A Farnesyltransferase Inhibitor Restores Cognitive Deficits in Tsc2+/- Mice through Inhibition of Rheb1.

Tuberous sclerosis complex (TSC) is caused by mutations in Tsc1 or Tsc2, whose gene products inhibit the small G-protein Rheb1. Rheb1 activates mTORC1, which may cause refractory epilepsy, intellectual disability, and autism. The mTORC1 inhibitors have been used for TSC patients with intractable epilepsy. However, its effectiveness for cognitive symptoms remains unclear. We found a new signaling pathway for synapse formation through Rheb1 activation, but not mTORC1. Here, we show that treatment with the farnesyltransferase inhibitor lonafarnib increased unfarnesylated (inactive) Rheb1 levels and restored synaptic abnormalities in cultured Tsc2+/- neurons, whereas rapamycin did not enhance spine synapse formation. Lonafarnib treatment also restored the plasticity-related Arc (activity-regulated cytoskeleton-associated protein) expression in cultured Tsc2+/- neurons. Lonafarnib action was partly dependent on the Rheb1 reduction with syntenin. Oral administration of lonafarnib increased unfarnesylated protein levels without affecting mTORC1 and MAP (mitogen-activated protein (MAP)) kinase signaling, and restored dendritic spine morphology in the hippocampi of male Tsc2+/- mice. In addition, lonafarnib treatment ameliorated contextual memory impairments and restored memory-related Arc expression in male Tsc2+/- mice in vivo Heterozygous Rheb1 knockout in male Tsc2+/- mice reproduced the results observed with pharmacological treatment. These results suggest that the Rheb1 activation may be responsible for synaptic abnormalities and memory impairments in Tsc2+/- mice, and its inhibition by lonafarnib could provide insight into potential treatment options for TSC-associated neuropsychiatric disorders.SIGNIFICANCE STATEMENT Tuberous sclerosis complex (TSC) is an autosomal-dominant disease that causes neuropsychiatric symptoms, including intractable epilepsy, intellectual disability (ID) and autism. No pharmacological treatment for ID has been reported so far. To develop a pharmacological treatment for ID, we investigated the mechanism of TSC and found that Rheb1 activation is responsible for synaptic abnormalities in TSC neurons. To inhibit Rheb1 function, we used the farnesyltransferase inhibitor lonafarnib, because farnesylation of Rheb1 is required for its activation. Lonafarnib treatment increased inactive Rheb1 and recovered proper synapse formation and plasticity-related Arc (activity-regulated cytoskeleton-associated protein) expression in TSC neurons. Furthermore, in vivo lonafarnib treatment restored contextual memory and Arc induction in TSC mice. Together, Rheb1 inhibition by lonafarnib could provide insight into potential treatments for TSC-associated ID.

[Prevalence of Foodborne Pathogens in Retail Meat in Saitama, Japan].

We investigated the prevalence of Campylobacter jejuni, Campylobacter coli, Salmonella, enterohemorrhagic Escherichia coli, enterotoxigenic Escherichia coli, Yersinia enterocolitica, and Escherichia albertii in domestic chicken and pork sold at retail stores in Saitama Prefecture, Japan. Campylobacter was detected in 35.7% (60/168) of chicken samples and 7.3% (14/190) of pork samples. C. jejuni and C. coli were predominant in chicken and pork, respectively. Salmonella was found in 58.1% (100/172) of chicken samples and 19.9% (41/206) of pork samples. Moreover, Salmonella Schwarzengrund was the major serovar observed in chicken isolates, whereas S. Typhimurium monophasic variant was in pork isolates. Furthermore, ETEC was found in 0.6% (1/160) of chicken samples and 2.4% (5/206) of pork samples. Y. enterocolitica was absent from all (83/83) chicken samples but was present in 9.3% (18/193) of pork samples, with a prevalence in pork tongues as high as 21.0% (13/62 samples). However, EHEC and E. albertii were not detected in our study. Therefore, the results of this study indicate that chicken was highly contaminated with Campylobacter sp. and Salmonella, and pork was with Y. enterocolitica serotype O3, Campylobacter sp., Salmonella, and ETEC.

