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Historically, forest thinning in Japan was conducted to obtain high-quality timber from plantations. Today, in contrast, thinning is also motivated by forest water balance and climate change considerations. It is in this context that the present study examines the effects of thinning on the ecophysiological responses of remaining trees, which are inadequately understood, especially in relation to changes in the magnitude and duration of transpiration. Sap flux densities were measured in both outer and inner sapwood to obtain stand-scale transpiration for two years in the pre-thinning state and three years post-thinning. The effects of thinning on transpiration were quantitatively evaluated based on canopy conductance models. The larger increases in outer sap flux density were found in the first year after the treatment, while those in inner sap flux density were detected in the second and third years. The remaining trees required a few of years to adjust to improved light conditions of the lower crown, resulting in a delayed response of inner sap flux density. As a result of this lag, transpiration was reduced to 71 % of the pre-thinning condition in the first year, but transpiration recovered to the pre-thinning levels in the second and third years due to compensating contributions from inner sap flow. In terms of more accurately chronicling the thinning effect, the distribution of sap flux density with respect to its radial pattern, is necessary. Such measurements are key to more comprehensively examining the ecophysiological response of forest plantations to thinning and, ultimately, its effect on the forest water balance.
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Cryptomeria , Cryptomeria/fisiologia , Transpiração Vegetal/fisiologia , Florestas , Árvores/fisiologia , ÁguaRESUMO
Quantitative analysis of binary mixtures of tris(2-phenylpyridinato)iridium(III) (Ir(ppy)3) and tris(8-hydroxyquinolinato)aluminum (Alq3) by using an artificial neural network (ANN) system to mass spectra was attempted based on the results of a VAMAS (Versailles Project on Advanced Materials and Standards) interlaboratory study (TW2 A31) to evaluate matrix-effect correction and to investigate interface determination. Monolayers of binary mixtures having different Ir(ppy)3 ratios (0, 0.25, 0.50, 0.75, and 1.00), and the multilayers containing these mixtures and pure samples were measured using time-of-flight secondary ion mass spectrometry (ToF-SIMS) with different primary ion beams, OrbiSIMS (SIMS with both Orbitrap and ToF mass spectrometers), laser desorption ionization (LDI), desorption/ionization induced by neutral clusters (DINeC), and X-ray photoelectron spectroscopy (XPS). The mass spectra were analyzed using a simple ANN with one hidden layer. The Ir(ppy)3 ratios of the unknown samples and the interfaces of the multilayers were predicted using the simple ANN system, even though the mass spectra of binary mixtures exhibited matrix effects. The Ir(ppy)3 ratios at the interfaces indicated by the simple ANN were consistent with the XPS results and the ToF-SIMS depth profiles. The simple ANN system not only provided quantitative information on unknown samples, but also indicated important mass peaks related to each molecule in the samples without a priori information. The important mass peaks indicated by the simple ANN depended on the ionization process. The simple ANN results of the spectra sets obtained by a softer ionization method, such as LDI and DINeC, suggested large ions such as trimers. From the first step of the investigation to build an ANN model for evaluating mixture samples influenced by matrix effects, it was indicated that the simple ANN method is useful for obtaining candidate mass peaks for identification and for assuming mixture conditions that are helpful for further analysis.
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RATIONALE AND OBJECTIVES: To evaluate the prevalence, size, and characteristics of gynecomastia on thoracic computed tomography (CT) in patients with spinal and bulbar muscular atrophy (SBMA) or amyotrophic lateral sclerosis (ALS), compared to those of patients with myasthenia gravis (as controls). MATERIALS AND METHODS: A total of 189 male patients (SBMA [n = 15]; ALS [n = 76]; control [n = 98]) who underwent thoracic computed tomography were included. The size of breast glandular tissue diameters, and characteristic of CT-depicted gynecomastia were compared. RESULTS: On multivariate logistic regression analysis, mean breast glandular tissue diameter (adjusted odds ratio [aOR] 1.13, 95% confidence interval [CI] 1.08-1.19), maximum breast glandular tissue diameter (aOR 1.14, 95% CI 1.08-1.20), prevalence of CT-depicted gynecomastia (aOR 21.71, 95% CI 5.39-87.38), dendritic or diffuse pattern of gynecomastia (aOR 35.30, 95% CI 8.02-155.40), and bilateral gynecomastia (aOR 41.96, 95% CI 10.20-172.69) were positively associated with SBMA, but not ALS. On receiver operating characteristic (ROC) analysis, the area under the curve of the mean breast tissue diameter for predicting SBMA was 0.92 with the optimal cutoff value of 16.5 mm. The ROC analysis showed that a maximum breast tissue diameter of 18.6 mm can also effectively distinguish SBMA from controls. CONCLUSION: These findings suggest that the evaluation of breast glandular tissue on thoracic CT could be a screening examination to distinguish SBMA patients and assist in its differential diagnosis.
