Mass, Spectroscopy, and Two-Neutron Decay of ^{16}Be

The structure and decay of the most neutron-rich beryllium isotope, ^{16}Be, has been investigated following proton knockout from a high-energy ^{17}B beam. Two relatively narrow resonances were observed for the first time, with energies of 0.84(3) and 2.15(5) MeV above the two-neutron decay threshold and widths of 0.32(8) and 0.95(15) MeV, respectively. These were assigned to be the ground (J^{π}=0^{+}) and first excited (2^{+}) state, with E_{x}=1.31(6)  MeV. The mass excess of ^{16}Be was thus deduced to be 56.93(13) MeV, some 0.5 MeV more bound than the only previous measurement. Both states were observed to decay by direct two-neutron emission. Calculations incorporating the evolution of the wave function during the decay as a genuine three-body process reproduced the principal characteristics of the neutron-neutron energy spectra for both levels, indicating that the ground state exhibits a strong spatially compact dineutron component, while the 2^{+} level presents a far more diffuse neutron-neutron distribution.

Observation of the Exotic 0_{2}^{+} Cluster State in ^{8}He

We report here the first observation of the 0_{2}^{+} state of ^{8}He, which has been predicted to feature the condensatelike α+^{2}n+^{2}n cluster structure. We show that this state is characterized by a spin parity of 0^{+}, a large isoscalar monopole transition strength, and the emission of a strongly correlated neutron pair, in line with theoretical predictions. Our finding is further supported by the state-of-the-art microscopic α+4n model calculations. The present results may lead to new insights into clustering in neutron-rich nuclear systems and the pair correlation and condensation in quantum many-body systems under strong interactions.

Highly Similar Tetramerization Domains from the p53 Protein of Different Mammalian Species Possess Varying Biophysical, Functional and Structural Properties

The p53 protein is a transcriptional regulatory factor and many of its functions require that it forms a tetrameric structure. Although the tetramerization domain of mammalian p53 proteins (p53TD) share significant sequence similarities, it was recently shown that the tree shrew p53TD is considerably more thermostable than the human p53TD. To determine whether other mammalian species display differences in this domain, we used biophysical, functional, and structural studies to compare the properties of the p53TDs from six mammalian model organisms (human, tree shrew, guinea pig, Chinese hamster, sheep, and opossum). The results indicate that the p53TD from the opossum and tree shrew are significantly more stable than the human p53TD, and there is a correlation between the thermostability of the p53TDs and their ability to activate transcription. Structural analysis of the tree shrew and opossum p53TDs indicated that amino acid substitutions within two distinct regions of their p53TDs can dramatically alter hydrophobic packing of the tetramer, and in particular substitutions at positions corresponding to F341 and Q354 of the human p53TD. Together, the results suggest that subtle changes in the sequence of the p53TD can dramatically alter the stability, and potentially lead to important changes in the functional activity, of the p53 protein.

Extreme low pH, not Al3+ , is a key abiotic stressor for the extremophyte Carex angustisquama (Cyperaceae) in highly acidic solfatara fields

Volcanic acidification creates extreme soil conditions, where rhizotoxicity from extremely low pH (2-3) and high Al³⁺ strongly inhibit plant growth. C. angustisquama is a dominant extremophyte in highly acidic solfatara fields, where no other vascular plants can survive. Here we investigated the key abiotic stressor determining survival of this extremophyte. Soil analyses and topographic surveys were conducted to examine the effects of low pH and Al³⁺ , two major abiotic stressors in acidic soils, on the occurrence of C. angustisquama in solfatara fields. Hydroponic culture experiments were also performed to test its growth responses to these stressors. In field surveys, the spatial distribution of soil pH was consistent with vegetation zonation within a solfatara field. In contrast, soil exchangeable Al content was overall low due to strong eluviation. Statistical analysis also supported the significant role of soil pH in determining the distribution of C. angustisquama in a solfatara field. Furthermore, hydroponic culture experiments revealed a higher tolerance of C. angustisquama to low pH than a sister species, especially in the range pH 2-3, corresponding to the pH values of the actual habitats of C. angustisquama. Conversely, no significant interspecific difference was detected in Al³⁺ tolerance, indicating that both species had high Al³⁺ tolerance. This study suggests that low pH is a critical abiotic stressor leading to formation of the extremophyte in highly acidic solfatara fields. In contrast, C. angustisquama displayed high tolerance to Al³⁺ toxicity, probably acquired prior to speciation.

