Discovery of New Isotope ^{241}U and Systematic High-Precision Atomic Mass Measurements of Neutron-Rich Pa-Pu Nuclei Produced via Multinucleon Transfer Reactions

The new isotope ^{241}U was synthesized and systematic atomic mass measurements of nineteen neutron-rich Pa-Pu isotopes were performed in the multinucleon transfer reactions of the ^{238}U+^{198}Pt system at the KISS facility. The present experimental results demonstrate the crucial role of the multinucleon transfer reactions for accessing unexplored neutron-rich actinide isotopes toward the N=152 shell gap in this region of nuclides.

Extension of microglial activation is associated with epilepsy and cognitive dysfunction in Tuberous sclerosis complex: A TSPO-PET study

BACKGROUND AND OBJECTIVES

Neuroinflammation contributes to the severity of various neurological disorders, including epilepsy. Tuberous sclerosis complex (TSC) is a condition that results in the overactivation of the mammalian target of rapamycin (mTOR) pathway, which has been linked to the activation of microglia responsible for neuroinflammation. To clarify the involvement of neuroinflammation in the neuropathophysiology of TSC, we performed a positron emission tomography (PET) study using the translocator protein (TSPO) radioligand, [¹¹C] DPA713, and investigated microglial activation in relation to neurological manifestations, especially epilepsy and cognitive function.

METHODS

This cross-sectional study included 18 patients with TSC (6 in the no-seizure group, 6 in the refractory seizure group, and 6 in the mTOR-inhibitor [mTOR-i] group). All participants underwent [¹¹C] DPA713-PET. PET results were superimposed with a 3D T2-weighted fluid-attenuated inversion-recovery (FLAIR) and T1-weighted image (T1WI) to evaluate the location of cortical tubers. Microglial activation was assessed using the standardized uptake value ratio (SUVr) of DPA713 binding. The volume ratio of the DPA713-positive area to the intracranial volume (volume ratio of DPA713/ICV) was calculated to evaluate the extent of microglial activation. A correlation analysis was performed to examine the relationship between volume ratio of DPA713/ICV and severity of epilepsy and cognitive function.

RESULTS

Most cortical tubers with hyperintensity on FLAIR and hypo- or isointensity on T1WI showed microglial activation. The extent of microglial activation was significantly greater in the refractory seizure group than in the no-seizure or mTOR-i groups (p < 0.001). The extent of microglial activation in subjects without mTOR-i treatment correlated positively with epilepsy severity (r = 0.822, P = 0.001) and negatively with cognitive function (r = -0.846, p = 0.001), but these correlations were not present in the mTOR-i group (r = 0.232, P = 0.658, r = 0.371, P = 0.469, respectively).

CONCLUSION

Neuroinflammation is associated with the severity of epilepsy and cognitive dysfunction in brains with TSC. mTOR-i may suppress the extent of neuroinflammation in TSC. Investigating the spread of microglial activation using TSPO-PET in these patients may help to predict the progression of neuropathy by assessing the degree of neuroinflammation and therefore be useful for determining how aggressive the treatment should be and in assessing the effectiveness of such treatment in patients with TSC.

First Application of Mass Measurements with the Rare-RI Ring Reveals the Solar r-Process Abundance Trend at A=122 and A=123

