Comparison of cytopathic changes in oral hairy leukoplakia with in situ hybridization for EBV DNA

OBJECTIVE: It has been observed that the cytopathic changes in hairy leukoplakia (HL) correlate with ultra-structural evidence of intra-keratinocyte herpes-type viral particles. In situ hybridization is considered to be the definitive confirmation of Epstein-Barr virus (EBV)-induced HL. This study evaluated the consistency of histopathological findings, which many believe to be diagnostic, with in situ hybridization for EBV-DNA in 60 patients with lesions clinically suggestive of HL.
MATERIALS AND METHODS: Hematoxylin and eosin (H&E)-stained sections were reviewed independently by three oral pathologists who did not know the hybridization results. The presence in keratinocytes of nuclear inclusions and/or homogenization, believed to be specific for EBV in these lesions, was used as an indicator for infection. Cytoplasmic changes were evaluated separately.
RESULTS: With in situ hybridization, 48 cases were positive and 12 were negative. When the two methods were compared, pathologist concurrence ranged from 83% to 92%. False negatives ranged from 6% to 19%, and false positives ranged from 8% to 25%. Cytoplasmic ballooning, homogenization, and perinuclear clearing were evident in all cases of hybridization-confirmed HL; however, these changes were also noted in 75% (9/12) of the cases with negative hybridization results. Most confirmed HL cases exhibited both nuclear homogenization and inclusions, although the former was more consistently seen.
CONCLUSION: Cytoplasmic changes did not agree well with EBV-DNA hybridization results, whereas nuclear changes demonstrated good, but not complete, agreement. In appropriate clinical settings, the finding of nuclear inclusions and/or homogenization may be of diagnostic value. However, because the potential for false positives and negatives is high, H&E cytopathology should not be used as a substitute for in situ hybridization in the definitive diagnosis of oral hairy leukoplakia.     

微小染色体维持蛋白与肿瘤的研究进展

微小染色体维持(MCM)蛋白家族是一类从太古代生物到高等真核生物广泛存在的高度保守的蛋白质。MCM蛋白与其他相关因子相互影响,共同在DNA复制、延长、转录及修复过程中发挥作用。MCM蛋白在细胞周期中异常高表达意味着细胞非典型增生甚至肿瘤的发生,提示MCM蛋白可作为增殖细胞的特殊标志物,在肿瘤的诊断、预后评价、临床治疗等方面具有广泛的应用前景。     

Alzheimer's β-Secretase (BACE1) Regulates the cAMP/PKA/CREB Pathway Independently of β-Amyloid

β-Amyloid protein (Aβ), the major component of neuritic plaques in Alzheimer's disease (AD), is derived from proteolytic cleavages of the amyloid precursor protein (APP) by β-site APP-cleaving enzyme 1 (BACE1) and the γ-secretase complex. BACE1 is the rate-limiting enzyme for Aβ production, and an increase in BACE1 level/activity contributes to the pathogenesis of sporadic AD. In addition to cleaving APP for Aβ generation, BACE1 plays multiple physiological roles including the regulation of synaptic functions. Here, we found that overexpression of BACE1 reduces cAMP response element binding protein (CREB) phosphorylation, protein kinase A (PKA) activity, and cAMP levels, whereas downregulation of BACE1 has the opposite effect. We showed that BACE1's effect is independent of its activity for Aβ production, which is corroborated by the observation that BACE1 transgenic mice have impaired learning/memory in the absence of neurotoxic human Aβ. Furthermore, we demonstrated that BACE1 interacts via its transmembrane domain with adenylate cyclase, resulting in reduction of cellular cAMP levels and thus PKA inactivation and reduced CREB phosphorylation. Our study suggests that in addition to its function as the β-secretase to produce Aβ, BACE1 may contribute to the memory and cognitive deficits typical of AD by regulating the cAMP/PKA/CREB pathway, which is important for memory functions.     

