Pemphigus vulgaris identifies plakoglobin as key suppressor of c-Myc in the skin

The autoimmune disease pemphigus vulgaris (PV) manifests as loss of keratinocyte cohesion triggered by autoantibody binding to desmoglein (Dsg)3, an intercellular adhesion molecule of mucous membranes, epidermis, and epidermal stem cells. Here we describe a so far unknown signaling cascade activated by PV antibodies. It extends from a transient enhanced turn over of cell surface-exposed, nonkeratin-anchored Dsg3 and associated plakoglobin (PG), through to depletion of nuclear PG, and as one of the consequences, abrogation of PG-mediated c-Myc suppression. In PV patients (6/6), this results in pathogenic c-Myc overexpression in all targeted tissues, including the stem cell compartments. In summary, these results show that PV antibodies act via PG to abolish the c-Myc suppression required for both maintenance of epidermal stem cells in their niche and controlled differentiation along the epidermal lineage. Besides a completely novel insight into PV pathogenesis, these data identify PG as a potent modulator of epithelial homeostasis via its role as a key suppressor of c-Myc.     

X线、CT、SPECT、PET在评估小鼠的骨成像中的作用

目的利用各种影像诊断设备对正常小鼠的骨进行成像,观察其在小鼠骨成像中最佳成像参数。方法分别使用X线、CT、SPECT、PET对小鼠的骨进行拍摄成像。结果X线和CT均可以清楚地对小鼠的骨组织成像,而SPECT、PET由于其分辨率和特异性不高,成像较模糊。结论X线和CT检查对小鼠的骨成像明显,对小鼠疾病的观察有重要意义。而SPECT、PET对诊断小鼠的骨疾病意义不是很大。     

Combined genotoxic effects of radiation and a tobacco-specific nitrosamine in the lung of gpt delta transgenic mice

It is important to evaluate the health effects of low-dose-rate or low-dose radiation in combination with chemicals as humans are exposed to a variety of chemical agents. Here, we examined combined genotoxic effects of low-dose-rate radiation and 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanone (NNK), the most carcinogenic tobacco-specific nitrosamine, in the lung of gpt delta transgenic mice. In this mouse model, base substitutions and deletions can be separately analyzed by gpt and Spi- selections, respectively. Female gpt delta mice were either treated with gamma-irradiation alone at a dose rate of 0.5, 1.0 or 1.5 mGy/h for 22 h/day for 31 days or combined with NNK treatments at a dose of 2 mg/mouse/day, i.p. for four consecutive days in the middle course of irradiation. In the gpt selection, the NNK treatments enhanced the mutation frequencies (MFs) significantly, but no obvious combined effects of gamma-irradiation were observable at any given radiation dose. In contrast, NNK treatments appeared to suppress the Spi- large deletions. In the Spi- selection, the MFs of deletions more than 1 kb in size increased in a dose-dependent manner. When NNK treatments were combined, the dose-response curve became bell-shaped where the MF at the highest radiation dose decreased substantially. These results suggest that NNK treatments may elicit an adaptive response that eliminates cells bearing radiation-induced double-strand breaks in DNA. Possible mechanisms underlying the combined genotoxicity of radiation and NNK are discussed, and the importance of evaluation of combined genotoxicity of more than one agent is emphasized.     

Genome scan identifies a locus affecting gamma-globin level in human beta-cluster YAC transgenic mice

Genetic factors affecting postnatal γ-globin expression—a major modifier of the severity of both β-thalassemia and sickle cell anemia—have been difficult to study. This is especially so in mice, an organism lacking a globin gene with an expression pattern equivalent to that of human γ-globin. To model the human β-cluster in mice, with the goal of screening for loci affecting human γ-globin expression in vivo, we introduced a human β-globin cluster YAC transgene into the genome of FVB/N mice. The β-cluster contained a Greek hereditary persistence of fetal hemoglobin (HPFH) γ allele, resulting in postnatal expression of human γ-globin in transgenic mice. The level of human γ-globin for various F₁ hybrids derived from crosses between the FVB/N transgenics and other inbred mouse strains was assessed. The γ-globin level of the (C3HeB/FeJ × FVB/N)F₁ transgenic mice was noted to be significantly elevated. To map genes affecting postnatal γ-globin expression, we performed a 20-centiMorgan (cM) genome scan of a (C3HeB/FeJ × FVB/N)F₁ transgenics × FVB/N backcross, followed by high-resolution marker analysis of promising loci. From this analysis we mapped a locus within an 18-cM interval of mouse Chromosome (Chr) 1 (LOD = 4.3) that contributes 10.9% of variation in γ-globin level. Combining transgenic modeling of the human β-globin gene cluster with quantitative trait analysis, we have identified and mapped a murine locus that impacts on human γ-globin level in vivo. Received: 26 January, 2000 / Accepted: 2 May 2000     

