ABSTRACT
The objective of this study was to propose prognostic factors and optimal treatment strategies by analyzing the clinicopathological features and programmed death-ligand 1 (PD-L1) expression. We analyzed 31 patients diagnosed with uterine or ovarian melanoma between 1997 and 2017 in the Kansai Clinical Oncology Group/Intergroup. Twenty-four and seven patients with cervical and ovarian melanomas were included, respectively. Immune checkpoint inhibitors were used in seven patients, and the objective response rate was 40%. Notably, two patients with objective responses had a high PD-L1 expression. Ten and four patients with cervical and ovarian melanomas, respectively, had high PD-L1 immunohistochemical expressions. Multivariate analysis revealed that tumor stage was an independent prognostic factor for progression-free survival in patients with cervical melanomas. In patients with ovarian melanomas, the 1-year cumulative progression-free and overall survival rates were 0 and 29%, respectively. Kaplan-Meier analyses revealed that age <60 years was associated with poorer progression-free and overall survivals in patients with ovarian melanomas. In patients with cervical melanomas, the 1-, 3-, and 5-year cumulative overall survival rates were 53, 32, and 16%, respectively. Histological atypia was associated with a poorer progression-free survival, but there was no difference in survival between patients who underwent radical hysterectomy and those who did not. The present study is a large cohort study of uterine and ovarian melanomas, which are aggressive tumors with a significantly poor prognosis, even after standard surgery and adjuvant therapy. The use of immune checkpoint inhibitors is a promising and effective treatment option.
Subject(s)
Melanoma , B7-H1 Antigen , Cohort Studies , Female , Humans , Immune Checkpoint Inhibitors , Japan , Middle Aged , Prognosis , Retrospective StudiesABSTRACT
Recent studies suggested that aggregates of mutant p53 proteins may propagate and impair normal p53 functioning in recipient cells. Our previous study showed that cancer cell-derived p53 aggregates that cells internalized interfered with p53-dependent apoptosis in recipient cells. However, involvement of p53 aggregate propagation in cancer pathology has not been fully elucidated. Here, we screened patients with high-grade serous ovarian carcinoma, which is characterized by an extremely high frequency of TP53 gene mutations, to show that patients with cytoplasmic p53 deposits have a poor prognosis compared with patients with complete p53 absence or strong nuclear p53 positivity. Cytoplasmic p53 in the patients with poor prognosis consisted of protein aggregates, which suggests that p53 aggregates are oncogenic drivers. Indeed, an inhibitor of p53 aggregation restored cellular apoptosis, a proper p53 function, in p53 aggregate-bearing patient-derived tumor organoids. In cell-based assays, endogenous and exogenous mutant p53 aggregates hindered chemotherapeutic activity of cisplatin, which depends on normal p53 functions. This inhibition was reduced by blocking p53 aggregation or internalization of p53 aggregates. Our study, thus indicates the involvement of p53 aggregate transmission in poor prognosis and in chemotherapy resistance in cancers.
ABSTRACT
Retained products of conception (RPOC) is a complication that occurs in the second trimester of pregnancy. We enrolled 98 women who had a miscarriage or termination with gemeprost in the second trimester of pregnancy. Eighteen cases (18.4%) were RPOC-positive. The gestational week at miscarriage or termination was earlier in the RPOC-positive group than those in the RPOC-negative group (p = .003). The period of the third stage of labour was longer in the RPOC-positive group than in RPOC-negative group (p = .040). The proportion of placental forceps use was higher in the RPOC-positive group than in RPOC-negative group (p = .003). Multivariate logistic regression analysis showed that gestational week (OR: 3.53; p = .04) and use of placental forceps at delivery (OR: 2.21; p = .012) were independent risk factors for RPOC. Earlier gestational weeks at miscarriage or termination and use of placental forceps at delivery were predictive factors for RPOC after second trimester miscarriage or termination with gemeprost.Impact StatementWhat is already known on this subject? There have been some reports on risk factors of RPOC. A previous report showed that the termination of pregnancy with misoprostol at earlier periods was associated with an increased risk of RPOC.What the results of this study add? There have been few studies on the risk factors of RPOC after miscarriage or termination with gemeprost. In this study, we evaluated the risk factors of RPOC after miscarriage or termination of pregnancy with gemeprost in the second trimester. We found that an earlier gestational age (between 12 and 17 weeks) at delivery and using placental forceps to remove placenta were significant risk factors of RPOC after miscarriage or termination of pregnancy with gemeprost in the second trimester.What the implications are of these findings for clinical practice and/or further research? An earlier gestational age and using forceps to remove placenta may be significant risk factors for RPOC. The accurate evaluation and treatment for RPOC is important for maternal life-saving efforts and subsequent pregnancies. Further research is needed to draft a standardised protocol for RPOC.
