Living with COVID-19: mass gatherings and minimizing risk

During the COVID-19 pandemic, it has been important to both minimize the risk of infection and restore daily life. As a typical example, mass gathering events, such as sporting events, are gradually becoming more common, thanks to the measures taken to contain COVID-19. Some pilot studies have been launched at governments' initiative to investigate the risk of infection without measures such as face masks and physical distancing at mass gathering events, but the ethics of these studies should be carefully considered. On the other hand, it is still beneficial to implement infection control measures at mass gathering events and, in parallel, to estimate the risk of infection with measures in place, especially under a lack of vaccination progress or the spread of mutant strains possibly resistant to vaccines. To help improve compliance with measures taken by spectators and organizers and to ensure their effectiveness, we have conducted quantitative evaluations of the implementation of such measures by monitoring CO2 concentrations, assessing the proportion of people wearing face masks and analysing human flow at the event. This approach allows us to share our observations with stakeholders and participants, enabling us to protect the culture of mass gathering events, minimize the risk of infection and restore a sense of well-being in daily life.

Abstract OT2-05-02: International retrospective cohort study of locoregional and systemic therapy in oligometastatic breast cancer (OLIGO-BC1)

Breast cancer (BC) is so-called “systemic disease”, because disseminated cancer cells in bone marrow and blood are detected even in early BC patients. Despite adjuvant therapy and postoperative radiation therapy, patients with triple negative BC and Luminal B-like BC often relapse early and systemic therapy is the only way to control disease progression. On the other hand, some BC patients relapse several years later. In such patients, oligometastases are occasionally diagnosed, because metastatic cancer cells are slowly growing and indolent. Oligometastatic BC is defined as low volume metastatic disease with limited number and size of metastatic lesions (up to five and not necessarily in the same organ). This definition is proposed in the Advanced Breast Cancer guidelines that are developed as a joint effort from European School of Oncology and European Society of Medical Oncology. Several retrospective studies demonstrated survival benefit of locoregional therapy in addition to systemic therapy. Locoregional therapy consisted of surgical resection, radiation therapy, ablation therapy, etc. However, it remains unclear about survival benefit of combined therapy in oligometastatic BC. To improve the standard of cancer treatment through the cooperate studies on more effective therapeutic strategies based on drugs, surgery and/or radiotherapy, Federation of Asian Clinical Oncology (FACO) was established in 2012 by Chinese Society of Clinical Oncology (CSCO), Korean Society of Medical Oncology (KSMO) and Japan Society of Clinical Oncology (JSCO). Thus, FACO conducted a retrospective cohort study on oligometastatic BC. The primary endpoint is to compare the estimated 5-year overall survival (OS) of oligometastatic BC patients treated with combined therapy and systemic therapy alone. To hypothesize that combined therapy has more advantage of OS in oligometastatic BC, the 5-year OS rates are expected to be 50% and 40%, respectively. The estimated sample size is calculated to be the number of 698 cases (349 cases in each group) needed to prove the superiority of survival with a two-sided type I error rate of 5% and a statistical power of 80%. Case registry opened in February 2018 and will close in January 2019. We planned to register 700 cases, i.e., 234 cases each from investigators of CSCO, KSMO and JSCO. Update information will be discussed.

Citation Format: Imoto S, Futamura M, Toi M, Fujiwara Y, Ueno T, Im Y-H, Im S-A, Ahn SG, Lee JE, Park YH, Wang K, Kitagawa Y, Nishiyama M. International retrospective cohort study of locoregional and systemic therapy in oligometastatic breast cancer (OLIGO-BC1) [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 OT2-05-02.

Abstract OT2-01-01: Observational study of axilla treatment for breast cancer patients with 1 to 3 positive micrometastases or macrometastases in sentinel lymph nodes

[Background] Axilla surgery in node-positive breast cancer is dramatically changing from axillary lymph node dissection (ALND) to sentinel node biopsy (SNB). From the results of ACOSOG Z0011, IBCSG23-01 and AMAROS trials, adjuvant therapy and regional node irradiation could reduce regional lymph node recurrence for sentinel node-positive breast cancer patients. However, optimal indication of SNB alone remains uncertain. Trial design: To evaluate the outcome of sentinel node-positive breast cancer patients, the Japanese Society for Sentinel Node Navigation Surgery (SNNS) conducted a prospective cohort study in 2013 (UMIN000011782, Jpn J Clin Oncol, p.876-9, 2014). [Eligibility criteria] For eligible patients, SNB was performed or scheduled after 1 January 2012. Then 1 to 3 positive micrometastases or macrometastases in sentinel lymph nodes are confirmed by histological or molecular diagnosis. Primary chemotherapy before or after SNB is also acceptable for registration. [Specific aims] The primary endpoint is the 5-year recurrence rate of regional lymph node in patients treated with SNB alone. The secondary endpoint is the 5-year overall survival rate of this cohort. Patients treated with SNB followed by ALND are also registered simultaneously to compare the prognosis. The propensity score matching (PSM) is used to make the distributions of baseline risk factors comparable. [Statistical method] Based on an estimated recurrence rate of 5% at 5 years among patients treated with SNB alone, 240 patients are needed to give a 80% power to reject the null hypothesis that the recurrence rate is 10% with a one-sided type I error rate of 2.5%. If we consider that some patients will be lost to follow-up or become ineligible, a total of 250 patients will be needed to comprise the sample. [Present accrual] Eight hundred and eighty patients who underwent SNB alone or SNB followed by ALND were registered from 27 participating institutes between 2013 and 2016. Data cleaning is being performed. Patient's background and PSM will be reported.

Citation Format: Imoto S, Saito Oba M, Masuda N, Nagashima T, Wada N, Takashima T, Kitada M, Kawada M, Hayashida T, Taguchi T, Aihara T, Miura D, Toh U, Yoshida M, Sugae S, Yoneyama K, Matsumoto H, Jinno H, Sakamoto J. Observational study of axilla treatment for breast cancer patients with 1 to 3 positive micrometastases or macrometastases in sentinel lymph nodes [abstract]. In: Proceedings of the 2017 San Antonio Breast Cancer Symposium; 2017 Dec 5-9; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2018;78(4 Suppl):Abstract nr OT2-01-01.

