Comparative study of non-invasive force and stress inference methods in tissue

In the course of animal development, the shape of tissue emerges in part from mechanical and biochemical interactions between cells. Measuring stress in tissue is essential for studying morphogenesis and its physical constraints. For that purpose, a possible new approach is force inference (up to a single prefactor) from cell shapes and connectivity. It is non-invasive and can provide space-time maps of stress in a whole tissue, unlike existing methods. To validate this approach, three force-inference methods, which differ in their approach of treating indefiniteness in an inverse problem between cell shapes and forces, were compared. Tests using two artificial and two experimental data sets consistently indicate that our Bayesian force inference, by which cell-junction tensions and cell pressures are simultaneously estimated, performs best in terms of accuracy and robustness. Moreover, by measuring the stress anisotropy and relaxation, we cross-validated the force inference and the global annular ablation of tissue, each of which relies on different prefactors. A practical choice of force-inference methods in different systems of interest is discussed.

Collective excitation of an electric dipole on a molecular dimer in an organic dimer-Mott insulator

The terahertz response in 10-100 cm(-1) was investigated in an organic dimer-Mott (DM) insulator κ-(ET)(2)Cu(2)(CN)(3) that exhibits a relaxorlike dielectric anomaly. An ~30 cm(-1) band in the optical conductivity was attributable to collective excitation of the fluctuating intradimer electric dipoles that are formed by an electron correlation. We succeeded in observing photoinduced enhancement of this ~30 cm(-1) band, reflecting the growth of the electric dipole cluster in the DM phase. Such optical responses in κ-(ET)(2)Cu(2)(CN)(3) reflect an instability near the boundary between the DM-ferroelectric charge ordered phases.

Abstract P3-07-10: Effect of lifestyle and single nucleotide polymorphisms on breast cancer risk: A case-control study in Japanese women

[Background] Lifestyle, including diet and physical activity, and birth/breastfeeding history are known to affect the risk for breast cancer. A correlation between single nucleotide polymorphisms (SNPs) and breast cancer risk has also been suggested in some reports, but the gene-environment interaction with breast cancer risk has not been examined widely.

[Methods] The subjects were 476 breast cancer patients and 528 controls who attended a health check and had no history of breast cancer. Lifestyle was examined using a questionnaire with 48 questions about diet, physical activity, smoking habits, alcohol intake, and birth/breastfeeding history, etc. Based on past reports, we analyzed 6 SNPs (TNRC9-rs3803662, LSP1/11q-rs3817198, MAP3K1-rs889312, 8q24-rs13281615, 5p12-rs981782, and TGFβ1-rs1800470) using blood samples, and calculated age-adjusted odds ratios in a multiple logistic regression analysis.

[Results] The study was performed from December 2010 to November 2011. Lifestyle factors (age-adjusted odds ratio, [95% confident interval]) found to have a significant correlation with development of breast cancer included BMI (1.041, [1.00–1.08]), smoking history (2.28, [1.45–3.65]), small number of births (1.18, [1.05–1.34]), no exercise during leisure time (1.36, [1.06–1.77]), low intake of green and yellow vegetables (1.69, [1.01–2.85]), and low intake of mushrooms (1.58, [1.05–2.39]). Stratified analysis based on menopause status showed that smoking history (1.85, [1.00–3.49]) and low intake of green and yellow vegetables (2.5, [1.03–5.88]) were significant risk factors before menopause, and that smoking history (2.28, [1.45–3.65]), low intake of green and yellow vegetables (2.24, [1.09–4.68]), no exercise during leisure time (1.67, [1.19–2.36]), small number of births (1.49, [1.25–1.78]), and no breastfeeding history (1.03, [1.01–1.06]) were significant risk factors after menopause. The results of SNP analysis suggested that TNRC9-rs3803662 was a significant risk factor in women before menopause (2.29, [1.25–4.25]). However, in multivariate analysis including lifestyle factors and SNPs, only smoking history emerged as a significant risk factor in women before menopause.