Subject(s)
Abortifacient Agents, Nonsteroidal , Abortion, Induced , Abortion, Spontaneous , Abortifacient Agents, Nonsteroidal/adverse effects , Abortion, Induced/adverse effects , Abortion, Spontaneous/etiology , Alprostadil/analogs & derivatives , Female , Humans , Infant , Japan , Placenta , Pregnancy , Pregnancy Trimester, Second , Retrospective Studies , Risk FactorsABSTRACT
Low-grade endometrial stromal sarcoma (LG-ESS) is a rare tumor that mostly occurs in perimenopausal women. Treatment with total hysterectomy and bilateral salpingo-oophorectomy is recommended, although fertility preservation or ovarian preservation may be considered in younger patients. The present study reports a case of LG-ESS in a young woman diagnosed after resection of endometrial polyp-like lesions. A 26-year-old nulligravid woman was referred to our hospital after being diagnosed with endometrial polyps. Hysteroscopic endometrial polypectomy was performed twice, and LG-ESS was suspected on postoperative pathological examination. Magnetic resonance imaging revealed a tumor 5-cm in diameter on the right side of the uterus. In light of the young age of the patient, tumorectomy was first performed, and postoperative pathological diagnosis was LG-ESS with the positive resection margin. After thorough discussion with the patient about fertility preservation and recurrence risk, a total abdominal hysterectomy and ovarian preservation was performed. Medroxyprogesterone therapy was performed postoperatively and no recurrence was observed for 2 years.
ABSTRACT
There have been very few reports on the use of immune checkpoint inhibitors for malignant tumors during pregnancy. Herein, the current study reports a case of a patient diagnosed with advanced malignant melanoma who was treated with pembrolizumab during pregnancy. A 40-year-old primigravida underwent noninvasive prenatal testing at 10 weeks of gestation, and the result was inconclusive, suggesting the possibility of maternal malignancy. A biopsy of the gluteal mass led to a diagnosis of malignant melanoma, and computed tomography revealed extensive metastases in her lungs and lymph nodes. She had a strong desire to proceed with pregnancy. In consideration of fetal growth and maturation, monotherapy was administered with pembrolizumab from 21 weeks of gestation, aiming for 28 weeks of gestation. The fetus grew well without maternal complications. At 28 weeks of pregnancy, the patient gave birth to a healthy boy by cesarean section. There was no evidence of metastasis in the placenta. The patient received nivolumab-ipilimumab combination therapy from postpartum day 13, followed by nivolumab monotherapy, and has been alive with controlled disease for 20 months.
ABSTRACT
Liquid biopsies from circulating tumor DNA (ctDNA) have been employed recently as a non-invasive diagnostic tool for detecting cancer-specific gene mutations. Here, we show the comprehensive gene mutation profiles of ctDNA in 51 patients with different histological subtypes of stage I-IV ovarian cancer, and their association with clinical outcomes. The ctDNA extracted from pre-treatment patients' plasma were analyzed using Cancer Personalized Profiling by Deep Sequencing targeting 197 genes. Of 51 patients, 48 (94%) showed one or more non-synonymous somatic mutations, including TP53 (37.3%), APC (17.6%), KRAS (15.7%), EGFR (13.7%), MET (11.8%), PIK3CA (11.8%), NPAP1 (11.8%), and ALK (9.8%). The most frequently mutated genes were as follows: TP53 in high-grade serous carcinoma (66.7%), APC in clear cell carcinoma (30.8%), PIK3CA in endometrioid carcinoma (40%), and KRAS in mucinous carcinoma (66.7%). Higher cell-free (cf)DNA concentration significantly correlated with worse progression-free survival (PFS) in all patients as well as stage III-IV patients (p = 0.01 and 0.005, respectively). Further, patients with any pathogenic mutations showed significantly worse PFS (p = 0.048). Blood tumor mutational burden detected from ctDNA did not significantly correlate with the histological subtypes or survival. Collectively, clinico-genomic profiles of individual ovarian cancer patients could be identified using ctDNA and may serve as a useful prognostic indicator. These findings suggest that ctDNA-based gene profiling might help in establishing personalized therapeutic strategies.