The hnRNP-Htt axis regulates necrotic cell death induced by transcriptional repression through impaired RNA splicing

In this study, we identify signaling network of necrotic cell death induced by transcriptional repression (TRIAD) by α-amanitin (AMA), the selective RNA polymerase II inhibitor, as a model of neurodegenerative cell death. We performed genetic screen of a knockdown (KD) fly library by measuring the ratio of transformation from pupa to larva (PL ratio) under TRIAD, and selected the cell death-promoting genes. Systems biology analysis of the positive genes mapped on protein-protein interaction databases predicted the signaling network of TRIAD and the core pathway including heterogeneous nuclear ribonucleoproteins (hnRNPs) and huntingtin (Htt). RNA sequencing revealed that AMA impaired transcription and RNA splicing of Htt, which is known as an endoplasmic reticulum (ER)-stabilizing molecule. The impairment in RNA splicing and PL ratio was rescued by overexpresion of hnRNP that had been also affected by transcriptional repression. Fly genetics with suppressor or expresser of Htt and hnRNP worsened or ameliorated the decreased PL ratio by AMA, respectively. Collectively, these results suggested involvement of RNA splicing and a regulatory role of the hnRNP-Htt axis in the process of the transcriptional repression-induced necrosis.

Abstract P3-13-07: Radiofrequency ablation (RFA) is a promising treatment option for primary breast cancer: Experience in 386 Japanese breast cancer patients

Background. Radiofrequency ablation (RFA) is used for the treatment of various solid tumors. Several small experiences have reported as a primary treatment for breast cancer using RFA. However, the clinical benefits remain uncertain. We retrospectively studied 386 patients and analyzed their RFA-related complications and outcomes.

Methods. A clinical database was constructed from 10 institutions. RFA was performed using an electrical generator connected to a single cooled-tip electrode or multiple electrodes. Adjuvant systemic therapy and whole breast radiation were administered according to the clinicopathological background of each patient. Follow-up periods ranged from 1 to 90 months (mean 45.4 months). RFA-related complications and risk factors for in-breast recurrence after RFA were evaluated. Variables evaluated included patient characteristics, pre- and post-operative imaging modalities, tissue sampling modalities, and RFA-related factors.

Results. Skin burns were observed in 7 patients (1.8 %) and RFA-induced damage to the nipple-areolar complex in 7 patients (1.8 %). Persistent induration of the breast after RFA was observed in 137 patients (35.5 %). Eleven patients (2.8 %) developed in-breast recurrence. In-breast recurrence was more frequent in patients with tumor size >2.0 cm, ER-negative tumor, HER2-positive tumor, positive nodes, no breast irradiation and adjuvant chemotherapy.

Conclusions. Skin burns were a major problem after RFA, but the frequency of burns was relatively low. Breast induration was also developed, but it did not bring harmful effect to the patients with this complication. We conclude that RFA is a promising treatment option for solid T1 breast cancer without malignant potential.

Citation Format: Takahashi M, Ito T, Oura S, Nagamine S, Yamamoto N, Yamamichi N, Earashi M, Doihara H, Imoto S, Mitsuyama S, Akazawa K. Radiofrequency ablation (RFA) is a promising treatment option for primary breast cancer: Experience in 386 Japanese breast cancer patients. [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 P3-13-07.

Find the Word! — But Where?: Maturana’s ‘Coordination’ and Sartre’s ‘Reflection’ around Naming

‘Behavioral coordination’ theory of language of Maturana (1928–) does not give a clear explanation for the questions of how naming takes place and where a word adequate for our experience comes from. This flaw may be alleviated by Sartre (1905–1980)s ‘reflection’ theory. According to Sartre’s theory, we can make two types of sentences from the same data: for example, “I am conscious of this chair” and “There is consciousness of this chair.” The difference between the two sentences is the existence of ‘I’ in the first or its lack in the second. Where did ‘I’ come from or how was it removed? There must be a field in which ‘I’ is brought forth, and it may also be a field where naming can take place. This essay concerns a naming process with special reference to Sartre’s philosophy. At first, Maturana’s biology and his linguistic theory are explained, and Sartre’s fundamental ontology and in relation to this, his theory of reflection (two types of reflection) are introduced. Next, Sartre’s notions of language (words and naming) are explained. Then, after operational correspondences between Maturana’s ‘coordination’ and Sartre’s ‘reflection’ are examined, our primary questions are answered. Finally, constraints burdened on our cognition with language and the possibility of liberation from them are discussed. Main arguments: (1) Maturana’s ‘coordination’ and Sartre’s ‘reflection’ are operationally equivalent concepts; (2) Sartre can complement Maturana’s languaging theory of naming by providing both the domain for naming (the domain for the synthesis of identification, or for universalizing synthesis) and a mediator of naming (the cogito, namely the consciousness, of a languaging person).

Quantitative characterization of T-cell repertoire in allogeneic hematopoietic stem cell transplant recipients

Allogeneic hematopoietic stem cell transplantation (HSCT) is one of curative treatment options for patients with hematologic malignancies. Although GVHD mediated by the donor's T lymphocytes remains the most challenging toxicity of allo-HSCT, graft-versus-leukemia (GVL) effect targeting leukemic cells, has an important role in affecting the overall outcome of patients with AML. Here we comprehensively characterized the TCR repertoire in patients who underwent matched donor or haplo-cord HSCT using next-generation sequencing approach. Our study defines the functional kinetics of each TCRA and TCRB clone, and changes in T-cell diversity (with identification of CDR3 sequences) and the extent of clonal expansion of certain T-cells. Using this approach, our study demonstrates that higher percentage of cord-blood cells at 30 days after transplant was correlated with higher diversity of TCR repertoire, implicating the role of cord-chimerism in enhancing immune recovery. Importantly, we found that GVHD and relapse, exclusive of each other, were correlated with lower TCR repertoire diversity and expansion of certain T-cell clones. Our results highlight novel insights into the balance between GVHD and GVL effect, suggesting that higher diversity early after transplant possibly implies lower risks of both GVHD and relapse following the HSCT transplantation.

In utero gene therapy rescues microcephaly caused by Pqbp1-hypofunction in neural stem progenitor cells

Human mutations in PQBP1, a molecule involved in transcription and splicing, result in a reduced but architecturally normal brain. Examination of a conditional Pqbp1-knockout (cKO) mouse with microcephaly failed to reveal either abnormal centrosomes or mitotic spindles, increased neurogenesis from the neural stem progenitor cell (NSPC) pool or increased cell death in vivo. Instead, we observed an increase in the length of the cell cycle, particularly for the M phase in NSPCs. Corresponding to the developmental expression of Pqbp1, the stem cell pool in vivo was decreased at E10 and remained at a low level during neurogenesis (E15) in Pqbp1-cKO mice. The expression profiles of NSPCs derived from the cKO mouse revealed significant changes in gene groups that control the M phase, including anaphase-promoting complex genes, via aberrant transcription and RNA splicing. Exogenous Apc4, a hub protein in the network of affected genes, recovered the cell cycle, proliferation, and cell phenotypes of NSPCs caused by Pqbp1-cKO. These data reveal a mechanism of brain size control based on the simple reduction of the NSPC pool by cell cycle time elongation. Finally, we demonstrated that in utero gene therapy for Pqbp1-cKO mice by intraperitoneal injection of the PQBP1-AAV vector at E10 successfully rescued microcephaly with preserved cortical structures and improved behavioral abnormalities in Pqbp1-cKO mice, opening a new strategy for treating this intractable developmental disorder.

