Reconsidering resectable oncological conditions in pancreatic tail cancer: A multicenter retrospective study on prognostic factors in pancreatic tail cancer after resection (HOPS Pt-01).

BACKGROUND: Pancreatic tail cancer (Pt-PC) is generally considered resectable when metastasis is absent, but doubts persist in clinical practice due to the variability in local tumor extent. We conducted a multicenter retrospective study to comprehensively identify prognostic factors associated with Pt-PC after resection. METHODS: We enrolled 100 patients that underwent distal pancreatectomy. The optimal combination of factors influencing relapse-free survival (RFS) was determined using the maximum likelihood method (MLM) and corrected Akaike and Bayesian information criteria (AICc and BIC). Prognostic elements were then validated to predict oncological outcomes. RESULTS: Therapeutic interventions included neoadjuvant treatment in 16 patients and concomitant visceral resection (CVR) in 37 patients; 89 patients achieved R0. Median RFS and OS after surgery were 23.1 and 37.1 months, respectively. AICc/BIC were minimized in the model with ASA-PS (≥2), CA19-9 (≥112 U/mL at baseline, non-normalized postoperatively), need for CVR, 6 pathological items (tumor diameter ≥19.5 mm, histology G1, invasion of the anterior pancreatic border, splenic vein invasion, splenic artery invasion, lymph node metastasis), and completed adjuvant treatment (cAT) for RFS. Regarding the predictive value of these 11 factors, area under the curve was 0.842 for 5-year RFS. Multivariate analysis of these 11 factors showed that predictors of RFS include CVR (hazard ratio, 2.13; 95 % confidence interval, 1.08-4.19; p = 0.028) and cAT (0.38, 0.19-0.76; p = 0.006). CONCLUSIONS: The MLM identified certain Pt-PC cases warranting consideration beyond resectable during clinical management. Particular attention should be paid to conditions requiring CVR, even though immortal time bias remains unresolved with adjuvant treatment.

A case report of carcinoma of the papilla of Vater associated with a hyperplasia-dysplasia-carcinoma sequence by pancreaticobiliary maljunction.

BACKGROUND: Pancreaticobiliary maljunction (PBM) is a known risk factor for biliary tract cancer. However, its association with carcinoma of the papilla of Vater (PVca) remains unknown. We report a case with PVca that was thought to be caused by the hyperplasia-dysplasia-carcinoma sequence, which is considered a mechanism underlying PBM-induced biliary tract cancer. CASE PRESENTATION: A 70-year-old woman presented with white stool and had a history of cholecystectomy for the diagnosis of a non-dilated biliary tract with PBM. Esophagogastroduodenoscopy revealed a tumor in the papilla of Vater, and PVca was histologically proven by biopsy. We finally diagnosed her with PVca concurrent with non-biliary dilated PBM (cT1aN0M0, cStage IA, according to the Union for International Cancer Control, 8th edition), and subsequently performed subtotal stomach-preserving pancreaticoduodenectomy. Pathological findings of the resected specimen revealed no adenomas and dysplastic and hyperplastic mucosae in the common channel slightly upstream of the main tumor, suggesting a PBM related carcinogenic pathway with hyperplasia-dysplasia-carcinoma sequence. Immunostaining revealed positivity for CEA. CK7 positivity, CK20 negativity, and MUC2 negativity indicated that this PVca was of the pancreatobiliary type. Genetic mutations were exclusively detected in tumors and not in normal tissues, and bile ducts from formalin-fixed paraffin-embedded samples included mutated-ERBB2 (Mutant allele frequency, 81.95%). Moreover, of the cell-free deoxyribonucleic acid (cfDNA) extracted from liquid biopsy mutated-ERBB2 was considered the circulating-tumor deoxyribonucleic acid (ctDNA) of this tumor. CONCLUSIONS: Herein, we report the first case of PVca with PBM potentially caused by a "hyperplasia-dysplasia-carcinoma sequence" detected using immunostaining and next-generation sequencing. Careful follow-up is required if pancreaticobiliary reflux persists, considering the possible development of PVca.

Postpartum regression of human papillomavirus-related vulvar cancer: A case report.