ABSTRACT
Cancer Personalized Profiling by deep Sequencing (CAPP-Seq) is a novel ultrasensitive next-generation sequencing-based approach that is used to detect circulating tumor DNA (ctDNA). The aim of the present study was to compare the gene mutation profiles and blood tumor mutation burden (bTMB) measured between pre- and post-neoadjuvant chemotherapy (NAC), utilizing CAPP-seq for plasma ctDNA in patients with advanced ovarian cancer. The current study included 10 patients (6 NAC-sensitive and 4 NAC-resistant) clinically diagnosed as having stage III or IV ovarian cancer and were administered NAC between May 2017 and February 2019. The plasma ctDNA samples were collected at pre- and post-NAC, and comprehensive gene mutation analysis was performed using CAPP-seq. In 5 out of 6 NAC-sensitive cases, the variant allele frequency (VAF) of non-synonymous somatic mutations decreased following NAC. In 2 out of the 4 NAC-resistant cases, the VAF of non-synonymous somatic mutations increased, and new somatic mutations emerged following NAC. In regard to TP53 mutation, the rate of TP53 mutation in the NAC-resistant cases was significantly higher compared with NAC-sensitive cases. Finally, the bTMB decreased significantly after NAC treatment in the NAC-sensitive cases, even though there were no significant differences in the pretreatment bTMB levels between the NAC-sensitive and NAC-resistant cases. These results indicated that gene mutation can be profiled and monitored using liquid biopsy-based CAPP-Seq in patients with advanced ovarian cancer with NAC treatment, and TP53 mutation in the ctDNA and bTMB may be novel biomarkers that can be used for patient monitoring during NAC treatment.
ABSTRACT
Castleman's disease is a rare benign disorder of unknown etiology characterized by proliferation of lymphoid tissues. Castleman's disease arising from pelvic retroperitoneum is clinically rare. The present case report describes a rare case of laparoscopically resected Castleman's disease in the pelvic retroperitoneum associated with benign ovarian cyst. A 47-year-old woman, gravida 5, para 3, was referred to to the Department of Obstetrics and Gynecology of Wakayama Medical University with a suspected pelvic tumor. Magnetic resonance imaging revealed that the solid tumor was localized in the retroperitoneal space at the right side of the pelvis. The patient underwent laparoscopic surgery for the resection of the pelvic retroperitoneal tumor, with complete tumor resection. Postoperative pathological examination established the diagnosis of Castleman's disease. The postoperative course was uneventful, with no evidence of local recurrence or systemic disease 6 months after diagnosis.
ABSTRACT
Liquid biopsies of circulating tumor DNA (ctDNA) have recently been used as a non-invasive diagnostic tool for detecting tumor-specific mutations. We present a study of ctDNA liquid biopsies in gynecological cancer using an ultrasensitive next-generation sequencing-based method for ctDNA detection named CAncer Personalized Profiling by deep Sequencing (CAPP-Seq). We performed CAPP-Seq with plasma-ctDNA obtained from 16 patients with gynecological cancer. In all cases, at least one non-synonymous somatic mutation was detected in the ctDNA. In the pre-treatment ctDNA, 4 of 16, 4/16, 5/16, 2/16, 2/16, and 2/16 patients had TP53, KRAS, APC, PIK3CA, BRCA1, and EGFR mutations, respectively. MET gene copy-number gains were detected in the ctDNA of 2 of 16 patients, and FISH analysis of the paired tumor samples confirmed these results. In 2 neoadjuvant chemotherapy-treated ovarian cancer patients, the changes in gene mutation patterns were associated with the treatment response. These findings suggest that CAPP-Seq-based liquid biopsies can be used for the genetic characterization of independent gynecological cancers with high frequency, and might be clinically useful for non-invasive tumor genotyping and therapeutic response monitoring.
