Inhibitory Effects of Acyclic Nucleoside Phosphonate Analogues on Hepatitis B Virus DNA Synthesis in HB611 Cells

By using an assay system based on a human hepatoblastoma cell line (HB611) that continuously synthesizes hepatitis B virus (HBV) DNA, 56 acyclic nucleoside phosphonate analogues were examined for their inhibitory effects on HBV DNA synthesis. The following compounds were found to inhibit HBV DNA synthesis at concentrations that were significantly lower than their minimum cytotoxic concentrations; 9-(2-phosphonylmethoxyethyl)adenine (PMEA), 9-(2-phosphonylmethoxyethyl) guanine(PMEG), 9-(2-phosphonylmethoxyethyl) guanine ethyl ester (PMEGEE), 9 - (2 - phosphonylmethoxyethyl) - 1 - deazaadenine (PMEC1A), 9-(2-phosphonylmethoxyethyl)-2,6-diaminopurine (PMEDAP), ( S)-9-(3-hydroxy-2-phosphonylmethoxypropyl)adenine (HPMPA), 9-(3-isopropoxy-2-phosphonylmethoxypropyl)adenine (IPPMPA), 9-( RS)-(2-phosphonylmethoxypropyl)adenine (PMPA) and 9-(3-hydroxy-2-phosphonylmethoxypropyl)-2, 6-diaminopurine (HPMPDAP). The most selective compounds (with indexes greater than 100) were PMEDAP, PMEA, IPPMPA, and PMPA. Acyclic pyrimidine nucleoside phosphonate analogues did not prove markedly selective as anti-HBV agents. Diphosphoryl derivatives of some acyclic purine nucleoside phos-phonates (i.e. PMEA, PMEDAP, HPMPA) were prepared. They proved inhibitory to HBV DNA polymerase but not cellular DNA polymerase α.

Inhibition of Thymidylate Synthetase Activity Induced in Varicella-Zoster Virus Infected Cells by (E)-5-(2-bromovinyl)-2′-deoxyuridine

The authors investigated the effect' of thymidylate synthetase (TS) on the antivariclllazoster virus (VZV) activity of ( E)5-(2-bromovinyl)-2′-deoxyuridine (BVDU). TS catalyses the conversion of deoxyuridylate (dUMP) to thymidylate (dTMP) and is a key enzyme in pyrimidine biosynthesis, providing the only source of dTMP synthesized de novo in mammalian cells. VZV encodes a specialized viral form of TS. TS activity in cells infected with VZV (TIO-VZV and TK−-VZV) increased proportionally with focus formation. From kinetic analysis using the Michaelis-Menten equation, the authors determined a Km value of 6.6μm for dUMP of TS induced in VZV-infected cells and a corresponding value from mock-infected cells of only 2.8μm. BVDU inhibited the induction of TS activity in TK+-VZV-infected cells at concentrations under ×10−3μm, but did not inhibit TS activity of TK−-VZV- or mock-infected cells at concentrations as high as 10μm. Inhibitory activity of BVDU against TS induced in TK+-VZV-infected cells appears to occur when BVDU is phosphorylated to BVDU monophosphate by viral pyrimidine kinase. These results suggest that the selective inhibitory action of BVDU on VZV replication depends on a specific interaction with both viral TK and TS. 5-Bromodeoxyuridine and 5-iododeoxyuridine inhibited TS activities induced in both VZV (TK+, TK−) and mock-infected cells. Other antiherpes compounds [i.e. 1-β-D-arabinofuranosyl- E-5-(2-bromovinyl)uracil, 9- 2-hydroxyethoxymethyl)-guanine, arabinosyladenine, and others] did not inhibit TS activity in VZV-infected cells at concentrations Of 10μm.

Ingenol Derivatives are Highly Potent and Selective Inhibitors of HIV Replication in Vitro

Ingenol 3,5,20-triacetate has recently been identified as a highly potent and selective inhibitor of HIV replication in vitro. To evaluate the potential of ingenol derivatives as anti-HIV agents, several ingenol derivatives have been synthesized and investigated for their anti-HIV activities, structure-activity relationships, and possible mechanisms of action. Among the ingenol derivatives, 13-hydroxyingenol-3-(2,3-dimethylbutanoate)-13-dodecanoate (RD4-2138) proved to be a highly potent and selective inhibitor of HIV replication. Its 50% effective concentration for viral replication in MT-4 cells was 0.07-0.5 nM depending on viral strains, including HIV-2. This concentration was approximately 105-fold lower than its cytotoxic threshold. RD4-2138 was also inhibitory to the syncytium formation induced by cocultivation of Molt-4 cells with Molt-4/IIIB cells (Molt-4 cells chronically infected with HIV-1). Some correlation was observed with the ingenol derivatives between their inhibitory effects on HTLV-IIIB replication and surface CD4 expression in MT-4 cells, suggesting that the mechanism of inhibition is in part attributed to the inhibition of virus adsorption through down-regulation of CD4 molecules in the host cells. However, such correlation was not identified between the inhibition of HTLV-IIIB and the activation of protein kinase C. Thus, they might have a potential as effective anti-HIV agents when toxicity in vivo could be elucidated.

Abstract P6-12-04: Delayed hospital visits in patients with breast cancer after the great East Japan earthquake and the subsequent Fukushima Daiichi nuclear power plant accident: A retrospective comparative analysis

Introduction

In breast cancer, delay in first presentation and self-interruption of continuous treatment are associated with lower survival. It has been suggested that risk factors for such behavioral patterns include poor social support.

