Epidemiology of group B streptococcal disease in infants younger than 1 year in Japan: a nationwide surveillance study 2016-2020.

We aimed to define the burden and clinical features of invasive group B streptococcus (GBS) disease in infants younger than 1 year in Japan, to explore transmission route of late-onset disease (LOD), and to identify risk factors associated with recurrent GBS disease. We conducted a retrospective, questionnaire-based nationwide surveillance study between 2016 and 2020. A total of 875 GBS cases were identified, including 186 early-onset disease, 628 LOD, and 61 ultra-late-onset disease. Case fatality rate in each age category was 6.5%, 3.0%, and 3.3%, respectively. Patients with meningitis had neurodevelopmental sequelae in 21.5% (64/297). Annual incidence in infants younger than 1 year and in LOD significantly increased from 0.28 to 0.45/1000 livebirths (p = 0.021) and from 0.19 to 0.29/1000 livebirths (p = 0.046), respectively. Maternal colonization status at the LOD diagnosis was available for 148 mothers, of whom 21/58 (36.2%) had positive rectovaginal swabs and 42/117 (36.2%) had GBS in breastmilk culture. These two sites are potentially infectious routes in LOD. The four leading disease-causing serotypes III, Ia, Ib, and V represented 95% of the available serotypes. Thirty-one recurrent cases were identified, accounting for 3.7% of total patients. A multivariate regression analysis showed that prematurity (p = 0.029) and antepartum maternal GBS colonization (p = 0.032) were significantly associated with risk for the recurrence. Our findings indicated that GBS disease burden still remains with considerable mortality and morbidity in Japan, and provided important information for developing better strategies for the prevention of GBS disease, including maternal vaccination.

Lincomycin-Induced Secondary Metabolism in Streptomyces lividans 66 with a Mutation in the Gene Encoding the RNA Polymerase Beta Subunit.

Activating the genetic potential of Streptomyces strains to produce secondary metabolites can improve the production of useful biologically active compounds and facilitate the discovery of novel biologically active compounds. In this study, we found that Streptomyces lividans carrying the R440H mutation in rpoB, encoding the RNA polymerase beta subunit, grown in the presence of lincomycin at concentrations below the minimum inhibitory concentration (MIC) produced abundant amounts of actinorhodin and certain cryptic secondary metabolites despite culture conditions that restrict their production by the wild-type strain. The results indicate that lincomycin at concentrations below the MIC may strongly potentiate secondary metabolite production by Streptomyces strains carrying a specific rpoB mutation. In this study, we report an interesting phenomenon induced by combining the positive effects of certain rpoB mutations and concentration-dependent responses to lincomycin on secondary metabolism in S. lividans 66 and discuss the mechanisms and their applicability in exploring cryptic secondary metabolite production in streptomycetes.

Mathematical analysis of gefitinib resistance of lung adenocarcinoma caused by MET amplification.

Gefitinib, one of the tyrosine kinase inhibitors of epidermal growth factor receptor (EGFR), is effective for treating lung adenocarcinoma harboring EGFR mutation; but later, most cases acquire a resistance to gefitinib. One of the mechanisms conferring gefitinib resistance to lung adenocarcinoma is the amplification of the MET gene, which is observed in 5-22% of gefitinib-resistant tumors. A previous study suggested that MET amplification could cause gefitinib resistance by driving ErbB3-dependent activation of the PI3K pathway. In this study, we built a mathematical model of gefitinib resistance caused by MET amplification using lung adenocarcinoma HCC827-GR (gefitinib resistant) cells. The molecular reactions involved in gefitinib resistance consisted of dimerization and phosphorylation of three molecules, EGFR, ErbB3, and MET were described by a series of ordinary differential equations. To perform a computer simulation, we quantified each molecule on the cell surface using flow cytometry and estimated unknown parameters by dimensional analysis. Our simulation showed that the number of active ErbB3 molecules is around a hundred-fold smaller than that of active MET molecules. Limited contribution of ErbB3 in gefitinib resistance by MET amplification is also demonstrated using HCC827-GR cells in culture experiments. Our mathematical model provides a quantitative understanding of the molecular reactions underlying drug resistance.

Comparison of medical image classification accuracy among three machine learning methods.

