Usefulness of 18F-Fluorodeoxyglucose Positron Emission Tomography for Follow-Up of 13-cis-Retinoic Acid Treatment for Residual Neuroblastoma After Myeloablative Chemotherapy

13-cis-retinoic acid (13-cis-RA) treatment is used as a second-line treatment for residual or recurrent neuroblastoma. However, determining the duration of 13-cis-RA treatment for residual and recurrent neuroblastoma can be a problem because it is difficult to evaluate the effectiveness of the treatment.We performed 13-cis-RA treatment to remove residual active neuroblastoma cells in an 8-year-old boy with stage 4 neuroblastoma that developed from a left sympathetic ganglion and had been treated with chemotherapy, surgery, autologous peripheral blood stem-cell transplantation, and radiotherapy. ¹⁸F-fluorodeoxyglucose positron emission tomography (¹⁸F-FDG-PET) and iodine-123 metaiodobenzylguanidine (¹²³I-MIBG) scintigraphy obtained immediately before 13-cis-RA treatment both showed positive findings in the area of the primary lesion. At 18 months after 13-cis-RA treatment, there was accumulation on ¹²³I-MIBG scintigraphy but no uptake on ¹⁸F-FDG-PET, and 13-cis-RA treatment was suspended. The patient has been in complete remission for 3 years. In comparing the effectiveness of the 2 imaging modalities for monitoring the response to 13-cis-RA treatment, we considered that ¹⁸F-FDG-PET was superior to ¹²³I-MIBG scintigraphy because ¹⁸F-FDG-PET images were not affected by the cell differentiation induced by 13-cis-RA treatment in our case. Thus, ¹⁸F-FDG-PET was useful for determining the treatment response and outcomes.We have reported a case of residual neuroblastoma treated with differentiation-inducing 13-cis-RA therapy. Different results were produced with ¹⁸F-FDG-PET and ¹²³I-MIBG scintigraphy. The cessation of 13-cis-RA treatment was based on ¹⁸F-FDG-PET findings and there has been no relapse for 3 years.     

Autocrine regulation of ecdysone synthesis by β3-octopamine receptor in the prothoracic gland is essential for Drosophila metamorphosis

In Drosophila, pulsed production of the steroid hormone ecdysone plays a pivotal role in developmental transitions such as metamorphosis. Ecdysone production is regulated in the prothoracic gland (PG) by prothoracicotropic hormone (PTTH) and insulin-like peptides (Ilps). Here, we show that monoaminergic autocrine regulation of ecdysone biosynthesis in the PG is essential for metamorphosis. PG-specific knockdown of a monoamine G protein-coupled receptor, β3-octopamine receptor (Octβ3R), resulted in arrested metamorphosis due to lack of ecdysone. Knockdown of tyramine biosynthesis genes expressed in the PG caused similar defects in ecdysone production and metamorphosis. Moreover, PTTH and Ilps signaling were impaired by Octβ3R knockdown in the PG, and activation of these signaling pathways rescued the defect in metamorphosis. Thus, monoaminergic autocrine signaling in the PG regulates ecdysone biogenesis in a coordinated fashion on activation by PTTH and Ilps. We propose that monoaminergic autocrine signaling acts downstream of a body size checkpoint that allows metamorphosis to occur when nutrients are sufficiently abundant.In many animal species, the developmental transition is a well-known biological process in which the organism alters its body morphology and physiology to proceed from the juvenile growth stage to the adult reproductive stage. For example, in mammals, puberty causes a drastic change from adolescent to adulthood, whereas in insects, metamorphosis initiates alteration