Abstract P2-13-04: Superior efficacy of anastrozole to tamoxifen as adjuvant therapy for postmenopausal patients with hormone-responsive breast cancer. Efficacy results of long-term follow-up data from N-SAS BC 03 trial

Background: Aromatase inhibitors have been shown to be superior to tamoxifen as adjuvant therapy in postmenopausal patients with hormone-responsive breast cancer. Here we report the efficacy results of long-term follow-up data from N-SAS BC 03 trial (UMIN CTRID: C000000056), in which anastrozole was compared to tamoxifen in hormone-responsive postmenopausal early breast cancer patients who had taken tamoxifen for 1—4 years out of a total of 5 years of treatment as adjuvant therapy.

Patients and methods: Out of a total of 706 recruited patients, 696 patients (tamoxifen group, n=345; anastrozole group, n=351) were used as the full analysis set for the present study. The log-rank test was used to compare the two groups in terms of disease-free survival (DFS) and relapse-free survival (RFS), Kaplan-Meier estimates were calculated. The treatment effects were estimated by Cox's proportional hazard model and were expressed as hazard ratios, with associated 95% confidence intervals (CIs).

Results: After a median follow-up of 76.1 months, (range: 1.3–110 months), the unadjusted hazard ratio was 0.87 (95%Cl 0.60–1.26; log-rank p = 0.457) for DFS and 0.77 (95%Cl 0.49–1.22; log-rank p = 0.266) for RFS, both in favor of anastrozole. The estimated hazard ratio (95%CIs) for DFS and for RFS until each time point (right censored data) was as follows: until 30 months: 0.54 (0.30–0.98) and 0.48 (0.23–0.98), until 42 months; 0.65 (0.40–1.06) and 0.53 (0.29–0.97), until 54 months: 0.77 (0.50–1.19) and 0.63 (0.37–1.06), until 66 months: 0.82 (0.55–1.24) and 0.72 (0.44–1.17), until 78 months: 0.83 (0.57–1.23) and 0.73 (0.46–1.17), respectively. The hazard ratios (95%CIs) for DFS and for RFS until 36 months were 0.72 (95%Cl 0.43–1.22) and 0.58 (95%Cl 0.30–1.12), and those after 36 months were 1.06 (95%Cl 0.62–1.81) and 0.98 (95%Cl 0.51–1.88), respectively.

Conclusion: Superior efficacy of anastrozole to tamoxifen in the Japanese population was suggested over a long-term follow-up period. It was the greatest early after switching from tamoxifen and then decreased thereafter.

Citation Information: Cancer Res 2012;72(24 Suppl):Abstract nr P2-13-04.

P1-01-10: Immune Suppression of Regulatory T Cells and M2 Macrophage in Breast Cancer Patients

Background: Recent multi-disciplinary treatments of breast cancer (BC) could decrease the mortality rate, but successful immune therapy remains uncertain. To explore new strategy of immune therapy of BC, we are investigating about host-tumor immune response in BC patients. Materials and methods: Tumor tissue specimens and peripheral blood mononuclear cells (PBMC) were obtained from early and advanced BC patients. PBMC were also collected from healthy volunteers. Regulatory T (Treg) cells were examined by counting CD4+CD25highCD127low/−cells in PBMC with flow cytometry analysis. Immunohistochemical evaluation of tumor specimens was performed with monoclonal antibodies of HLA-ABC and DR, CD56, CD68, CD83, and CD163. The number of stained cells was analyzed using a semiquantitative ordinal scale ranging from 0 to 3 (0, +/−, ++, +++). Results: HLA-ABC and DR were stained negative in 44% and 82% of 50 BC cases. When host-tumor immune response were compared between 38 early BC cases and 12 advanced BC cases, numbers of CD68-positive cells significantly increased in peripheral tumor tissues of advanced BC cases than in those of early BC cases (92% versus 53%). CD163-positive tumor cells were also detected more frequently in advanced BC cases than in early BC cases (75% versus 16%). There were no significant differences of distribution of CD4, CD8, CD56, and CD83-positive cells in early and advanced BC cases. Treg cells in PBMC significantly increased in percentage of the population in 37 BC patients than in 21 healthy volunteers (4.2% versus 2.5% of CD4-positive cells at mean value). Interestingly, Treg cells decreased in percentage of the population in 36 postoperative BC patients. Conclusions: Our results suggest that Treg cells render BC patients under immune suppression and M2 macrophage plays an important role of tumor progression. Targeted therapy against M2 macrophage may be a promising strategy of breast cancer.

Citation Information: Cancer Res 2011;71(24 Suppl):Abstract nr P1-01-10.

P1-01-11: CD4+CD25highCD127low/− Regulatory T Cells Have Immunosuppressive Function in Patients with Breast Cancer

CD4+CD25highFoxp3+ regulatory T cells play a central role in self-tolerance and suppress antitumor immune response. Recent studies have shown that low levels of the IL-7 receptor (CD127) are expressed on CD4+CD25highFoxp3+ regulatory T cells surfaces and the expression of CD127 is inversely correlated with the suppressive function of CD4+CD25high regulatory T cells. We evaluated the frequency of CD4+CD25highCD127low/− T cells in peripheral blood lymphocytes of 72 breast cancer patients and 21 healthy volunteers. The expression of Foxp3 mRNA was inversely correlated with the CD127 expression and correlated with CD25 expression. The frequency of CD4+CD25highCD127low/− T cells in breast cancer patients was significantly higher than that of healthy volunteers (p=0.0045). CD4+CD25highCD127low/− T cells were increased in hormone receptor negative patients and HER2 positive patients, but no statistical significant was observed in stage progression. In addition, the frequency of CD4+CD25highCD127low/− T cells decreased after curative resection in breast cancer patients (p=0.005). CD4+CD25highCD127low/−T cells also suppress proliferation of autologous CD4+CD25− helper T cells and CD8+ cytotoxic T cells in CFSE-based cell proliferation assay. These findings suggest that CD4+CD25highCD127low/− T cells a useful marker for regulatory T cells in breast cancer. Circulative peripheral regulatory T cells may participate in immune tolerance to breast carcinoma.

