Predicting the Outcome of the Buckwheat Oral Challenge Test: A First Evaluation Assuming a Single Serving of Boiled Buckwheat Noodles.

Summary: Background. Global increase in buckwheat consumption has led to a surge in buckwheat allergy reports. However, studies scrutinizing the predictive accuracy of buckwheat-specific immunoglobulin E (IgE) antibody levels in correlation with symptom manifestation remain limited. A critical concern is the discrepancy between the total buckwheat amount featured in prior studies and the quantity consumed per occasion. We aimed to determine open Oral Food Challenge (OFC) positivity rates with buckwheat, using a single serving of boiled buckwheat noodles, and assess the predictability of positive responses using buckwheat-specific IgE levels. Methods. Patients aged 20 years or younger, suspected of buckwheat allergy, were subjected to an OFC involving consumption of 100 g (4800 mg of protein) of boiled buckwheat noodles for those under six years, and 200 g (9600 mg of protein) for those six years or older. The predictive accuracy of the OFC, corresponding with buckwheat-specific IgE antibody levels, was evaluated using Receiver Operating Characteristic (ROC) analysis. Results. Our study involved 80 patients who undertook a buckwheat OFC. Among these, 14 (17.5%) tested positive for a buckwheat allergy, with 3 (3.8%) developing anaphylaxis. The comparative analysis of buckwheat-specific IgE antibody levels did not offer a reliable predictive measure for OFC outcomes. However, a past history of symptom manifestation following buckwheat consumption was significantly correlated with a positive OFC. Conclusions. Forecasting OFC outcomes based on buckwheat-specific IgE antibody levels poses a challenge, even when taking into account the total quantity of buckwheat that can be consumed in a single occasion.

Extent of absent end-diastolic flow in umbilical artery and outcome of pregnancy.

OBJECTIVE: To investigate if the extent of absent end-diastolic flow (AEDF) on umbilical artery (UA) Doppler velocimetry predicts pregnancy outcome. METHODS: This was a retrospective observational study based on data from 25 000 Doppler examinations of UA flow performed between 1998 and 2017 at the Blood Flow Laboratory, Level III Perinatal Center, Lund, Sweden. All pregnancies with AEDF in the UA were identified, and the duration of AEDF as a proportion of the total duration of the cardiac cycle (Ta /Ttot ratio) was measured in digital images of the Doppler spectrum recorded at the last examination showing AEDF before delivery. Clinical data on pregnancies and neonatal outcomes were extracted from the regional perinatal database and the hospital patient records. The predictive performance of the Ta /Ttot ratio for intrauterine death and any (intrauterine or postnatal) death was assessed. RESULTS: A total of 170 fetuses (122 (72%) singletons and 48 (28%) twins) were included in the study. Median gestational age at birth was 189.5 days (range, 163-279 days) (i.e. 27 + 0 weeks (range, 23 + 2 to 39 + 6 weeks)), birth weight was 650 g (range, 320-3326 g) and deviation from expected birth weight (standard deviation score) was -2.975 (range, -6.38 to 0.69). There were 15 (9%) intrauterine and 26 (15%) postnatal deaths. The principal outcome variables and their relationship with Doppler velocimetry results did not differ significantly between singletons and twins, giving a rationale for using the Ta /Ttot ratio in the total study group. Mean Ta /Ttot ratio was 0.42 ± 0.08 and 0.34 ± 0.08 in stillborn and liveborn fetuses, respectively (P = 0.002). For fetuses examined before 30 weeks' gestation, a Ta /Ttot ratio cut-off of 0.30 predicted intrauterine death with 92% sensitivity and a negative predictive value (NPV) of 98% (area under receiver-operating-characteristics curve (AUC), 0.74) and predicted any death with 83% sensitivity and a NPV of 85% (AUC, 0.66). CONCLUSIONS: In fetuses with AEDF in the UA, duration of absent flow for at least 30% of the total cardiac cycle length might predict the risk of fetal demise, even when assessed before 30 weeks' gestation. This finding is particularly relevant to growth-restricted fetuses. After evaluation in further studies, the extent of AEDF might facilitate obstetric decision-making in very preterm growth-restricted fetuses. © 2020 International Society of Ultrasound in Obstetrics and Gynecology.

A comparison of thyroidal protection by iodine and perchlorate against radioiodine exposure in Caucasians and Japanese.