of body structures to produce sexually mature adults, a process accompanied by changes in habitat and behavior. These developmental transitions are primarily regulated by steroid hormones, production of which is regulated coordinately by developmental timing and nutritional conditions (1–3). How these processes are precisely regulated in response to developmental and environmental cues is a longstanding question in biology.In holometabolous insects, the steroid hormone ecdysone plays a pivotal role in metamorphosis. In Drosophila, metamorphic development from the third-instar larva into the adult, through the prepupa and pupa, initiates 90–96 h after hatching (hAH) at 25 °C under a standard culture condition (4). At the onset of the larval–prepupal transition, ecdysone is produced in the prothoracic gland (PG) and then converted into its active form, 20-hydroxyecdysone (20E), in the peripheral organs. The activities of 20E terminate larval development and growth and initiates metamorphosis (5). Ecdysone biosynthesis is regulated in the PG by neuropeptides, enabling modulation of the timing of 20E pulses during development (2–4). The best-known stimulator of ecdysone biosynthesis is prothoracicotropic hormone (PTTH), which is produced by neurons in the CNS. PTTH activates the receptor tyrosine kinase Torso in the PG to stimulate expression of ecdysone biosynthetic genes through the Ras85D/Raf/MAPK kinase (MEK)/extracellular signal-regulated kinase (ERK) pathway (6, 7). Insulin-like peptides (Ilps), members of another class of neuron-derived factors, activate PI3K in the PG, resulting in production of ecdysone biosynthetic proteins (8–11). The Activin/transforming growth factor-β (TGF-β) signaling pathway is also required in the PG for the expression of PTTH and Ilps receptors, although to date it remains unclear which organ produces the ligand that acts on the PG (12).In addition to these neuropeptides, the larval–prepupal transition is modulated by environmental cues such as nutritional conditions that influence larval body size. For example, at 56 hAH, early third-instar larvae attain the minimal viable weight (MVW), at which sufficient nutrition is stored in larvae to ensure their survival through metamorphosis (2, 13, 14). After attaining MVW, larvae pass another checkpoint, critical weight (CW), defined as the minimum larval size at which starvation no longer delays the larval–prepupal transition (2, 13, 14). In Drosophila, both checkpoints occur almost simultaneously, making it difficult to distinguish them (2). However, CW is regarded as a body size checkpoint that initiates metamorphosis and is therefore believed to ultimately modulate ecdysone production in the PG. However, its downstream effectors and signaling pathway remain elusive.Based on data obtained in Manduca and Bombyx (15, 16), a G protein-coupled receptor (GPCR) has long been postulated to be essential for ecdysone biosynthesis in the PG. However, this GPCR and its ligand have not yet been identified. Here we show that monoaminergic autocrine signaling through a GPCR, β3-octopamine receptor (Octβ3R), plays an essential role in ecdysone biosynthesis to execute the larval–prepupal transition. Octβ3R is also required for activation of PTTH and Ilps signaling. We propose that this autocrine system acts downstream of the CW checkpoint to allow the larval–prepupal transition. We speculate that monoamines play an evolutionarily conserved role in the regulation of steroid hormone production during developmental transitions.     