Use of transgenic mice as models for prostate cancer chemoprevention

Prostate cancer is a long latency type of tumor that usually develops in men older than 50 years of age. Prostate epithelial neoplasia (PIN), the initial malignant lesion, progresses to invasive carcinoma over the course of years. Because of the particular features of prostate carcinogenesis, this type of tumor may represent a paradigm for cancer prevention. Several clinical trials have evaluated the effect of different compounds on prostate tumor development, including finasteride, selenium, vitamin E, and carotenes. Although some results are promising, no conclusive data have been achieved as to recommend any of these compounds as preventive agents. Results from some trials, such as SELECT, where supplementation of selenium and/or vitamin-E was used, have been rather disappointing. However, many novel chemopreventive agents that target different cancer-related pathways are being developed lately. Appropriate animal models (in particular, genetically modified mice) are being used to assess the efficacy of these novel compounds. The transgenic adenocarcinoma of the mouse prostate (TRAMP) model has been validated as an accurate model to test a variety of preventive agents. Genistein, alpha-difluoromethylornithine, toremifene, R-flurbiprofen, celecoxib, and green tea polyphenols have been shown to prevent prostate cancer development in TRAMP mice. In conclusion, new chemopreventive compounds which are effective in animal models are likely to be tested soon in clinical trials, with the final goal of reducing prostate cancer incidence in men.     

早期肺癌诊断中PET/CT的应用价值

目的:探讨PET/CT在早期肺癌诊断中的应用价值.方法:应用PET/CT对16例肺部孤立性病灶进行PET/CT检查,手术切除病灶组织送病理检查,以判断诊断符合率与细胞类型.结果:16例肺病灶患者PET/CT检查与手术切除组织病理结果相比较,诊断符合率为87.5%,其中腺癌13例(包括细支气管肺泡细胞癌6例),鳞癌2例,肺粘膜相关B细胞淋巴瘤1例.结论:结合临床症状,PET/CT检查能够准确的对肺癌做出早期诊断,及早治疗,改善患者预后     

Improved calcium imaging in transgenic mice expressing a troponin C-based biosensor

Fluorescent Ca(2+) indicator proteins (FCIPs) are attractive tools for studying Ca(2+) dynamics in live cells. Here we describe transgenic mouse lines expressing a troponin C (TnC)-based biosensor. The biosensor is widely expressed in neurons and has improved Ca(2+) sensitivity both in vitro and in vivo. This allows FCIP-based two-photon Ca(2+) imaging of distinct neurons and their dendrites in vivo, and opens a new avenue for structure-function analysis of intact neuronal circuits.     

Green fluorescent protein as a marker in transgenic mice

Green fluorescent protein (GFP) found in Aequorea victoria absorbs blue light and emits green fluorescence without exogenous substrates or co-factors. We studied the possibility of using the GFP as a marker in mammals. Transgenic mice were produced using the GFP coding sequence, ligated with the chicken beta-actin promoter. Green fluorescence was observed in muscle, pancreas, kidney, heart and other organs in all the three transgenic mouse lines. Detection of the transgenic mouse was possible by observing a tail or fingers of new born pups under a fluorescent microscope. The marker also enabled us to detect localized expression of the transgene in intact tissues without preliminary steps. It was also demonstrated that the GFP expression could be quantified by measuring the fluorescence in tissue extracts.     