Citation Information: Cancer Res 2011;71(24 Suppl):Abstract nr P1-01-11.

Oxidative Stress Levels in Myelodysplastic Syndrome Patients: Their Relationship to Serum Ferritin and Haemoglobin Values

Reactive oxygen species (ROS) and serum ferritin levels are both considered to be important biological factors in the pathogenesis of myelodysplastic syndrome (MDS). This study evaluated the levels of ROS in 40 patients with MDS (19 males and 21 females) using the Free Radical Analytical System, FRAS4, and derivatives of reactive oxygen metabolite kits. The patients' mean age was 67.3 years (range 58–86 years). The sera of 34 (85%) patients exhibited higher levels of oxidative stress than the reference range. There was a positive correlation between ROS levels and serum ferritin levels, and a negative correlation between ROS levels and haemoglobin levels. There was a negative relationship between serum haemoglobin and ferritin levels. The results indicated that iron accumulation or severe anaemia could contribute to oxidative stress in MDS patients. Iron chelation and antioxidant therapy may be suitable for the management of MDS.

Abstract P1-12-07: Neo-Adjuvant Exemestane in Post Menopausal Estrogen and/or Progesterone Receptor Positive Breast Cancer: A Randomized Phase II Trial To Investigate Optimal Duration (4 Month Versus 6 Month) of Preoperative Endocrine Therapy (PTEX46 Trial)

Background: Since the 1990s, primary endocrine therapy has been considered the gold standard in the adjuvant and metastatic treatment settings for estrogen and/or progesterone receptor (ER and/or PgR) positive breast cancer. This therapy has also been shown to be effective as neo-adjuvant endocrine therapy in these indications. In recent years, the focus of clinical interest has shifted to the third-generation aromatase inhibitors from tamoxifen. The optimal treatment duration time and causal relationship between neo-adjuvant endocrine therapy and survival, however, are not clear. We therefore conducted the present study to investigate the potential benefits of neo-adjuvant exemestane (E) therapy with the goal of identifying the optimal treatment duration (4 months versus 6 months).

Methods: Conducted at three hospitals in Japan, this study was a multicenter, randomized phase II trial of pre-operative E treatment in postmenopausal women with untreated primary breast cancer. Fifty postmenopausal women with ER positive and/or PgR positive invasive breast cancer were randomly assigned to E (25 mg/day) for 4 months (4 mo) or E (25 mg/day) for 6 months (6 mo). All patient data were collected by UMIN and were analyzed by the National Cancer Center in Japan. Tumor regression (by clinical examination, ultrasound, and MRI), pathological response, shift towards breast-conserving surgery, and safety assessments were the main outcome measures.

Results: Of the 50 patients that enrolled, 28 patients had undergone surgery. The mean ages in the 4 mo and 6 mo treatment groups were 66.7 years and 66.8 years, respectively. No significant differences in the patient characteristics were found in the two groups. The response rates (partial or complete responses) by clinical examination in the 4 mo and 6 mo groups were 37.5% and 50%, respectively. Pathological responses (minimal response or better) were found in 13.3% and 41.7% of patients and a partial mastectomy was performed in 50.0% and 58.3% of patients after 4 mo and 6 mo, respectively.

Conclusion: To date, the results of this study demonstrate that treatment with E for 6 mo was more efficacious than treatment with E for 4 mo. Further work is in progress to obtain data from additional patients and to identify the optimal duration of neo-adjuvant E.

Citation Information: Cancer Res 2010;70(24 Suppl):Abstract nr P1-12-07.

Infectivity of HBV DNA positive donations identified in look-back studies in Hyogo-Prefecture, Japan

AIMS/OBJECTIVES

To clarify transfusion incidence of hepatitis B virus (HBV) infected blood negative for mini pool-nucleic acid amplification testing (MP-NAT).

BACKGROUND

Japanese Red Cross (JRC) blood centres screen donated blood to avoid contamination with HBV. However, a low copy number of HBV may be overlooked.

METHODS/MATERIALS

In Hyogo-Prefecture, JRC blood centres screened 787 695 donations for HBV from April 2005 to March 2009. Of these, 685 844 were donations from the repeat donors. To detect the donors with HBV, serological tests, MP-NAT and/or individual donation (ID)-NAT were performed. To detect the recipients with transfusion-transmitted HBV infection (TTHBI), serological analysis and/or ID-NAT were performed.

RESULTS

In this study, 265 of the 685 844 repeat donations were serologically and/or MP-NAT positive for HBV. Their repository samples from the previous donation were examined in a look-back study; 13 of the 265 repository samples proved ID-NAT positive. Twelve recipients were transfused with HBV-infected blood components derived from 10 of the 13 HBV-infected donors. Only 1 of the 12 recipients was identified as TTHBI case. Seven of the 12 recipients escaped from our follow-up study and 4 recipients were negative for HBV during the observation period.

CONCLUSION

On the basis of the look-back study among the repeat donors in Hyogo-Prefecture, Japan, donations with HBV-infected blood negative for MP-NAT occurred with a frequency of 13 in 685 844 donations (∼1/53 000 donations). However, more than half of the recipients transfused with HBV-infected blood negative for MP-NAT could not be followed up. It is necessary to establish a more cautious follow-up system.

When should we intervene to control the 2009 influenza A(H1N1) pandemic?

We simulated the early phase of the 2009 influenza A(H1N1) pandemic and assessed the effectiveness of public health interventions in Japan. We show that the detection rate of border quarantine was low and the timing of the intervention was the most important factor involved in the control of the pandemic, with the maximum reduction in daily cases obtained after interventions started on day 6 or 11. Early interventions were not always effective.