BACKGROUND: Low-quality medical images may influence the accuracy of the machine learning process. OBJECTIVE: This study was undertaken to compare accuracy of medical image classification among machine learning methods, as classification is a basic aspect of clinical image inspection. METHODS: Three types of machine learning methods were used, which include Support Vector Machine (SVM), Artificial Neural Network (ANN), and Convolution Neural Network (CNN). To investigate changes in accuracy related to image quality, we constructed a single dataset using two different file formats of DICOM (Digital Imaging and Communications in Medicine) and JPEG (Joint Photographic Experts Group). RESULTS: The JPEG format contains less color information and data capacity than the DICOM format. CNN classification was accurate for both datasets, whereas SVM and ANN accuracy decreased with the loss of data from DICOM to JPEG formats. CONCLUSIONS: CNN is more accurate than conventional machine learning methods that utilize the manual feature extraction.

Expression of a splicing variant of the CADM1 specific to small cell lung cancer.

CADM1, a member of the immunoglobulin superfamily cell adhesion molecule, acts as a tumor suppressor in a variety of human cancers. CADM1 is also ectopically expressed in adult T-cell leukemia (ATL), conferring an invasive phenotype characteristic to ATL. Therefore, CADM1 plays dual roles in human oncogenesis. Here, we investigate the roles of CADM1 in small cell lung cancer (SCLC). Immunohistochemistry demonstrates that 10 of 35 (29%) primary SCLC tumors express CADM1 protein. Western blotting and RT-PCR analyses reveal that CADM1 is significantly expressed in 11 of 14 SCLC cells growing in suspension cultures but in neither of 2 SCLC cells showing attached growth to plastic dishes, suggesting that CADM1 is involved in anchorage-independent growth in SCLC. In the present study, we demonstrate that SCLC expresses a unique splicing variant of CADM1 (variant 8/9) containing additional extracellular fragments corresponding to exon 9 in addition to variant 8, a common isoform in epithelia. Variant 8/9 of CADM1 is almost exclusively observed in SCLC and testis, although this variant protein localizes along the membrane and shows similar cell aggregation activity to variant 8. Interestingly, both variant 8/9 and variant 8 of CADM1 show enhanced tumorigenicity in nude mice when transfected into SBC5, a SCLC cell lacking CADM1. Inversely, suppression of CADM1 expression by shRNA reduced spheroid-like cell aggregation of NCI-H69, an SCLC cell expressing a high amount of CADM1. These findings suggest that CADM1 enhances the malignant features of SCLC, as is observed in ATL, and could provide a molecular marker specific to SCLC.

[Prevention of food poisoning in children].

Proper food storage and preparation can reduce the risk of food poisoning. For example, avoid touching between cooked and uncooked foods, refrigerate foods promptly after purchase or preparation. Washing hands and cleaning surfaces after handling raw meats, poultry, fish, and eggs before touching with other foods, and heating them thoroughly inside is also useful for reducing the risk. To avoid eating raw or undercooked meat, poultry, bivalvia (for example, oyster) is also important for prevention of food poisoning in children. In addition, it is important for medical staff to prevent secondary infection to those who may contact the patients.

Pediatric Advance Care Planning for a Patient with a Severe Motor and Intellectual Disorder through Cooperation between an Acute Care Hospital and a Residential Facility.

Background: With the rapid progress of medical technology, the number of children with medical complexities who require advanced medical care, including mechanical ventilators, has been increasing steadily in Japan. Accordingly, the issue of how to provide holistic care and support for the entire life of the children with severe motor and intellectual disabilities (SMID) who live at home has become a new challenge. Case Presentation: We present the case of a three-year-old boy with SMID due to HHV-6B-induced hemorrhagic shock encephalopathy who was cared for at home by the home visit medical team of Osaka Developmental Rehabilitation Center (ODRC; residential facilities with the department of home medical treatment and care). He developed septic shock triggered by an urinary tract infection and was admitted to Osaka General Medical Center (OGMC; acute care facility not directly affiliated with ODRC), where he deteriorated to a terminal stage. After discussing advance care planning (ACP) with his parents, along with the medical team, an ACP document with parental wishes was created through collaboration between the two facilities. The document was approved by the Ethics Committee at OGMC and the parents signed the document. Special end-of-life care planning was given by nurses at OGMC based on the best interests of the patient and the family. The patient passed away peacefully surrounded by his family in a private room of OGMC according to the ACP, despite special limitations caused by the coronavirus disease 2019 (COVID-19) pandemic. Conclusions: ACP provides a good opportunity to think about the best total care for a child with SMID, for whom it is too difficult to express his or her wishes, together with the parents, who are the legal representatives. The collaboration between two institutions with different roles brought out the best of each, and the resulting ACP was beneficial to the patient and their family.