Multiple Mechanisms in Proton-Induced Nucleon Removal at ∼100 MeV/Nucleon

We report on the first proton-induced single proton- and neutron-removal reactions from the neutron-deficient ^{14}O nucleus with large Fermi-surface asymmetry S_{n}-S_{p}=18.6  MeV at ∼100  MeV/nucleon, a widely used energy regime for rare-isotope studies. The measured inclusive cross sections and parallel momentum distributions of the ^{13}N and ^{13}O residues are compared to the state-of-the-art reaction models, with nuclear structure inputs from many-body shell-model calculations. Our results provide the first quantitative contributions of multiple reaction mechanisms including the quasifree knockout, inelastic scattering, and nucleon transfer processes. It is shown that the inelastic scattering and nucleon transfer, usually neglected at such energy regime, contribute about 50% and 30% to the loosely bound proton and deeply bound neutron removal, respectively. These multiple reaction mechanisms should be considered in analyses of inclusive one-nucleon removal cross sections measured at intermediate energies for quantitative investigation of single-particle strengths and correlations in atomic nuclei.

Comparative reproductive ecology of two sister Asarum species (Aristolochiaceae) in relation to the evolution of elongated floral appendage

Genus Asarum (Aristolochiaceae) shows diverse floral morphology and is hypothesized to have diversified as a result of pollinator-mediated selection. Yet most aspects of their reproductive ecology, including pollinators, remain unclear. This study focuses on A. costatum and A. minamitanianum in Japan, a sister species pair having remarkable differences in calyx lobe length (10-20 mm and 70-180 mm, respectively). The objectives of this study are to elucidate multiple aspects of reproductive ecology of these two species and obtain evolutionary insights into floral organ elongation. We adopted combined approaches, including field observations, molecular analyses and cultivation experiments, such as pollinator observation for 3 years, fine-scale spatial genetic analysis of 769 individuals, paternity analysis based on 566 seeds over 4 years, and control pollination experiments. Both Asarum species had strong spatial genetic structures, indicating limited seed dispersal. Pollinator observation revealed that flies and ground-dwelling insects visited flowers of both species, but that the pollinator fauna differed between the species. The visitation rate of flies was extremely low but was more than twice as high in the species with an elongated floral appendage. Paternity analysis revealed A. minamitanianum was predominantly outcrossing, while A. costatum showed a wide range of selfing rates among fruits. These two Asarum species are likely adapted to fly pollination in the shady forest understorey, where available pollinator fauna is limited. In addition, although its function remains unclear, the elongated calyx lobe of A. minamitanianum could have evolved for effective pollen dispersal by attracting fly visitors.

Quasifree Neutron Knockout Reaction Reveals a Small s-Orbital Component in the Borromean Nucleus ^{17}B

A kinematically complete quasifree (p,pn) experiment in inverse kinematics was performed to study the structure of the Borromean nucleus ^{17}B, which had long been considered to have a neutron halo. By analyzing the momentum distributions and exclusive cross sections, we obtained the spectroscopic factors for 1s_{1/2} and 0d_{5/2} orbitals, and a surprisingly small percentage of 9(2)% was determined for 1s_{1/2}. Our finding of such a small 1s_{1/2} component and the halo features reported in prior experiments can be explained by the deformed relativistic Hartree-Bogoliubov theory in continuum, revealing a definite but not dominant neutron halo in ^{17}B. The present work gives the smallest s- or p-orbital component among known nuclei exhibiting halo features and implies that the dominant occupation of s or p orbitals is not a prerequisite for the occurrence of a neutron halo.

Surface Localization of the Dineutron in ^{11}Li

The formation of a dineutron in the ^{11}Li nucleus is found to be localized to the surface region. The experiment measured the intrinsic momentum of the struck neutron in ^{11}Li via the (p,pn) knockout reaction at 246  MeV/nucleon. The correlation angle between the two neutrons is, for the first time, measured as a function of the intrinsic neutron momentum. A comparison with reaction calculations reveals the localization of the dineutron at r∼3.6  fm. The results also support the density dependence of dineutron formation as deduced from Hartree-Fock-Bogoliubov calculations for nuclear matter.

How Different is the Core of ^{25}F from ^{24}O_{g.s.} ?