Multiaddressable molecular rectangles with reversible host–guest interactions: Modulation of pH-controlled guest release and capture

A series of multiaddressable platinum(II) molecular rectangles with different rigidities and cavity sizes has been synthesized by endcapping the U-shaped diplatinum(II) terpyridine moiety with various bis-alkynyl ligands. The studies of the host–guest association with various square planar platinum(II), palladium(II), and gold(III) complexes and the related low-dimensional gold(I) complexes, most of which are potential anticancer therapeutics, have been performed. Excellent guest confinement and selectivity of the rectangular architecture have been shown. Introduction of pH-responsive functionalities to the ligand backbone generates multifunctional molecular rectangles that exhibit reversible guest release and capture on the addition of acids and bases, indicating their potential in controlled therapeutics delivery on pH modulation. The reversible host–guest interactions are found to be strongly perturbed by metal–metal and π–π interactions and to a certain extent, electrostatic interactions, giving rise to various spectroscopic changes depending on the nature of the guest molecules. Their binding mode and thermodynamic parameters have been determined by 2D NMR and van’t Hoff analysis and supported by computational study.The study of metal–metal interactions has drawn enormous attention since the past two decades because of the intriguing spectroscopic and photophysical properties arising from the close proximity of the metal centers (1, 2). Square planar d⁸ platinum(II) complexes with coordination unsaturation are one of the important classes of metal complexes that have been extensively explored because of their capability to exhibit metal–metal interactions and display rich photophysical properties (3–26). Platinum(II) terpyridine complexes have been found to exhibit rich polymorphism in the solid state (16–20) owing to their square planar coordination geometry, which permits facile access to Pt(II)···Pt(II) interactions as well as π–π interactions between the chromophores. It was not until 2001 that the first successful synthesis of platinum(II) terpyridine alkynyl complexes, which possess enhanced solubility and luminescence compared with the chloro counterpart, was reported (16). Additional efforts have been devoted to the use of the system to respond to external stimuli, such as variation in solvent composition (17, 18), pH (19, 20), temperature (21, 22), addition of ionic (24–26), and polymeric species (27, 28), in which spectral changes induced by strong Pt(II)···Pt(II) and π−π interactions have been displayed.In the past few decades, enormous efforts have been devoted to the construction of molecular architectures by fusing the organic framework to the transition metal centers through self-assembly processes (29–57). There has been continuous interest in the construction of stimuli-responsive metallosupramolecular architectures with diverse sizes, shapes, and symmetries to rationalize the criteria for molecular recognition and impart them on unique areas of applications, such as stereoselective guest encapsulation and molecular transporting devices (45–65). Although such a variety of metal–organic macrocyclic architectures has been reported, those involving the use of noncovalent interactions other than those of hydrogen bonding, donor–acceptor, electrostatic, and hydrophobic–hydrophobic interactions as well as luminescence changes that depend on the nature of the guests, which would be attractive for chemo- and biosensing, have been rare and are rather underexplored. Examples of such systems that can exhibit reversible host–guest association are also limited.Since the discovery of anticancer properties of cisplatin in 1969 (58), the coordination chemistry and the development of related species with enhanced properties and reduced cytotoxicity have received enormous attention. Although the potency and cytotoxicity studies are important, the availability of the drugs and their transport and release to the site of action are equally important. Thus, the design of smart drug delivery systems has been an area of growing interest. The first phosphorescent molecular tweezers making use of the alkynylplatinum(II) terpyridine moiety have been reported by our group to show their host–guest interactions with transition metal complexes (57). However, the opened structures of the tweezers have limited their selectivity and functionality. To accomplish the controlled drug delivery functionalities, the first main strategy is to rigidify the molecular architecture of the host from tweezers to a rectangle, so that the guest molecules would be better accommodated within the cavity, which may lead to a more selective encapsulation of guests within a definite size and steric environment. The possibility of introducing responsive functionalities into the molecular rectangles, which may serve as models for the study of on-demand controlled guest capture and release systems, has also been explored. pH-sensitive pyridine moieties have, therefore, been incorporated into the backbone of the rectangle to modulate the reversible host–guest interaction within the constrained rectangle environment on protonation/deprotonation of the pyridine nitrogen atom to achieve multiaddressable functions that would not have been readily achievable with the molecular tweezers structure. Additionally, the use of various platinum and gold complexes as guest molecules, which have been shown to display anticancer therapeutic behavior (58–65), may lead to the design of a smart multiaddressable molecular rectangle system that could capture and release specific guest molecules under different pH conditions to achieve proof-of-principle on-demand controlled drug delivery. Herein, the design and synthesis of a series of alkynylplatinum(II) terpyridine molecular rectangles (Fig. 1) with different geometries, topologies and electronic properties are reported. Moreover, the encapsulation of various guest molecules is also investigated in detail to provide a proof-of-principle model for the design of artificial drug delivery systems with the modulation of drug release by pH.Open in a separate windowFig. 1.Molecular structures of rectangles 1−4.     

Hyaluronan stimulates chondrogenic gene expression in human meniscus cells

Purpose/Aim of the Study: Inner meniscus cells have a chondrocytic phenotype, whereas outer meniscus cells have a fibroblastic phenotype. In this study, we examined the effect of hyaluronan on chondrocytic gene expression in human meniscus cells. Materials and Methods: Human meniscus cells were prepared from macroscopically intact lateral meniscus. Inner and outer meniscus cells were obtained from the inner and outer halves of the meniscus. The cells were stimulated with hyaluronan diluted in Dulbecco’s modified Eagle’s medium without serum to the desired concentration (0, 10, 100, and 1000 μg/mL) for 2–7 days. Cellular proliferation, migration, and polymerase chain reaction analyses were performed for the inner and outer cells separately. Meniscal samples perforated by a 2 mm diameter punch were maintained for 3 weeks in hyaluronan-supplemented medium and evaluated by histological analyses. Results: Hyaluronan increased the proliferation and migration of both meniscus cell types. Moreover, cellular counts at the surface of both meniscal tissue perforations were increased by hyaluronan treatments. In addition, hyaluronan stimulated α1(II) collagen expression in inner meniscus cells. Accumulation of type II collagen at the perforated surface of both meniscal samples was induced by hyaluronan treatment. Hyaluronan did not induce type I collagen accumulation around the injured site of the meniscus. Conclusion: Hyaluronan stimulated the proliferation and migration of meniscus cells. Our results suggest that hyaluronan may promote the healing potential of meniscus cells in damaged meniscal tissues.     