CADM1 interacts with Tiam1 and promotes invasive phenotype of human T-cell leukemia virus type I-transformed cells and adult T-cell leukemia cells.

CADM1 encodes a multifunctional immunoglobulin-like cell adhesion molecule whose cytoplasmic domain contains a type II PSD95/Dlg/ZO-1 (PDZ)-binding motif (BM) for associating with other intracellular proteins. Although CADM1 lacks expression in T lymphocytes of healthy individuals, it is overexpressed in adult T-cell leukemia-lymphoma (ATL) cells. It has been suggested that the expression of CADM1 protein promotes infiltration of leukemic cells into various organs and tissues, which is one of the frequent clinical manifestations of ATL. Amino acid sequence alignment revealed that Tiam1 (T-lymphoma invasion and metastasis 1), a Rac-specific guanine nucleotide exchange factor, has a type II PDZ domain similar to those of membrane-associated guanylate kinase homologs (MAGUKs) that are known to bind to the PDZ-BM of CADM1. In this study, we demonstrated that the cytoplasmic domain of CADM1 directly interacted with the PDZ domain of Tiam1 and induced formation of lamellipodia through Rac activation in HTLV-I-transformed cell lines as well as ATL cell lines. Our results indicate that Tiam1 integrates signals from CADM1 to regulate the actin cytoskeleton through Rac activation, which may lead to tissue infiltration of leukemic cells in ATL patients.

Simultaneous brain structure segmentation in magnetic resonance images using deep convolutional neural networks.

In brain magnetic resonance imaging (MRI) examinations, rapidly acquired two-dimensional (2D) T1-weighted sagittal slices are typically used to confirm brainstem atrophy and the presence of signals in the posterior pituitary gland. Image segmentation is essential for the automatic evaluation of chronological changes in the brainstem and pituitary gland. Thus, the purpose of our study was to use deep learning to automatically segment internal organs (brainstem, corpus callosum, pituitary, cerebrum, and cerebellum) in midsagittal slices of 2D T1-weighted images. Deep learning for the automatic segmentation of seven regions in the images was accomplished using two different methods: patch-based segmentation and semantic segmentation. The networks used for patch-based segmentation were AlexNet, GoogLeNet, and ResNet50, whereas semantic segmentation was accomplished using SegNet, VGG16-weighted SegNet, and U-Net. The precision and Jaccard index were calculated, and the extraction accuracy of the six convolutional network (DCNN) systems was evaluated. The highest precision (0.974) was obtained with the VGG16-weighted SegNet, and the lowest precision (0.506) was obtained with ResNet50. Based on the data, calculation times, and Jaccard indices obtained in this study, segmentation on a 2D image may be considered a viable and effective approach. We found that the optimal automatic segmentation of organs (brainstem, corpus callosum, pituitary, cerebrum, and cerebellum) on brain sagittal T1-weighted images could be achieved using SegNet with VGG16.

Evaluating medical images using deep convolutional neural networks: A simulated CT phantom image study.

BACKGROUND: Applied research on artificial intelligence, mainly in deep learning, is widely performed. If medical images can be evaluated using artificial intelligence, this could substantially improve examination efficiency. OBJECTIVE: We investigated an evaluation system for medical images with different noise characteristics using a deep convolutional neural network. METHODS: Simulated computed tomography images are the targets of the system. We used an AlexNet trained with natural images for the deep convolutional neural network and a support vector machine for classification. Synthetic computed tomography images with circular and rectangular signal bodies at different levels of contrast and added Gaussian noise were used for training and testing. RESULTS: Two transfer learning methods were tested: classification by a re-trained support vector machine using the AlexNet features, and a method that fine-tuned the deep convolutional neural network. Using the first method, all the test image noise levels could be classified correctly. The fine-tuning method achieved an accuracy rate of 92.6%. CONCLUSIONS: An image quality evaluation method using artificial intelligence will be useful for clinical images and different image quality indices in the future.

Development of a quantitative statistical analysis system for double inversion recovery (DIR) MRI: A preliminary clinical study.