The structure of a neutron-rich ^{25}F nucleus is investigated by a quasifree (p,2p) knockout reaction at 270A  MeV in inverse kinematics. The sum of spectroscopic factors of π0d_{5/2} orbital is found to be 1.0±0.3. However, the spectroscopic factor with residual ^{24}O nucleus being in the ground state is found to be only 0.36±0.13, while those in the excited state is 0.65±0.25. The result shows that the ^{24}O core of ^{25}F nucleus significantly differs from a free ^{24}O nucleus, and the core consists of ∼35% ^{24}O_{g.s.}. and ∼65% excited ^{24}O. The result may infer that the addition of the 0d_{5/2} proton considerably changes neutron structure in ^{25}F from that in ^{24}O, which could be a possible mechanism responsible for the oxygen dripline anomaly.

The tetramerization domain of the tree shrew p53 protein displays unique thermostability despite sharing high sequence identity with the human p53 protein

The p53 protein plays a number of roles in protecting organisms from different genotoxic stresses and this includes DNA damage induced by acetaldehyde, a metabolite of alcohol. Since the common tree shrew ingests high levels of alcohol as part of its normal diet, this suggests that its p53 protein may possess unique properties. Using a combination of biophysical and modeling studies, we demonstrate that the tetramerization domain of the tree shrew p53 protein is considerably more stable than the corresponding domain from humans despite sharing almost 90% sequence identity. Based on modeling and mutagenesis studies, we determine that a glutamine to methionine substitution at position 354 plays a key role in this difference. Given the link between stability of the p53 tetramerization domain and its transcriptional activity, the results suggest that this enhanced stability could lead to important consequences at p53-regulated genes in the tree shrew.

Abstract OT1-05-03: Efficacy and safety of scalp cooling device for prevention of alopecia in patients with breast cancer

Background

Chemotherapy for breast cancer causes alopecia as a side effect. Some patients refuse chemotherapy because of alopecia, resulting in the omission of a standard therapy. It is believed that a scalp cooling device can prevent alopecia by promoting vasoconstriction of the scalp and reducing exposure of the hair root cells to anticancer agents. There are phenotypic differences of the efficacy of a scalp cooling device for alopecia. In fact, a Dutch scalp cooling registry reported that the success rate of scalp cooling was 51% in European women and 33% in Asian women. Therefore, we aimed to investigate the efficacy of scalp cooling device for chemotherapy-induced alopecia among Asian women with breast cancer.

Trial design

This is a phase II trialto evaluate the efficacy and safety of scalp cooling device for risk reduction of alopecia in women with stage I/II/III breast cancer treated with adjuvant/neoadjuvant chemotherapy in a single institute.

Eligibility criteria

Women diagnosed with Stage I to III breast cancer who are scheduled to receive preoperative or postoperative adjuvant chemotherapy containing anthracycline and/or taxanes are enrolled. Patients who have blood malignancies (leukemia, non-Hodgkin lymphoma, other systemic lymphoma), and cold allergy, are excluded.

Specific aims

The primary endpoint is the proportion of patients with Common Terminology Criteria for Adverse Events (CTCAE) grade 0-1 alopecia after the completion of all cycles of chemotherapy (success rate). Secondary endpoints are safety, quality of life, use of wig or cap, and success rates after the completion of all cycles of chemotherapy distinguished by anthracycline(AC) and taxane.

The cooling device is the Paxman scalp cooling system. Scalp cooling was performed from 30 mins before initiation until 90 mins (25 min for taxane) after chemotherapy. Pictures of the scalp were taken at the time of the initiation of each course.

Statistical methods

Successful treatment was defined as the presence of less than 50% of hair-loss area. The sample size was calculated using the Simon method, with a type I error of 10% (two-sided) and a study power of 80%.The expected success rate is 30%, with a threshold success rate of 10%, and the required number of patients was estimated to be 19.

Present and target accrual

Patient accrual was started in April 2018 and present accrual is 3. We plan to enroll a total of 20 patients in the trial.

Citation Format: Kodera A, Ogura K, Hattori A, Yukawa H, Sakaguchi S, Matsuoka A, Tanaka N, Kamimura M, Jibiki N, Naritaka Y, Hirano A. Efficacy and safety of scalp cooling device for prevention of alopecia in patients with breast cancer [abstract]. In: Proceedings of the 2018 San Antonio Breast Cancer Symposium; 2018 Dec 4-8; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2019;79(4 Suppl):Abstract nr OT1-05-03.