[Conclusion] A correlation between lifestyle and breast cancer risk was found in this study, consistent with previous findings. Lifestyle and environmental factors such as births and breastfeeding may be more important than SNPs as risk factors for breast cancer.

Citation Information: Cancer Res 2012;72(24 Suppl):Abstract nr P3-07-10.

Sensitive pupil response of early-onset alzheimer's patients to a dilute mixture of cholinergic antagonist and α-Adrenergic stimulant

To investigate possible differences in pupil dilation and light reflex in Alzheimer's disease patients that can be attributed to the age of onset of the disease, a statistical comparison was made of pupil dilation and light reflex among early- and late-onset Alzheimer's disease, Down syndrome, and patients with vascular dementia, and normal controls. The subjects included 53 probable Alzheimer's disease outpatients, including both early-onset type (AD: n=21) and late-onset type (SD: n=32). They were compared with normal controls (n=15), Down syndrome patients (DS: n=6), and patients with vascular dementia (VD: n=9). All subjects and controls were dark-eyed Japanese. Pupil dilation and light reflex were tested in 21 AD and 32 SD patients, and were compared with those in the control subjects; 6 DS and 9 VD patients. The measured maximum increase in pupil diameter after instilling a mixture of anticholinergic and α -adrenergic stimulating drugs (Midrin-P®), in one eye was significantly greater in AD and DS than in the controls. However, there was no difference among SD, VD, and controls, suggesting a stronger pupil response to these drugs in AD than in SD. Pupil movement in response to light became significantly smaller and faster after instillation of the drugs in Alzheimer's disease patients. The above findings may be useful for the early detection of Alzheimer's disease.

Photoinduced change in the spin state of itinerant correlated electron systems

A photoinduced spin-state change in the itinerant correlated electron system is studied. A photon introduced in the low-spin band insulator induces a bound state of the high-spin state and a photoexcited hole. This bound state brings a characteristic peak in the pump-probe optical absorption spectra which are completely different from the spectra in thermal-excited states. The present results well explain the recent experiments of the ultrafast optical spectroscopy in perovskite cobaltites.

Down-regulation of single immunoglobulin interleukin-1R-related molecule (SIGIRR)/TIR8 expression in intestinal epithelial cells during inflammation

Single immunoglobulin (Ig) interleukin-1R-related molecule (SIGIRR) is an Ig-like membrane protein critical for negative regulation of Toll-like receptor (TLR)-4-mediated signalling. We investigated SIGIRR expression and its regulation mechanism in intestinal epithelial cells (IECs) during inflammation. Endoscopic biopsy specimens were obtained from active and inactive colonic mucosa of ulcerative colitis (UC) patients, then SIGIRR expression was examined using real-time polymerase chain reaction (PCR) and immunohistochemistry (IH). Mice experimental colitis models were established by administrations of sulphonic acid (TNBS) and dextran sodium sulphate (DSS), and epithelial expression of SIGIRR was examined using real-time PCR, IH and flow cytometry. The effects of lipopolysaccharide (LPS) and tumour necrosis factor (TNF)-α on SIGIRR expression were evaluated in vitro using cultured IECs. To elucidate SIGIRR expression regulation in IECs, binding ability of the transcription factor SP1 at the responsive element of the SIGIRR promoter was examined using gel-shift and chromatin immunoprecipitation (ChIP) assays. In human colonic samples, SIGIRR was expressed mainly in IECs at levels significantly higher in inactive compared to active mucosa. In the mice, SIGIRR colonic expression decreased rapidly after colitis development and returned gradually to basal levels. Experimental colitis-mediated down-regulation of SIGIRR in IECs was also confirmed by IH and flow cytometry results. Further, inflammatory conditions induced by TLR ligands and TNF-α caused significant down-regulation of SIGIRR expression in IECs, which was dependent upon decreased SP1 binding at the responsive element of the SIGIRR promoter. We found that SIGIRR is expressed in IECs and serves as a negative regulator to maintain gut innate immunity, which is down-regulated during inflammation by inhibition of an SP1-mediated pathway.