Subject(s)
Genital Neoplasms, Female/genetics , Mutation/genetics , Biomarkers, Tumor/genetics , Circulating Tumor DNA/genetics , DNA, Neoplasm/genetics , Female , Genital Neoplasms, Female/pathology , High-Throughput Nucleotide Sequencing/methods , Humans , Liquid Biopsy/methods , Male , Neoplastic Cells, Circulating/pathologyABSTRACT
Programmed cell death ligand 1 (PD-L1) on tumor cells suppresses anti-tumor immunity and has an unfavorable prognostic impact in ovarian cancer patients. We herein report the pathophysiological and therapeutic impacts of PD-L1 disruption in ovarian cancer. PD-L1 was genetically disrupted in the murine ovarian cancer cell line ID8 using clustered regularly interspaced short palindromic repeats (CRISPR)/Cas9-mediated genome editing. PD-L1 knockout (KO) and control ovarian cancer cells were intraperitoneally inoculated into syngeneic mice, and survival and tumor dissemination were evaluated. Survival times were significantly longer in the PD-L1-KO ID8-inoculated groups than in their control groups, and its therapeutic benefit was enhanced in combination with the cisplatin treatment. Tumor weights and ascites volumes were significantly lower in the PD-L1-KO ID8 groups than in their control groups. Immunohistochemical and immunofluorescence analyses showed that intratumoral CD4+ T cells, CD8+ T cells, NK cells and CD11c+ M1 macrophages were significantly increased, whereas regulatory T cells were significantly decreased in the PD-L1-KO ID8 groups compared with those in their control groups. The intratumoral mRNA expression of interferon-γ, tumor-necrosis factor-α, interleukin (IL)-2, IL-12a, CXCL9 and CXCL10 was significantly stronger, while that of IL-10, vascular endothelial growth factor, CXCL1 and CXCL2 was significantly weaker in the PD-L1-KO ID8 groups. These results indicate that CRISPR/Cas9-mediated PD-L1 disruption on tumor cells promotes anti-tumor immunity by increasing tumor-infiltrating lymphocytes and modulating cytokine/chemokine profiles within the tumor microenvironment, thereby suppressing ovarian cancer progression. These results suggest that PD-L1-targeted therapy by genome editing may be a novel therapeutic strategy for ovarian cancer.
Subject(s)
B7-H1 Antigen/metabolism , CRISPR-Cas Systems , Gene Editing , Immunity , Ovarian Neoplasms/genetics , Ovarian Neoplasms/metabolism , Animals , B7-H1 Antigen/genetics , Cell Line, Tumor , Cell Survival/genetics , Cytokines/metabolism , Disease Progression , Enzyme-Linked Immunosorbent Assay , Female , Gene Deletion , Genetic Loci , Humans , Immunomodulation , Lymphocytes, Tumor-Infiltrating/immunology , Lymphocytes, Tumor-Infiltrating/metabolism , Lymphocytes, Tumor-Infiltrating/pathology , Macrophages/immunology , Macrophages/metabolism , Mice , Neoplasm Metastasis , Ovarian Neoplasms/immunology , Ovarian Neoplasms/pathologyABSTRACT
Papillary thyroid carcinoma arising from ovarian mature cystic teratoma is clinically rare. We herein present a case of live birth following two laparoscopic surgeries for papillary thyroid carcinoma arising in a mature ovarian cystic teratoma. A 30-year-old female patient, gravida 1 para 1, was treated by laparoscopic bilateral ovarian cystectomy for suspicion of bilateral mature cystic teratoma. The diagnosis of papillary thyroid carcinoma arising from right ovarian mature cystic teratoma was established based on postoperative pathological examination of the tumor. Such rare neoplasms may be difficult to diagnose preoperatively based on radiological examinations alone. The patient underwent laparoscopic fertility-preserving unilateral (right) salpingo-oophorectomy. Following an extensive discussion with the patient and her family, appropriate informed consent was obtained for the treatment option and the patient and her family chose to preserve her fertility. She could have a baby following the treatment and no evidence of disease for 6 years. Gynecologists should be aware of the possibility of such rare cases, and the available surgical interventions should be fully discussed with patients who wish to preserve their fertility. Laparoscopic fertility-sparing surgery may be a feasible option when encountering such a rare condition.