BACKGROUND: Gray matter (GM) imaging is important in the investigation of many neurological diseases, including schizophrenia, multiple sclerosis, stroke, Alzheimer's disease, tuberous sclerosis, and epilepsy, which are all associated with changes in cortical GM. OBJECTIVE: The aim of this study was to develop a quantitative statistical analysis system for double inversion recovery (DIR) MRI and to evaluate the new system using preliminary clinical data. METHODS: The study population comprised of 10 healthy volunteers and six patients with or without brain degeneration. A quantitative statistical analysis system for DIR images was developed using the following steps: 1) brain spatial normalization, 2) mean and standard deviation (SD) map creation, and 3) Z-score map creation. To evaluate the new voxel-based morphometry system, Z-scores of lesions in patients with brain degeneration were measured and then compared with Z-scores of normal regions. RESULTS: All DIR images were adequately spatially normalized to Montreal Neurological Institute MNI coordinate. Lesions in each patient were indicated by high Z-score values on a Z-score map, which were significantly higher than Z-scores of normal regions (p< 0.05). CONCLUSIONS: In this study, we developed a quantitative statistical analysis system for DIR MRI. Using our system, clinicians might accurately diagnose early brain degeneration.

Disruption of spermatogenic cell adhesion and male infertility in mice lacking TSLC1/IGSF4, an immunoglobulin superfamily cell adhesion molecule.

TSLC1/IGSF4, an immunoglobulin superfamily molecule, is predominantly expressed in the brain, lungs, and testes and plays important roles in epithelial cell adhesion, cancer invasion, and synapse formation. We generated Tslc1/Igsf4-deficient mice by disrupting exon 1 of the gene and found that Tslc1(-/-) mice were born with the expected Mendelian ratio but that Tslc1(-/-) male mice were infertile. In 11-week-old adult Tslc1(-/-) mice, the weight of a testis was 88% that in Tslc1(+/+) mice, and the number of sperm in the semen was approximately 0.01% that in Tslc1(+/+) mice. Histological analysis revealed that the round spermatids and the pachytene spermatocytes failed to attach to the Sertoli cells in the seminiferous tubules and sloughed off into the lumen with apoptosis in the Tslc1(-/-) mice. On the other hand, the spermatogonia and the interstitial cells, including Leydig cells, were essentially unaffected. In the Tslc1(+/+) mice, TSLC1/IGSF4 expression was observed in the spermatogenic cells from the intermediate spermatogonia to the early pachytene spermatocytes and from spermatids at step 7 or later. These findings suggest that TSLC1/IGSF4 expression is indispensable for the adhesion of spermatocytes and spermatids to Sertoli cells and for their normal differentiation into mature spermatozoa.

Can Slow-Motion Footage of Forehand Strokes Be Used to Immediately Improve Anticipatory Judgments in Tennis?

Slow-motion footage of sports actions is widely used as a visual learning tool in observing the dynamic motor behaviors of athletes. Recent studies on action observation have reported that extending the observation time in slow-motion footage provides benefits of understanding the intention of an opponent's action, at least when observing rapid movements. As such, the use of slow-motion footage may have the potential to improve the anticipatory judgments of an opponent's action outcome without training (or feedback). To verify this possibility, we examined the effects of the replay speed of slow-motion footage on the anticipatory judgments of shot directions and recognition of kinematic positions of opponents' forehand strokes in tennis. Nine skilled and nine novice tennis players were asked to anticipate the direction of their opponent's shots (left or right) and then attempted to recognize proximal (trunk center) and distal (ball) kinematic positions. Computer graphic animations of forehand strokes were used as visual stimuli, which were presented at four different replay speeds (normal, three-quarter, half, and quarter speeds). We failed to show the immediate effect of the use of slow-motion footage on the anticipatory performance of the skilled and novice players, although the anticipatory performance of the skilled players was superior to that of the novice players. Instead, we found an effect of the use of slow-motion footage in terms of promoting recognition of important kinematic cues (trunk center) for effective anticipation by skilled players. Moreover, no significant correlations were observed between the anticipatory judgments and motion recognition in all experimental conditions. These results suggest that even if the use of slow-motion footage enhances the recognition of key kinematic cues, it may not immediately improve anticipatory judgments in tennis.

Promoter methylation of DAL-1/4.1B predicts poor prognosis in non-small cell lung cancer.