[Evaluation of the Capacity to Produce Histamine by Histamine-Producing Bacteria during Storage at 10℃].

Histamine is produced from histidine using histidine decarboxylase of histamine-producing bacteria. However, associated histamine food poisoning demands microbiological controls. Furthermore, studies reported that histamine production by histamine-producing bacteria is affected by temperature. Therefore, to prevent histamine food poisoning, it is desirable to store foods below 4℃. However, it is challenging to maintain the storage temperature of food substances in refrigerators constantly below 4℃. Thus, we investigated histamine production capacity using seven histamine-producing bacterial strains under storage at 10℃, a more reasonable cold storage condition. Subsequently, we examined the variation of histamine production in buffers, the correlation between bacterial density and histamine production quantities, and the growth rate in broths. Results showed that similar levels of histamine were produced in buffers even after 5 days of storage under certain conditions in which histamine-producing bacteria did not grow. Moreover, bacterial density was proportional to histamine production, and the coefficient of determination was more than 0.97, and the bacterial density required to produce 200 µg/mL of histamine during storage at 10℃ was calculated to be 4×107-4×108 CFU/mL. When the initial bacterial density was 102-103 CFU/mL, psychrophilic bacteria required 2 or 3 days and mesophilic bacteria required more than 4 days to grow above 107 CFU/mL. The above results suggest that understanding the capacity of histamine-producing bacteria to produce histamine and its growth rate in foods is important for the prevention of histamine food poisoning.

A cross-cultural study of acceptability and food pairing for hot sauces.

This study was conducted to understand the acceptance levels of hot sauces among consumers from different culinary cultures. Two newly developed hot sauces [fermented red chili pepper with soybean-paste-based sauce(GS) and fermented red chili-pepper-based sauce(KS)] were compared with Tabasco sauce(TB) and Sriracha sauce(SR). Two separate cross-cultural home-use tests(HUTs) were conducted: pizza and cream soup were provided as food items in HUT 1, whereas grilled chicken wings and rice noodle soup were provided in HUT 2. Consumers residing in Denmark, South Korea, and US participated in each HUT (n≅100 per country). Acceptance levels and the reasons for (dis)liking particular hot sauces applied to food systems were assessed. The food items that paired well with different hot sauces when the sauces were applied freely to regular meals were also analyzed among the US and Korean subjects. When the hot-sauce samples were applied to pizza and cream soup, the preferred order of the samples exhibited a cross-cultural agreement (GS = KS > TB). In the case of grilled chicken and rice noodle soup, the acceptance rating was similar for the three types of hot sauces among Koreans, whereas the acceptance was higher for SR among the US subjects for both foodstuffs, while Danish subjects preferred GS and KS over SR. The US subjects did not like hot-sauce samples with sweet and weak spiciness, whereas the Korean and Danish subjects disliked the hot-sauce sample when it was too spicy and not sufficiently sweet. These findings indicate that the matching of particular sauces with specific food items is culture-dependent, and this needs to be considered when trying to export food products such as hot sauce to other countries.

Evidence of exposure to chemicals and heavy metals during pregnancy in Japanese women.

Purpose: Prenatal exposure to environmental chemicals is a growing concern, because such exposures have been shown to be associated with various diseases. The levels of chemicals and heavy metals in maternal blood, cord blood, maternal urine and amniotic fluid in Japanese pregnant women were investigated. Methods: A total of 145 women, including 14 fetal growth restriction cases, were included in the present study. The levels of phthalates (di[2-ethylhexyl]phthalate and mono[2-ethylhexyl]phthalate), perfluorinated compounds (perfluorooctane sulfonate, perfluorohexanoic acid, perfluorooctanoic acid, and perfluorononanoic acid), pesticides (dimethylphosphate, dimethylthiophosphate, diethylphosphate, diethylthiophosphate, 3-phenoxybenzoic acid, and octachlorodipropyl ether), bisphenol A, nicotine (nicotine, nornicotine, cotinine, norcotinine, and trans-3'-hydroxycotinine), polybrominated diphenyl ethers, and heavy metals were measured. The relationship between fetal growth and the levels of chemicals and heavy metals were investigated. Results: Phthalates, perfluorinated compounds, pesticides, polybrominated diphenyl ethers, and heavy metals were detected in high frequency, whereas nicotine and bisphenol A were almost negative. Phthalates, perfluorinated compounds, and several heavy metals were transferred to the fetus. High perfluorononanoic acid levels in the maternal blood and cord blood, and low perfluorooctanoic acid level in the cord blood were significantly and negatively associated with fetal growth. Conclusions: The present study showed that pregnant women in Japan and their fetuses are exposed to a variety of chemicals and heavy metals.