Radioactive iodine released in nuclear accidents may accumulate in the thyroid and by irradiation enhances the risk of cancer. Radioiodine uptake into the gland can be inhibited by large doses of stable iodine or perchlorate. Nutritional iodine daily intake may impact thyroid physiology, so that radiological doses absorbed by the thyroid as well as thyroid blocking efficacy may differ in Japanese with a very rich iodine diet compared to Caucasians. Based on established biokinetic-dosimetric models for the thyroid, we derived the parameters for Caucasians and Japanese to quantitatively compare the effects of radioiodine exposure and the protective efficacy of thyroid blocking by stable iodine at the officially recommended dosages (100 mg in Germany, 76 mg in Japan) or perchlorate. The maximum transport capacity for iodine uptake into the thyroid is lower in Japanese compared to Caucasians. For the same radioiodine exposure pattern, the radiological equivalent thyroid dose is substantially lower in Japanese in the absence of thyroid blocking treatments. In the case of acute radioiodine exposure, stable iodine is less potent in Japanese (ED50 = 41.6 mg) than in Caucasians (ED50 = 2.7 mg) and confers less thyroid protection at the recommended dosages because of a delayed responsiveness to iodine saturation of the gland (Wolff-Chaikoff effect). Perchlorate (ED50 = 10 mg in Caucasians) at a dose of 1000 mg has roughly the same thyroid blocking effect as 100 mg iodine in Caucasians, whereas it confers a much better protection than 76 mg iodine in Japanese. For prolonged exposures, a single dose of iodine offer substantially lower protection than after acute radioiodine exposure in both groups. Repetitive daily iodine administrations improve efficacy without reaching levels after acute radioiodine exposure and achieve only slightly better protection in Japanese than in Caucasians. However, in the case of continuous radioiodine exposure, daily doses of 1000 mg perchlorate achieve a high protective efficacy in Caucasians as well as Japanese (> 0.98). In Caucasians, iodine (100 mg) and perchlorate (1000 mg) at the recommended dosages seem alternatives in case of acute radioiodine exposure, whereas perchlorate has a higher protective efficacy in the case of longer lasting radioiodine exposures. In Japanese, considering protective efficacy, preference should be given to perchlorate in acute as well as prolonged radioiodine exposure scenarios.

The association between 11C-methionine uptake, IDH gene mutation, and MGMT promoter methylation in patients with grade II and III gliomas.

AIM: To evaluate the association between 11C-methionine positron-emission tomography (11C-methionine PET) findings, isocitrate dehydrogenase (IDH) gene mutation, and O6-methylguanine-DNA methyltransferase (MGMT) promoter methylation in patients with grade II and III gliomas. MATERIALS AND METHODS: Data were collected from 40 patients with grade II and III gliomas who underwent both magnetic resonance imaging (MRI) and 11C-methionine PET as part of their pre-surgical examination. IDH mutation was examined via DNA sequencing, and MGMT promoter methylation via quantitative methylation-specific polymerase chain reaction (PCR). RESULTS: A threshold of MGMT promoter methylation of 1% was significantly associated with tumour/normal tissue (T/N) ratio. The T/N ratio in samples with MGMT promoter methylation ≥1% was higher than that in samples with MGMT promoter methylation <1%, and the difference was statistically significant (p=0.011). Reliable prediction of MGMT promoter methylation (<1% versus ≥1%) was possible using the T/N ratio under the receiver operator characteristic (ROC) curve with a sensitivity and specificity of 75% each (cut-off value=1.6: p=0.0226, area under the ROC curve [AUC]=0.76172). Conversely, the T/N ratio had no association with IDH mutation (p=0.6). The ROC curve revealed no reliable prediction of IDH mutation using the T/N ratio (p=0.606, AUC=0.60577). CONCLUSION: 11C-methionine PET parameters can predict MGMT promoter methylation but not IDH mutation status. 11C-methionine uptake may have limited potential to reflect DNA methylation processes in grade II and III gliomas.

Cytological diagnostic clues in poorly differentiated squamous cell carcinomas of the breast: Streaming arrangement, necrotic background, nucleolar enlargement and cannibalism of cancer cells.