Acute non-hemolytic transfusion reactions and HLA class I antibody: advantages of solid phase assay compared with conventional complement-dependent assay

To evaluate the specific reactivity of HLA Class I antibodies (HLA-I Abs) in acute non-hemolytic transfusion reactions (ANHTRs) using solid phase assays (SPAs) and conventional complement-dependent lymphocyte cytotoxicity test (LCT). ANHTRs are major issues in transfusion medicine. Anti-leukocyte antibodies have been implicated as one of the causative agents of transfusion-related acute lung injury (TRALI) and febrile reaction. Antibodies to HLA Class I and/or Class II (HLA Abs) have been intensively studied using SPAs for TRALI, but not for febrile reaction. About 107 patients and 186 donors associated with ANHTRs were screened for HLA Abs by SPAs such as enzyme-linked immunosorbent assay (ELISA) and the Luminex method. When HLA-I Ab was detected, its specific reactivity was evaluated by comparing its specificity identified by the Luminex method using recombinant HLA molecules and cognate HLA antigens (Ags), as well as LCT with or without anti-human globulin (AHG). The incidences of HLA Abs were as high as 32·7% of patients' serum samples and 16% of donors' serum samples. The incidence of HLA-I Abs did not differ significantly between cases of febrile and allergic reactions. However, HLA-I Abs associated with febrile reaction showed a significantly higher rate of possessing specific reactivity to cognate HLA Ags than those associated with allergic reactions. In addition, the Luminex method enabled the detection of HLA-I Abs much earlier than AHG-LCT in serum samples from a patient with febrile reaction and platelet transfusion refractoriness (PTR). SPAs seem more useful than AHG-LCT for evaluating reactivity of antibodies in ANHTR cases.

Early recurrence of breast cancer after sentinel node navigation surgery: A multicenter prospective study in Japan

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Background: To assess lymphatic mapping technique and prognosis after sentinel node navigation surgery (SNNS), the Japanese society for SNNS conducted a non-randomized multi-center prospective study on SNNS in early breast cancer. Primary endpoint is to evaluate the success rate and adverse events of SNNS, and secondary endpoint is to observe the outcome of patients who underwent SNNS during 5 years. Methods: We demonstrated the results of primary endpoint at 2007 ASCO annual meeting (#606). Fourteen hundred and sixty-eight cases had pre-registration from 65 investigators at 23 institutions between July 2004 and October 2005. As 46 cases were withdrawn for some reasons and 11 cases were diagnosed as benign disease, 1,411 cases were entered in this study and will be observed until 2010. At this meeting, early recurrence at 3 years follow-up is reported. Results: As of June 2008, 38 of the 1,138 cases (3%) treated with SNNS alone and 16 of the 258 (6%) cases treated with SNNS followed by axillary lymph node dissection (ALND) relapsed. Seven cases died of disease. From the patient background, 50 cases had invasive ductal carcinoma, one had non-invasive ductal carcinoma, and three had special type. Thirty-three cases had negative nodes, 3 had micrometastatic nodes, and 18 had macrometastatic nodes. Fifty-two cases received chemotherapy and/or endocrine therapy. Regional recurrence including axillary, parasternal, and/or supraclavicular nodes was found in 11 cases after SNNS and in 2 cases after SNNS followed by ALND. Conclusions: Annual regional recurrence rate after SNNS was about 0.3%. SNNS in breast cancer is reliable to optimize surgical management in the axilla without increase of regional recurrence.

No significant financial relationships to disclose.

Comparison of acute non-haemolytic transfusion reactions in female and male patients receiving female or male blood components

To study the relationship between antibodies detected in patients’ and/or donors’ sera and the clinical features of acute non-haemolytic transfusion reactions (ANHTRs), and to determine any gender-related difference. ANHTRs range from urticaria to transfusion-related acute lung injury (TRALI). Antibodies to human leukocyte antigen (HLA), granulocytes, platelets, and/or plasma proteins are implicated in some of the ANHTRs. A higher antibody positivity is expected for females than for males. A comparative study of ANHTRs for antibody positivity and their clinical features between females and males for both patients and donors is helpful for characterizing ANHTRs including TRALI more clearly, but such studies are few and outdated. Two hundred and twenty-three ANHTR cases reported by 45 hospitals between October 2000 and July 2005 were analysed. The patients and 196 donors of suspect blood products were screened for antibodies to HLA Class I, HLA Class II, granulocytes, and platelets. The patients were also screened for anti-plasma protein antibodies. The types and severity of ANHTR did not differ significantly between female and male patients. The frequency of the anti-HLA antibodies, but not that of the non-HLA antibodies, was significantly higher in females. Non-HLA antibodies were significantly associated with severe reactions in females. All the TRALI cases had predisposing risk factors for acute lung injury, and 60% of the cases showed anti-leucocyte antibodies. Although the anti-HLA antibodies were detected more frequently in females than males, no significant association of ANHTRs including TRALI with gender, not only for patients, but also for donors, could be shown in this study.

Sentinel node biopsy in primary breast cancer: Radioactive detection and metastatic disease

AIM

To examine the relationship between the intensity of the radioactive counts and the presence of tumor metastasis in sentinel lymph nodes (SLNs) in order to correctly identify the number of SLNs to be removed.

PATIENTS AND METHODS

Five hundred three breast cancer patients with successful radioisotope localization of SLNs using the combined blue dye and radioisotope method were analyzed. SLN biopsy was continued until all the blue-stained and radioactive nodes were removed.

RESULTS

The mean number of harvested SLNs was 1.7+/-0.9, and the number of radioactive SLNs among the harvested nodes was 1.6+/-0.8. SLN metastasis was found in 123 of the 503 cases. The metastasis was detected in the SLN with the highest radioactive count (the hottest SLN) in 94 of the 123 cases with positive SLNs. The positive rate in the hottest SLN was 89% in 61 cases with a single radioactive SLN, and 65% in 62 cases with multiple radioactive SLNs. Of the 29 cases with positivity in other than the hottest SLNs, the metastasis was detected in the second hottest SLN in 16 cases, in the third hottest SLN in one case, in a mixture of negative radioactive SLNs and blue-dye-stained in four cases, and in the negative SLNs and positive non-SLNs (false-negative) in eight cases. Of 123 node-positive cases, 111 cases had metastasis that was detected within the first three hottest SLNs.

CONCLUSIONS

These data suggest that lymph node metastasis may not always be detected in the hottest SLN. Thus, in practice, all radioactive and/or blue-dye-stained nodes should be removed for further examination.