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The objective was to evaluate the long-term efficacy and safety of tacrolimus monotherapy in myasthenia gravis (MG) patients. Immunosuppressive drug-naïve MG patients were administered tacrolimus, followed by thymectomy in some of the cases according to the clinical guideline for MG. Additional aggressive immunosuppressive therapies were allowed if the patients without thymectomy did not achieve minimal manifestation (MM) or better status after 3 weeks of tacrolimus administration or in the thymectomized patients by 1-2 weeks after the operation (i.e., 1st evaluation). Of all 14 patients included in this study, 8 of them (57%) achieved MM or better status at the 1st evaluation, and the remaining 6 (43%), who had failed to gain MM or better status at the 1st evaluation, also achieved MM or better status with 1 course of aggressive immunosuppressive therapy. The quantitative MG (QMG) scores, MG-Activities of Daily Living (ADL) scales, and anti-acetylcholine receptor (AchR) antibody levels were significantly decreased at 6 months and maintained thereafter. At the end of the follow-up period (41-70 months), all patients were in MM or better status. None of the patients experienced severe adverse effects. Our small preliminary study indicates that long-term tacrolimus monotherapy is possibly effective and safe for MG patients.
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Imunossupressores/uso terapêutico , Miastenia Gravis/tratamento farmacológico , Tacrolimo/uso terapêutico , Atividades Cotidianas , Adulto , Idoso , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Tacrolimo/administração & dosagem , TimectomiaRESUMO
We report the results of a VAMAS (Versailles Project on Advanced Materials and Standards) interlaboratory study on the identification of peptide sample TOF-SIMS spectra by machine learning. More than 1000 time-of-flight secondary ion mass spectrometry (TOF-SIMS) spectra of six peptide model samples (one of them was a test sample) were collected using 27 TOF-SIMS instruments from 25 institutes of six countries, the U. S., the U. K., Germany, China, South Korea, and Japan. Because peptides have systematic and simple chemical structures, they were selected as model samples. The intensity of peaks in every TOF-SIMS spectrum was extracted using the same peak list and normalized to the total ion count. The spectra of the test peptide sample were predicted by Random Forest with 20 amino acid labels. The accuracy of the prediction for the test spectra was 0.88. Although the prediction of an unknown peptide was not perfect, it was shown that all of the amino acids in an unknown peptide can be determined by Random Forest prediction and the TOF-SIMS spectra. Moreover, the prediction of peptides, which are included in the training spectra, was almost perfect. Random Forest also suggests specific fragment ions from an amino acid residue Q, whose fragment ions detected by TOF-SIMS have not been reported, in the important features. This study indicated that the analysis using Random Forest, which enables translation of the mathematical relationships to chemical relationships, and the multi labels representing monomer chemical structures, is useful to predict the TOF-SIMS spectra of an unknown peptide.