Extraction of the Landau-Migdal Parameter from the Gamow-Teller Giant Resonance in ^{132}Sn

The key parameter to discuss the possibility of the pion condensation in nuclear matter, i.e., the so-called Landau-Migdal parameter g^{'}, was extracted by measuring the double-differential cross sections for the (p,n) reaction at 216  MeV/u on a neutron-rich doubly magic unstable nucleus, ^{132}Sn with the quality comparable to data taken with stable nuclei. The extracted strengths for Gamow-Teller (GT) transitions from ^{132}Sn leading to ^{132}Sb exhibit the GT giant resonance (GTR) at the excitation energy of 16.3±0.4(stat)±0.4(syst)  MeV with the width of Γ=4.7±0.8  MeV. The integrated GT strength up to E_{x}=25  MeV is S_{GT}^{-}=53±5(stat)_{-10}^{+11}(syst), corresponding to 56% of Ikeda's sum rule of 3(N-Z)=96. The present result accurately constrains the Landau-Migdal parameter as g^{'}=0.68±0.07, thanks to the high sensitivity of the GTR energy to g^{'}. In combination with previous studies on the GTR for ^{90}Zr and ^{208}Pb, the result of this work shows the constancy of this parameter in the nuclear chart region with (N-Z)/A=0.11 to 0.24 and A=90 to 208.

Excitation of the Isovector Spin Monopole Resonance via the Exothermic ^{90}Zr(^{12}N,^{12}C) Reaction at 175 MeV/u

The (^{12}N, ^{12}C) charge-exchange reaction at 175  MeV/u was developed as a novel probe for studying the isovector spin giant monopole resonance (IVSMR), whose properties are important for better understanding the bulk properties of nuclei and asymmetric nuclear matter. This probe, now available through the production of ^{12}N as a secondary rare-isotope beam, is exothermic, is strongly absorbed at the surface of the target nucleus, and provides selectivity for spin-transfer excitations. All three properties enhance the excitation of the IVSMR compared to other, primarily light-ion, probes, which have been used to study the IVSMR thus far. The ^{90}Zr(^{12}N,^{12}C) reaction was measured and the excitation energy spectra up to about 70 MeV for both the spin-transfer and non-spin-transfer channels were deduced separately by tagging the decay by γ emission from the ^{12}C ejectile. Besides the well-known Gamow-Teller and isobaric analog transitions, a clear signature of the IVSMR was identified. By comparing with the results from light-ion reactions on the same target nucleus and theoretical predictions, the suitability of this new probe for studying the IVSMR was confirmed.

Abstract OT1-01-03: A phase II trial of neoadjuvant epirubicin/cyclophosphamide followed by weekly nanoparticle albumin-bound paclitaxel with trastuzumab for HER2-positive breast cancer

Background

Paclitaxel (PTX) is a standard treatment for metastatic breast cancer (MBC) and it is often used as adjuvant and neoadjuvant chemotherapy for patients with early-stage disease. Nanoparticle albumin-bound (Nab)-PTX was also effective in patients with metastatic and early-stage. A comparison of weekly and triweekly nab-PTX regimens suggested that weekly nab-PTX resulted in superior progression-free survival. However, the optimal dose and schedule of weekly nab-PTX have not been determined. The efficacy and tolerability of epirubicin/cyclophosphamide (EC) followed by weekly nab-PTX (125 mg/m2) ± trastuzumab in node-positive breast cancer was determined in our previous trial. A high pathologic complete response (pCR) rate was obtained in HER2-positive patients. However, because nab-PTX administration was frequently postponed and discontinued, the optimal dose needs to be determined. In the previous trial, the median relative dose intensity of nab-PTX was 80% among patients with pCR. Therefore the dose of nab-PTX was reduced by 20% in this newly designed trial.

Trial design

This phase II trial aimed to evaluate the efficacy and toxicity of neoadjuvant EC followed by weekly nab-PTX with trastuzumab in patients with HER2-positive breast cancer. Patients will receive 4 cycles of epirubicin (90 mg/m2) and cyclophosphamide (600 mg/m2) every 3 weeks, followed by 4 cycles of nab-PTX (100 mg/m2) on days 1, 8, and 15, over a 28-day cycle. Fifteen cycles of trastuzumab (2 mg/kg, loading dose: 4 mg/kg) will be added to the nab-PTX regimen.