[Comparison of Contrast to Noise Ratio and Signal Difference to Noise Ratio Based on QA and QC Guidelines in CR Mammography].

The measurement methods of contrast to noise ratio (CNR) and signal difference to noise ratio (SDNR) in digital mammography are different among several quality assurance (QA) guidelines, that is, the type of pixel value (PV), phantom shape, location of aluminum plate, and the size of region of interest (ROI) principally differ in data acquisition. We compared CNR (SDNR) obtained from three QA guidelines. They are the European Reference Organisation for Quality Assured Breast Screening and Diagnostic Services (EUREF), the International Electrotechnical Commission (IEC), and the International Atomic Energy Agency (IAEA). In EUREF and IEC, CNR was calculated using linearized pixel value (LPV). In IAEA, because the type of pixel value to use in SDNR was not specified, SDNR was calculated using PV and LPV, and CNR was calculated using LPV. Target/filter combinations are molybdenum/molybdenum (Mo/Mo) and molybdenum/rhodium (Mo/Rh). Applied various tube voltages are 25, 30, and 35 kV, and various phantom thicknesses are 20, 45, and 70 mm of polymethyl methacrylate (PMMA). The PV-SDNR of IAEA showed the largest value among the three methods, following LPV-CNR of IEC, LPV-CNR of EUREF at 20 mm PMMA thickness. In IAEA, SDNR changed by the kind of pixel value (PV or LPV). When CNR is calculated, every researcher should describe the type of guidelines, the kind of pixel value, and formula for calculation.

[Influence of Detector Radiation Damage on CR Mammography Quality Control].

Recently, radiation damage to the detector apparatus employed in computed radiography (CR) mammography has become problematic. The CR system and the imaging plate (IP) applied to quality control (QC) program were also used in clinical mammography in our hospital, and the IP to which radiation damage has occurred was used for approximately 5 years (approximately 13,000 exposures). We considered using previously acquired QC image data, which is stored in a server, to investigate the influence of radiation damage to an IP. The mammography unit employed in this study was a phase contrast mammography (PCM) Mermaid (KONICA MINOLTA) system. The QC image was made newly, and it was output in the film, and thereafter the optical density of the step-phantom image was measured. An input (digital value)-output (optical density) conversion curve was plotted using the obtained data. The digital values were then converted to optical density values using a reference optical density vs. digital value curve. When a high radiation dose was applied directly, radiation damage occurred at a position on the IP where no object was present. Daily QC for mammography is conducted using an American College of Radiology (ACR) accreditation phantom and acrylic disc, and an environmental background density measurement is performed as one of the management indexes. In this study, the radiation damage sustained by the acrylic disc was shown to differ from that of the background. Thus, it was revealed that QC results are influenced by radiation damage.

Influence of femtosecond lenticule extraction and small incision lenticule extraction on corneal nerve density and ocular surface: a 1-year prospective, confocal, microscopic study.