ABSTRACT
Liquid biopsies of circulating tumor DNA (ctDNA) can detect molecular alterations, including tumor-specific mutations, and have recently been used as a non-invasive diagnostic, prognostic, and predictive tool. However, this technique is not commonly used in the gynecological field. Gene mutation profiling of liquid biopsy samples was performed using CAncer Personalized Profiling by deep Sequencing (CAPP-Seq), a novel next-generation sequencing-based approach to ultrasensitive ctDNA detection, in order to make it possible to molecularly diagnose metastatic colorectal cancer to the ovary. Liquid biopsy (plasma) samples and formalin-fixed paraffin-embedded tumor samples were obtained from two patients with ovarian tumors, who had a history of surgery for colorectal cancer, and comprehensive gene mutation profiling was conducted using CAPP-Seq. In patient 1, mutations were identified in the same three regions in both the ovarian tumor and preoperative plasma sample (in the KRAS G13D, APC E1306*, and TP53 H193Y genes). In patient 2, mutation was identified in the same one region in all the primary colorectal tumor, the ovarian tumor, and preoperative plasma sample (in APC R216* gene). These mutations are well-known genetic signatures of colorectal cancer, suggesting that the ovarian tumor was metastatic. Tthe gene mutation patterns of colorectal cancer were examined by subjecting liquid biopsy samples from patients with suspected metastatic ovarian tumors to CAPP-Seq. Gene mutation profiling of liquid biopsy samples can contribute to the preoperative differential diagnosis of metastatic ovarian cancer and its subsequent personalized treatment.
ABSTRACT
Malignant melanoma (MM) in the female genital tract accounts for less than 2% of all melanomas, and the vast majority associated occur in the vulva and vagina. Primary MM of the uterine cervix is extremely rare and its prognosis is very poor. We report a case of primary MM of the cervix with dissemination throughout the vaginal wall. A 66-year-old woman presented with postmenopausal bleeding. Gynecologic examination demonstrated a 2 cm polypoid blackish-pigmented tumor on the cervix with multiple small blackish-pigmented lesions throughout the vaginal wall. Cervical Pap smear cytology showed malignant melanoma. MRI and PET/CT did not detect any distant or lymph node metastases. She underwent radical hysterectomy, pelvic lymphadenectomy, and total vaginectomy. The pathological diagnosis was FIGO stage IIIA primary cervical MM. She received adjuvant chemotherapy with 6 courses of dacarbazine, but 6 months later, multiple lung metastases were detected. Despite 4 courses of anti-PD-1 antibody (nivolumab) treatment, she died of the disease 13 months after surgery.
ABSTRACT
We report a case of elderly metastatic breast cancer with a complete response to the treatment with XC (X: capecitabine and C: cyclophosphamide). A 78-year-old woman, who presented with left breast cancer, underwent pectoralis-preserving mastectomy when she was 76 years old. Pathological findings were as follows: invasive ductal carcinoma (scirrhous type), pT1c (2.0 cm), n (1/10), ly3, v1, ER (-), PgR (-), HER2: score 1. After one year and a half, a left supraclavicular lymph node metastasis, a left interpectoral lymph node metastasis, and mediastinal lymph nodes metastasis were noted. Capecitabine and cyclophosphamide were administered as first-line chemotherapy. After 8 cycles, all metastases responded, and this therapy is now being continued (19 cycles) on an outpatient basis. The complete response has continued for nine months. XC therapy can be the first-line chemotherapy for elderly metastatic breast cancer patients since it has been effective and no serious side effects have been encountered while maintaining quality of life.
Subject(s)
Antineoplastic Combined Chemotherapy Protocols/therapeutic use , Breast Neoplasms/drug therapy , Carcinoma, Ductal, Breast/drug therapy , Deoxycytidine/analogs & derivatives , Fluorouracil/analogs & derivatives , Aged , Antimetabolites, Antineoplastic/administration & dosage , Antineoplastic Agents, Alkylating/administration & dosage , Breast Neoplasms/pathology , Capecitabine , Carcinoma, Ductal, Breast/pathology , Cyclophosphamide/administration & dosage , Deoxycytidine/administration & dosage , Drug Administration Schedule , Female , Fluorouracil/administration & dosage , Humans , Lymphatic Metastasis , Neoplasm Metastasis , Treatment OutcomeABSTRACT
The key issue in the field of therapeutic endoscopy in recent years is the development of a new therapeutic strategy for early gastric cancers using endoscopic submucosal dissection (ESD) technique. ESD was developed to overcome the problem of remnant or recurrent tumors after incomplete resection by conventional endscopic mucosal resection (EMR). Ever since after the emergence of ESD, indication criteria for endoscopic resection of early gastric cancers were extended through expansion of both theoretical and technical conditions. Complete en bloc resection rates were 96.7% and 62.6% in the ESD group and the EMR group, respectively, in our institution. ESD is a highly effective technique enabling us to resect much larger and difficult lesions, which cannot be resected by conventional EMR techniques. However, it involves a much higher complication rate and requires much higher skills. A small lesion less than 20 mm located in a good position can be resected completely, without any difficulties using conventional EMR techniques. Therefore, we must consider the approach to treatment, when conducting an endoscopic resection,it terms of the situation and skills of the endoscopist.