OBJECTIVE: Squamous cell carcinoma (SCC) is a rare histological type of breast cancer. The cytological diagnosis of non-keratinising, poorly differentiated SCC is often difficult, and distinguishing it from invasive ductal carcinoma or apocrine carcinoma (AC) is especially challenging. We aimed to define the diagnostic cytological features of poorly differentiated SCC of the breast. METHODS: We studied the cytological findings of poorly differentiated SCC (n=10) and compared them to those of IDC (n=15) and AC (n=14). The following six cytological features were evaluated: streaming arrangement, nucleolar enlargement, dense nuclei, cannibalism, atypical keratinocytes and necrotic background. RESULTS: SCC exhibited significantly higher frequencies of streaming arrangement (70% vs 6.7%, P=.002), nucleolar enlargement (80% vs 27%, P=.02), and necrotic background (80% vs 36%, P=.002) than invasive ductal carcinoma. The detection of two or three of these features yielded a higher sensitivity (80%) and specificity (93%) for the diagnosis of SCC. Streaming arrangement (70% vs 0%, P<.001), cannibalism (60% vs 0%, P=.002), and a necrotic background (80% vs 36%, P=.047) were all significantly more frequent in SCC than in AC. When distinguishing SCC from AC, the presence of two or three of these features yielded a high sensitivity (80%) and specificity (100%). CONCLUSIONS: Cytological features such as a streaming arrangement, a necrotic background, nucleolar enlargement and cannibalism are useful indicators for the diagnosis of SCC of the breast. As such, greater attention should be paid to these morphological features in daily clinical practice.

Telomere length determined by the fluorescence in situ hybridisation distinguishes malignant and benign cells in cytological specimens.

BACKGROUND: Telomeres are tandem repeats of TTAGGG at the end of eukaryotic chromosomes that play a key role in preventing chromosomal instability. The aim of the present study is to determine telomere length using fluorescence in situ hybridisation (FISH) on cytological specimens. METHODS: Aspiration samples (n = 41) were smeared on glass slides and used for FISH. RESULTS: Telomere signal intensity was significantly lower in positive cases (cases with malignancy, n = 25) as compared to negative cases (cases without malignancy, n = 16), and the same was observed for centromere intensity. The difference in DAPI intensity was not statistically significant. The ratio of telomere to centromere intensity did not show a significant difference between positive and negative cases. There was no statistical difference in the signal intensities of aspiration samples from ascites or pleural effusion (n = 23) and endoscopic ultrasound-guided FNA samples from the pancreas (n = 18). CONCLUSIONS: The present study revealed that telomere length can be used as an indicator to distinguish malignant and benign cells in cytological specimens. This novel approach may help improve diagnosis for cancer patients.

Recurrent mutations of CD79B and MYD88 are the hallmark of primary central nervous system lymphomas.

AIMS: Primary central nervous system lymphoma (PCNSL) manifest aggressive clinical behaviour and have poor prognosis. Although constitutive activation of the nuclear factor-κB (NF-κB) pathway has been documented, knowledge about the genetic alterations leading to the impairment of the NF-κB pathway in PCNSLs is still limited. This study was aimed to unravel the underlying genetic profiles of PCNSL. METHODS: We conducted the systematic sequencing of 21 genes relevant to the NF-κB signalling network for 71 PCNSLs as well as the pyrosequencing of CD79B and MYD88 mutation hotspots in a further 35 PCNSLs and 46 glioblastomas (GBMs) for validation. RESULTS: The results showed that 68 out of 71 PCNSLs had mutations in the NF-κB gene network, most commonly affecting CD79B (83%), MYD88 (76%), TBL1XR1 (23%), PRDM1 (20%) and CREBBP1 (20%). These mutations, particularly CD79B and MYD88, frequently coincided within each tumour in various combinations, simultaneously affecting diverse pathways within the network. No GBMs had hotspot mutation of CD79B Y196 and MYD88 L265. CONCLUSIONS: The prevalence of CD79B and MYD88 mutations in PCNSLs was considerably higher than reported in systemic diffuse large B-cell lymphomas. This observation could reflect the paucity of antigen stimuli from the immune system in the central nervous system (CNS) and the necessity to substitute them by the constitutive activation of CD79B and MYD88 that would initiate the signalling cascades. These hotspot mutations may serve as a genetic hallmark for PCNSL serving as a genetic marker for diagnose and potential targets for molecular therapy.

Polylactic acid nanosheets in prevention of postoperative intestinal adhesion and their effects on bacterial propagation in an experimental model.