多媒体技术在医学影像教学实践中的应用

医学影像学是一门实践性很强的形象思维学科,如何合理应用多媒体技术手段开展现代医学影像学教学,本文就多媒体技术与传统板书教学的有机结合进行了有益的探讨。强调做好现代多媒体技术手段教学与传统教学的重要性是医学影像学教学一个值得重视和思考的问题。     

Anti-Abeta42- and anti-Abeta40-specific mAbs attenuate amyloid deposition in an Alzheimer disease mouse model

Accumulation and aggregation of amyloid β peptide 1–42 (Aβ₄₂) in the brain has been hypothesized as triggering a pathological cascade that causes Alzheimer disease (AD). To determine whether selective targeting of Aβ₄₂ versus Aβ₄₀ or total Aβ is an effective way to prevent or treat AD, we compared the effects of passive immunization with an anti-Aβ₄₂ mAb, an anti-Aβ₄₀ mAb, and multiple Aβ_1–16 mAbs. We established in vivo binding selectivity of the anti-Aβ₄₂ and anti-Aβ₄₀ mAbs using novel TgBRI-Aβ mice. We then conducted a prevention study in which the anti-Aβ mAbs were administered to young Tg2576 mice, which have no significant Aβ deposition, and therapeutic studies in which mAbs were administered to Tg2576 or CRND8 mice with modest levels of preexisting Aβ deposits. Anti-Aβ₄₂, anti-Aβ₄₀, and anti-Aβ_1–16 mAbs attenuated plaque deposition in the prevention study. In contrast, anti-Aβ₄₂ and anti-Aβ₄₀ mAbs were less effective in attenuating Aβ deposition in the therapeutic studies and were not effective in clearing diffuse plaques following direct injection into the cortex. These data suggest that selective targeting of Aβ₄₂ or Aβ₄₀ may be an effective strategy to prevent amyloid deposition, but may have limited benefit in a therapeutic setting.     

Identification and characterization of a high-affinity granulocyte- macrophage colony-stimulating factor receptor on primary rat oligodendrocytes

We previously showed the presence of receptors for granulocyte- macrophage colony-stimulating factor (GM-CSF) on tumor tissues and tumor cell lines that are derived from the neural crest. To determine whether normal neural cells express functional GM-CSF receptors, we isolated and analyzed primary rat brain cells, including microglia, astrocytes, and oligodendrocytes. Scatchard analysis of equilibrium binding of 125I-GM-CSF to primary rat oligodendrocytes showed an average of 1,110 GM-CSF binding sites per cell, with a kd of 20 pmol/L. In six separate experiments, no specific binding was detectable on the astrocyte population. Microglia were used in competitive binding experiments with oligodendrocytes, and addition of microglia did not increase the specific binding of labeled ligand to oligodendrocytes. In dose-response assays, we measured 3H-thymidine uptake in rat oligodendrocytes, microglia and control murine 32D cells stimulated with various concentrations of GM-CSF. Over concentration ranges of 0.025 to 1000 pmol/L, cell proliferation and peak 3H-thymidine incorporation was observed at approximately 30 pmol/L for both the control cells and the oligodendrocytes. However, the microglial cells did not proliferate in response to GM-CSF. These data indicate the presence of a functional receptor for GM-CSF on primary rat oligodendrocytes, and suggest that hematopoietic growth factors such as GM-CSF may play a role in nerve cell development, function, or response to injury.     

Therapy for neutropenia in hairy cell leukemia with recombinant human granulocyte colony-stimulating factor

STUDY OBJECTIVE: To determine whether recombinant human granulocyte colony-stimulating factor (G-CSF) is effective in increasing neutrophil counts in patients with hairy cell leukemia and neutropenia. DESIGN: Open label, phase I/II study of G-CSF, given by daily subcutaneous injection for up to 7 weeks. SETTING: Outpatient oncology clinic of a university medical center. PATIENTS: A consecutive sample of four patients with hairy cell leukemia complicated by severe neutropenia. Three patients completed the study; one patient was removed after 2 weeks of therapy. INTERVENTIONS: Granulocyte colony-stimulating factor was given by daily subcutaneous injection. Each patient began therapy with 1 microgram/kg body weight.d; after 1 week the dose was increased to 3 micrograms/kg.d, and 1 week later to 6 micrograms/kg.d. Therapy was continued for 5 to 6 weeks. Patients were taught self-injection, and administered treatment at home. MEASUREMENTS and MAIN RESULTS: In three patients, an increase in absolute neutrophil counts from less than 0.9 X 10(9)/L to greater than 4.0 X 10(9)/L was noted within 2 weeks of beginning G-CSF therapy. In two patients, infections resolved during therapy. One patient developed acute neutrophilic dermatosis (the Sweet syndrome) while receiving 3 micrograms/kg.d of G-CSF, and drug therapy was discontinued. CONCLUSIONS: Granulocyte colony-stimulating factor may increase neutrophil counts within 2 weeks in patients with hairy cell leukemia and neutropenia. This therapy may be a useful adjunct to definitive treatment of hairy cell leukemia with interferon or pentostatin.