Biomarkers for the activation of calcium metabolism in dairy cows: elevation of tartrate-resistant acid phosphatase activity by lowering dietary cation-anion difference is associated with the prevention of milk fever

In our previous study, it was demonstrated that the administration of anion salts, which slightly lower the dietary cation-anion difference (DCAD), in the prepartum period is safe and effective for preventing milk fever in multiparous cows. In the present study, several biomarkers, which might show activation of Ca metabolism, were analyzed using stored samples in the previous study to investigate the mechanism of the preventive effect on milk fever by lowering DCAD. Changes in bone-specific alkaline phosphatase activity, osteocalcin and insulin-like growth factor I concentrations in serum were almost the same among the three groups of multiparous cows with or without the oral administration of anion salts, while the levels of these serum biomarkers in the group of primiparous cows (heifer group) were much higher compared with those in the three multiparous groups throughout the experimental period. Urinary deoxypyridinoline excretion was not a useful biomarker for dairy cows because it hardly changed during the peripartum period in all groups. However, serum tartrate-resistant acid phosphatase (TRAP) activity, which is known as a biomarker of osteoclast activity, was well associated with the administration of anion salts lowering DCAD because among the three multiparous groups, only the group of multiparous cows fed the anion salts (anion group) showed an increased level, which rose to the level in the heifer group, and was markedly higher than those in the other control groups of multiparous cows. The increased activity of serum TRAP in the anion group suggested that Ca in the plasma pool was mobilized smoothly from bone-bound Ca via mature osteoclasts at parturition, which might be due to prior activation under mild acidosis induced by slightly lowering DCAD. Therefore, TRAP was the best biomarker to monitor the activation of Ca metabolism in dairy cows fed anion salts.

Multi-center prospective study on sentinel node navigation surgery in early breast cancer

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Background: Sentinel node navigation surgery (SNNS) is a standard technique to identify lymph node metastases in clinically node-negative breast cancer. However, the dye and radiopharmaceuticals for lymphatic mapping commonly used in Western countries are not available in Japan. Methods: To assess the optimal lymphatic mapping and the outcome after SNNS, the Japanese society for SNNS conducted a non-randomized multi-center prospective study on SNNS in early breast cancer. Primary endpoint is to evaluate the success rates and adverse events associated with various lymphatic mapping and SNNS, and secondary endpoint is to observe the outcome of patients who underwent SNNS during 5 years. After the protocol was approved by institutional review board, SNNS had been registered between July 2004 and October 2005. Results: Fourteen hundred and sixty-eight cases had pre-registration from 65 investigators at 23 institutions. As 46 cases were withdrawn for some reasons and 11 cases were diagnosed as benign disease, 1,411 cases were finally entered in this study. Dyes used for lymphatic mapping were indigocarmine, indocyanin green, patent blue, and isosulfun blue, and radiopharmaceuticals were 99m-technetium-labelled tin colloid, human serum albumin, and phytate. In 19 cases, superparamagnetic iron oxide was used for MRI- guided SNNS. As of December 2006, 98% of clinical report forms were analyzed. Dye-guided SNNS was performed in 240 cases, radio-guided SNNS in 56 cases, and combined method in 1,016 cases. Overall success rate was 99%. SNNS alone was treated in 1,138 cases (82%) and SNNS followed by axillary lymph node dissection in 258 cases (12%). Breast-conserving surgery was undergone in 1,175 cases (85%) and total mastectomy in 217 cases (15%). Dye-induced allergic adverse events were not reported. Postoperative adverse events of bleeding, wound infection and seroma were observed in about 1 % of cases, respectively. Conclusions: Dye-guided and/or radio-guided SNNS proved reliable for lymphatic mapping in breast cancer. The prognosis of all cases will be observed until 2010.

No significant financial relationships to disclose.

Clinico-pathological findings in peripartum dairy cows fed anion salts lowering the dietary cation-anion difference: involvement of serum inorganic phosphorus, chloride and plasma estrogen concentrations in milk fever

In our previous study, it was demonstrated that the administration of anion salts, which slightly lower the dietary cation-anion difference (DCAD), in the prepartum period is safe and effective for preventing milk fever in multiparous cows. In the present study, several clinico-pathological constituents in serum and urine, which might be related to milk fever, were analyzed using stored samples from the previous study to identify clinico-pathological parameters for easily evaluating the efficacy of lowering DCAD and to further investigate the mechanism by which lowering DCAD prevents milk fever. Among the parameters analyzed in the present study, inorganic phosphorus (iP) was involved in milk fever because the serum concentration and urinary excretion of iP were significantly higher in the group of primiparous cows (heifer group), which did not develop hypocalcemia, than those in other groups of multiparous cows. Serum chloride concentrations in the heifer group and the group of multiparous cows fed anion salts (anion group) tended to remain higher than those in other control groups of multiparous cows suggesting that serum chloride concentration may be utilized for evaluating the status of metabolic acidosis and the efficacy of lowerng DCAD in dairy cows fed anion salts. In addition, plasma estradiol-17beta concentration in the heifer group tended to be lower at parturition compared with that in other multiparous groups suggesting that estrogen known as a potent inhibitor of bone resorption may be involved in developing milk fever.

DUSP22/LMW-DSP2 regulates estrogen receptor-alpha-mediated signaling through dephosphorylation of Ser-118

In the previous study, we demonstrated the involvement of dual specificity phosphatase 22 (DUSP22/LMW-DSP2) in regulating the leukemia inhibitory factor/interleukin-6/signal transducer and activator of transcription 3-mediated signaling pathway. In this study, we show beta-estradiol (E2)-induced DUSP22 mRNA expression in estrogen receptor alpha (ERalpha)-positive breast cancer cells, whereas E2-induced phosphorylation and activation of ERalpha was suppressed by overexpression of DUSP22 but not catalytically inactive mutants. Furthermore, small-interfering RNA-mediated reduction of DUSP22 expression enhanced ERalpha-mediated transcription and endogenous gene expression. In fact, DUSP22 associated with ERalpha in vivo and both endogenous proteins interacted in ERalpha-positive breast cancer T47D cells. These results strongly suggest that DUSP22 acts as a negative regulator of the ERalpha-mediated signaling pathway.

Preventive Effect of Mildly Altering Dietary Cation-Anion Difference on Milk Fever in Dairy Cows