BACKGROUND: Ultrathin films (nanosheets) adhere tightly to organ surfaces but prevent adhesion to other organs. The antiadhesive effect of nanosheets and their effect on bacterial propagation were investigated in a murine intestinal adhesion model. METHODS: Polylactic acid nanosheets (approximately 80 nm thick) were produced. Serosal defects were created by peeling off the intestinal serosa; these were left open or covered with nanosheets or Seprafilm® and the formation of intestinal adhesions was analysed. To examine bacterial propagation, a nanosheet or Seprafilm® was placed on intact murine jejunum followed by Escherichia coli inoculation at the site. RESULTS: Treatment both with nanosheets and with Seprafilm® reduced postoperative intestinal adhesion (mean adhesion score 0·67 for nanosheets, 0·43 for Seprafilm® and 2·87 for no antiadhesive treatment; P < 0·001 for nanosheets or Seprafilm® versus no adhesive treatment). Nanosheet treatment did not affect bacterial propagation in the peritoneal cavity, whereas Seprafilm®-treated mice showed bacterial propagation, leading to increased mortality. CONCLUSION: Nanosheets may be effective novel antiadhesive agents even in the presence of bacterial contamination. Surgical relevance Intra-abdominal adhesions following surgical contamination can trigger postoperative complications and lead to deterioration in long-term quality of life. However, currently there are no effective antiadhesion materials to prevent the formation of adhesions. Treatment with ultrathin nanosheets effectively reduced postoperative intestinal adhesion in an experimental mouse model, and did not affect bacterial propagation in the peritoneal cavity. These nanosheets are potent novel antiadhesive materials that potentially can be applied even in contaminated conditions.

Magnetic Reversal of Electric Polarization with Fixed Chirality of Magnetic Structure in a Chiral-Lattice Helimagnet MnSb_{2}O_{6}.

The correlation between magnetic and dielectric properties has been investigated for the single crystal of the chiral triangular-lattice helimagnet MnSb_{2}O_{6}. We found that the spin-spiral plane in the ground state has a considerable tilting from the (110) plane and that the sign of the spin-spiral tilting angle is coupled to the clockwise or counterclockwise manner of spin rotation and accordingly to the sign of magnetically induced electric polarization. This leads to unique magnetoelectric responses such as the magnetic-field-induced selection of a single ferroelectric domain as well as the reversal of electric polarization just by a slight tilting of the magnetic field direction, where the chiral nature of the crystal structure plays a crucial role through the coupling of the chirality between the crystal and magnetic structures. Our results demonstrate that crystallographic chirality can be an abundant source of novel magnetoelectric functions with coupled internal degrees of freedom.

Bone marrow lesions, subchondral bone cysts and subchondral bone attrition are associated with histological synovitis in patients with end-stage knee osteoarthritis: a cross-sectional study.

OBJECTIVE: The aim of this study was to examine the osteoarthritis (OA)-related structural changes associated with histological synovitis in end-stage knee OA patients. METHODS: Forty end-stage knee OA patients (female: 88%, mean age: 71.8 y) were enrolled. All participants underwent 3.0-T MRI. The structural changes, such as cartilage morphology, subchondral bone marrow lesion (BML), subchondral bone cyst (SBC), subchondral bone attrition (SBA), osteophytes, meniscal lesion and synovitis, were scored using the whole-organ MRI scoring (WORMS) method. Synovial samples were obtained from five regions of interest (ROIs) of the knee joint during total joint replacement surgery. The associations between the histological synovitis score (HSS) and WORMS or the synovial expression levels of cyclooxygenase (COX)-2, interleukin (IL)-1ß, IL-6 and transforming growth factor (TGF)-ß were examined using Spearman's correlation coefficient. RESULTS: Among the seven OA-related structural changes, the BML, SBC, SBA and synovitis were significantly associated with the HSS (r = 0.33, 0.35, 0.48 and 0.36, respectively), while other morphological changes were not. Although synovial COX-2, IL-1ß or IL-6 expression levels were not associated with the HSS, the synovial TGF-ß expression levels were associated with the HSS. CONCLUSION: The presence of BML, SBC and SBA was associated with histological synovitis in end-stage knee OA patients.

The degeneration and destruction of femoral articular cartilage shows a greater degree of deterioration than that of the tibial and patellar articular cartilage in early stage knee osteoarthritis: a cross-sectional study.

