Functional Analysis of the Role of Equilibrative Nucleobase Transporter 1 (ENBT1/SLC43A3) in Adenine Transport in HepG2 Cells

Equilibrative nucleobase transporter 1 (ENBT1/SLC43A3) has recently been identified as a purine-selective nucleobase transporter. Although it is highly expressed in the liver, its role in nucleobase transport has not been confirmed yet in hepatocytes or any relevant cell models. We, therefore, examined its role in adenine transport in the HepG2 cell line as a human hepatocyte model. The uptake of [³H]adenine in HepG2 cells was highly saturable, indicating the involvement of carrier-mediated transport. The carrier-mediated transport component, for which the Michaelis constant was estimated to be 0.268 μM, was sensitive to decynium-22, an ENBT1 inhibitor, with the half maximal inhibitory concentration of 2.59 μM, which was comparable to that of 2.30 μM for [³H]adenine uptake by ENBT1 in its transient transfectant human embryonic kidney 293 cells. Although equilibrative nucleoside transporter 1 (ENT1/SLC29A1) and ENT2/SLC29A2 are also known to be able to transport adenine, [³H]adenine uptake in HepG2 cells was not inhibited by the ENT1/2-specific inhibitor of either dipyridamole or nitrobenzylthioinosine. Finally, [³H]adenine uptake was extensively reduced by silencing of ENBT1 by RNA interference in the hepatocyte model. All these results, taken together, suggest the predominant role of ENBT1 in the uptake of adenine in HepG2 cells.

Crucial role of plasmacytoid dendritic cells in the development of acute colitis through the regulation of intestinal inflammation

Disruption of intestinal homeostasis can lead to inflammatory bowel diseases endowed susceptibility genes and environmental factors affecting intestinal accumulation and activation of colitogenic phagocytes. Plasmacytoid dendritic cells (pDCs) are immune cells that had been proposed to control innate and adaptive immunity through the massive secretion of type I interferon (IFN-I). However, the contribution of pDCs to the progression of intestinal inflammation remains unclear. Here we show a critical role of pDCs in the initiation of acute colonic inflammation using T-cell-independent acute colitis model with a selective ablation of pDCs. Although pDCs accumulated in the inflamed colon upon mucosal injury, deficiency of pDCs attenuated the development of acute colitis independent of IFN-I signaling, accompanied by the diminished colonic production of proinflammatory cytokines. Furthermore, deficiency of pDCs impaired the mobilization of colitogenic phagocytes into the inflamed colon possibly mediated by the abrogated mucosal production of C-C chemokine receptor 2 ligand. Thus, our findings highlight a critical role of pDCs in the induction of the colonic inflammation that regulates the colonic accumulation of inflammatory phagocytes leading to the initiation and exacerbation of acute colitis, and they may serve a key role in controlling gut mucosal immune homeostasis.

Particle therapy using carbon ions or protons as a definitive therapy for patients with primary sacral chordoma

OBJECTIVE

This study retrospectively evaluated the efficacy and toxicity of particle therapy using carbon ions or protons for primary sacral chordomas.

METHODS

We evaluated 23 patients with primary sacral chordoma treated with carbon ion therapy (CIT) or proton therapy (PT) between July 2005 and June 2011 at the Hyogo Ion Beam Medical Center, Hyogo, Japan. The median patient age was 72 years. 14 patients were treated with 70.4 Gy equivalents (GyE) in 16 fractions and 9 were treated with 70.4 GyE in 32 fractions. CIT was used for 16 patients, and PT was used for 7 patients.

RESULTS

The median follow-up period was 38 months. At 3 years, local control (LC), overall survival (OS) and progression-free survival (PFS) for all patients were 94%, 83% and 68%, respectively. The log-rank test revealed that male sex was significantly related to better PFS (p=0.029). No other factors, including dose fractionation and ion type, were significant for LC, OS or PFS. In nine patients, ≥ Grade 3 acute dermatitis was observed, and ≥ Grade 3 late toxicities were observed in nine patients. The 32-fraction protocol reduced severe toxicities in both the acute and late phases compared with the 16-fraction protocol.