Eligibility criteria

Surgery and chemotherapy-naïve patients with pathologically confirmed T2-4 N0-3 invasive breast cancer, as diagnosed by core needle biopsy, are included. Eligibility criteria include age 20–70 years, a performance status of 0–2, and adequate organ function.

Specific aims

The primary endpoint is the pCR rate in the breast and axilla. Secondary endpoints include the breast conservation rate, toxicities, relative dose intensities, feasibility, and overall survival. A pCR is defined as the disappearance of invasive cancer cells, including in the axilla; residual intraductal cancer is acceptable.

Statistical methods

The sample size was calculated using the Simon method, with a type I error of 5% and a study power of 80%. The expected rate of pCR is 72% with a threshold pCR rate of 45%. The required number of patients was estimated to be 25.

Present and target accrual

Patient accrual within two medical centers began in May 2014. A final study population of 30 patients is expected (Trial registration: UMIN000013886).

Citation Format: Kodera A, Hirano A, Inoue H, Ogura K, Hattori A, Sakaguchi S, Yukawa H, Matsuoka A, Tanaka N, Kamimura M, Jibiki N, Fujibayasi M, Naritaka Y, Shimizu T. A phase II trial of neoadjuvant epirubicin/cyclophosphamide followed by weekly nanoparticle albumin-bound paclitaxel with trastuzumab for HER2-positive breast cancer [abstract]. In: Proceedings of the 2016 San Antonio Breast Cancer Symposium; 2016 Dec 6-10; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2017;77(4 Suppl):Abstract nr OT1-01-03.

Abstract P3-13-13: Breast-conserving surgery plus hormone therapy without irradiation in elderly women with early breast cancer

Background

The meta-analysis of the Early Breast Cancer Trialists' Collaborative Group (EBCTCG) revealed that whole-breast irradiation after breast conserving surgery (BCS) decreased ipsilateral breast tumor recurrence (IBTR) and breast cancer-related death. However, elderly patients can find daily hospital attendance difficult, and their IBTR risk is low. A randomized control trial was performed in women aged ≥70 years with hormone-positive breast cancer to investigate the usefulness of breast-conserving therapy without irradiation (Hughes et al. N Engl J Med 2004). Since September 2001, we have offered BCS plus hormone therapy without irradiation in patients who satisfy the following criteria: age ≥60 years; pathologically node negative, hormone-positive breast cancer; a negative surgical margin; and no lymphovascular invasion. We assessed prognosis in patients who chose this option.

Patients and methods

Between September 2001 and December 2014, 219 patients met the inclusion criteria; 90 and 129 patients underwent BCS plus hormone therapy with or without irradiation, respectively. The cumulative IBTR incidence and overall survival (OS) for the groups was evaluated. A negative surgical margin was defined as a margin of ≥5 mm.

Results

The median ages at operation were 73 years (range, 60–88 years) and 65 years (range, 60–80 years) for the without and with irradiation groups, respectively (p <0.001). There were no significant differences in tumor size, lymph node metastasis, or adjuvant therapy between the groups. The median follow-up duration is presently 4.6 years. IBTR was observed in 5 (3.9%) and 1 (1.1%) patient(s) in the without and with irradiation groups, respectively (p = 0.192). The 5-year IBTR cumulative incidences were 0.9% and 2.2%, and the 10-year were 6.7% and 2.2%, for the without and with irradiation groups, respectively (p = 0.390). The 5-year OS rates were 93.8% and 98.5%, and the 10-year OS rates were 89.7% and 94.0 for the without and with irradiation groups, respectively (p = 0.205).

Conclusion

BCS plus hormone therapy without irradiation in elderly patients is an appropriate option.

Citation Format: Inoue H, Hirano A, Ogura K, Hattori A, Yukawa H, Sakaguchi S, Matsuoka A, Tanaka N, Kodera A, Kamimura M, Fujibayashi M, Naritaka Y, Shimizu T. Breast-conserving surgery plus hormone therapy without irradiation in elderly women with early breast cancer [abstract]. In: Proceedings of the 2016 San Antonio Breast Cancer Symposium; 2016 Dec 6-10; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2017;77(4 Suppl):Abstract nr P3-13-13.