OBJECTIVE: The aim of the present study was to examine whether the degenerative and morphological changes of articular cartilage in early stage knee osteoarthritis (OA) occurred equally for both femoral- and tibial- or patellar- articular cartilage using magnetic resonance imaging (MRI)-based analyses. DESIGN: This cross-sectional study was approved by the ethics committee of our university. Fifty patients with early stage painful knee OA were enrolled. The patients underwent 3.0 T MRI on the affected knee joint. Healthy volunteers who did not show MRI-based OA changes were also recruited as controls (n = 19). The degenerative changes of the articular cartilage were quantified by a T2 mapping analysis, and any structural changes were conducted using Whole Organ Magnetic Resonance Imaging Score (WORMS) technique. RESULTS: All patients showed MRI-detected OA morphological changes. The T2 values of femoral condyle (FC) (P < 0.0001) and groove (P = 0.0001) in patients with early stage knee OA were significantly increased in comparison to those in the control, while no significant differences in the T2 values of patellar and tibial plateau (TP) were observed between the patients and the control. The WORMS cartilage and osteophyte scores of the femoral articular cartilage were significantly higher than those in the patellar- (P = 0.001 and P = 0.007, respectively) and tibial- (P = 0.0001 and P < 0.0001, respectively) articular cartilage in the patients with early stage knee OA. CONCLUSIONS: The degradation and destruction of the femoral articular cartilage demonstrated a greater degree of deterioration than those of the tibial- and patellar- articular cartilage in patients with early stage knee OA.

Visualization of angiographical arteriovenous shunting in perisylvian glioblastomas.

BACKGROUND: Arteriovenous shunting visualized by angiography is one of the major features of glioblastomas, and the visualization is dependent on the presence of extensive shunting. Extensive arteriovenous shunting is associated with the risk of poorly controlled intraoperative bleeding. When a tumor with extensive arteriovenous shunting is located in close proximity to the eloquent regions of the brain, a meticulous surgical procedure is necessary. In the present study, the site-oriented visualization of angiographical arteriovenous shunting was evaluated from the perspective of surgical treatment, with a particular focus on the perisylvian region that is in close proximity to motor and language regions (dominant hemisphere), as well as large arteries and veins. METHODS: Twenty-six consecutive patients underwent a resection of glioblastoma between February 2007 and September 2012. All patients were presurgically examined using digital subtraction angiography. The patients were subdivided into the following two groups based on the location of the tumor: 1) perisylvian glioblastoma (18 patients) and 2) non-perisylvian glioblastoma (eight patients). Angiography to detect the arteriovenous shunting was performed. In addition, the number of intratumoral vessels, tumor proliferative activity (MIB-1 labeling index), and volume of intraoperative bleeding were evaluated and compared between the two groups. RESULTS: Angiographical arteriovenous shunting was definitively visualized in 13 of 18 (72 %) perisylvian glioblastomas, in contrast to only one of eight (13 %) non-perisylvian glioblastomas (p = 0.007). There were no significant differences between the two groups with respect to the number of intratumoral vessels, MIB-1 labeling index, and volume of intraoperative bleeding. However, massive intraoperative bleeding of > 2,000 mL occurred in one perisylvian glioblastoma patient. CONCLUSIONS: Glioblastomas in the perisylvian region tend to be associated with extensive arteriovenous shunting that can be definitively visualized by performing an angiography. Because arteriovenous shunting carries the risk of intraoperative bleeding, perisylvian glioblastomas-particularly in the dominant hemisphere-should be resected with a meticulous surgical procedure and strategy.

Radiation-induced anaplastic ependymoma with a remarkable clinical response to temozolomide: a case report.

Radiation-induced gliomas are uncommon and therapeutic options are limited due to prior exposure to radiotherapy. Meanwhile, the chemotherapeutic response of anaplastic ependymoma, another rare entity in adults, is often disappointing. We report on the first recorded case of radiation-induced anaplastic ependymoma, in which an excellent clinical response to temozolomide was demonstrated.

Borg proteins control septin organization and are negatively regulated by Cdc42.

The Cdc42 GTPase binds to numerous effector proteins that control cell polarity, cytoskeletal remodelling and vesicle transport. In many cases the signalling pathways downstream of these effectors are not known. Here we show that the Cdc42 effectors Borg1 to Borg3 bind to septin GTPases. Endogenous septin Cdc10 and Borg3 proteins can be immunoprecipitated together by an anti-Borg3 antibody. The ectopic expression of Borgs disrupts normal septin organization. Cdc42 negatively regulates this effect and inhibits the binding of Borg3 to septins. Borgs are therefore the first known regulators of mammalian septin organization and provide an unexpected link between the septin and Cdc42 GTPases.

Mice with cleavage-resistant N-cadherin exhibit synapse anomaly in the hippocampus and outperformance in spatial learning tasks.