CONCLUSION

Particle therapy for patients with sacral chordoma showed favourable LC and OS. Severe toxicities were successfully reduced by modifying the dose fractionation and treatment planning in the later treatment era. Thus, this therapeutic modality should be considered useful and safe.

ADVANCES IN KNOWLEDGE

This is the first study including both CIT and PT for sacral chordomas.

Risk factors for survival and local recurrence after particle radiotherapy for single small hepatocellular carcinoma

BACKGROUND

Particle radiotherapy is a novel treatment for malignant tumours. The present study aimed to evaluate risk factors for overall survival and local control after particle radiotherapy of single small hepatocellular carcinoma (HCC), and to identify suitable candidates for this treatment.

METHODS

All patients with a single HCC smaller than 5 cm in diameter treated by particle radiotherapy between 2001 and 2008 were identified retrospectively from a prospectively collected database. Clinical outcomes and prognostic factors were analysed.

RESULTS

A total of 150 patients were included. Five-year overall survival and local control rates were 50.9 and 92.3 per cent respectively. Multivariable analysis revealed that several factors, including age and Child-Pugh classification, significantly influenced overall survival. Proximity to the digestive tract and Child-Pugh classification were independent risk factors for local recurrence. Other tumour factors including size, gross classification, previous treatment, macroscopic vascular invasion, and tumour location in relation to the diaphragm and large vessels did not influence local control rate.

CONCLUSION

Particle radiotherapy seems safe and effective, and may be a novel treatment for small HCC. Recurrences are more frequent when the tumour is located close to the gut.

Scatter factors in proton therapy with a broad beam

In the absence of a predictor of beam output in proton therapy using a broad beam, the beam output is obtained for individual treatments by calibrating the beam monitors. The calibration is carried out under conditions similar to the treatment conditions but with a phantom instead of the patient. However, the dose in the phantom a priori differs from that in the patient. In order to deliver the accurate dose, a correction factor has been introduced to correct the difference. This correction factor is referred to as a scatter factor in an analogy with photon therapy, and is defined as the ratio of the dose at the prescription point in the patient to the dose at the calibration point in the phantom. Under the calibration conditions at Hyogo Ion Beam Medical Center (HIBMC), the range compensator and the collimator, which are usually required in proton therapy with a broad beam, are not used. Therefore the scatter factor includes the effects of the devices as well as the difference between the dose in the patient and that in the phantom. We have developed an estimator using a dose calculation based on the pencil beam algorithm and implemented it in a treatment planning system (TPS) for clinical use. This estimator estimates the scatter factor by calculating the ratio of the doses under the same conditions in the TPS. In order to evaluate the performance of the estimator, demonstrations were carried out for cases with measurable outcomes using a gantry nozzle at HIBMC. We observed 2-3% differences between the measurements and the estimations. These differences were considered to result from the limitations of the dose calculation algorithm in modelling the beam and the patient.

CSF hypocretin measures in patients with obstructive sleep apnea

The majority of patients with narcolepsy-cataplexy were reported to have very low cerebrospinal fluid (CSF) hypocretin-1 (orexin-A) levels. The hypocretin-1 levels of secondary excessive daytime sleepiness (EDS) disorders are not known. In this study, we found that CSF hypocretin levels in the patients with obstructive sleep apnea syndrome were within the control range. The low hypocretin levels seem to reflect only the presence of cataplexy and DR2 positive in narcoleptics but not EDS itself.

Localization in situ of specific RNA by electron microscopy

To better understand the metabolism of RNA in nuclei, the analysis of precise nuclear distribution of specific RNA would be essential. For this purpose, nonradioactive electron microscopic (EM) in situ hybridization may be the most appropriate technique while the details required for the technique have not been fully established. In the present study, we attempted to localize 28S and 18S rRNAs in the nuclei of mouse Sertoli cells by EM in situ hybridization as a model system. After various preliminary experiments we chose the pre-embedding method; fresh-frozen sections of mouse testis were fixed with a mixture of 4% paraformaldehyde and 0.1% glutaraldehyde, digested with 10 microg/ml of proteinase K and hybridized with thymine-thymine (T-T) dimerized oligodeoxynucleotides (oligo-DNA) complementary to a part of 28S and 18S rRNAs. Then, the T-T dimers were detected enzyme-immunohistochemically with horseradish peroxidase (HRP) labeled anti-T-T dimer. After osmification of HRP products, the sections were embedded in Epon resin, cut into 100 nm ultra-thin sections and observed under a transmission electron microscope. As a result, we successfully localized both 28S and 18S rRNAs in the dense fibrillar and granular components of the nucleolus, showing the usefulness of nonradioactive EM in situ hybridization in the nuclear localization of specific RNA.