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Irrigated agriculture contributes 40% of total global food production. In the US High Plains, which produces more than 50 million tons per year of grain, as much as 90% of irrigation originates from groundwater resources, including the Ogallala aquifer. In parts of the High Plains, groundwater resources are being depleted so rapidly that they are considered nonrenewable, compromising food security. When groundwater becomes scarce, groundwater withdrawals peak, causing a subsequent peak in crop production. Previous descriptions of finite natural resource depletion have utilized the Hubbert curve. By coupling the dynamics of groundwater pumping, recharge, and crop production, Hubbert-like curves emerge, responding to the linked variations in groundwater pumping and grain production. On a state level, this approach predicted when groundwater withdrawal and grain production peaked and the lag between them. The lags increased with the adoption of efficient irrigation practices and higher recharge rates. Results indicate that, in Texas, withdrawals peaked in 1966, followed by a peak in grain production 9 y later. After better irrigation technologies were adopted, the lag increased to 15 y from 1997 to 2012. In Kansas, where these technologies were employed concurrently with the rise of irrigated grain production, this lag was predicted to be 24 y starting in 1994. In Nebraska, grain production is projected to continue rising through 2050 because of high recharge rates. While Texas and Nebraska had equal irrigated output in 1975, by 2050, it is projected that Nebraska will have almost 10 times the groundwater-based production of Texas.
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Irrigação Agrícola/normas , Conservação dos Recursos Hídricos/métodos , Produtos Agrícolas/crescimento & desenvolvimento , Grão Comestível/crescimento & desenvolvimento , Água Subterrânea/análise , Modelos Teóricos , Abastecimento de Água/normas , Recursos Hídricos/provisão & distribuiçãoRESUMO
RATIONALE: Organic light-emitting diode (OLED) products based on display applications have become popular in the past 10 years, and new products are being commercialized with rapid frequency. Despite the many advantages of OLEDs, these devices still have a problem concerning lifetime. To gain an understanding of the degradation process, the authors have investigated the molecular information for deteriorated OLED devices using time-of-flight secondary ion mass spectrometry (TOF-SIMS). METHODS: TOF-SIMS depth profiling is an indispensable method for evaluating OLED devices. However, the depth profiles of OLEDs are generally difficult due to the mass interference among organic compounds, including degradation products. In this study, the tandem mass spectrometry (MS/MS) depth profiling method was used to characterize OLED devices. RESULTS: After degradation, defects comprised of small hydrocarbons were observed. Within the defect area, the diffusion of all OLED compounds was also observed. It is supposed that the source of the small hydrocarbons derives from decomposition of the OLED compounds and/or contaminants at the ITO interface. CONCLUSIONS: The true compound distributions have been determined using MS/MS depth profiling methods. The results suggest that luminance decay is mainly due to the decomposition and diffusion of OLED compounds, and that OLED decomposition may be accelerated by adventitious hydrocarbons present at the ITO surface.
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Objective To assess the correlation between the angiographic appearance of cerebral collateral pathways or the degree of internal carotid artery stenosis (ICAS) and reduced cerebrovascular reactivity (CVR) estimated by single-photon emission computed tomography (SPECT) image analysis in patients with unilateral ICAS. Methods A retrospective analysis was performed in 42 patients with unilateral ICAS who underwent cerebral angiography and acetazolamide-challenged SPECT of the brain. Cerebral blood flow quantitation was performed using the quantitative SPECT/dual-table autoradiography method. The CVR in the middle cerebral artery (MCA) territory was evaluated using the stereotactic extraction estimation based on the Japanese extracranial-intracranial bypass trial (SEE-JET) program and classified as reduced (<18.4%) or non-reduced (≥18.4%). Angiographic collateralization was classified as circle of Willis (type 1), extracranial-intracranial (type 2), and leptomeningeal (type 3). The degree of ICAS was defined as severe (≥70% stenosis) or non-severe (<70%). Results Eight patients showed reduced CVR, including 6 (46%) of 13 with type 3 collaterals and 2 (7%) of 29 without type 3 collaterals (p=0.006). In contrast, type 1 and type 2 collaterals and severe ICAS were not significantly associated with reduced CVR. Conclusion In patients with unilateral ICAS, leptomeningeal collaterals are strongly correlated with reduced CVR in the MCA territory, which presumably increases the risk of cerebral hyperperfusion after carotid artery stenting (CAS). Therefore, these findings may be clinically applicable to the perioperative management of CAS.