Dual-time-point PET/CT study protocol can improve the larynx cancer diagnosis

AimTo evaluate whether the sequential dual-time-point fluorine-18-fluorodeoxyglucose positron emission tomography/computed tomography (DTP 18F-FDG PET/CT) study improves the differential diagnosis in the larynx.BackgroundIn some cases, the clinical and metabolic similarity of laryngitis and larynx cancer make differential diagnostics difficult when performing standard 18F-FDG PET/CT examinations; therefore, an additional study protocol performance seems to be of reasonable value.Materials and methods90 patients (mean age: 61 ± 11 years, range: 41–84 years): 23 women (mean age: 63 ± 10 years, range: 51–84 years) and 67 men (mean age: 61 ± 11 years, range: 41–80 years) underwent delayed 18F-FDG PET/CT examinations at 60 and 90 min post intravenous injection (p.i.) of the radiopharmaceutical 18F-FDG. We compared the metabolic activity of 90 structures divided into following groups: normal larynx (30 patients), laryngitis (30 lesions) and larynx cancer (30 tumors) with maximal and mean standardized uptake value (SUVmax, SUVmean) and the retention index (RI-SUVmax). We used the receiver operating characteristics (ROC) curve to evaluate the SUVmax cut-off values.ResultsThe SUVmax cut-off value at 60 and 90 min p.i. of 2.3 (sensitivity/specificity: 96.4%/100%) and 2.4 (94.2%/100%), respectively, distinguished normal and abnormal metabolic activity in the larynx. When laryngitis and tumors were compared, the SUVmax cut-off values obtained after initial and delayed imaging were 3.6 (87.5%/52.0%) and 6.1 (58.3%/84%), respectively. The RI-SUVmax of 1.3% (71.4%/88.1%) suggested abnormality, while RI-SUVmax of 6.6%, malignant etiology (75.0%/80.0%).ConclusionsIn this study, the sequential DTP scanning protocol improved the sensitivity and specificity of the PET/CT method in terms of differential diagnosis within the larynx.     

MAGE-C2/CT10 promotes growth and metastasis through upregulating c-Myc expression in prostate cancer

Molecular and Cellular Biochemistry - Prostate cancer (PC) is the most common reproductive cancer in men and the third leading cause of cancer death among men worldwide. Recently targeted therapy...     

Relative efficacy of short-term tests in detecting genotoxic effects of cadmium chloride in mice in vivo

The ability of intraperitoneally administered cadmium chloride (0.42-6.75 mg/kg) to induce genotoxic damage in somatic and germ cells of mice was evaluated using chromosomal aberrations, sister-chromatid exchanges (SCE), micronuclei and sperm-head abnormalities as end-points. A significant increase in the frequency of chromosomal aberrations and SCEs was observed in almost all treated series when compared to the negative control. Micronucleus formation in polychromatic erythrocytes was not affected significantly except at the highest concentration used (6.75 mg/kg). Significant differences were observed in the frequency of sperm with abnormal head morphology at all concentrations tested except the lowest one. The clastogenic effects of cadmium chloride in both somatic and germinal cells are found to depend directly on the concentrations used.     

Radiation dosimetry of 18F-flurocholine PET/CT studies in prostate cancer patients

PurposeWe aimed to evaluate the Equivalent Doses (H_Ts) to highly exposed organs as well as the Effective Dose (ED) for ¹⁸F-fluorocholine PET/CT scan in the follow-up of prostate cancer patients.MethodsFifty patients were administered with ¹⁸F-fluorocholine. The activities in organs with the highest uptake were derived by region-of-interest (ROI) analysis. OLINDA/EXM1.0 and Impact software were used to assess ED for the administered ¹⁸F-fluorocholine and CT scan, respectively, and the ¹⁸F-fluorocholine and CT-scan EDs summed to yield the total ED for the PET/CT procedure.ResultsThe calculated ¹⁸F-fluorocholine and CT scans EDs based on ICRP Publication 103 were 5.2 mSv/300 MBq and 6.7 mSv, respectively. The ¹⁸F-fluorocholine H_Ts to the liver, kidneys, spleen and pancreas were about threefold higher than those from the CT, which contributed a greater proportion of the total ED than the ¹⁸F-fluorocholine did.ConclusionsFor ¹⁸F-fluorocholine PET/CT procedures, about 40% of the ED is contributed by administered ¹⁸F-fluorocholine and 60% by the CT scan. The kidneys and liver were the highly exposed organs. Considering the large number of diagnostic procedures oncology patients undergo, radiation dosimetry is important in relation to the stochastic risk of such procedures.     