The role of P-glycoprotein in human gastric cancer xenografts in response to chemotherapy

BACKGROUND

To clarify the contribution of P-glycoprotein (P-GP) to drug resistance of gastric cancer, the correlation between chemosensitivity of the tumor and expression of P-GP was examined using human gastric cancer xenografts in nude mice.

METHODS

Two strains, P-GP-positive and -negative, were established using primary explants from patients who had not received chemotherapy. Their stable growth was obtained by serial passages as subcutaneous tumors in nude mice. Mitomycin C (MMC, 3.25 mg/kg), adriamycin (ADR, 6mg/kg), or cisplatin (CDDP, 6mg/kg) was administered intraperitoneally once a week for 3 weeks.

RESULTS

In the P-GP-negative strain, all three drugs significantly suppressed the tumor growth, while in the P-GP-positive strain, only MMC did so. However, the growth inhibition of MMC was apparently greater in the P-GP-negative strain than in the positive tumor. The expressions of metallothionein (MT), glutathione-S-transferase-pi (GST-pi), and p53 were not different between the strains. Bcl-2 was expressed only in the P-GP-negative strain. Induction of P-GP expression was observed in some specimens after treatment with MMC and with CDDP.

CONCLUSIONS

P-GP might affect inherent and acquired resistance against chemotherapeutic agents in gastric cancer.

Expression of metallothionein in colorectal cancers and synchronous liver metastases

The aim of this study is to clarify whether the expression of metallothionein (MT) is related with the malignant potential in primary colorectal cancer and/or synchronous liver metastasis. Immunohistochemical staining for MT was performed on the specimens of adenocarcinoma of the colon and rectum and its liver metastases in 34 patients treated with curative surgery, respectively. Expression of MT was compared with clinicopathological variables and patient survival. In patients with primary colorectal cancer, positive expression was found in 7 of 34 (20.6%) patients, but MT was not detected in any of the cases of liver metastases (0%; p = 0.0111). In the primary tumor, positive MT expression was significantly associated with a higher degree of lymph node involvement (mean +/- SD: 48.4 +/- 33.8 vs. 18.6 +/- 24.4% in MT-positive and MT-negative tumors, respectively; p = 0.0122). The survival rate in the patients with MT-negative tumors was significantly better than that in those with MT-positive tumors as primary sites (p = 0.0198). MT expression in colorectal cancer may be a potential marker affecting lymph node metastases and may be a predictor of a poor prognosis, particularly in patients with synchronous liver metastases.

Total sleep deprivation induces an acute and transient increase in NK cell activity in healthy young volunteers

STUDY OBJECTIVES

To investigate the effects of one night's total sleep deprivation (TSD) on NK cell activity, with rigorous control of circadian phase of sampling points as well as physical exercise level in association with sleep deprivation.

DESIGN

The mean sleep onset time of each subject before starting the study was defined as his 0000 h. This study was composed of a Sleep-Sleep session (sleep times, 00:00 h - 08:00 h and 24:00 h - 32:00 h) and a Sleep-Wake session (sleep time, 00:00 h - 08:00 h) with TSD (24:00 h - 32:00 h) placed in a cross-over design with 2-week interval between each session. In each session, the subjects were rested in the supine position under dim light from - 06:00 h to 36:00 h (for 42 hours).

SETTING

University-based sleep and chronobiology laboratory

PARTICIPANTS

10 healthy adult men (mean age, 20.9 y; age range, 19-23 y)

INTERVENTIONS

NA.