We report a case of a 23-year-old pregnant woman (gravida 2 para 0, pregnancy 33 weeks and 3 days) with a history of laser ablation for cervical intraepithelial neoplasia-3 at 22 years. At initial visit, a 2 × 2 × 1-cm elevated mass was found on right labia majora. Biopsy results revealed squamous cell carcinoma of right labia; immunostaining revealed p16 positivity. Patient was diagnosed with human papillomavirus-related vulvar cancer. Selective cesarean section was performed at 36 weeks and 4 days of gestation. Postoperative histopathological diagnosis of squamous cell carcinoma, and 1.7-mm deep infiltrations led to vulvar cancer stage IB diagnosis. Reduction operation was performed, and postoperative follow-up of 1 year and 8 months revealed no recurrence. These results emphasize that small vulvar tumors during pregnancy should not be underestimated and histological examinations should be performed without hesitation. Careful observation and evaluation of tumors is necessary during pregnancy and after delivery because they may shrink postdelivery.

Tumor-Informed Approach Improved ctDNA Detection Rate in Resected Pancreatic Cancer.

Pancreatic cancer is one of the cancers with very poor prognosis; there is an urgent need to identify novel biomarkers to improve its clinical outcomes. Circulating tumor DNA (ctDNA) from liquid biopsy has arisen as a promising biomarker for cancer detection and surveillance. However, it is known that the ctDNA detection rate in resected pancreatic cancer is low compared with other types of cancer. In this study, we collected paired tumor and plasma samples from 145 pancreatic cancer patients. Plasma samples were collected from 71 patients of treatment-naïve status and from 74 patients after neoadjuvant therapy (NAT). Genomic profiling of tumor DNA and plasma samples was conducted using targeted next-generation sequencing (NGS). Somatic mutations were detected in 85% (123/145) of tumors. ctDNA was detected in 39% (28/71) and 31% (23/74) of treatment-naïve and after-NAT groups, respectively, without referring to the information of tumor profiles. With a tumor-informed approach (TIA), ctDNA detection rate improved to 56% (40/71) and 36% (27/74) in treatment-naïve and after-NAT groups, respectively, with the detection rate significantly improved (p = 0.0165) among the treatment-naïve group compared to the after-NAT group. Cases who had detectable plasma ctDNA concordant to the corresponding tumor showed significantly shorter recurrence-free survival (RFS) (p = 0.0010). We demonstrated that TIA improves ctDNA detection rate in pancreatic cancer, and that ctDNA could be a potential prognostic biomarker for recurrence risk prediction.

Clinical usefulness of saphenous vein graft in major arterial reconstruction during extended pancreatectomy.

PURPOSE: Extended pancreatectomy for locally advanced pancreatobiliary malignancy often involves combined major arterial resection (AR) and reconstruction (ARc). By limiting candidate inflow for ARc after combined resection of the celiac arterial system over a long distance, we evaluated whether great saphenous vein graft (GSVG) is an alternative conduit for obtaining non-anatomical arterial inflow. METHODS: ARc with GSVG conduit was undertaken prior to resection. GSVG was harvested and anastomosed end-to-side with the reconstructing artery and then mostly passed via the retroperitoneal para-inferior vena cava route. Side-to-end anastomosis of GSVG inflow was established with the right common iliac artery or abdominal aorta. RESULTS: Among 468 consecutive pancreatobiliary surgeries, ARc with GSVG was undertaken in seven cases. Primary cancers were in the pancreas in six patients and distal bile duct in one. Radical surgery was performed with pancreaticoduodenectomy in six patients and total pancreatectomy in one. Hepatic artery (HA) was concomitantly resected and reconstructed by GSVG in six patients or by the jejunal artery in one patient. Median operative time and intraoperative blood loss were 763 min and 350 ml, respectively. Serum level of AST, ALT, and LDH in patients with HA reconstruction by GSVG peaked by the second postoperative day and promptly normalized. Postoperative morbidity (CD ≥ III) was encountered in one patient. No surgical mortality was observed. Postoperative serum liver enzymes promptly decreased in ARc patients with GSVG to HA. CONCLUSION: Arterial reconstruction with GSVG prior to resection was performed securely and might help to reduce postoperative liver dysfunction.

[A Case of Gastric Cancer with Necrotic Lymph Node Perforation in the Stomach during Chemotherapy].