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Encéfalo/diagnóstico por imagem , Estenose das Carótidas/diagnóstico por imagem , Artéria Cerebral Média/diagnóstico por imagem , Tomografia Computadorizada de Emissão de Fóton Único/métodos , Acetazolamida/farmacocinética , Idoso , Idoso de 80 Anos ou mais , Encéfalo/patologia , Estenose das Carótidas/patologia , Angiografia Cerebral , Circulação Cerebrovascular/fisiologia , Constrição Patológica , Feminino , Humanos , Imageamento Tridimensional , Masculino , Pessoa de Meia-Idade , Artéria Cerebral Média/patologia , Estudos RetrospectivosRESUMO
BACKGROUND: Methylenetetrahydrofolate reductase (MTHFR) deficiency is a rare inborn error of metabolism inherited in autosomal recessive pattern and is associated with a wide spectrum of neurological abnormalities. CASE PRESENTATION: We herein describe a 15-year-old boy with MTHFR deficiency who presented with a slowly progressive decline of school performance and a spastic gait. Rapidly deteriorating psychosis and repetitive seizures triggered by a febrile infection prompted neurological investigation. He had significantly elevated total plasma homocysteine and urinary homocystine levels, as well as a decreased plasma methionine level. Brain magnetic resonance imaging (MRI) revealed leukoencephalopathy. DNA gene sequencing showed c.446_447 del GC ins TT and c.137G > A, and c.665C > T heterozygous mutations in the MTHFR gene of the patient. Oral administration of betaine drastically improved his clinical symptoms within a few months. After 8 months of treatment, his total plasma homocysteine level moderately decreased; and the plasma methionine concentration became normalized. Furthermore, the white matter lesions on MRI had disappeared. CONCLUSION: This patient demonstrates the possibility that MTHFR deficiency should be considered in mentally retarded adolescents who display an abnormally elevated plasma level of homocysteine in association with progressive neurological dysfunction and leukoencephalopathy. Febrile infections may be an aggravating factor in patients with MTHFR deficiency.
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Homocistinúria/fisiopatologia , Leucoencefalopatias/diagnóstico por imagem , Metilenotetra-Hidrofolato Redutase (NADPH2)/deficiência , Espasticidade Muscular/fisiopatologia , Transtornos Psicóticos/etiologia , Adolescente , Sequência de Bases , Humanos , Imageamento por Ressonância Magnética , Masculino , Metionina/sangue , Metilenotetra-Hidrofolato Redutase (NADPH2)/genética , Espasticidade Muscular/etiologia , Mutação , Transtornos Psicóticos/fisiopatologiaRESUMO
A 49-year-old woman with neuromyelitis optica (NMO) developed severe quadriplegia and frequent paroxysmal tonic spasms (PTS). Carbamazepine, although initially effective against PTS, caused drug eruption and she was unable to continue. PTS re-emerged after discontinuation of carbamazepine and hindered rehabilitation. Then topiramate was started, and PTS promptly disappeared. The patient became able to resume rehabilitation and her activity of daily life improved significantly. Carbamazepine and topiramate have a common pharmacological action to block voltage-gated sodium channels. The action may have contributed to inhibition of ephaptic transmission in the demyelinating lesions by NMO and eventually improved PTS.