The Rare-RI Ring (R3) is a recently commissioned cyclotronlike storage ring mass spectrometer dedicated to mass measurements of exotic nuclei far from stability at Radioactive Isotope Beam Factory (RIBF) in RIKEN. The first application of mass measurement using the R3 mass spectrometer at RIBF is reported. Rare isotopes produced at RIBF-^{127}Sn, ^{126}In, ^{125}Cd, ^{124}Ag, ^{123}Pd-were injected in R3. Masses of ^{126}In, ^{125}Cd, and ^{123}Pd were measured whereby the mass uncertainty of ^{123}Pd was improved. This is the first reported measurement with a new storage ring mass spectrometry technique realized at a heavy-ion cyclotron and employing individual injection of the preidentified rare nuclei. The latter is essential for the future mass measurements of the rarest isotopes produced at RIBF. The impact of the new ^{123}Pd result on the solar r-process abundances in a neutron star merger event is investigated by performing reaction network calculations of 20 trajectories with varying electron fraction Y_{e}. It is found that the neutron capture cross section on ^{123}Pd increases by a factor of 2.2 and β-delayed neutron emission probability, P_{1  n}, of ^{123}Rh increases by 14%. The neutron capture cross section on ^{122}Pd decreases by a factor of 2.6 leading to pileup of material at A=122, thus reproducing the trend of the solar r-process abundances. The trend of the two-neutron separation energies (S_{2n}) was investigated for the Pd isotopic chain. The new mass measurement with improved uncertainty excludes large changes of the S_{2n} value at N=77. Such large increase of the S_{2n} values before N=82 was proposed as an alternative to the quenching of the N=82 shell gap to reproduce r-process abundances in the mass region of A=112-124.

Alkaline phosphatase in pediatric patients with genu varum caused by vitamin D-deficient rickets

An elevated serum alkaline phosphatase (ALP) level is one of the markers for the presence of rickets in children, but it is also associated with bone formation. However, its role in diagnosing genu varum in pediatric patients with vitamin D-deficient rickets is still unknown. To clarify the role of the serum ALP level in assessing the severity of genu varum, we retrospectively investigated this issue statistically using data on rickets such as serum intact parathyroid hormone (iPTH), 25-hydroxyvitamin D, 1,25-dihydroxyvitamin D, ALP, the level of creatinine as the percentage of the median according to age (%Cr), and the metaphyseal diaphyseal angle (MDA) in the lower extremities as an index of the severity of genu varum. A multiple regression analysis revealed that log ALP and %Cr values were negatively associated with MDA values. The former association was also confirmed by a linear mixed model, while iPTH was positively associated with MDA by path model analysis. To elucidate the association of ALP with MDA in the presence of iPTH, we investigated three-dimensional figures by neural network analysis. This indicated the presence of a biphasic association of ALP with MDA: the first phase increases while the second decreases MDA. The latter phenomenon is considered to be associated with the increase in bone formation due to the mechanical stress loaded on the lower extremities. These findings are important and informative for pediatricians to understand the significance of the serum ALP level in pediatric patients with genu varum caused by vitamin D deficiency.

Properties of ^{187}Ta Revealed through Isomeric Decay

Mass-separated ^{187}Ta_{114} in a high-spin isomeric state has been produced for the first time by multinucleon transfer reactions, employing an argon gas-stopping cell and laser ionization. Internal γ rays revealed a T_{1/2}=7.3±0.9  s isomer at 1778±1  keV, which decays through a rotational band with perturbations associated with the approach to a prolate-oblate shape transition. Model calculations show less influence from triaxiality compared to heavier elements in the same mass region. The isomer-decay reduced E2 hindrance factor f_{ν}=27±1 supports the interpretation that axial symmetry is approximately conserved.

THU0232 INTERFERON SIGNATURE IN LUPUS KIDNEY IS CORRELATED WITH REMISSION WITHIN 56 WEEKS

Background:

Activation of the type I interferon (IFN) pathway has been implicated in the initiation of systemic lupus erythematosus(SLE) and most SLE patients show increased expression of IFN-regulated genes in peripheral blood mononuclear cells or whole blood. However, the IFN signature in lupus kidney is not well examined especially at single cell resolution.