Subject(s)
Digestive System Surgical Procedures/methods , Gastric Mucosa/surgery , Gastroscopy , Stomach Neoplasms/surgery , Humans , Practice Guidelines as Topic , Quality of Life , Stomach Neoplasms/pathologyABSTRACT
The bactericidal activity induced by the introduction of silver ions into zeolite was studied. Escherichia coli was used as the test microorganism. Silver ions were loaded into zeolite by the ion-exchange method. Silver-loaded zeolite was demonstrated the strong bactericidal activity. Dissolved oxygen was an essential factor for the occurrence of the bactericidal activity because the activity was observed only under aerated condition. Superoxide anions, hydrogen peroxide, hydroxyl radicals and singlet oxygen were formed. Scavengers of these each reactive oxygen species (ROS) inhibited the bactericidal activity. This means that all ROS contributed to the activity.
Subject(s)
Anti-Bacterial Agents/pharmacology , Oxygen/metabolism , Reactive Oxygen Species/metabolism , Silver , Zeolites/pharmacology , Aerobiosis , Catalase/metabolism , Cytochrome c Group/metabolism , Escherichia coli/drug effects , Escherichia coli/growth & development , Escherichia coli/metabolism , Free Radical Scavengers/metabolism , Hydrogen Peroxide/metabolism , Hydroxyl Radical/metabolism , Nitrogen/pharmacology , Singlet Oxygen/metabolism , Solvents , Superoxides/metabolismABSTRACT
A redox species was extracted from water (50 x 10(-6) dm3) into a single micro-oil-droplet (30 x 10(-12) dm3) in contact with a microelectrode using microcapillary injection and manipulation techniques. Further, an in situ microanalysis of the solute in a single oil droplet was demonstrated by differential pulse voltammetry. The redox species of 10(-16) mol concentrated in the droplet could be quantitatively analyzed independently of the distribution coefficient of the solute between the oil and water phases. The potential of this technique was considered in terms of the preconcentration and separation as well as a microanalysis and an ultratrace analysis.
ABSTRACT
Five trinuclear complexes [M(bpca)(2)(M'(hfac)(2))(2)] (where MM'(2) = NiMn(2), CuMn(2), FeMn(2), NiFe(2), and FeFe(2); Hbpca = bis(2-pyridylcarbonyl)amine; and Hhfac = hexafluoroacetylacetone) were synthesized almost quantitatively by the reaction of [M(bpca)(2)] and [M'(hfac)(2)] in 1:2 molar ratio, and their structures and magnetic properties were investigated. Three complexes, with M' = Mn, crystallize in the same space group, Pna2(1), whereas two complexes, with M' = Fe, crystallize in P4(1), and complexes within each set are isostructural to one another. In all complexes, [M(bpca)(2)] acts as a bis-bidentate bridging ligand to form a linear trinuclear complex in which three metal ions are arranged in the manner M'-M-M'. The central metal ion is in a strong ligand field created by the N(6) donor set, and hence the Fe(II) in the [Fe(bpca)(2)] moiety is in a low-spin state. The terminal metal ions (M') are surrounded by O(6) donor sets with a moderate ligand field, which leads to the high-spin configuration of Fe(II). Three metal ions in all complexes are almost collinear, and metal-metal distances are ca. 5.5 A. The magnetic behavior of NiMn(2) and NiFe(2) shows a weak ferromagnetic interaction between the central Ni(II) ion and the terminal Mn(II) or Fe(II) ions. In these complexes, sigma-spin orbitals of the central Ni(II) ion and those of terminal metal ions have different symmetry about a 2-fold rotation axis through the Ni-N(amide)-M'(terminal) atoms, and this results in orthogonality between the neighboring sigma-spin orbitals and thus ferromagnetic interactions.