PURPOSE: To compare the influence of femtosecond lenticule extraction (FLEx) and small incision lenticule extraction (SMILE) on corneal nerve density and the ocular surface for equivalent degrees of correction of myopia. METHODS: Sixty eyes of 30 patients (8 males and 22 females, mean age: 31.0 ± 6.0 years) were included in the study. The patients underwent FLEx in 1 eye and SMILE in the other eye by random assignment. Subbasal nerve density was measured using confocal microscopy preoperatively and at 1 week, 1 and 3 months, and 1 year postoperatively. Ocular surface parameters such as Schirmer's test results, tear film break-up time, and corneal sensation were performed preoperatively and at 1 and 3 months postoperatively. RESULTS: In the FLEx group, subbasal nerve density was 18,390 ± 6,090 µm/mm(2) preoperatively and 5,770 ± 3,490 µm/mm(2) at 1 year postoperatively (P < .001, Dunnett's test). In the SMILE group, subbasal nerve density was 16,810 ± 6,220 µm/mm(2) preoperatively and 11,870 ± 8,200 µm/mm(2) at 1 year postoperatively (P = .21). The decrease in corneal nerve density was significantly less after SMILE than after FLEx at all postoperative visits (Mann-Whitney U test, P < .05). FLEx resulted in a significant decrease in Schirmer's test results, tear film break-up time, and corneal sensation at all postoperative visits, whereas SMILE induced no significant changes in these parameters (P > .05). CONCLUSIONS: There was less damage to the sub-basal nerve plexus of the cornea and less effect on the ocular surface parameters after SMILE than after FLEx.

Identifying the drivers of liking by investigating the reasons for (dis)liking using CATA in cross-cultural context: a case study on barbecue sauce.

BACKGROUND: The present study cross-culturally investigated the drivers of liking for traditional and ethnic chicken marinades using descriptive analysis and consumer taste tests incorporating the check-all-that-apply (CATA) method. Seventy-three Koreans and 86 US consumers participated. The tested sauces comprised three tomato-based sauces, a teriyaki-based sauce and a Korean spicy seasoning-based sauce. Chicken breasts were marinated with each of the five barbecue sauces, grilled and served for evaluation. Descriptive analysis and consumer taste tests were conducted. Consumers rated the acceptance on a hedonic scale and checked the reasons for (dis)liking by the CATA method for each sauce. A general linear model, multiple factor analysis and chi-square analysis were conducted using the data. RESULTS: The results showed that the preference orders of the samples between Koreans and US consumers were strikingly similar to each other. However, the reasons for (dis)liking the samples differed cross-culturally. The drivers of liking of two sauces sharing relatively similar sensory profiles but differing significantly in hedonic ratings were effectively delineated by reasons of (dis)liking CATA results. CONCLUSION: Reasons for (dis)liking CATA proved to be a powerful supporting method to understand the internal drivers of liking which can be overlooked by generic descriptive analysis.

Protection of free radical-induced cytotoxicity by 2-O-α-D-glucopyranosyl-L-ascorbic acid in human dermal fibroblasts.

The stable ascorbic acid (AA) derivative, 2-O-α-D-glucopyranosyl-L-ascorbic acid (AA-2G), exhibits vitamin C activity after enzymatic hydrolysis to AA. The biological activity of AA-2G per se has not been studied in detail, although AA-2G has been noted as a stable source for AA supply. The protective effect of AA-2G against the oxidative cell death of human dermal fibroblasts induced by incubating with 2,2'-azobis(2-amidinopropane) dihydrochloride (AAPH) for 24 h was investigated in this study. AA-2G showed a significant protective effect against the oxidative stress in a concentration-dependent manner. AA-2G did not exert a protective effect during the initial 12 h of incubation, but had a significant protective effect in the later part of the incubation period. Experiments using a α-glucosidase inhibitor and comparative experiments using a stereoisomer of AA-2G confirmed that AA-2G had a protective effect against AAPH-induced cytotoxicity without being converted to AA. Our results provide an insight into the efficacy of AA-2G as a biologically interesting antioxidant and suggest the practical use of AA-2G even before being converted into AA as a beneficial antioxidant.

[Two cases of unresectable advanced gastric cancer treated with S-1, CDDP and trastuzumab].