Objectives:

To clarify the significance of the IFN signature in lupus kidney at single cell resolution

Methods:

18 lupus kidney (LN) and 34 transplanted kidney (KTx) samples were included in the study. Residual frozen kidney biopsies were collected after clinical diagnosis. The tissue from one donor was split into two. One portion was used for total RNA-Seq (tRNA-Seq) by SMARTer Stranded Total RNA-Seq Kit v2 - Pico Input Mammalian (Takara/Clontech). The rest was used for single nucleus RNA-Seq (snRNA-Seq) using Chromium Single Cell 3’ Reagent Kits v3 (10x Genomics) (7 LN and 17 KTx). For the tRNA-Seq, the sequence reads were aligned to Ensembl genome annotation (Ens93) by STAR and the aligned reads were counted by htseq. IFN score of tRNA-Seq was calculated using the reported method [1] per each module (M1.2, M3.4 and M5.12). For the snRNA-Seq, the sequenced reads were processed on the standard pipeline of CellRanger (10x Genomics) and the data was visualized using Seurat. IFN score of snRNA-Seq was computed by the method reported by Arazi A,et al[2].

Clinical outcomes of LN were examined on the medical records retrospectively and the clinical remission in 56 weeks for LN was defined as a urinary protein/creatinine ratio less than 0.5 g/gCr.

Results:

11 LN had clinical remission and 7 LN showed non remitted disease within 56 weeks after the biopsy. There were no statistical significance co-variants such as age, gender and WHO class in pathology. IFN score of M1.2, M3.4 and M5.12 were significantly increased in LN with remission within 56 weeks (median 0.773 vs 0.659, 0.595 vs 0.243 and 0.415 vs 0.100: p-value 0.03, 0.01 and 0.02 [Wilcox rank-test]) in tRNA-Seq. In the snRNA-Seq, the lupus kidney with low IFN score showed restricted IFN signature in the endothelial cells mainly, which can be detected even in the controls, but those with high IFN score indicated broadly spread IFN signature among all of the cell types.

Conclusion:

LN with high IFN score in kidney tissue is correlated with remission within 56 weeks. LN with low IFN score showed IFN signature restricted to endothelial cells but those with a higher IFN score revealed broadly affected cell types with IFN signature. These results suggest that the IFN signature of LN may start from endothelial cells and then spread to the whole kidney.

References:

[1]Chiche L, Jourde-Chiche N, Whalen E,et al.Modular Transcriptional Repertoire Analyses of Adults With Systemic Lupus Erythematosus Reveal Distinct Type I and Type II Interferon Signatures.Arthritis & Rheumatology2014;66:1583–95.doi:10.1002/art.38628

[2]Arazi A, Rao DA, Berthier CC,et al.The immune cell landscape in kidneys of patients with lupus nephritis.Nat Immunol2019;20:902–14.

doi:10.1038/s41590-019-0398-x

Disclosure of Interests: :

Masatoshi Kanda: None declared, Takahiro Tsuji: None declared, Masaya Mukai: None declared, Hiroki Takahashi: None declared, Tatsuya Atsumi Grant/research support from: Eli Lily Japan K.K., Alexion Pharmaceuticals, Inc., Bristol-Myers Squibb Co., AbbVie Inc., Daiichi Sankyo Co., Ltd., Pfizer Inc., Chugai Pharmaceutical Co., Ltd., Mitsubishi Tanabe Pharma Co., Astellas Pharma Inc., Consultant of: Gilead Sciences, Inc., Eli Lilly Japan K.K., UCB Japan Co. Ltd., AbbVie Inc., Daiichi Sankyo Co., Ltd., Pfizer Inc., Chugai Pharmaceutical Co., Ltd., Speakers bureau: Eli Lilly Japan K.K., UCB Japan Co. Ltd., Bristol-Myers Squibb Co., AbbVie Inc., Eisai Co. Ltd., Otsuka Pharmaceutical Co., Ltd., Daiichi Sankyo Co., Ltd., Pfizer Inc., Chugai Pharmaceutical Co., Ltd., Mitsubishi Tanabe Pharma Co., Takeda Pharmaceutical Co., Ltd., Astellas Pharma Inc., Norbert Hübner: None declared

Efficient two-color two-step laser ionization schemes of λ1∼ 250 nm and λ2 = 307.9 nm for heavy refractory elements-Measurements of ionization cross-sections and hyperfine spectra of tantalum and tungsten