MEASUREMENTS AND RESULTS

NK cell activity was measured every 4 hours from 12:00 h. NK cell activity during TSD (at 28:00 h) has been revealed to significantly increase (p=0.01) compared with the corresponding value in the Sleep-Sleep session. This effect was weaker at their usual waking time 32:00 h (p=0.07), and disappeared until 36:00 h (4 hours after awakening). The circadian rhythm phases (dim light melatonin onset time) were coincident between the 2 sessions.

CONCLUSIONS

The present findings suggest that one night TSD induces an acute and transient increase in NK cell activity that is not influenced by the effects of circadian rhythm or the amount of physical exercise undertaken during TSD.

Dosimetric predictors of radiation esophagitis in patients treated for non-small-cell lung cancer with carboplatin/paclitaxel/radiotherapy

PURPOSE

To establish dosimetric predictors of radiation esophagitis (RE) in patients treated with a combination of carboplatin, paclitaxel, and radiotherapy.

METHODS AND MATERIALS

Three-dimensional radiotherapy plans of 26 patients with non-small-cell lung cancer who received 50-60 Gy of radiotherapy concurrently with weekly administration of carboplatin (AUC 2) and paclitaxel (40-45 mg/m(2)) were reviewed in conjunction with RE. The factors analyzed included the following: percentages of organ volumes receiving >40 Gy (V40), >45 Gy (V45), >50 Gy (V50), and >55 Gy (V55); the length of esophagus (total circumference) treated with >40 Gy (LETT40), >45 Gy (LETT45), >50 Gy (LETT50), and >55 Gy (LETT55); the maximum dose in the esophagus (Dmax); and the mean dose in the esophagus (Dmean). Data were obtained on the basis of superposition algorithm.

RESULTS

All factors except Dmax showed statistical correlation with RE. Good correlations were shown between RE and LETT45 (rho = 0.714) and V45 (rho = 0.686).

CONCLUSIONS

LETT45 and V45 appear to be useful dosimetric predictors of RE. It is also suggested that Dmax does not predict RE.

Hypersomnia due to acute disseminated encephalomyelitis in a 5-year-old girl

A 5-year-old girl suffering from hypersomnia due to acute disseminated encephalomyelitis (ADEM) is reported. Brain CT revealed a large low-density lesion involving the lentiform nucleus, posterior limb of the internal capsule, thalamus, posterior hypothalamus and midbrain in the left side. She was treated with intravenous dexamethazone. After the initial dose of dexamethazone, hypersomnia was dramatically and rapidly improved. A later brain CT study disclosed that the lesion in the brain disappeared. The brain lesion in this case involved the waking center in the brain, which was described by Von Economo. We concluded that hypersomnia in this case was due to ADEM involving the neural mechanism for maintaing wakefulness, probably in the thalamus and posterior hypothalamus. Repeat all night polysomnograpy in this case disclosed prolonged total sleep time and increased amount of stage 3-4 sleep in the hypersomniac state.

Partial tolerance of subcutaneously transplanted xenogeneic tumour cell graft by Fas-mediated immunosuppression

Certain anti-Fas antibodies, such as RMF2, induce apoptosis of Fas-expressing cells. We applied the Fas/anti-Fas system to induce killing of Fas-expressing immunocytes with resultant immunosuppression. W7TM-1 tumour cells, a rat T-cell line, were inoculated subcutaneously in BALB/c mice and tumour growth was monitored in untreated mice and in mice treated with RMF2. Prior to treatment with RMF2, we examined the expression of Fas in isolated splenocytes and in tumour-infiltrating lymphocytes by flow cytometry and immunohistochemistry, respectively. There was a remarkable increase in Fas-positive lymphocytes, including natural killer (NK) cells, among splenocytes at day 5 after tumour cell inoculation. The number of Fas-positive infiltrating lymphocytes also increased markedly, from day 5 to day 10. We then examined whether RMF2 could induce apoptosis of Fas-positive activated lymphocytes isolated from the spleen at day 5 in vitro. Terminal deoxy (d) -UTP nick end labelling (TUNEL) and Annexin V staining methods showed apoptosis of isolated cells when incubated with RMF2, and typical apoptotic features were confirmed by 4',6-diamidino-2-phenylindole dihydrochloride (DAPI) staining. Furthermore, suppression of cellular and humoral immunity was noted in RMF2-treated mice by mixed lymphocyte reaction and assay of serum levels of immunoglobulin G, respectively. Finally, treatment of animals with RMF2 daily from day 5 to day 9 could maintain the tumour size, while the tumour mass began to diminish in untreated mice immediately after reaching a maximum size. We confirmed the enhancing effects of long-term treatment with RMF2, through the induction of immunosuppression, on the growth of unvascularized xenogeneic tumour cell grafts.