PURPOSE: DAL-1/4.1B is an actin-binding protein originally identified as a molecule whose expression is down-regulated in lung adenocarcinoma. We have previously shown that a lung tumor suppressor, TSLC1, associates with DAL-1, suggesting that both proteins act in the same cascade. The purpose of this study is to understand the molecular mechanisms and clinical significance of DAL-1 inactivation in lung cancer. EXPERIMENTAL DESIGN: We studied aberration of the DAL-1 in 103 primary non-small cell lung cancers (NSCLC) and 18 lung cancer cells. Expression and allelic and methylation status of DAL-1 was examined by reverse transcription-PCR, microsatellite analysis, and bisulfite sequencing or bisulfite single-strand conformational polymorphism, respectively. RESULTS: Loss of DAL-1 expression was strongly correlated with promoter methylation in lung cancer cells, whereas DAL-1 expression was restored by a demethylating agent, 5-aza-2'-deoxycytidine. The DAL-1 promoter was methylated in 59 (57%) primary NSCLC tumors, 37% of which were associated with loss of heterozygosity around the DAL-1 on chromosomal region 18p11.3. In squamous cell carcinomas, DAL-1 methylation was observed in 9 of 10 tumors at stage I, whereas the incidence of methylation gradually increased in adenocarcinomas as they progressed [13 of 36 (36%), 4 of 12 (33%), 14 of 17 (82%), and 3 of 3 (100%) tumors at stages I, II, III, and IV, respectively; P = 0.0026]. Furthermore, in adenocarcinomas, disease-free survival and overall survival were significantly shorter in patients with tumors harboring the methylated DAL-1 (P = 0.0011 and P = 0.045, respectively). CONCLUSIONS: DAL-1 methylation is involved in the development and progression of NSCLC and provides an indicator for poor prognosis.

Direct association of TSLC1 and DAL-1, two distinct tumor suppressor proteins in lung cancer.

The tumor suppressor gene TSLC1, which we recently identified in human non-small cell lung cancer, encodes a membrane glycoprotein of the immunoglobulin superfamily. Here, we report that TSLC1 directly associates with DAL-1, a gene product of another lung tumor suppressor belonging to the protein 4.1 family. TSLC1 additionally interacts with the actin filament through DAL-1 at the cell-cell attached site where the complex formation of TSLC1 and DAL-1 is dependent on the integrity of actin cytoskeleton. Redistribution of both TSLC1 and DAL-1 to the newly generated membrane ruffling areas suggests that these proteins are also involved in cell motility accompanying the actin rearrangement. Furthermore, restoration of TSLC1 expression strongly suppressed the metastasis of a human non-small cell lung cancer cell line, A549, from the spleen to the liver in nude mice. These findings, together with frequent loss of their expression in lung cancers, suggest that TSLC1 and DAL-1 play a critical role in the same pathway involved in the suppression of lung tumor formation and metastasis.

Association of a lung tumor suppressor TSLC1 with MPP3, a human homologue of Drosophila tumor suppressor Dlg.

We have previously identified the tumor suppressor in lung cancer 1 (TSLC1) gene as a novel tumor suppressor in human non-small cell lung cancer (NSCLC) by functional complementation. TSLC1 encodes a membrane glycoprotein belonging to an immunoglobulin superfamily and participates in cell adhesion. A truncating mutation of the TSLC1 corresponding to its cytoplasmic domain in a primary NSCLC tumor suggests that this domain is important for tumor suppressor activity. Here, we report that TSLC1 directly associates with MPP3, one of the human homologues of a Drosophila tumor suppressor gene, Discs large (Dlg). This interaction was dependent on the presence of a PDZ-binding motif at the carboxyl terminus of TSLC1. Furthermore, TSLC1 and MPP3 were colocalized at the cell-cell attachment sites in both a low and a high cell density. The MPP3 gene was expressed in normal lung as well as in many tissues examined except for peripheral blood lymphocytes but lost its expression in one of the nine NSCLC cell lines. These results suggest that TSLC1 and MPP3 are involved in the same cascade of cell-cell interaction, and that the disruption of this cascade might lead cells to malignant growth and tumor formation in lung cancer.

Dynamic regulation of a cell adhesion protein complex including CADM1 by combinatorial analysis of FRAP with exponential curve-fitting.