In the present study, we examined whether mildly altering dietary cation-anion difference (DCAD) contributes to the prevention of milk fever in dairy cows. Thirty multiparous cows and ten primiparous cows (heifer group) were used in this study and the multiparous cows were randomly divided into three groups of ten animals each (anion, non-anion and control groups). The cows in the anion group were given supplemental salts that slightly lowered DCAD. These salts consisted of 115 g of CaCO3, 42 g of CaHPO4, 65 g of MgSO4 x 7 H2O and 80 g of CaCl2 x 2 H2O as a daily dose for each cow, using a catheter from 21 days before the expected date of parturition until parturition. The cows in the non-anion group were given only the same Ca, Mg and ip supplement but no sulfate and chloride salts as that in the anion group. The cows in the control and heifer groups were not given any additional supplement. The incidence of hypocalcemia in the anion group decreased to approximately half of those in the non-anion and control groups, while the heifer group did not develop hypocalcemia at all. In addition, the number of days spent for the treatment of hypocalcemia and the number of drug bottles (calcium borogluconate solution) used for the treatment decreased to less than half in the anion group compared with those in the non-anion and control groups. At parturition, the serum Ca concentration in the control (6.2 +/- 1.9 mg/dl, mean +/- standard deviation) and non-anion groups (6.4 +/- 1.7 mg/dl) were significantly lower than that in the heifer group (8.3 +/- 0.4 mg/dl), and the level in the anion group was intermediate (7.3 +/- 1.3 mg/dl). The change in ionized Ca concentration was almost the same as that in serum Ca concentration, but only the concentration in the anion group tended to increase slightly from a week before parturition and was significantly higher than that in all other groups three days before parturition. Urinary pH in the anion group was maintained at a mildly acidic level (6.8-7.0) for the last two weeks before parturition, compared with those in the control (7.3-7.5) and non-anion groups (7.9-8.1), and similar to that in the heifer group (6.3-7.3). The urinary Ca excretion was the highest in the anion group among all groups during the prepartum period. There were no specific changes in the excretion of parathyroid hormone and 1,25-dihydroxyvitamin D in all groups of multiparous cows while the levels of these hormones remained low in the heifer group throughout the experimental period. The data in the present study indicates that the administration of anion salts that slightly lowered DCAD in the preparum period was effective for preventing milk fever in multiparous cows. Safe and mild metabolic acidosis induced by the anion salts could be evaluated by urinary pH (6.8-7.0), and might increase the responsiveness to Ca requirement at parturition through some complex mechanisms unrelated to the excretion of Ca-related hormones. In addition, it was clarified that primiparous cows have a high potential to respond to sudden Ca demand unrelated to hormone excretion, and their Ca metabolism was in some respects similar to that in multiparous cows fed anion salts. Therefore, manipulating mildly DCAD is expected to be an effective, safe and natural method for preventing milk fever in dairy cows.

Impact of isolated tumor cells in sentinel lymph nodes detected by immunohistochemical staining

AIM

Isolated tumor cells (ITCs) in lymph nodes are defined histologically as node-negative. The clinical impact of ITCs in sentinel lymph nodes (SLNs) remains unclear. We report the prognosis of breast cancer patients with ITC-positive SLNs detected by immunohistochemical staining.

PATIENTS AND METHODS

One hundred and sixty-five breast cancer patients with histologically negative SLNs were seen between January 1998 and December 2000. In 69 patients, sentinel node biopsy (SNB) was immediately followed by axillary lymph node dissection, and 96 had undergone SNB alone. Permanent sections of 301 SLNs were re-examined after hematoxylin-eosin staining and cytokeratin 19 immunohistochemical staining.

RESULTS

ITCs were found in 18 SLNs of 17 patients and a micrometastasis was found in one SLN of one patient. As of November 2005, only one patient with ITCs in one SLN had supraclavicular lymph node recurrence. In contrast, 18 of the 147 patients with negative SLNs had tumor recurrence. Surgical management of the axilla had no influence on recurrence-free survival in all of the patients.

CONCLUSION

This study shows that breast cancer patients with ITC-positive SLNs should be clinically managed as node-negative patients.

Predictors of tumour involvement in remaining axillary lymph nodes of breast cancer patients with positive sentinel lymph node

AIMS

To characterize the various clinicopathologic features in cases of breast cancer with positive sentinel lymph nodes (SLNs), in order to determine factors that might help in predicting the involvement of the non-SLNs.

METHODS

A retrospective database review was performed of 726 breast cancer patients with stage 0-II, in whom SLNs were successfully identified. One hundred eighty-five of these patients showed positive SLNs, and subsequently underwent axillary lymph node dissection (ALND). These cases were divided into two groups based on the presence or absence of metastases in the non-SLNs, i.e. positive non-SLNs (NSLN+; 81 cases) and negative non-SLNs (NSLN-; 104 cases).

RESULTS

Multivariate analysis revealed that a larger size of the primary tumour (>2.0cm), presence of lymphatic invasion, larger size of the largest SLN metastasis (>2mm), and a 100% metastatic rate in the SLNs (number of positive SLNs/number of harvested SLNs) were significantly associated with NSLN+. Among the cases in which all the four factors were present, 73% (30/41) were found to have NSLN+.

CONCLUSION

We found four independent predictors in relation to non-SLN metastasis. Although these factors might be useful for determining the need of additional ALND, it would seem that even the presence of all of these four factors in combination may be insufficient to safely omit ALND. Thus, until further evidence is accumulated from the results of large clinical trials, ALND would still be recommended for patients with SLN metastasis.

Primary tumour-vessel tumour-nodal tumour classification for patients with invasive ductal carcinoma of the breast

There are many studies that show biological differences between invasive ductal carcinoma (IDC) with and without nodal metastasis, but no prognostic classification taking into consideration any biological differences between them is currently available. We previously investigated the histological characteristics that play an important role in tumour progression of IDCs according to their nodal status, and a new prognostic histological classification, the primary tumour–vessel tumour–nodal tumour (PVN) classification, was devised based on the histological characteristics of IDCs with and without nodal metastasis. Multivariate analyses using the Cox proportional hazard regression models were used to compare the ability of the PVN classification to predict tumour recurrence and death in 393 IDC patients based on the following histological classifications: (1) the pTNM classification, (2) the Nottingham Prognostic Index, (3) the modified Nottingham Prognostic Index, and (4) the histologic grade. In IDCs without nodal metastasis, only the PVN classification significantly increased the hazard rates (HRs) of tumour recurrence and death (P<0.05), independent of the hormone receptor status. Similarly, in IDCs with nodal metastases, only the PVN classification significantly increased the HRs of tumour recurrence and death (P<0.05), independent of the hormone receptor status. We conclude that the PVN prognostic histological classification is the best classification available for IDC of the breast.

Predicting gene regulation by sigma factors in Bacillus subtilis from genome-wide data

MOTIVATION

Sigma factors regulate the expression of genes in Bacillus subtilis at the transcriptional level. We assess the accuracy of a fold-change analysis, Bayesian networks, dynamic models and supervised learning based on coregulation in predicting gene regulation by sigma factors from gene expression data. To improve the prediction accuracy, we combine sequence information with expression data by adding their log-likelihood scores and by using a logistic regression model. We use the resulting score function to discover currently unknown gene regulations by sigma factors.