Nasu-Hakola disease with a splicing mutation of TREM2 in a Japanese family

BACKGROUND

  Nasu-Hakola disease (NHD) is a rare autosomal recessive disorder, characterized by a combination of progressive presenile dementia and formation of multifocal bone cysts, caused by genetic mutations of DAP12 and TREM2, which constitute a receptor/adapter signaling complex expressed on osteoclasts, dendritic cells, macrophages, and microglia. No Japanese patients with TREM2 mutations have been reported previously.

METHODS

  We reported three siblings affected with NHD in a Japanese family. Amongst them, two died of NHD during the fourth decade of life. The analysis of genomic DNA, cDNA cloning, and western blot of lymphocyte proteins was performed on samples of the living patient. The transcriptome was studied in the autopsied brain of one patient.

RESULTS

  We identified a homozygous conversion of a single nucleotide T to C at the second position of intron 3 in the splice-donor consensus site (c.482+2T>C) of the TREM2 gene, resulting in exon 3 skipping and aberrant expression of truncated proteins. We identified 136 upregulated genes involved in inflammatory response and immune cell trafficking and 188 downregulated genes including a battery of GABA receptor subunits and synaptic proteins in the patient's brain.

CONCLUSIONS

  This is the first report of a Japanese NHD family caused by a splicing mutation of TREM2 that induces both neuroinflammation and neurodegeneration.

A case of fulminant amebic colitis with multiple large intestinal perforations

Amebic colitis normally causes mucous and bloody diarrhea stool as predominant symptoms, thus leading to a course of chronic colitis. However, though rare, there exists a fulminating type that causes intestinal perforations due to wide necrosis of the large intestine. We encountered a case of fulminant amebic colitis that lead to death due to multiple large intestinal perforations. The patient was a 72-year-old female. The patient was admitted to our hospital with symptoms of fever, abdominal pain, and diarrhea. She continued to have a fever of over 38 degrees C and increased left abdominal pain. An abdominal computed tomography scan revealed free gas on the abdominal side of the kidney. Therefore, gastrointestinal perforations were diagnosed and surgery was performed. In surgery, many perforated parts were observed from the appendix to the descending colon, and subtotal colectomy was performed. However, sepsis and disseminated intravascular coagulation occurred, and the patient died on the eighth postoperative day.

Lattice effect of strong electron correlation: implication for ferroelectricity and superconductivity

Much theoretical work has been devoted to understanding the role of strong electron correlations in high-temperature superconductivity mainly through magnetic interactions, but the possible role of electron correlation in ferroelectricity of metal oxides has not received attention. Diagonalization of a simple many-body, tight-binding Hamiltonian shows that the electron-lattice interaction is dramatically enhanced in some cases by strong electron correlation because of deformation-induced charge transfer. This effect may be closely related to ferroelectricity and superconductivity in transition metal oxides.

Apatite Containing Aspartic Acid for Selective Protein Loading

Physico-chemical modifications of hydroxyapatite (HAp) materials are considered as pre-requisites for the development of new bioactive carrier materials for drug delivery and tissue engineering applications. Since acidic amino acids have well-documented affinities to both HAp and basic proteins, HAp modified by aspartic acid (Asp, acidic amino acid) might be one of the candidate substrates for a basic protein carrier. Here, we synthesized HAp in the presence of various concentrations of Asp and observed that HAp crystallinity and other physico-chemical properties were effectively modulated. Detailed studies indicated that Asp was not incorporated in the HAp crystal lattice, but rather was trapped in HAp crystals. Protein adsorption studies indicated that the HAp particles modified by Asp had a selective loading capacity for basic protein. Therefore, HAp particles containing Asp might have potential in drug delivery applications, especially as the carrier of basic proteins including bFGF and BMP.