A 63-year-old man was diagnosed with gastric cancer. Distal gastrectomywas performed in November 2011. The pathologic finding was pT3N2M0, Stage ⅢA. S-1 was administered as adjuvant chemotherapy. However, in August 2012, computed tomographyrevealed a tumor measuring 3 cm in size in the dorsal pancreas. Based on endoscopic ultrasound-guided fine- needle aspiration, he was diagnosed with lymph node recurrence of gastric cancer. Injection chemotherapy of CDDP/CPT-11 was initiated in November 2012. In January 2013, the patient developed fever owing to a ruptured abscess from the posterior wall in the stomach. In the 6 years since, although the patient has not undergone chemotherapy, recurrence has not been observed.

New CETP inhibitor K-312 reduces PCSK9 expression: a potential effect on LDL cholesterol metabolism.

Despite significant reduction of cardiovascular events by statin treatment, substantial residual risk persists, driving emerging needs for the development of new therapies. We identified a novel cholesteryl ester transfer protein (CETP) inhibitor, K-312, that raises HDL and lowers LDL cholesterol levels in animals. K-312 also suppresses hepatocyte expression of proprotein convertase subtilisin/kexin 9 (PCSK9), a molecule that increases LDL cholesterol. We explored the underlying mechanism for the reduction of PCSK9 expression by K-312. K-312 inhibited in vitro human plasma CETP activity (IC50; 0.06 µM). Administration of K-312 to cholesterol-fed New Zealand White rabbits for 18 wk raised HDL cholesterol, decreased LDL cholesterol, and attenuated aortic atherosclerosis. Our search for additional beneficial characteristics of this compound revealed that K-312 decreases PCSK9 expression in human primary hepatocytes and in the human hepatoma cell line HepG2. siRNA silencing of CETP in HepG2 did not compromise the suppression of PCSK9 by K-312, suggesting a mechanism independent of CETP. In HepG2 cells, K-312 treatment decreased the active forms of sterol regulatory element-binding proteins (SREBP-1 and -2) that regulate promoter activity of PCSK9. Chromatin immunoprecipitation assays demonstrated that K-312 decreased the occupancy of SREBP-1 and SREBP-2 on the sterol regulatory element of the PCSK9 promoter. PCSK9 protein levels decreased by K-312 treatment in the circulating blood of cholesterol-fed rabbits, as determined by two independent mass spectrometry approaches, including the recently developed, highly sensitive parallel reaction monitoring method. New CETP inhibitor K-312 decreases LDL cholesterol and PCSK9 levels, serving as a new therapy for dyslipidemia and cardiovascular disease.

Hydrothermal Synthesis of Yttria-Stabilized Zirconia Nanocrystals with Controlled Yttria Content.

In this study, we demonstrate for the first time the hydrothermal synthesis of yttria-stabilized zirconia (YSZ) nanocrystals with controlled yttria content (x = 3-12 mol %; xYSZ) with negligible aggregation from aqueous solution. The nanocrystals were grown via the hydrothermal treatment of basic Zr(IV) and Y(III) carbonate complex aqueous solutions in the presence of a cationic ligand, N(CH3)4(+). The nanocrystals were characterized in detail by dynamic light scattering, ζ-potential measurement, X-ray diffraction, specific surface area measurement based on the Brunauer-Emmett-Teller theory, transmission electron microscopy, energy dispersive X-ray spectroscopy, and Raman spectroscopy. Shorter reaction times and higher Y2O3 content produce aqueous solutions with higher transparencies containing nanocrystals with sizes of 10 nm or less. Nanocrystals with the target composition were obtained by hydrothermal reaction for longer than 3 h, regardless of the Y2O3 content. The main phase is tetragonal for (3-6)YSZ and cubic with disordered oxygen vacancies for (8-12)YSZ. The characteristics of the nanocrystalline material synthesized are consistent with those of bulk YSZ crystals, indicating the growth of high-quality nanocrystals.

A system for the targeted amplification of bacterial gene clusters multiplies antibiotic yield in Streptomyces coelicolor.