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Anticonvulsivantes/uso terapêutico , Distonia/tratamento farmacológico , Distonia/fisiopatologia , Frutose/análogos & derivados , Neuromielite Óptica/fisiopatologia , Anticonvulsivantes/efeitos adversos , Carbamazepina/efeitos adversos , Carbamazepina/uso terapêutico , Toxidermias , Distonia/reabilitação , Feminino , Frutose/uso terapêutico , Humanos , Pessoa de Meia-Idade , Neuromielite Óptica/tratamento farmacológico , Neuromielite Óptica/reabilitação , Bloqueadores dos Canais de Sódio/efeitos adversos , Bloqueadores dos Canais de Sódio/uso terapêutico , Topiramato , Resultado do TratamentoRESUMO
OBJECTIVE: Carbon monoxide (CO) levels in expired gas are higher in patients with bronchial asthma than in healthy individuals. Heme oxygenase-1 (HO-1) is a rate-limiting enzyme that catalyzes the degradation of heme to yield biliverdin, CO and free iron. Thus, HO-1 is implicated in the pathogenesis of bronchial asthma. However, whether HO-1 expression and activity in lung tissue are related to allergic airway inflammation remains unclear. We investigated whether expression of HO-1 is related to allergic airway inflammation in lungs and whether HO-1 could influence airway hyperresponsiveness and eosinophilia in mice sensitized to ovalbumin (OVA). METHODS: C57BL/6 mice immunized with OVA were challenged thrice with an aerosol of OVA every second day for 8 days. HO-1-positive cells were identified by immunostaining in lung tissue, and zinc protoporphyrin (Zn-PP), a competitive inhibitor of HO-1, was administered intraperitoneally to OVA-immunized C57BL/6 mice on day 23 (day before inhalation of OVA) and immediately before inhalation on the subsequent 4 days (total five doses). Mice were analyzed for effects of HO-1 on AHR, inflammatory cell infiltration and cytokine levels in lung tissue. Ethical approval was obtained from the concerned institutional review board. RESULTS: Number of HO-1-positive cells increased in the subepithelium of the bronchi after OVA challenge, and HO-1 localized to alveolar macrophages. Zn-PP clearly inhibited AHR, pulmonary eosinophilia and IL-5 and IL-13 expression in the lung tissue. CONCLUSION: Expression of HO-1 is induced in lung tissue during attacks of allergic bronchial asthma, and its activity likely amplifies and prolongs allergic airway inflammation.
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Asma/imunologia , Hiper-Reatividade Brônquica/imunologia , Eosinofilia/imunologia , Heme Oxigenase-1/biossíntese , Inflamação/imunologia , Pulmão/imunologia , Acetilcolina/farmacologia , Animais , Contagem de Linfócito CD4 , Modelos Animais de Doenças , Macrófagos/metabolismo , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Ovalbumina/imunologia , Protoporfirinas/farmacologiaRESUMO
A 75-year-old woman presented with intermittent dull abdominal pain, gradually exacerbating over eight months. Computed tomography demonstrated a large mass straddling both the right lower lobe of the lung and the right hepatic lobe. An 18-fluoro-2-deoxy-D-glucose positron emission computed tomography scan (PET/CT) demonstrated high accumulation in the lesion and carinal lymph nodes. Transbronchial biopsy revealed squamous cell carcinoma; thus, primary lung cancer with transdiaphragmatic invasion into the liver was diagnosed. Chemotherapy with carboplatin (AUC = 5) on day one and weekly paclitaxel (70 mg/m2 ) doses were introduced for four courses. The size of the main tumor was reduced and the mediastinal lymph node accumulation disappeared in a subsequent PET/CT. Thus, en-bloc radical resection of the lung tumor by right lower lobectomy with partial resection of invaded middle lobe and the diaphragm, subsegmentectomy of the liver, and standard mediastinal dissection were undertaken. The postoperative course was uneventful and the patient was discharged on day 30. Her nutrition status dramatically improved and she gained five kilograms of body weight in two months following the resection. The patient, however, then had a fall and suffered femur and multiple pelvic fractures and died of acute pneumonia five weeks after the femur fixation and 14 weeks after the lung surgery.
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The nanostructure of the light emissive layer (EL) of polymer light emitting diodes (PLEDs) was investigated using force modulation microscopy (FMM) and scanning time-of-flight secondary ion mass spectrometry (ToF-SIMS) excited with focused Bi(3)(2+) primary beam. Three-dimensional nanostructures were reconstructed from high resolution ToF-SIMS images acquired with different C(60)(+) sputtering times. The observed nanostructure is related to the efficiency of the PLED. In poly(9-vinyl-carbazole) (PVK) based EL, a high processing temperature (60 °C) yielded less nanoscale phase separation than a low processing temperature (30 °C). This nanostructure can be further suppressed by replacing the host polymer with poly[oxy(3-(9H-9-carbazol-9-ilmethyl-2-methyltrimethylene)] (SL74) and poly[3-(carbazol-9-ylmethyl)-3-methyloxetane] (RS12), which have similar chemical structures and energy levels as PVK. The device efficiency increases when the phase separation inside the EL is suppressed. While the spontaneous formation of a bicontinuous nanostructure inside the active layer is known to provide a path for charge carrier transportation and to be the key to highly efficient polymeric solar cells, these nanostructures are less efficient for trapping the carrier inside the EL and thus lower the power conversion efficiency of the PLED devices.