We demonstrated efficient two-color two-step laser ionization schemes in the combined use of λ₁ ∼ 250 nm and λ₂ = 307.9 nm, which are applicable to heavy refractory elements with an atomic number in the wide range of Z = 69-78. We investigated newly observed ionization schemes of tantalum and tungsten atoms in an argon-gas-cell-based laser ion source for the efficient ionization of atoms of unstable nuclei through the two-color two-step laser resonance ionization technique. We experimentally determined the ionization cross sections from the measured saturation curves by solving the rate equations for the ground, intermediate, and ionization continuum populations. Hyperfine structures of these elements were also studied to deduce the isotope-shift, pressure-shift, and pressure-broadening in the resonance spectra of the excitation transitions in the argon gas cell. The electronic factor F₂₅₅ of the excitation transition λ₁ = 255.2115 nm between the ground and intermediate states was deduced from the measured isotope shifts of stable ^{182,183,184,186}W isotopes. The ionization schemes investigated here are applicable to extract any isotopes of these elements by considering the measured pressure shift and nuclear isotope shift in optimizing the wavelength λ₁.

First Direct Mass Measurements of Nuclides around Z=100 with a Multireflection Time-of-Flight Mass Spectrograph

The masses of ^{246}Es, ^{251}Fm, and the transfermium nuclei ^{249-252}Md and ^{254}No, produced by hot- and cold-fusion reactions, in the vicinity of the deformed N=152 neutron shell closure, have been directly measured using a multireflection time-of-flight mass spectrograph. The masses of ^{246}Es and ^{249,250,252}Md were measured for the first time. Using the masses of ^{249,250}Md as anchor points for α decay chains, the masses of heavier nuclei, up to ^{261}Bh and ^{266}Mt, were determined. These new masses were compared with theoretical global mass models and demonstrated to be in good agreement with macroscopic-microscopic models in this region. The empirical shell gap parameter δ_{2n} derived from three isotopic masses was updated with the new masses and corroborates the existence of the deformed N=152 neutron shell closure for Md and Lr.

7Be and 8B reaction dynamics at Coulomb barrier energies

We investigated the reaction dynamics induced by the 7Be,8B+208Pb collisions at energies around the Coulomb barrier. Charged particles originated by both the col- lisions were detected by means of 6 ΔE-Eres telescopes of a newly developed detector array. Experimental data were analysed within the framework of the Optical Model and the total reaction cross-sections were compared together and with the 6,7Li+208Pb colli-sion data. According to the preliminary results, 7Be nucleus reactivity is rather similar to the 7Li one whereas the 8B+208Pb total reaction cross section appears to be much larger than those measured for reactions induced by the other weakly-bound projectiles on the same target.

Nerve growth factor regulation and production by macrophages in osteoarthritic synovium

Nerve growth factor (NGF) functions to modulate osteoarthritis (OA)-associated pain. Although recent studies suggest that tumour necrosis factor (TNF)-α and interleukin (IL)-1β mediate NGF activity in human synovial fibroblasts, the regulation of NGF expression in human synovial macrophages remains unclear. Here, we examined the role of macrophages in the production and regulation of synovial (SYN) NGF in osteoarthritic knee joints by examining the mRNA expression of TNF-α and IL-1β in freshly isolated CD14-positive (macrophage-rich fraction) and CD14-negative cells (fibroblast-rich fraction) in synovial tissue from OA patients by quantitative polymerase chain reaction. We also examined the effects of IL-1β and TNF-α on NGF mRNA expression in cultured CD14-positive (macrophage-rich fraction) and CD14-negative cells (fibroblast-rich fraction). In addition, to examine the contribution of macrophages to NGF, TNF-α and IL-1β expression, we injected clodronate liposomes systemically into STR/Ort mice, an osteoarthritis animal model, to deplete macrophages. TNF-α and IL-1β mRNA levels in CD14-positive cells from the SYN of OA patients was significantly higher than that in CD14-negative cells, while NGF expression did not differ markedly between the two cell fractions. In addition, treatment of human cultured CD14-positive and -negative cells with IL-1β and TNF-α enhanced NGF mRNA and protein levels. Expression of NGF, IL-1β and TNF-α was also reduced significantly in STR/Ort mice upon macrophage depletion. These findings suggest that IL-1β and TNF-α regulate NGF expression and production in synovial macrophages and fibroblasts in osteoarthritic joints.