Protein components of cell adhesion machinery show continuous renewal even in the static state of epithelial cells and participate in the formation and maintenance of normal epithelial architecture and tumor suppression. CADM1 is a tumor suppressor belonging to the immunoglobulin superfamily of cell adhesion molecule and forms a cell adhesion complex with an actin-binding protein, 4.1B, and a scaffold protein, MPP3, in the cytoplasm. Here, we investigate dynamic regulation of the CADM1-4.1B-MPP3 complex in mature cell adhesion by fluorescence recovery after photobleaching (FRAP) analysis. Traditional FRAP analysis were performed for relatively short period of around 10 min. Here, thanks to recent advances in the sensitive laser detector systems, we examine FRAP of CADM1 complex for longer period of 60 min and analyze the recovery with exponential curve-fitting to distinguish the fractions with different diffusion constants. This approach reveals that the fluorescence recovery of CADM1 is fitted to a single exponential function with a time constant (τ) of approximately 16 min, whereas 4.1B and MPP3 are fitted to a double exponential function with two τs of approximately 40-60 sec and 16 min. The longer τ is similar to that of CADM1, suggesting that 4.1B and MPP3 have two distinct fractions, one forming a complex with CADM1 and the other present as a free pool. Fluorescence loss in photobleaching analysis supports the presence of a free pool of these proteins near the plasma membrane. Furthermore, double exponential fitting makes it possible to estimate the ratio of 4.1B and MPP3 present as a free pool and as a complex with CADM1 as approximately 3:2 and 3:1, respectively. Our analyses reveal a central role of CADM1 in stabilizing the complex with 4.1B and MPP3 and provide insight in the dynamics of adhesion complex formation.

Clinical characteristics of seizures associated with viral gastroenteritis in children.

OBJECTIVE: We analyzed the clinical features of seizures during gastroenteritis in children by comparing the norovirus and rotavirus pathogen, and the impact of fever, if present, during the seizure episodes. METHODS: Retrospective analysis was performed on 293 consecutive pediatric patients admitted with viral gastroenteritis to Osaka General Hospital between November 2007 and May 2009. Eighteen patients developed seizures, 12 of whom were positive for norovirus and six for rotavirus, as revealed by antigen detection. Of these 18 seizure patients, eight presented without fever (the aFS group) and 10 presented with febrile episodes (FS group). RESULTS: Seizure patients in the rotavirus group (83%) were more likely to be febrile than those in the norovirus group (58%). Compared with the aFS group, 90% of patients in the FS group presented seizures at an early stage of gastroenteritis. The frequency of clustered seizures in the FS group was considerably higher than that of febrile seizures in general and was also as high as that of "convulsions with mild gastroenteritis (CwG)". All seizure patients, whether febrile or afebrile, presented with generalized tonic clonic seizures (GTCS), complex partial seizures (CPS), or both. Diazepam (DZP) was less effective and carbamazepine (CBZ) was completely effective for the cessation of seizures in the FS group, similar to the drug response observed in CwG. CONCLUSIONS: The causative pathogen (norovirus or rotavirus) affected the frequency of febrile episodes during gastroenteritis, but fever had little effect on the clinical features of seizures. However, seizures occurred earlier during gastroenteritis in the FS group. On the whole, the clinical features of febrile seizures during viral gastroenteritis may closely resemble those of "convulsions with mild gastroenteritis" (CwG) than those of febrile seizures in general with respect to the frequency of clustered seizures and the antiepileptic drug responses and may have a pathogenic mechanism distinct from those of febrile seizures due to other causes.

Isolation of the mouse Tsll1 and Tsll2 genes, orthologues of the human TSLC1-like genes 1 and 2 (TSLL1 and TSLL2).

We have recently identified the human TSLL1 and TSLL2 genes, which are highly homologous to the human lung tumor suppressor gene, TSLC1. Loss of expression of the TSLL1 or TSLL2 in several cancers suggests that these genes could also act as tumor suppressors. Here, we report the isolation of the mouse orthologous genes, Tsll1 and Tsll2. The Tsll1 and Tsll2 cDNAs contain a single open reading frame of 1188 and 1164 bp encoding a putative immunoglobulin-like cell adhesion molecules of 396 and 388 amino acids, which display 95% and 98% identity with those of human TSLL1 and TSLL2, respectively. The Tsll1 and Tsll2 genes are both composed of nine exons and mapped on mouse chromosome 1q H2-H4 and on 7q A3-B2, respectively, both of which conserve syntenies with human chromosomes 1q and 19q. Like the human TSLL1, the mouse Tsll1 was expressed exclusively in the brain and neurogenic cells, while Tsll1 expression was lost in one of four rodent neuroblastoma cell lines. Tsll2 was expressed in the brain and several organs including the kidney and liver, whereas loss of Tsll2 expression was detected in some rodent cancer cells derived from these tissues. Furthermore, both murine TSLL1 and TSLL2 proteins were expressed on the plasma membrane, especially at the cell-cell attached site. These data, together with their strong conservation during the vertebrate evolution, suggest that TSLL1and TSLL2 could play an important role in cell-cell interaction as well as in tumor suppression.