dense tumor staining may suggest hemangioblastoma rather than metastasis.⁸ However, cerebral angiography is invasive and involves risks of complications, such as stroke. MR perfusion imaging can provide useful information about vascularization in hemangioblastoma. Previous studies using dynamic susceptibility contrast and dynamic contrast-enhanced MR perfusion imaging have reported increased vascular perfusion in hemangioblastomas.^9,10Arterial spin-labeling (ASL), unlike DSC and dynamic contrast-enhanced perfusion imaging, is a noninvasive MR perfusion technique that uses electromagnetic endogenous arterial water as a freely diffusible tracer instead of an exogenous MR imaging contrast agent. The utility of ASL perfusion imaging in the evaluation of the vascularity of brain tumors has been explored in several recent studies.^11–14 One prior study differentiated hemangioblastomas from metastases on the basis of quantitative blood flow measurements using ASL.¹⁵ The authors reported that tumor blood flow was significantly higher in hemangioblastomas than in metastases. However, their study included a limited number of patients and examined metastatic tumors located primarily in the supratentorial region. Because metastasis usually presents with multiple enhancing supratentorial and infratentorial masses and 90%–95% of hemangioblastomas are in the posterior fossa, it is difficult to differentiate hemangioblastoma from metastasis in patients with only cerebellar masses in daily clinical practice.Therefore, the aim of this study was to determine whether the addition of ASL imaging is useful for differentiating hemangioblastoma from metastasis in a homogeneous cohort of patients with only cerebellar masses and to validate the findings by investigating observer performance.     

短暂脑缺血再灌流后ATP含量变化与细胞凋亡的关系

目的:探讨短暂脑缺血再灌流后能量的动态变化及其与细胞凋亡之间的关系。方法:采用线栓法建立大鼠大脑中动脉闭塞(MCAO)模型,缺血10min后于再灌流后0h、1h、3h、6h、12h、24h和72h应用毛细血管电泳法分别测定额顶叶皮质的ATP含量,同时采用荧光显微镜、流式细胞仪和脱氧核苷酸末端转移酶介导的缺口末端标记法(TUNEL)检测细胞凋亡情况,分析两者之间的关系。结果:缺血10min后额顶叶皮质ATP的含量急剧下降至对照组的20%。再灌流后ATP的含量逐渐恢复,于再灌流后1h、3h、6h和12h恢复至对照组的70.5%、65.7%、84.8%和86.9%。再灌流后24hATP含量再次下降,再灌流后24h和72hATP含量仅为对照组的50%,与对照组相比差异有统计学意义(P<0.01和0.05)。缺血10min再灌流24h额顶叶皮质开始出现细胞凋亡现象,并随着时间延长凋亡细胞数目逐渐增加。结论:短暂脑缺血再灌流后大鼠额顶叶皮质存在细胞能量系统功能恢复滞后的现象和继发性细胞能量系统功能衰竭的现象,其中继发性细胞能量系统功能衰竭现象与细胞凋亡之间可能存在互为因果的关系。