The use of transgenic mice for short-term,in vivo mutagenicity testing

In order to develop a short-term, in vivo assay to study the mutagenic effects of chemical exposure, transgenic mice were generated using a lambda shuttle vector containing a lacZ target gene. Following exposure to mutagens, this target can be rescued efficiently from genomic DNA prepared from tissues of the treated mice using restriction minus, in vitro lambda phage packaging extract and restriction minus Escherichia coli plating cultures. Mutations in the target gene appear as colorless plaques on a background of blue plaques when plated on indicator agar. Spontaneous background levels were ′1 × 10⁻⁵ in each of three mouse lineages analyzed. Exposure of lambda transgenic mice to N-ethyl-N-nitrosourea resulted in as much as a 14-fold induction in detected mutations over background levels. The assay is currently being modified to incorporate lacI as the target for ease of mutation detection as well as in vivo excision properties of the Lambda ZAP vector, facilitating sequence analysis of mutant plaques.     

Combination of [68Ga]Ga-PSMA PET/CT and [18F]FDG PET/CT in demonstrating dedifferentiation in castration-resistant prostate cancer

Aim of the studyIn this study, we aimed to determine the factors affecting increased glucose metabolism, which is one of the dedifferentiation mechanisms, by using [¹⁸F]FDG and [⁶⁸Ga]Ga-PSMA PET/CT in patients with castration-resistant prostate cancer (CRPC).Materials and methodNinety-three patients with CRPC were included in the study. Gleason score (GS), and total PSA and free PSA levels of the patients were recorded. Patient- and organ-based evaluations were performed according to the lesion uptakes as follows: score 0: PSMA (-) FDG (-), score 1: PSMA (+) FDG (-), score 2: PSMA (+) FDG (+) (FDG < PSMA), score 3: PSMA (+) FDG (+) (FDG = PSMA), score 4: PSMA (+) FDG (+) (FDG > PSMA), and score 5: PSMA (-) FDG (+). scores 1 and 2 were classified as group 1, and scores 3 to 5 were classified as group 2.ResultsThe median age of our patients was 70 (51–88) years. Eighty-eight patients (94.6%) were PSMA-positive, 78 patients (83.8%) were FDG-positive, and 89 patients (95.6%) were or PSMA or FDG positive. When the two groups were compared in terms of patient-based parameters, the median age and GS were found to be significantly higher in group 2. ROC analyses revealed that age and GS were significant in predicting group 2.ConclusionSince glucose metabolism can increase in CRPC patients with advanced age and high GS, we recommend combining [¹⁸F]FDG PET/CT with [⁶⁸Ga]Ga-PSMA PET/CT in routine clinical practice in order to identify this patient subset and refer them to additional therapies.     

A cell permeable peptide analog as a potential-specific PET imaging probe for prostate cancer detection

Non-invasive detection of prostate cancer or metastases still remains a challenge in the field of molecular imaging. In our recent work of screening arginine- or lysine-rich peptides for intracellular delivery of a therapeutic agent into prostate cancer cells, an arginine-rich cell permeable peptide (NH₂GR₁₁) was found with an unexpectedly preferential uptake in prostate cancer cell lines. The goal of this work was to develop this peptide as a positron emission tomography (PET) imaging probe for specific detection of distant prostate cancer metastases. The optimal length of arginine-rich peptides was evaluated by the cell uptake efficiency of three fluorescein isothiocyanate (FITC)-tagged oligoarginines (NHGR₉, NHGR₁₁, and NHGR₁₃) in four human prostate cell lines (LNCaP, PZ-HPV-7, DU145, and PC3). Of the three oligoarginines, NH₂GR₁₁ showed the highest cell uptake and internalization efficiency with its subcellular localization in cytosol. The biodistribution of FITC-NHGR₉, FITC-NHGR₁₁, and FITC-NHGR₁₃ performed in control nude mice displayed the unique preferential accumulation of FITC-NHGR₁₁ in the prostate tissue. Further in vivo evaluation of FITC-NHGR₁₁ in PC3 tumor-bearing nude mice revealed elevated uptake of this peptide in tumors as compared to other organs. In vivo pharmacokinetics evaluated with ⁶⁴Cu-labeled NH₂GR₁₁ showed that the peptide was rapidly cleared from the blood (t _1/2 = 10.7 min) and its elimination half-life was 17.2 h. The PET imaging specificity of ⁶⁴Cu-labled NH₂GR₁₁ was demonstrated for the detection of prostate cancer in a comparative imaging experiment using two different human cancer xenograft models.