We report two cases of unresectable advanced gastric cancer treated with S-1, CDDP and trastuzumab. A significant reduction of tumors was observed in these cases. A 77-year-old man was diagnosed as unresectable gastric cancer. The pathological diagnosis was tub2 and human epidermal growth factor receptor 2(HER2)positive(3+IHC method). We started chemotherapy(S-1+CDDP+trastuzumab). After 2 courses of S-1+CDDP, the findings of upper gastrointestinal endoscopy and CT were much improved to PR. But after 6 courses of S-1+CDDP, they worsened to PD. The regimen of chemotherapy was changed to weekly paclitaxel. The other patient, a 68-year-old woman, was diagnosed as far advanced gastric cancer. The pathological diagnosis was tub2=por2 and HER2 positive(3+IHC method). We started chemotherapy(S- 1+CDDP+trastuzumab). After 3 courses of S-1+CDDP, the tumor reduced significantly to PR. We continued this regimen. From the result of the ToGA trial, addition of trastuzumab to chemotherapy(capecitabine+CDDP or fluorouracil+CDDP) has been recommended as a new standard first-line regimen for HER2-positive advanced gastric cancer. But there is no evidence that trastuzumab added to the other regimen improved survival in patients with advanced gastric cancer. It is necessary to conduct a clinical trial to evaluate the treatment effect of this chemotherapy.

Novel presynaptic assay system revealed that metformin ameliorates exaggerated synaptic release and Munc18-1 accumulation in presynapses of neurons from Fragile X syndrome mouse model.

Fragile X syndrome (FXS) is a developmental disorder characterized by intellectual disability and autistic-like behaviors. These symptoms are supposed to result from dysregulated translation in pre- and postsynapses, resulting in aberrant synaptic plasticity. Although most drug development research on FXS has focused on aberrant postsynaptic functions by excess translation in postsynapses, the effect of drug candidates on FXS in presynaptic release is largely unclear. In this report, we developed a novel assay system using neuron ball culture with beads to induce presynapse formation, allowing for the analysis of presynaptic phenotypes, including presynaptic release. Metformin, which is shown to rescue core phenotypes in FXS mouse model by normalizing dysregulated translation, ameliorated the exaggerated presynaptic release of neurons of FXS model mouse using this assay system. Furthermore, metformin suppressed the excess accumulation of the active zone protein Munc18-1, which is supposed to be locally translated in presynapses. These results suggest that metformin rescues both postsynaptic and presynaptic phenotypes by inhibiting excess translation in FXS neurons.

[Derivation of Conversion Formula of Image Quality Figure (IQFinv) Values by Old and New Analysis Software for Mammographic Contrast-detail Phantom].

PURPOSE: This study deals with the conversion of the image quality figure (IQFinv) values with CDMAM Analyser ver. 1 (old analysis software) used to analyse the images of CDMAM 3.4 phantom into the IQFinv values with a new analysis software, that is, CDMAM Analyser (ver. 2 and ver. 2.3), which is a software improved to be closer to human visual evaluation. METHODS: The IQFinv values were calculated using four mammography units and three analysis software. The IQFinv values using the old and new software were compared. RESULTS: The IQFinv values had no difference according to mammography units and beam quality. The conversion formula of IQFinv from CDMAM Analyser ver. 1 to CDMAM Analyser ver. 2 was derived. Furthermore, the conversion formula of IQFinv from CDMAM Analyser ver. 1 to CDMAM Analysis ver. 2.3 was also derived. CONCLUSION: Using each conversion formula, the IQFinv values using the old software can be converted to those using the new software. There was a slight difference between the IQFinv values using the new software.

[A Method to Obtain a Sheet-like X-ray Phantom Made from Iodine Contrast Agent].

PURPOSE: A sheet-like X-ray phantom on which thin Iodine is uniformly coated was developed to facilitate the handling of iodined objects used in any X-ray imaging studies. METHODS: The most recommendable protocol as follows: (1) prepare undiluted 240 mg/ml Iohexol-based contrast agent and drop around 1.6 g on a horizontal surface. (2) infiltrate the agent into a membrane filter (47 mm in diameter) from the secondary side. (3) one minute later, the excess liquid components should be removed by a softy absorbent paper, and the infiltrated membrane filter should be left until substantially dried. RESULT: The dried membrane filter can be utilized as a sheet-like X-ray phantom on which the iodine of around 2.45 mg is almost uniformly distributed per 1 cm2. However, since the iodine density is slightly higher on the periphery part of the sheet, less than 80% area of the entire sheet is recommended to be used from a viewpoint of the spatial uniformity. CONCLUSION: In the practical experiments, the X-ray attenuation factor can be controlled by changing the stacking number of the sheet, and the spatial size and form can also be designed by cutting the sheet. This capability is expected to improve the efficiency of any X-ray experiments and quality control works that requires iodined materials.