Roles of organic anion transporters (OATs) in renal proximal tubules and their localization

Organic anions (OAs) are secreted in renal proximal tubules in two steps. In the first step, OAs are transported from the blood through basolateral membranes into proximal tubular cells. The prototypical substrate for renal organic anion transport systems, para-aminohippurate (PAH), is transported across basolateral membranes of proximal tubular cells via OAT1 (SLC22A6) and OAT3 (SLC22A8) against an electrochemical gradient in exchange for intracellular dicarboxylates. In the second step, OAs exit into urine through apical membranes of proximal tubules. This step is thought to be performed by multidrug efflux transporters and a voltage-driven organic anion transporter. However, the molecular nature and precise functional properties of these efflux systems are largely unknown. Recently, we characterized an orphan transporter known as human type I sodium-phosphate transporter 4, hNPT4 (SLC17A3), using the Xenopus oocyte expression system. hNPT4 acts as a voltage-driven efflux transporter (“human OATv1”) for several OAs such as PAH, estrone sulfate, diuretic drugs, and urate. Here, we describe a model for an OA secretory pathway in renal tubular cells in which OAs exit cells and enter the tubular lumen via hOATv1 (hNPT4). Additionally, hOATv1 functions as a common renal secretory pathway for both urate and drugs, indicating that hOATv1 may be a leak pathway for excess urate that is reabsorbed via apical URAT1 to control the intracellular urate levels. Therefore, we propose a molecular mechanism for the induction of hyperuricemia by diuretics: the diuretics enter proximal tubular cells via basolateral OAT1 and/or OAT3 and may then interfere with the NPT4-mediated apical urate efflux in the renal proximal tubule.     

Renal function on admission modifies prognostic impact of diuretics in acute heart failure: a propensity score matched and interaction analysis

Although intravenous diuretics have been mainstay drugs in patients with acute heart failure (AHF), they have been suggested to have some deleterious effects on prognosis. We postulated that renal function may modify their deleterious effects in AHF patients. The study population consisted of 1094 AHF patients from three hospitals. Renal dysfunction (RD) was defined as estimated glomerular filtration rate (eGFR) <60 mL/min/1.73 m² on admission, and the cohort was divided into a high-dose furosemide (≥100 mg/48 h) and low-dose furosemide group according to the amount of intravenous furosemide used within 48 h from admission. In the whole cohort, in-hospital mortality rate was higher in the high-dose furosemide group than the low-dose furosemide group (12.5 vs. 6.6 %, respectively, P = 0.001). However, this difference in the in-hospital mortality rates was significant only in the RD subgroup (15.6 vs. 7.0 %, respectively, P < 0.001), and not in the non-RD subgroup (2.5 vs. 5.9 %, respectively, P = 0.384). Propensity score-matched analysis was performed to evaluate the impact of high-dose furosemide on prognosis. After propensity score matching, high-dose furosemide was not associated with in-hospital mortality (OR 1.25, 95 % CI 0.73–2.16, P = 0.408). However, there was a qualitative difference in OR for in-hospital mortality between AHF with RD (OR 1.77, 95 % CI 0.96–3.28, P = 0.068) and without RD (OR 0.23, 95 % CI 0.05–1.10, P = 0.064), and there was a significant interaction between eGFR and prognostic impact of high-dose furosemide (P for OR interaction = 0.013). An inverse relationship was observed between eGFR and OR for in-hospital death in the group treated with high-dose furosemide (decreasing OR with better eGFR). The deleterious effect of diuretics was significantly modified with renal function in AHF. This association may be one reason for poorer prognosis of AHF patients complicated with renal impairment.     

Does restriction of glenohumeral horizontal adduction reflect posterior capsule thickening of the throwing shoulder?

[Purpose] Glenohumeral posterior capsule tightness possibly relates to posterior capsule thickness (PCT). The purpose of the current study was to analyze the relationships between PCT and glenohumeral range of motion (ROM) in horizontal adduction (HAdd) and internal rotation (IR). [Subjects and Methods] This study recruited 39 healthy collegiate baseball players. We measured PCT by using ultrasonography and ROM of the glenohumeral joint of the throwing shoulder by using a digital inclinometer. Pearson’s correlation coefficients were calculated between PCT and HAdd or IR ROM. [Results] There was no correlation between PCT and HAdd ROM, but PCT was significantly correlated with IR ROM. [Conclusion] This result indicates that posterior shoulder capsule tightness only relates to IR ROM, and that restricted HAdd ROM might reflect tightness of other tissue, such as the posterior deltoid.Key words: Capsule thickness, Horizontal adduction, Internal rotation