Putting the brakes on reproduction: Implications for conservation, global climate change and biomedicine

Seasonal breeding is widespread in vertebrates and involves sequential development of the gonads, onset of breeding activities (e.g. cycling in females) and then termination resulting in regression of the reproductive system. Whereas males generally show complete spermatogenesis prior to and after onset of breeding, females of many vertebrate species show only partial ovarian development and may delay onset of cycling (e.g. estrous), yolk deposition or germinal vesicle breakdown until conditions conducive for ovulation and onset of breeding are favorable. Regulation of this "brake" on the onset of breeding remains relatively unknown, but could have profound implications for conservation efforts and for "mismatches" of breeding in relation to global climate change. Using avian models it is proposed that a brain peptide, gonadotropin-inhibitory hormone (GnIH), may be the brake to prevent onset of breeding in females. Evidence to date suggests that although GnIH may be involved in the regulation of gonadal development and regression, it plays more regulatory roles in the process of final ovarian development leading to ovulation, transitions from sexual to parental behavior and suppression of reproductive function by environmental stress. Accumulating experimental evidence strongly suggests that GnIH inhibits actions of gonadotropin-releasing hormones on behavior (central effects), gonadotropin secretion (central and hypophysiotropic effects), and has direct actions in the gonad to inhibit steroidogenesis. Thus, actual onset of breeding activities leading to ovulation may involve environmental cues releasing an inhibition (brake) on the hypothalamo-pituitary-gonad axis.

Species and sex differences in propofol glucuronidation in liver microsomes of humans, monkeys, rats and mice

Propofol (2,6-diisopropylphenol) is a short-acting anesthetic commonly used in clinical practice, and is rapidly metabolized into glucuronide by UDP-glucuronosyltransferase (UGT). In the present study, propofol glucuronidation was examined in the liver microsomes of male and female humans, monkeys, rats, and mice. The kinetics of propofol glucuronidation by liver microsomes fit the substrate inhibition model for humans and mice, the Hill model for monkeys, and the isoenzyme (biphasic) model for rats. The K(m), V(max), and CL(int) values of human liver microsomes were 50 μM, 5.6 nmol/min/mg protein, and 110 μL/min/mg protein, respectively, for males, and 46 μM, 6.0 nmol/min/mg protein, and 130 μL/min/mg protein, respectively, for females. The rank order of the CL(int) or CL(max) (in vitro clearance) values of liver microsomes was mice humans > monkeys > rats (high-affinity phase) rats (low-affinity phase) in both males and females. Although no significant sex differences were observed in the values of kinetic parameters in any animal species, the in vitro clearance values of liver microsomes were males < females in humans, males = females in rats (low-affinity phase), and males > females in monkeys, rats (high-affinity phase), and mice. These results demonstrated that the kinetic profile of propofol glucuronidation by liver microsomes markedly differed among humans, monkeys, rats, and mice, and suggest that species and sex differences exist in the roles of UGT isoform(s), including UGT1A9, involved in its metabolism.

In vitro glucuronidation of propofol in microsomal fractions from human liver, intestine and kidney: tissue distribution and physiological role of UGT1A9