RESULTS

The coregulation-based supervised learning method gave the most accurate prediction of sigma factors from expression data. We found that the logistic regression model effectively combines expression data with sequence information. In a genome-wide search, highly significant logistic regression scores were found for several genes whose transcriptional regulation is currently unknown. We provide the corresponding RNA polymerase binding sites to enable a straightforward experimental verification of these predictions.

Predicting the operon structure of Bacillus subtilis using operon length, intergene distance, and gene expression information

We predict the operon structure of the Bacillus subtilis genome using the average operon length, the distance between genes in base pairs, and the similarity in gene expression measured in time course and gene disruptant experiments. By expressing the operon prediction for each method as a Bayesian probability, we are able to combine the four prediction methods into a Bayesian classifier in a statistically rigorous manner. The discriminant value for the Bayesian classifier can be chosen by considering the associated cost of misclassifying an operon or a non-operon gene pair. For equal costs, an overall accuracy of 88.7% was found in a leave-one-out analysis for the joint Bayesian classifier, whereas the individual information sources yielded accuracies of 58.1%, 83.1%, 77.3%, and 71.8% respectively. The predicted operon structure based on the joint Bayesian classifier is available from the DBTBS database (http://dbtbs.hgc.jp).

Finding optimal models for small gene networks

Finding gene networks from microarray data has been one focus of research in recent years. Given search spaces of super-exponential size, researchers have been applying heuristic approaches like greedy algorithms or simulated annealing to infer such networks. However, the accuracy of heuristics is uncertain, which--in combination with the high measurement noise of microarrays--makes it very difficult to draw conclusions from networks estimated by heuristics. We present a method that finds optimal Bayesian networks of considerable size and show first results of the application to yeast data. Having removed the uncertainty due to the heuristic methods, it becomes possible to evaluate the power of different statistical models to find biologically accurate networks.

Using protein-protein interactions for refining gene networks estimated from microarray data by Bayesian networks

We propose a statistical method to estimate gene networks from DNA microarray data and protein-protein interactions. Because physical interactions between proteins or multiprotein complexes are likely to regulate biological processes, using only mRNA expression data is not sufficient for estimating a gene network accurately. Our method adds knowledge about protein-protein interactions to the estimation method of gene networks under a Bayesian statistical framework. In the estimated gene network, a protein complex is modeled as a virtual node based on principal component analysis. We show the effectiveness of the proposed method through the analysis of Saccharomyces cerevisiae cell cycle data. The proposed method improves the accuracy of the estimated gene networks, and successfully identifies some biological facts.

Open source clustering software

SUMMARY

We have implemented k-means clustering, hierarchical clustering and self-organizing maps in a single multipurpose open-source library of C routines, callable from other C and C++ programs. Using this library, we have created an improved version of Michael Eisen's well-known Cluster program for Windows, Mac OS X and Linux/Unix. In addition, we generated a Python and a Perl interface to the C Clustering Library, thereby combining the flexibility of a scripting language with the speed of C.

AVAILABILITY

The C Clustering Library and the corresponding Python C extension module Pycluster were released under the Python License, while the Perl module Algorithm::Cluster was released under the Artistic License. The GUI code Cluster 3.0 for Windows, Macintosh and Linux/Unix, as well as the corresponding command-line program, were released under the same license as the original Cluster code. The complete source code is available at http://bonsai.ims.u-tokyo.ac.jp/mdehoon/software/cluster. Alternatively, Algorithm::Cluster can be downloaded from CPAN, while Pycluster is also available as part of the Biopython distribution.

Sentinel node biopsy for breast cancer patients in Japan

Sentinel node biopsy may become a standard procedure to detect lymph node metastases in early breast cancer. Numerous studies have confirmed and demonstrated the reliability of the hypothesis of sentinel node biopsy, with a high identification rate and overall accuracy connected with dye-guided and radio-guided sentinel node biopsy. To assess the benefit of sentinel node biopsy, randomized clinical trials are underway in Western countries comparing sentinel node biopsy with conventional axillary lymph node dissection. In Japan, feasibility studies on sentinel node biopsy started in the mid-1990s. The dye and radiopharmaceuticals associated with sentinel node biopsy commonly used in Western countries are not available in Japan. Japanese investigators have attempted to perform sentinel node biopsy using other dyes and radiopharmaceuticals. The results from feasibility studies have been similar to those reported previously. In conclusion, sentinel node biopsy for breast cancer patients is successful in Japan. The current status and the problems are discussed.

Usefulness of automatic detection of fragmented red cells using a hematology analyzer for diagnosis of thrombotic microangiopathy

We previously reported an automatic method for quantitative analysis of schistocytes or fragmented red cells using an automatic hematology analyzer, XE-2100. In the study reported here, we evaluated the accuracy of this detection method in patients with thrombotic microangiopathy (TMA). A follow-up study was performed on 14 patients with two types of TMA, thrombotic thrombocytopenic purpura or hemolytic uremic syndrome. Schistocyte percent was evaluated both with an automatic counter and by means of microscopic observation. Total activity and isoenzyme pattern of lactate dehydrogenase (LD) were also determined. In these patients, schistocyte percent determined by automatic counting correlated highly with that determined by manual counting under microscopic observation (r = 0.852, P < 0.0001). Schistocyte percent was shown to correlate significantly with isoenzyme fractions 1 and 2 of LD (r = 0.732, P < 0.02), reflecting hemolysis. Nine of 11 patients tested had high concentrations of LD isoenzyme five without distinct liver damage, and schistocyte percent did not relate to fraction 5 of LD. Automatic detection of schistocyte percent using a hematology analyzer was useful for an accurate diagnosis and follow-up of thrombotic microangiopathy. The origin of LD fraction 5 remains to be determined.

Statistical analysis of a small set of time-ordered gene expression data using linear splines

MOTIVATION

Recently, the temporal response of genes to changes in their environment has been investigated using cDNA microarray technology by measuring the gene expression levels at a small number of time points. Conventional techniques for time series analysis are not suitable for such a short series of time-ordered data. The analysis of gene expression data has therefore usually been limited to a fold-change analysis, instead of a systematic statistical approach.

METHODS

We use the maximum likelihood method together with Akaike's Information Criterion to fit linear splines to a small set of time-ordered gene expression data in order to infer statistically meaningful information from the measurements. The significance of measured gene expression data is assessed using Student's t-test.

RESULTS

Previous gene expression measurements of the cyanobacterium Synechocystis sp. PCC6803 were reanalyzed using linear splines. The temporal response was identified of many genes that had been missed by a fold-change analysis. Based on our statistical analysis, we found that about four gene expression measurements or more are needed at each time point.