Expression of Fas and Fas ligand in normal and ischemia-reperfusion testes: involvement of the Fas system in the induction of germ cell apoptosis in the damaged mouse testis

Apoptosis of germ cells is very common in normal and injured mammalian testes. The aim of this study was to examine the possible involvement of the Fas and Fas ligand (FasL) system in the induction of germ cell apoptosis in normal and ischemia-reperfusion testes of adult mice. Apoptosis was assessed by the TUNEL method and by DNA gel electrophoresis. Fas and FasL mRNAs were detected by Northern blotting and reverse transcription polymerase chain reaction techniques, and proteins were analyzed by Western blotting and immunohistochemistry. Apoptosis of germ cells was identified in the normal testis especially around stages XI and XII, whereas the expression of Fas and FasL was largely confined to Leydig cells and Sertoli cells, respectively. However, in the testes reperfused after 1 h of ischemia, a high number of TUNEL-positive cells were identified in parallel with increased Fas-positive germ cells, whereas FasL expression in Sertoli cells was almost constant irrespective of the duration of reperfusion. Moreover, i.p. injection of anti-Fas antibody, which blocks the interaction between Fas and FasL, inhibited apoptosis, as indicated by the reduced number of TUNEL-positive cells, except for apoptosis at stages XI and XII. Our results indicate that the Fas/FasL system mediates apoptosis of spermatogenic cells in the injured testis but not spontaneous apoptosis in the normal testis.

Endoscopic findings of radiation esophagitis in concurrent chemoradiotherapy for intrathoracic malignancies

BACKGROUND AND PURPOSE

The incidence and extent of radiation esophagitis were assessed endoscopically in patients treated with concurrent chemoradiotherapy.

PATIENTS AND METHODS

Eighty-two patients who received thoracic radiotherapy for lung, thymic, or esophageal cancer were investigated endoscopically from July 1991 to the end of 1997. Among them, 23 esophageal cancer patients were treated with radiation alone, and the others were treated with concurrent chemoradiotherapy. Esophageal endoscopy was performed during or just after radiotherapy. The presence of radiation esophagitis was assessed and assigned an endoscopic score (i.e. grade 0 for normal, 1 for erythema, 2 for erosion or sloughing, 3 for ulcer, hemorrhage, or stricture). The symptomatic grade was assessed using the RTOG (Radiation Therapy Oncology Group) acute radiation morbidity score.

RESULTS

A correlation was seen between endoscopic and RTOG scores. However, even some patients with RTOG grade 0 to 1 had endoscopic grade 3 esophagitis. Endoscopic grade 3 was observed in 16 (27.1%) patients in the concurrent chemoradiotherapy group, whereas it did not occur in any patient in the radiation alone group (P=0.004).

CONCLUSIONS

Our results suggest that (1) RTOG score correlates closely to esophageal mucosal damage, and (2) more severe esophagitis occurs in those undergoing concurrent chemoradiotherapy than those undergoing radiotherapy alone [corrected].

Another anti-allergic mechanism: antibody IgE deglycosylation induced by a substance extracted from human urine

Enzymically-deglycosylated antibody IgE lost its allergic activity in mouse systemic anaphylaxis, though the IgE kept its antibody activity. IgE antibody obtained from mice treated with a substance extracted from human urine was deglycosylated. This IgE also lost the allergic activity on the systemic anaphylaxis but kept its antibody activity. These findings strongly suggest that glycosylation of IgE has a close relation to the binding of the Fc receptor and that humans have another antiallergic mechanism: in vivo IgE antibody deglycosylation induced by the substance.