A deletion in a cis element of Foxe3 causes cataracts and microphthalmia in rct mice.

The Rinshoken cataract (rct) mutation, which causes congenital cataracts, is a recessive mutation found in SJL/J mice. All mutants present with opacity in the lens by 2 months of age. The rct locus was mapped to a 1.6-Mb region in Chr 4 that contains the Foxe3 gene. This gene is responsible for cataracts in humans and mice, and it plays a crucial role in the development of the lens. Furthermore, mutation of Foxe3 causes various ocular defects. We sequenced the genomic region of Foxe3, including the coding exons and UTRs; however, no mutations were discovered in these regions. Because there were no differences in Foxe3 sequences between the rct/rct and wild-type mice, we inferred that a mutation was located in the regulatory regions of the Foxe3 gene. To test this possibility, we sequenced a 5' noncoding region that is highly conserved among vertebrates and is predicted to be the major enhancer of Foxe3. This analysis revealed a deletion of 22-bp located approximately 3.2-kb upstream of the start codon of Foxe3 in rct mice. Moreover, we demonstrated by RT-PCR and in situ hybridization that the rct mutant has reduced expression of Foxe3 in the lens during development. We therefore suggest that cataracts in rct mice are caused by reduced Foxe3 expression in the lens and that this decreased expression is a result of a deletion in a cis-acting regulatory element.

Epigenetic assessment of environmental chemicals detected in maternal peripheral and cord blood samples.

Epigenetic alteration is an emerging paradigm underlying the long-term effects of chemicals on gene functions. Various chemicals, including organophosphate insecticides and heavy metals, have been detected in the human fetal environment. Epigenetics by DNA methylation and histone modifications, through dynamic chromatin remodeling, is a mechanism for genome stability and gene functions. To investigate whether such environmental chemicals may cause epigenetic alterations, we studied the effects of selected chemicals on morphological changes in heterochromatin and DNA methylation status in mouse ES cells (ESCs). Twenty-five chemicals, including organophosphate insecticides, heavy metals and their metabolites, were assessed for their effect on the epigenetic status of mouse ESCs by monitoring heterochromatin stained with 4¢,6-diamino-2-phenylindole (DAPI). The cells were surveyed after 48 or 96 h of exposure to the chemicals at the serum concentrations of cord blood. The candidates for epigenetic mutagens were examined for the effect on DNA methylation at genic regions. Of the 25 chemicals, five chemicals (diethyl phosphate (DEP), mercury (Hg), cotinine, selenium (Se) and octachlorodipropyl ether (S-421)) caused alterations in nuclear staining, suggesting that they affected heterochromatin conditions. Hg and Se caused aberrant DNA methylation at gene loci. Furthermore, DEP at 0.1 ppb caused irreversible heterochromatin changes in ESCs, and DEP-, Hg- and S-421-exposed cells also exhibited impaired formation of the embryoid body (EB), which is an in vitro model for early embryos. We established a system for assessment of epigenetic mutagens. We identified environmental chemicals that could have effects on the human fetus epigenetic status.

Coronin-1 is phosphorylated at Thr-412 by protein kinase Cα in human phagocytic cells.