Effect of Ticlopidine on Graft Patency Following Arterial Reconstructive Surgery in the Lower Extremity: A Multicenter Three-Year Prospective Study

A multicenter, randomized, prospective trial was conducted to determine the clinical efficacy of ticlopidine, an antiplatelet agent, in the prevention of graft occlusion following vascular reconstructive surgery of the lower extremity for arteriosclerosis obliterans. Ticlopidine was administered for two years to one group of patients (112 reconstructed arterial segments) while a control group received no antithrombotic therapy (108 segments). There was no significant difference between the treated and control groups in the overall cumulative patency rates for both suprainguinal and infrainguinal reconstructions. In the treated group, however, there was a significant reduction of occlusions in pa tients with rest pain or ischemic gangrene (p < 0.1) and in those with hyperlipi demia (p < 0.05). Ticlopidine-treated patients with infrainguinal arterial reconstructions developed more occlusions than controls between three and twelve months after surgery, but the controls had more occlusions both immedi ately after surgery and in the second postoperative year. It appeared, therefore, that ticlopidine reduced graft failure due to neointimal fibrous hyperplasia or progression of the underlying condition but caused an adverse effect by delaying graft healing. The clinical usefulness of antiplatelet therapy is limited, but it may be effective in the prevention of graft occlusion when administered to the selected patient groups above mentioned. Controversy about antiplatelet ther apy and future research on adjuvant drug therapy after arterial reconstruction are discussed.

Stent-Graft Treatment of Dissecting Aneurysm in Association with Aortic Intramural Hematoma: When Should the Procedure Be Performed?

Purpose:

To report 2 cases of stent-graft implantation for localized dissecting aneurysm during the conservative treatment of aortic intramural hematoma.

Case Reports:

One patient underwent stent-graft implantation for 2 localized dissecting aneurysms about 23 months after symptom onset. Computed tomography (CT) 1 year after the procedure demonstrated aneurysm shrinkage. In the other patient, a localized dissecting aneurysm was treated about 3 months after symptom onset, even though the intramural hematoma had not resolved. CT scanning 3 months after the procedure demonstrated aneurysm shrinkage, but also revealed poor attachment of the distal stent-graft to the aortic wall due to subsequent resolution of the hematoma.

Conclusions:

Endograft implantation for treatment of localized dissecting aneurysm associated with aortic intramural hematoma should probably not be performed before the hematoma has completely resolved.

Candidate Resonant Tetraneutron State Populated by the ^{4}He(^{8}He,^{8}Be) Reaction

A candidate resonant tetraneutron state is found in the missing-mass spectrum obtained in the double-charge-exchange reaction ^{4}He(^{8}He,^{8}Be) at 186  MeV/u. The energy of the state is 0.83±0.65(stat)±1.25(syst)  MeV above the threshold of four-neutron decay with a significance level of 4.9σ. Utilizing the large positive Q value of the (^{8}He,^{8}Be) reaction, an almost recoilless condition of the four-neutron system was achieved so as to obtain a weakly interacting four-neutron system efficiently.

Nonquenched Isoscalar Spin-M1 Excitations in sd-Shell Nuclei

Differential cross sections of isoscalar and isovector spin-M1 (0(+)→1(+)) transitions are measured using high-energy-resolution proton inelastic scattering at E(p)=295  MeV on (24)Mg, (28)Si, (32)S, and (36)Ar at 0°-14°. The squared spin-M1 nuclear transition matrix elements are deduced from the measured differential cross sections by applying empirically determined unit cross sections based on the assumption of isospin symmetry. The ratios of the squared nuclear matrix elements accumulated up to E(x)=16  MeV compared to a shell-model prediction are 1.01(9) for isoscalar and 0.61(6) for isovector spin-M1 transitions, respectively. Thus, no quenching is observed for isoscalar spin-M1 transitions, while the matrix elements for isovector spin-M1 transitions are quenched by an amount comparable with the analogous Gamow-Teller transitions on those target nuclei.

Histological changes in chronic autoimmune SKG-arthritis evaluated by quantitative three-dimensional stereological estimators

OBJECTIVES

To investigate the quantitative arthritic and bone erosive changes, including the number of osteoclasts and osteoclast precursors in the new SKG-model of inflammatory polyarthritis using three-dimensional (3D) stereological methods.

METHODS

Arthritis was induced in female SKG-mice with Zymosan A. Quantitative histology was made in four control mice and four mice with arthritis euthanised after 6 and 12 weeks. The right hind paw was embedded undecalcified in methylmethacrylate and cut exhaustively generating vertical uniform random sections. A computer controlled microscope and stereological software was used for histological quantification. Total volumes were estimated according to the Cavalieri principle, total surfaces were estimated using the vertical sections design, and the number of osteoclasts was counted in a physical fractionator.