Gene clusters found in bacterial species classified as Streptomyces encode the majority of known antibiotics as well as many pharmaceutically active compounds. A site-specific recombination system similar to those that mediate plasmid conjugation was engineered to catalyze tandem amplification of one of these gene clusters in a heterologous Streptomyces species. Three genetic elements were known to be required for DNA amplification in S. kanamyceticus: the oriT-like recombination sites RsA and RsB, and ZouA, a site-specific relaxase similar to TraA proteins that catalyze plasmid transfer. We inserted RsA and RsB sequences into the S. coelicolor genome flanking a cluster of 22 genes (act) responsible for biosynthesis of the polyketide antibiotic actinorhodin. Recombination between RsA and RsB generated zouA-dependent DNA amplification resulting in 4-12 tandem copies of the act gene cluster averaging nine repeats per genome. This resulted in a 20-fold increase in actinorhodin production compared with the parental strain. To determine whether the recombination event required taxon-specific genetic effectors or generalized bacterial recombination (recA), it was also analyzed in the heterologous host Escherichia coli. zouA was expressed under the control of an inducible promoter in wild-type and recA mutant strains. A plasmid was constructed with recombination sites RsA and RsB bordering a drug resistance marker. Induction of zouA expression generated hybrid RsB/RsA sites, evidence of site-specific recombination that occurred independently of recA. ZouA-mediated DNA amplification promises to be a valuable tool for increasing the activities of commercially important biosynthetic, degradative, and photosynthetic pathways in a wide variety of organisms.

The association of oral frailty with fall risk in community-dwelling older adults: a cross-sectional, observational study.

PURPOSE: This cross-sectional study examined the direct association of oral frailty with falls in community-dwelling older adults, controlling for the effects of sarcopenia and physical performance. METHODS: The participants were 237 community-dwelling older people (age: 76.0 ± 5.7 years, male: 23.6%). Oral frailty was assessed using the Oral Frailty Index-8. History of falls, timed up and go test (TUG), and sarcopenia were also assessed. The association between oral frailty and fall incidence was analyzed using multivariate logistic regression analysis adjusted for TUG and sarcopenia. RESULTS: Forty-six (19.4%) participants fell, and 130 (54.9%) had a risk of oral frailty. On multivariate logistic regression analysis, oral frailty was significantly associated with fall incidence (odds ratio = 2.38, 95% confidence interval 1.11-5.07), even after adjusting for TUG and sarcopenia. CONCLUSION: Oral frailty is a possible fall risk factor, independent of sarcopenia and physical performance, in community-dwelling older people.

Machine learning judged neutral facial expressions as key factors for a "good therapist" within the first five minutes: An experiment to simulate online video counselling.

Objective: Machine learning models were employed to discern patients' impressions from the therapists' facial expressions during a virtual online video counselling session. Methods: Eight therapists simulated an online video counselling session for the same patient. The facial emotions of the therapists were extracted from the session videos; we then utilized a random forest model to determine the therapist's impression as perceived by the patients. Results: The therapists' neutral facial expressions were important controlling factors for patients' impressions. A predictive model with three neutral facial features achieved an accuracy of 83% in identifying patients' impressions. Conclusions: Neutral facial expressions may contribute to patient impressions in an online video counselling environment with spatiotemporal disconnection. Innovation: Expression recognition techniques were applied innovatively to an online counselling setting where therapists' expressions are limited. Our findings have the potential to enhance psychiatric clinical practice using Information and Communication Technology.

High-throughput screening of radioprotectors using rat thymocytes.

We invented a high-throughput screening method for the examination of radioprotective activity of chemical compounds using rat thymocytes. X-irradiation of the rat thymocytes induced apoptosis, leading to a significant cell shrinkage, which could be easily detected and directly quantified by the flow cytometry analysis. The protective effect of some natural antioxidants against radiation induced apoptosis in the rat thymocytes, as well as their toxicities without X-irradiation, was successfully evaluated using this method. This method provides a powerful tool to develop novel radioprotectors without toxicity and can also be widely used to estimate other oxidative stress except for radiation.

Synthesis and biological evaluation of C-glucosides with azulene rings as selective SGLT2 inhibitors for the treatment of type 2 diabetes mellitus: discovery of YM543.

Here, a series of C-glucosides with azulene rings in the aglycon moiety was synthesized and the inhibitory activities toward hSGLT1 and hSGLT2 were evaluated. Starting from the azulene derivative 7 which had relatively good SGLT2 inhibitory activity, compound 8a which has a 3-[(azulen-2-yl)methyl]phenyl group was identified as a lead compound for further optimization. Introduction of a phenolic hydroxyl group onto the central benzene ring afforded a potent and selective SGLT2 inhibitor 8e, which reduced blood glucose levels in a dose-dependent manner in rodent diabetic models. A mono choline salt of 8e (YM543) was selected as a clinical candidate for use in treating type 2 diabetes mellitus.