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Solution processable fullerene and copolymer bulk heterojunctions are widely used as the active layers of solar cells. In this work, scanning time-of-flight secondary ion mass spectrometry (ToF-SIMS) is used to examine the distribution of [6,6]phenyl-C61-butyric acid methyl ester (PCBM) and regio-regular poly(3-hexylthiophene) (rrP3HT) that forms the bulk heterojunction. The planar phase separation of P3HT:PCBM is observed by ToF-SIMS imaging. The depth profile of the fragment distribution that reflects the molecular distribution is achieved by low energy Cs(+) ion sputtering. The depth profile clearly shows a vertical phase separation of P3HT:PCBM before annealing, and hence, the inverted device architecture is beneficial. After annealing, the phase segregation is suppressed, and the device efficiency is dramatically enhanced with a normal device structure. The 3D image is obtained by stacking the 2D ToF-SIMS images acquired at different sputtering times, and 50 nm features are clearly differentiated. The whole imaging process requires less than 2 h, making it both rapid and versatile.
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The large T antigens of polyomaviruses target cellular proteins that control fundamental processes, including p53 and the RB family of tumor suppressors. Mechanisms that underlie T-antigen-induced cell transformation need to be fully addressed, because as-yet unidentified target proteins might be involved in the process. In addition, recently identified polyomaviruses are associated with particular human diseases such as aggressive skin cancers. Here, we report that simian virus 40 (SV40) large T antigen interacts with the transforming acidic coiled-coil-containing protein TACC2, which is involved in stabilizing microtubules in mitosis. T antigen directly binds TACC2 and induces microtubule dysfunction, leading to disorganized mitotic spindles, slow progression of mitosis and chromosome missegregation. These mitotic defects are caused by N-terminal-deleted T antigen, which minimally interacts with TACC2, whereas T-antigen-induced microtubule destabilization is suppressed by overexpressing TACC2. Thus, TACC2 might be a key target of T antigen to disrupt microtubule regulation and chromosomal inheritance in the initiation of cell transformation.
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Antígenos Virais de Tumores/metabolismo , Proteínas de Transporte/metabolismo , Microtúbulos/metabolismo , Neoplasias/metabolismo , Vírus 40 dos Símios/metabolismo , Proteínas Supressoras de Tumor/metabolismo , Animais , Antígenos Virais de Tumores/genética , Células CHO , Proteínas de Transporte/genética , Transformação Celular Viral , Cricetinae , Cricetulus , Células HeLa , Humanos , Microtúbulos/genética , Mitose , Neoplasias/genética , Neoplasias/virologia , Ligação Proteica , Vírus 40 dos Símios/genética , Vírus 40 dos Símios/imunologia , Proteínas Supressoras de Tumor/genéticaRESUMO
The aim of this study was to investigate the mechanism of inhibition of Eg5 (kinesin spindle protein), a mitotic kinesin that plays an essential role in establishing mitotic spindle bipolarity, by the novel small molecule inhibitor K858. K858 was selected in a phenotype-based forward chemical genetics screen as an antimitotic agent, and subsequently characterized as an inhibitor of Eg5. K858 blocked centrosome separation, activated the spindle checkpoint, and induced mitotic arrest in cells accompanied by the formation of monopolar spindles. Long-term continuous treatment of cancer cells with K858 resulted in antiproliferative effects through the induction of mitotic cell death, and polyploidization followed by senescence. In contrast, treatment of nontransformed cells with K858 resulted in mitotic slippage without cell death, and cell cycle arrest in G(1) phase in a tetraploid state. In contrast to paclitaxel, K858 did not induce the formation of micronuclei in either cancer or nontransformed cells, suggesting that K858 has minimal effects on abnormalities in the number and structure of chromosomes. K858 exhibited potent antitumor activity in xenograft models of cancer, and induced the accumulation of mitotic cells with monopolar spindles in tumor tissues. Importantly, K858, unlike antimicrotubule agents, had no effect on microtubule polymerization in cell-free and cell-based assays, and was not neurotoxic in a motor coordination test in mice. Taken together, the Eg5 inhibitor K858 represents an important compound for further investigation as a novel anticancer therapeutic.