RESULTS

The arthritis score increased during the 12-week period and was paralleled by an increase in the volume of inflammatory tissue (r=0.96, p<0.001). The number of osteoclasts on bone (r=0.77, p<0.05) and osteoclast-covered bone surface (r=0.62, p<0.05) increased resulting in a decrease in the volume of bone (r=-0.65, p<0.05). However, the number of osteoclast precursors declined between week 6 and 12 (p<0.05). Furthermore, the total cartilage surface (r=-0.74, p<0.05) and cartilage volume (r=-0.74, p<0.05) decreased during the 12 weeks of arthritis.

CONCLUSIONS

In this study we demonstrated changes in 3D stereological parameters of inflammatory tissue, bone erosion, osteoclasts, and cartilage in mouse paws during the course of arthritis in the SKG mouse. This is the first time 3D quantitative histology has been applied in a mouse model of rheumatoid arthritis.

Perturbations of both nonregulatory and regulatory FOXP3+ T cells in patients with malignant melanoma

BACKGROUND

'FOXP3+ regulatory T cells' (Tregs) are reported to be increased in tumour-bearing hosts including patients with melanoma, leading to tumour immune suppression. However, this idea is challenged by recent evidence that the 'FOXP3+ Treg' fraction in fact contains activated 'nonregulatory' T cells. Also, FOXP3+ T cells are reported to have functionally and kinetically distinct subsets.

OBJECTIVES

To investigate whether either or both of regulatory and 'nonregulatory' FOXP3+ T cells are perturbed in patients with melanoma.

METHODS

FOXP3+ T cells were classified into three subsets, namely CD45RO+FOXP3(low) nonregulatory T cells, CD45RO+FOXP3(high) effector Tregs, and CD45RO-FOXP3(low) naïve Tregs, according to their expression levels of FOXP3 and CD45RO. The percentage and cytokine production of these FOXP3+ T-cell subsets were assessed by flow cytometry.

RESULTS

Both regulatory and nonregulatory T cells were increased in patients with melanoma. Moreover, we found three unexpected perturbations in FOXP3+ T-cell subsets: (i) patients with melanoma showed higher frequencies of FOXP3(low) nonregulatory T cells, which decreased and normalized after tumour removal; (ii) FOXP3(low) naïve Tregs containing higher frequencies of interferon-γ+ cells increased with tumour progression; and (iii) CD45RO+FOXP3(high) effector Tregs were pronouncedly infiltrated around tumour tissues.

CONCLUSIONS

These findings demonstrate that patients with melanoma have distinct and differential perturbation of both regulatory and nonregulatory FOXP3+ T cells. The degree of perturbation is associated with tumour burden and progression, suggesting that the perturbation reflects fundamental pathophysiological processes in patients with melanoma. The presented analysis provides a practical approach to investigate the immunological environment of cancer patients.

Lineage admixture during postglacial range expansion is responsible for the increased gene diversity of Kalopanax septemlobus in a recently colonised territory

We aimed to reveal the effects of range expansion and subsequent lineage admixture from separated glacial refugia on genetic diversity of Kalopanax septemlobus in Japan, by combining nuclear microsatellite data and ecological niche modelling. Allelic richness and gene diversity were compared at the population and regional level. We also statistically examined these indices as a function of population accessibility to the last glacial maximum (LGM) palaeodistribution reconstructed by ecological niche modelling to test a simple range expansion scenario from glacial refugia. Genetic diversity was highest in the populations of southern Japan and gradually decreased towards the north. However, an additional centre of genetic diversity, when measured as gene diversity, was found in northern Honshu Island, where distinct lineages were shown to be in contact. Positive effects of population accessibility to the LGM range were detected in both diversity indices at different spatial scales. The combined data support independent postglacial range expansions towards the north from the edge populations on the exposed coastal shelf of Pacific and Sea of Japan in northern Honshu during the LGM, which subsequently resulted in markedly low genetic diversity in the northernmost extant range, Hokkaido. The regional increase in gene diversity in northern Honshu is likely to be the result of postglacial lineage admixture. Relative difference in the spatial scales best relating population genetic diversity with the LGM distribution can be explained by a higher rate of allelic richness diversity loss during range expansions and stronger effects of lineage admixture on gene diversity.