Participation of gap junction communication in potentially lethal damage repair and DNA damage in human fibroblasts exposed to low- or high-LET radiation.

Existing research has not fully explained how different types of ionizing radiation (IR) modulate the responses of cell populations or tissues. In our previous work, we showed that gap junction intercellular communication (GJIC) mediates the propagation of stressful effects among irradiated cells exposed to high linear energy transfer (LET) radiations, in which almost every cells is traversed by an IR track. In the present study, we conducted an in-depth study of the role of GJIC in modulating the repair of potentially lethal damage (PLDR) and micronuclei formation in cells exposed to low- or high-LET IR. Confluent human fibroblasts were exposed in the presence or absence of a gap junction inhibitor to 200kV X rays (LET∼1.7keV/µm), carbon ions (LET∼76keV/µm), silicon ions (LET∼113keV/µm) or iron ions (LET∼400keV/µm) that resulted in isosurvival levels. The fibroblasts were incubated for various times at 37°C. As expected, high-LET IR were more effective than were low-LET X rays at killing cells and damaging DNA shortly after irradiation. However, when cells were held in a confluent state for several hours, PLDR associated with a reduction in DNA damage, occurred only in cells exposed to X rays. Interestingly, inhibition of GJIC eliminated the enhancement of toxic effects, which resulted in an increase of cell survival and reduction in the level of micronucleus formation in cells exposed to high, but not in those exposed to low-LET IR. The experiment shows that gap-junction communication plays an important role in the propagation of stressful effects among irradiated cells exposed to high-LET IR while GJIC has only a minimal effect on PLDR and DNA damage following low-LET irradiation. Together, our results show that PLDR and induction of DNA damage clearly depend on gap-junction communication and radiation quality.

The Combination of Hearing Impairment and Frailty Is Associated with Cognitive Decline among Community-Dwelling Elderly in Japan.

Hearing impairment and frailty are associated with cognitive decline in older people. This study aimed to investigate the effect of the interaction between hearing impairment and frailty on cognitive decline in community-dwelling older people. A mail survey of community-dwelling, older people (age ≥ 65 years) who lived independently was conducted. Cognitive decline was defined using the self-administered dementia checklist (≥18 out of 40 points). Hearing impairment was assessed using a validated self-rated questionnaire. Furthermore, frailty was assessed using the Kihon checklist, and robust, pre-frailty, and frailty groups were identified. Multivariate logistic regression analysis, adjusted for potential confounding factors, was performed to determine the association of the interaction between hearing impairment and frailty with cognitive decline. Data obtained from 464 participants were analyzed. Hearing impairment was independently associated with cognitive decline. Additionally, the interaction term of hearing impairment and frailty was significantly related to cognitive decline. For participants in the robust group, hearing impairment was not associated with cognitive decline. In contrast, for participants in the pre-frailty or frailty groups, hearing impairment was associated with cognitive decline. The association between hearing impairment and cognitive decline was affected by frailty status in community-dwelling, older people.

Discovery of Ipragliflozin (ASP1941): a novel C-glucoside with benzothiophene structure as a potent and selective sodium glucose co-transporter 2 (SGLT2) inhibitor for the treatment of type 2 diabetes mellitus.

A series of C-glucosides with various heteroaromatics has been synthesized and its inhibitory activity toward SGLTs was evaluated. Upon screening several compounds, the benzothiophene derivative (14a) was found to have potent inhibitory activity against SGLT2 and good selectivity versus SGLT1. Through further optimization of 14a, a novel benzothiophene derivative (14h; ipragliflozin, ASP1941) was discovered as a highly potent and selective SGLT2 inhibitor that reduced blood glucose levels in a dose-dependent manner in diabetic models KK-A(y) mice and STZ rats.

Patient handling system for carbon ion beam scanning therapy.

Our institution established a new treatment facility for carbon ion beam scanning therapy in 2010. The major advantages of scanning beam treatment compared to the passive beam treatment are the following: high dose conformation with less excessive dose to the normal tissues, no bolus compensator and patient collimator/multi-leaf collimator, better dose efficiency by reducing the number of scatters. The new facility was designed to solve several problems encountered in the existing facility, at which several thousand patients were treated over more than 15 years. Here, we introduce the patient handling system in the new treatment facility. The new facility incorporates three main systems, a scanning irradiation system (S-IR), treatment planning system (TPS), and patient handling system (PTH). The PTH covers a wide range of functions including imaging, geometrical/position accuracy including motion management (immobilization, robotic arm treatment bed), layout of the treatment room, treatment workflow, software, and others. The first clinical trials without respiratory gating have been successfully started. The PTH allows a reduction in patient stay in the treatment room to as few as 7 min. The PTH plays an important role in carbon ion beam scanning therapy at the new institution, particularly in the management of patient handling, application of image-guided therapy, and improvement of treatment workflow, and thereby allows substantially better treatment at minimum cost.