Minamisoma City, located within a 30 kilometers radius from Fukushima Daiichi nuclear power plant, has experienced rapid change in social structures following the Great East Japan Earthquake and the subsequent power plant accident. There has been a mass evacuation among young and middle-aged generations for fear of potential irradiation, and this has resulted in the separation of families and friends. These changes may have resulted in a deterioration of social support for residents, which could consequently lead to changed patterns of behavior in diseases such as breast cancer.

Objectives

This study compared the behavioral patterns before and after the disasters in patients with breast cancer in Minamisoma City.

Methods

We retrospectively analyzed data from patients with breast cancer who were diagnosed from January 2008 through March 2015 in the two main cancer centers in Minamisoma City. Demographic and clinical information was extracted from medical records, including age, stage, pathological findings, treatment, and the reason for the first hospital visit. The main outcome was a change of interval from the appearance of initial symptoms to the first hospital visit before and after the disasters. We also assessed whether continuous follow-up was maintained after the disasters. We used an unpaired t-test for numerical variables and a chi-squared test for categorical variables.

Results

A total of 102 and 97 patients were diagnosed with breast cancer before and after the disasters, respectively. There were no statistically significant differences between the 2 groups concerning average age (61 years old vs. 61 years old, p=1), stage 3 or 4 cancer (18% vs. 17%, p=0.81), invasive cancer (92% vs. 93%, p=0.87) and symptomatic patients (75% vs. 74%, p=0.74), respectively. However, after the disasters, there were significant increases in the ratio of patients with more than a one-year delay from the appearance of the initial symptom to the first hospital visit (5.4% vs. 15%, p<0.05). The patients with more than a one-year delay had a significantly higher ratio of advanced stage cancer compared with patients who visited a hospital earlier. Continuous follow-up was maintained in all patients diagnosed after the disasters.

Discussion

The characteristics of patients were not significantly different before and after the disasters, while the ratio of patients with more than a one-year delay of the first hospital visit significantly increased after the disasters. Although information on social capital and other sociodemographic factors was not available, we speculate that poor social support due to changed social structures after the disasters might contribute to delay in first presentation in symptomatic breast cancer patients. Further study is warranted to clarify the factors associated with delayed hospital visits, in order to establish effective health interventions in the aftermath of mass disasters.

Citation Format: Ozaki A, Tsubokura M, Nomura S, Morita T, Ochi S, Kato S, Saji S, Yokota T, Leppold C, Tanimoto T, Kami M, Tsukada M, Ohira H. Delayed hospital visits in patients with breast cancer after the great East Japan earthquake and the subsequent Fukushima Daiichi nuclear power plant accident: A retrospective comparative analysis. [abstract]. In: Proceedings of the Thirty-Eighth Annual CTRC-AACR San Antonio Breast Cancer Symposium: 2015 Dec 8-12; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2016;76(4 Suppl):Abstract nr P6-12-04.

Spinal cord ring enhancement in patients with neuromyelitis optica

OBJECTIVES

Clinical and pathological significance of gadolinium (Gd)-enhancing pattern on magnetic resonance imaging (MRI), including ring enhancement (RE), is well documented in multiple sclerosis but not in neuromyelitis optica (NMO), especially in the spinal cord. The purpose of this study is to examine the prevalence of spinal cord RE in NMO and to determine the association between clinical characteristics and spinal cord RE.

MATERIALS AND METHODS

We retrospectively examined Gd-enhanced spinal cord MRI scans, during the acute phase, in patients with anti-aquaporin 4-positive NMO, including NMO spectrum disorder. We then analysed their clinical features and MRI imaging characteristics of spinal cord lesions.

RESULTS

Of the 30 patients with NMO, we enrolled 12 patients with 16 Gd-enhanced spinal cord MRI scans in this study. Five scans revealed RE (31.2%). Male ratio, as well as myelin basic protein (MBP) levels, in the cerebrospinal fluid (CSF) of patients with RE was significantly higher than those of patients without RE (P = 0.018, P = 0.026, respectively).

CONCLUSIONS

Spinal cord RE is common in patients with NMO. Higher MBP levels in the CSF of patients with RE can be associated with a higher degree of myelin damage.

Topographical representations of taste response characteristics in the rostral nucleus of the solitary tract in the rat

The rostral nucleus of the solitary tract (rNST) is the first-order taste relay in rats. This study constructed topographical distributions of taste response characteristics (best-stimulus, response magnitude, and taste-tuning) from spike discharges of single neurons in the rNST. The rNST is divided into four subregions along the rostrocaudal (RC) axis, which include r1-r4. We explored single-neuron activity in r1-r3, using multibarreled glass microelectrodes. NaCl (N)-best neurons were localized to the rostral half of r1-r3, while HCl (H)-best and sucrose (S)-best neurons showed a tendency toward more caudal locations. NaCl and HCl (NH)-best neurons were distributed across r2-r3. The mean RC values and Mahalanobis distance indicated a significant difference between the distributions of N-best and NH-best neurons in which N-best neurons were located more rostrally. The region of large responses to NaCl (net response >5 spikes/s) overlapped with the distribution of N-best neurons. The region of large responses to HCl extended widely over r1-r3. The region of large responses to sucrose was in the medial part of r2. The excitatory region (>1 spike/s) for quinine overlapped with that for HCl. Neurons with sharp to moderate tuning were located primarily in r1-r2, while those with broad tuning were located in r2-r3. The robust responses to NaCl in r1-r2 primarily contributed to sharp to moderate taste-tuning. Neurons in r3 tended to have broad tuning, apparently due to small responses to both NaCl and HCl. Therefore, the rNST is spatially organized by neurons with distinct taste response characteristics, suggesting that these neurons serve different functional roles.