Propofol (2,6-diisopropylphenol) is intravenously administered for anesthetic induction and maintenance, and is rapidly metabolized into its glucuronide, mainly by UDP-glucuronosyltransferase 1A9 (UGT1A9). In this study, propofol glucuronidation by liver microsomes (HLM), intestinal microsomes (HIM) and kidney microsomes (HKM) of humans were examined. The expression of UGT1A9 protein in HLM, HIM and HKM was analyzed by immunoblotting. The staining band intensities for UGT1A9 of HIM and HKM were 12% and 119% those of HLM, respectively. The kinetics of propofol glucuronidation by HLM and HKM exhibited substrate inhibition, whereas the kinetics by HIM followed the Michaelis-Menten model. The K(m), V(max) and CL(int) values of HLM were 41.8 μM, 5.21 nmol/min/mg protein and 126 μl/min/mg protein, respectively. The K(m) value of HIM was significantly higher (6.7-fold) than that of HLM, and the V(max) and CL(int) values were significantly lower (56% and 8.3%, respectively) than those of HLM. The K(m) value of HKM was comparable to that of HLM, and the V(max) and CL(int) values were significantly higher (2.1- and 3.7-fold, respectively) than those of HLM, respectively. These findings suggest that UGT1A9 expressed in the kidney as well as in the liver plays an important role in propofol glucuronidation. The information gained in this study should contribute to an appropriate use of drugs metabolized by UGT1A9.

Long-term outcome in Japanese patients with lupus nephritis

The objective of this study was to clarify the long-term outcome in patients with lupus nephritis (LN) according to the International Society of Nephrology and Renal Pathology Society classification. This retrospective analysis comprised 186 Japanese patients given a diagnosis of LN by renal specimen with a mean observation period of 12 years. Primary end point was defined as death or end-stage renal disease, and standardized mortality ratios were calculated. Five patients presented with histopathological class I, 62 with II, 21 with III or III+V, 73 with IV or IV+V and 25 with V. Fourteen deaths occurred, corresponding to an overall standardized mortality ratio of 3.59 (95% confidence interval 2.02-5.81, p < 0.0001). Kaplan-Meier analysis revealed a 10-year overall survival of 95.7%. Nephrotic proteinuria (≥3.5 g/day) at baseline was identified as an independent poor prognostic factor for overall survival in Cox regression analysis. Kaplan-Meier analysis revealed a 10-year renal survival as 94.3%. Male gender and nephrotic proteinuria at baseline were identified as independent poor prognostic factors for renal survival in Cox regression analysis. In conclusion, LN was associated with a 3.59-fold increase in mortality compared with the general population. Male gender and nephrotic proteinuria were predictive for poor renal outcome.

In-gas-cell laser ion source for KEK isotope separation system

The KEK isotope separation system (KISS) is an element-selective isotope separator under development at RIKEN. The in-gas-cell laser ion source is a critical component of the KISS, a gas cell filled with argon gas of 50 kPa enclosed in a vacuum chamber. In the gas cell, nuclear reaction products are stopped (i.e., thermalized and neutralized) and transported by a laminar flow of argon to the ionization region just upstream of the gas outlet, and thereby an element of interest among those reaction products is selectively ionized by two-color resonant laser irradiation. Recently, we succeeded to extract laser-ionized Fe ions by injecting an energetic Fe beam into the gas cell. Recent off- and on-line test results were presented and discussed.

Acute respiratory distress in an alpaca

An alpaca was presented with a history of respiratory difficulty and death. Histology of the phrenic nerves and diaphragm revealed degenerative changes consistent with denervation atrophy, and a diagnosis of diaphragmatic paralysis was established. No gross or histological abnormalities were observed in the spinal cord or other organs. The etiology of the phrenic nerve neuropathy could not be determined. The need to examine phrenic nerves and diaphragm in camelids with respiratory distress is emphasized, as failure to examine these samples will preclude a diagnosis of diaphragmatic paralysis.

HOXB9, a gene promoting tumor angiogenesis and proliferation, as a prognostic factor in breast cancer

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Background: We demonstrated that HOXB9, a member of homeobox genes, expression promoted tumor neovascularization and metastasis in vitro and in vivo assay. These findings imply that overexpression of HOXB9 contributes to tumor progression through activation of signaling pathways that alter both tumor-specific cell fates and tumor-stromal microenvironment, leading to increased invasion and metastasis. (Hayashida et al., PNAS 2010) We sought to determine whether these results could be extended to the clinical application. In this study, we evaluated the correlation between HOXB9 expression, clinical outcomes, and the clinicopathological variables in breast cancer patients, and the contribution of HOXB9 expression to tumor cell proliferation and angiogenesis.