Association between tongue pressure and skeletal muscle mass and muscle function in community-dwelling older people without sarcopenia.

PURPOSE: This study aimed to cross-sectionally investigate relationships between maximum tongue pressure (MTP) and whole-body muscle mass and strength for non-sarcopenic older adults. METHODS: Study participants comprised 341 adults (105 men, 236 women) ≥ 65 years old (mean age, 72.7 ± 4.8 years). Participants were measured for MTP, grip strength, five-time chair stand test (FCST), gait speed, and skeletal muscle mass index (SMI). Multiple regression analysis adjusted for confounding factors was used to analyze relationships between MTP and each other variable. RESULTS: MTP was significantly related to SMI (r = 0.15, p < 0.001), grip strength (r = 0.12, p < 0.05), FCST (r = - 0.14, p < 0.05), and age (r = 0.25, p < 0.001). Multiple regression analysis showed a positive association between MTP and SMI, even after accounting for the influence of age, sex, physical performance, and other potential confounding factors. CONCLUSION: Whole-body muscle mass was suggested to be decreasing with tongue pressure decline before sarcopenia diagnosis in community-dwelling older adults.

Appropriate Lymph Node Dissection Sites for Cancer in the Body and Tail of the Pancreas: A Multicenter Retrospective Study.

Distal pancreatectomy (DP) with lymphadenectomy is the standard surgery for pancreatic body-tail cancer. However, the optimal lymph node (LN) dissection area for DP remains controversial. Thus, we evaluated the frequency and patterns of LN metastasis based on the tumor site. In this multicenter retrospective study, we examined 235 patients who underwent DP for pancreatic cancer. Tumor sites were classified as confined to the pancreatic body (Pb) or pancreatic tail (Pt). The efficacy index (EI) was calculated by multiplying the frequency of metastasis to each LN station by the five-year survival rate of patients with metastasis to that station. LN metastasis occurred in 132/235 (56.2%) of the patients. Patients with Pb tumors showed no metastasis to the splenic hilum LN. Distal splenic artery LNs and anterosuperior/posterior common hepatic artery LNs did not benefit from dissection for Pb and Pt tumors, respectively. In multivariate analysis, splenic artery LN metastasis was identified as an independent predictor of poor overall survival in patients with pancreatic body-tail cancer. In conclusion, differences in metastatic LN sites were evident in pancreatic body-tail cancers confined to the Pb or Pt. Spleen-preserving pancreatectomy might be feasible for Pb cancer.

ZouA, a putative relaxase, is essential for dna amplification in Streptomyces kanamyceticus.

Previously, we showed that a 145-kb DNA region, including the entire kanamycin biosynthetic gene cluster (with two kanamycin resistance genes), was tandemly amplified up to 36-fold in an industrial strain of Streptomyces kanamyceticus. Strain improvement had included the use of increased kanamycin resistance as an initial potential indicator of higher kanamycin productivity. We were able to recapitulate the DNA amplification by cultivating S. kanamyceticus under selection for kanamycin resistance. To identify the genes required for amplification, various chromosome deletions were constructed, and the DNA amplification was shown to depend on orf1082 (zouA), present in a putative mobile genetic element. ZouA consists of 1,481 amino acids and is homologous to the products of traA-like genes of some conjugative plasmids. These genes encode relaxases that initiate DNA transfer during conjugation by single-strand nicking at oriT. As in the original high-producing strain, DNA amplification occurred between 16-nucleotide (nt) sites (RsA and RsB) containing 14 identical nucleotides. Interestingly, RsA lies just 80 bp upstream of the initiation codon of zouA and is partially contained in an inverted repeat structure similar to those found in plasmid oriT sequences, suggesting that it might function in a manner similar to that of oriT. We therefore propose that DNA amplification in S. kanamyceticus is initiated by relaxase-mediated recombination between oriT-related sequences.