N-cadherin is a homophilic cell adhesion molecule that stabilizes excitatory synapses, by connecting pre- and post-synaptic termini. Upon NMDA receptor (NMDAR) activation by glutamate, membrane-proximal domains of N-cadherin are cleaved serially by a-disintegrin-and-metalloprotease 10 (ADAM10) and then presenilin 1(PS1, catalytic subunit of the γ-secretase complex). To assess the physiological significance of the initial N-cadherin cleavage, we engineer the mouse genome to create a knock-in allele with tandem missense mutations in the mouse N-cadherin/Cadherin-2 gene (Cdh2 R714G, I715D, or GD) that confers resistance on proteolysis by ADAM10 (GD mice). GD mice showed a better performance in the radial maze test, with significantly less revisiting errors after intervals of 30 and 300 s than WT, and a tendency for enhanced freezing in fear conditioning. Interestingly, GD mice reveal higher complexity in the tufts of thorny excrescence in the CA3 region of the hippocampus. Fine morphometry with serial section transmission electron microscopy (ssTEM) and three-dimensional (3D) reconstruction reveals significantly higher synaptic density, significantly smaller PSD area, and normal dendritic spine volume in GD mice. This knock-in mouse has provided in vivo evidence that ADAM10-mediated cleavage is a critical step in N-cadherin shedding and degradation and involved in the structure and function of glutamatergic synapses, which affect the memory function.

Expression of G protein-coupled receptor kinase 4 is associated with breast cancer tumourigenesis.

G-protein-coupled receptor kinases (GRKs) comprise a family of seven mammalian serine/threonine protein kinases that phosphorylate and regulate agonist-bound, activated, G-protein-coupled receptors (GPCRs). GRKs and beta-arrestins are key participants in the canonical pathways leading to phosphorylation-dependent GPCR desensitization, endocytosis, intracellular trafficking and resensitization. Here we show that GRK4 isoforms are expressed in human breast cancer but not in normal epithelia. In addition, GRK4-over-expressing cells activated the mitogen-activated protein kinase (MAPK) mediated by ERK 1/2 and JNK phosphorylation in breast cancer-derived cell lines. Furthermore, suppression of beta-arrestins decreased GRK4-stimulated ERK 1/2 or JNK phosphorylations. These data indicate that high-level expression of GRK4 may activate MAPK signalling pathways mediated by beta-arrestins in breast cancer cells, suggesting that GRK4 may be implicated in breast cancer carcinogenesis.

Topical negative pressure therapy for para-ileostomal ulceration in a patient with Behçet's disease.

BehCet's disease is a chronic, relapsing, inflammatory disorder. This case report describes how use of an improvised topical negative pressure (TNP) device in a patient with a non-healing para-ileostomal ulcer with Behçet's disease.

Inhibition of metastin (kisspeptin-54)-GPR54 signaling in the arcuate nucleus-median eminence region during lactation in rats.

Follicular development and ovulation are suppressed during lactation in various mammalian species, mainly due to the suppression of pulsatile GnRH/LH secretion. Metastin (kisspeptin-54), a KiSS-1 gene product, is an endogenous ligand for GPR54, a G-protein-coupled receptor, and suggested to play a critical role in regulating the gonadal axis. The present study therefore aims to determine whether metastin (kisspeptin-54)-GPR54 signaling in discrete brain areas is inhibited by the suckling stimulus that causes suppression of LH secretion in lactating rats. Quantitative RT-PCR revealed that the KiSS-1 mRNA level was significantly lower in the arcuate nucleus (ARC)-median eminence region in lactating ovariectomized (OVX) and estrogen-treated OVX rats than in nonlactating controls. KiSS-1 mRNA in the anteroventral periventricular nucleus was kept at a low level in both lactating and nonlactating rats despite estrogen treatment. GPR54 mRNA levels were significantly lower in lactating than nonlactating rats in the anteroventral periventricular nucleus, but the levels in lactating mothers of the preoptic area and ARC-median eminence were comparable with nonlactating controls. Although KiSS-1 mRNA-expressing cells or metastin (kisspeptin-54) immunoreactivities were densely located in the ARC of nonlactating controls, few were found in the ARC of lactating OVX animals. Various doses of metastin (kisspeptin-54) (0.02, 0.2, and 2 nmol) injected into the third ventricle caused a significant increase in LH secretion in both lactating and nonlactating OVX rats, suggesting that lactating rats are responsive to metastin (kisspeptin-54) stimulus. Thus, the present study demonstrated that KiSS-1 mRNA/metastin (kisspeptin-54) expression is inhibited in the ARC by the suckling stimulus, suggesting that the inhibition is most probably involved in suppressing LH secretion in lactating rats.