Methods: A consecutive series of 141 patients with invasive ductal carcinoma who underwent surgical treatment were examined. HOXB9 protein expression was analyzed immunohistochemically using the anti-human HOXB9 polyclonal antibody. Immunostaining of Ki-67, CD31, and CD34 were performed to evaluate the association of proliferation and tumor angiogenesis with HOXB9 expression.

Results: Of 141 tumor specimens immunostained for HOXB9, 69 specimens (48.9%) were positive staining. Univariate logistic regression revealed ER and PgR negativity, HER2 positivity, high nuclear grade, and large pathological tumor size as significant variables associated with HOXB9 expression. Moreover, 12 (92.3%) out of 13 triple negative breast cancer showed HOXB9 expression. The disease-free survival (DFS) and the overall survival were significantly different between the HOXB9 positive and negative group; HR=20.714, p=0.001, HR 9.206, p=0.003, respectively. A Multivariate analysis indicated that HOXB9 expression was the only independent prognostic factor for DFS (HR=15.532, p=0.009). In subgroup analysis, HOXB9 positive tumors showed a significant increase in the number of vasculature and the Ki-67 ratio in comparison with HOXB9 negative.

Conclusions: Our results suggest that HOXB9 expression promoting the tumor proliferation and the angiogenesis is a significant prognostic factor in breast cancer.

Prognosis and non-sentinel lymph node status of the breast cancer patients with micrometastatic sentinel lymph nodes

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Background: Sentinel lymph node biopsy (SLNB) is a more sensitive and accurate nodal staging procedure than axillary lymph node dissection (ALND). Because of detailed pathologic evaluation in SLNs, more nodal micrometastases have been identified. However, it remains controversial whether to perform ALND for patients with micrometastases in SLNs and their prognostic significance is also a matter of debate. The purpose of this study is to determine the non-sentinel lymph node (NSLN) status and prognosis of the patients with micrometastatic SLNs.

Methods: A prospective database of 1,012 clinically node-negative, T1-T2 breast cancer patients, who underwent SLNB from January 2002 to Dec 2010 at Keio University Hospital was analyzed. SLNs were detected using a combined method of isosulfun blue dye and small-sized technetium-99m-labeled tin colloid. Intraoperative frozen examination was performed with hematoxylin and eosin (HE) staining. SLNs, fixed and embedded in paraffin, were additionally diagnosed with HE staining and immunohistochemical (IHC) analysis.

Results: Micrometastases in SLNs were found in 69 (6.8%) of 1,012 patients. Thirty eight (55.1%) of 69 patients with micrometastatic SLNs underwent immediate or delayed ALND and revealed no NSLN metastasis. Among 31 (44.9%) patients with micrometastatic SLNs who omitted ALND and axillary radiation therapy, no axillary lymph node recurrence has been observed after a median follow-up of 50 months, although 29 patients (93.5%) in these 31 patients received adjuvant systemic therapy. There is no significant difference in recurrence free survival between the patients with micrometastatic and negative SLNs (98.0% vs. 95.7%, respectively).

Conclusions: These date suggested that it may not be necessary to perform ALND for the patients with micrometastatic SLNs and the presence of micrometastases in SLNs may not worsen prognosis with proper systemic therapy.

Primary primitive neuroectodermal tumor of the conus medullaris in an elderly patient: a case report and review of the literature

Primary spinal primitive neuroectodermal tumors (PNETs) are very rare conditions. Most of these tumors occur in children and young adults. A 63-year-old man with a primary spinal PNET in the conus medullaris from the L1 to L2 level is presented in this report. The optimal treatment of primary spinal PNETs is yet unknown. Surgical resection, radiation therapy, and chemotherapy have been advocated for the treatment of spinal PNET based on PNETs at other sites. However, the outcome is very poor. There are a few reports of cases with long-term survival and no recurrence. In these patients, en bloc resections were performed.