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Neoplasias Colorretais/tratamento farmacológico , Cinesinas/antagonistas & inibidores , Tiadiazóis/farmacologia , Animais , Proteínas de Ligação ao Cálcio/metabolismo , Proteínas de Ciclo Celular/metabolismo , Morte Celular/efeitos dos fármacos , Núcleo Celular/efeitos dos fármacos , Núcleo Celular/patologia , Neoplasias Colorretais/genética , Neoplasias Colorretais/patologia , Células HCT116 , Humanos , Proteínas Mad2 , Camundongos , Camundongos Endogâmicos BALB C , Camundongos Nus , Microtúbulos/efeitos dos fármacos , Microtúbulos/metabolismo , Mitose/efeitos dos fármacos , Paclitaxel/farmacologia , Poliploidia , Proteínas Repressoras/metabolismo , Fuso Acromático/efeitos dos fármacos , Fuso Acromático/metabolismo , Tiadiazóis/efeitos adversos , Ensaios Antitumorais Modelo de XenoenxertoRESUMO
In vivo cell cycle analysis in higher eukaryotes has been limited by the challenge of preserving the integrity of the living organism while visualizing dividing cells. Here, we propose a new model, which uses the unique combination of features of the Japanese medaka in order to visualize and manipulate the cell cycle progression in a live vertebrate. Our stable transgenic histone H2B-GFP medaka line allows fluorescence-based monitoring of the chromosomes. The system has a high specificity, with a strong GFP signal labeling the chromatin architecture. The subcellular resolution ensures detection of both normal and abnormal divisions in live recordings. This translates into the possibility to quantify temporal and spatial aspects of the cell cycle, such as length or nuclear size, as well as to expose drug toxicity at the earliest stage. We also show that acclimation to cold, a prominent feature of the eurytherm medaka, is a valuable natural way of inducing a reversible cell cycle arrest in the entire living organism. Our results suggest that this manipulation can be performed from the early stages of development, has no toxicity and does not alter the cell cycle profile of the embryo.
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Ciclo Celular/fisiologia , Oryzias/embriologia , Sequência de Aminoácidos , Animais , Animais Geneticamente Modificados , Proteínas de Fluorescência Verde/genética , Proteínas de Fluorescência Verde/metabolismo , Histonas/genética , Histonas/metabolismo , Humanos , Dados de Sequência Molecular , Oryzias/anatomia & histologia , Proteínas Recombinantes de Fusão/genética , Proteínas Recombinantes de Fusão/metabolismo , Alinhamento de SequênciaRESUMO
PURPOSE: L612, a human IgM monoclonal antibody produced by an EBV-transformed human B-cell line, binds to ganglioside GM3 and kills GM3-positive human melanoma cells in the presence of complement. It has been shown to be effective in some patients with late-stage melanoma. L612 consists of hexameric IgM (about 20%), pentameric IgM (about 74%), and other minor IgM molecules. Because hexameric IgM activates complement more effectively than pentameric IgM, we developed and evaluated a hexamer-dominant recombinant IgM for clinical applications. EXPERIMENTAL DESIGN: Chinese hamster ovary (CHO) cells were transfected with heavy- and light-chain genes of L612, with or without the joining-chain gene. Antitumor effects of the recombinant IgM secreted from CHO cells were evaluated in vitro and in vivo. RESULTS: Recombinant IgM secreted from CHO cells without the joining chain (designated CA19) was approximately 80% hexameric, whereas recombinant IgM from CHO cells transfected with heavy-, light-, and joining-chain genes (designated CJ45) was about 90% pentameric. Both CA19 and CJ45 recombinant IgMs caused complement-dependent cytotoxicity against human and mouse melanoma cell lines, but the amount of CA19 required for 50% specific cytotoxicity was 5 to 10 times smaller. I.v. injection of CA19 compared with CJ45 or native L612 elicited more profound antitumor activity in nude rats bearing a GM3-positive mouse melanoma xenograft. CONCLUSIONS: A hexamer-dominant human IgM against GM3 may provide a more potent treatment option for patients with GM3-positive melanoma.