Coronin-1, a hematopoietic cell-specific actin-binding protein, is thought to be involved in the phagocytic process through its interaction with actin filaments. The dissociation of coronin-1 from phagosomes after its transient accumulation on the phagosome surface is associated with lysosomal fusion. We previously reported that 1) coronin-1 is phosphorylated by protein kinase C (PKC), 2) coronin-1 has two phosphorylation sites, Ser-2 and Thr-412, and 3) Thr-412 of coronin-1 is phosphorylated during phagocytosis. In this study, we examined which PKC isoform is responsible for the phosphorylation of coronin-1 at Thr-412 by using isotype-specific PKC inhibitors and small interfering RNAs (siRNAs). Thr-412 phosphorylation of coronin-1 was suppressed by Gö6976, an inhibitor of PKCα and PKCßI. This phosphorylation was attenuated by siRNA for PKCα, but not by siRNA for PKCß. Furthermore, Thr-412 of coronin-1 was phosphorylated by recombinant PKCα in vitro, but not by recombinant PKCß. We next examined the effects of Gö6976 on the intracellular distribution of coronin-1 in HL60 cells during phagocytosis. The confocal fluorescence microscopic observation showed that coronin-1 was not dissociated from phagosomes in Gö6976-treated cells. These results indicate that phosphorylation of coronin-1 at Thr-412 by PKCα regulates intracellular distribution during phagocytosis.

[Comparison between Variance and Edge Methods for Measuring Image Resolution Properties in Digital Mammography].

We studied the image resolution properties in digital mammography using the variance and edge response function methods. The associated measurements were made using a polymethylmethacrylate phantom of 0-40 mm thickness while maintaining the incident dose to the detector constant, as well as with and without using the phantom but by varying the level of exposure to the detector. The results obtained using the two methods were compared on the object plane of the mammography unit with compensation for the magnification and rejection of the scattered radiation. In this unit, the imaging process of resolution enhancement may be performed according to the phantom thickness, shape of test device, exposure level, and so on. The modulation transfer function values of the variance method were slightly higher than those of the edge method, approximately 6% at 2 cycles/mm and 8% at 4 cycles/mm without resolution enhancement processing. We concluded that the variance method is more suitable than the edge method for the constancy test or quality control because of its lower coefficient of variation.

Myosin VI Haploinsufficiency Reduced Hearing Ability in Mice.

In human, myosin VI (MYO6) haploinsufficiency causes postlingual progressive hearing loss. Because the usefulness of mouse models remains unclear, we produced novel Myo6 null (-/-) mutant mice and analyzed the hearing phenotypes of Myo6+/- (+/-) heterozygous mutants. We first recorded and compared the auditory brainstem responses and distortion product otoacoustic emissions in control Myo6+/+ (+/+) wild-type and +/- mice. These hearing phenotypes of +/- mice were mild; however, we confirmed that +/- mice developed progressive hearing loss. In particular, the hearing loss of female +/- mice progressed faster than that of male +/- mice. The stereocilia bundles of +/- mice exhibited progressive taper loss in cochlear inner hair cells (IHCs) and outer hair cells (OHCs). The loss of OHCs in +/- heterozygotes occurred at an earlier age than in +/+ mice. In particular, the OHCs at the basal area of the cochlea were decreased in +/- mice. IHC ribbon synapses from the area at the base of the cochlea were significantly reduced in +/- mice. Thus, our study indicated that MYO6 haploinsufficiency affected the detection of sounds in mice, and we suggest that +/- mice with Myo6 null alleles are useful animal models for gene therapy and drug treatment in patients with progressive hearing loss due to MYO6 haploinsufficiency.

[Construction and Analysis of a Digital Mammography Database: Analysis of Breast Compression Pressures at Four Facilities].

We analyzed the compression pressures in 2772 mammography images of 807 patients acquired by digital mammography equipment at four facilities. The analysis included the average compression pressure at all facilities, difference in compression pressure at each facility, differences between the pressures used by radiological technologists in the same facility, and difference attributed to the breast structure. We also analyzed the effects of the compression pressure on the breast thickness and mean glandular dose (MGD) at each facility. The median values of the compression pressure and breast thickness for the 2772 images at all facilities were 86.5 N and 43 mm, respectively. The compression pressures differed among the institutions. The maximum difference in the median pressures among the four facilities was 38.6 N, while the difference in the breast thickness was 6 mm. The radiological technologists working at the same facility used almost the same compression pressure. However, differences between the compression pressures used by different radiological technologists were observed. The compression pressure in a dense breast was smaller than that in a non-dense breast. The difference in the compression pressure affected the breast thickness and MGD. The results of this analysis could be utilized for an optimal imaging in future digital mammography.