Impact of linked color imaging and blue laser imaging on the diagnosis of esophageal squamous cell carcinoma in iodine unstained areas

The pink color sign in iodine unstained areas is useful to differentiate esophageal squamous cell carcinoma (ESCC) from other lesions. However, some ESCCs have obscure color findings which affect the ability of endoscopists to differentiate these lesions and determine the resection line. Using white light imaging (WLI), linked color imaging (LCI) and blue laser imaging (BLI), 40 early ESCCs were retrospectively evaluated using images before and after iodine staining. Visibility scores for ESCC by expert and non-expert endoscopists were compared using these three modalities and color differences measured for malignant lesions and surrounding mucosa. BLI had the highest score and color difference without iodine staining. Each determination with iodine was much higher than without iodine regardless of the modality. With iodine, ESCC mainly appeared pink, purple and green using WLI, LCI and BLI, respectively and visibility scores determined by non-experts and experts were significantly higher for LCI (both p < 0.001) and BLI (p = 0.018 and p < 0.001) than for WLI. The score with LCI was significantly higher than with BLI among non-experts (p = 0.035). With iodine, the color difference using LCI was twice that with WLI and one with BLI was significantly larger than with WLI (p < 0.001). These greater tendencies were found regardless of location, depth of cancer or intensity of pink color using WLI. In conclusion, areas of ESCC unstained by iodine were easily recognized using LCI and BLI. Visibility of these lesions is excellent even by non-expert endoscopists, suggesting that this method is useful to diagnose ESCC and determine the resection line.

Usefulness of linked color imaging for the detection of obscure early gastric cancer: Multivariate analysis of 508 lesions

OBJECTIVES

Early gastric cancers (EGCs) of the elevated type or with submucosal invasion are easily found by routine endoscopy. However, most early cancers are challenging to detect because of subtle morphological or color differences from surrounding atrophic mucosa and intestinal metaplasia. Linked color imaging (LCI) enhances mucosal color difference, making it easier to detect EGCs. The aim of this study is to clarify the advantages and possible disadvantages of LCI for screening for obscure EGC.

METHODS

A total of 665 malignant gastric lesions resected using endoscopic submucosal dissection between January 2015 and April 2018 were retrospectively reviewed. Obviously detectable lesions were not included in the main analysis when determining the target lesion. White light imaging (WLI)/LCI images of 508 endoscopically obscure malignant lesions were included in the final analysis and evaluated by three non-expert and three expert endoscopists using visibility scores for detection and extent.

RESULTS

The detection visibility scores using LCI were significantly higher than those using WLI regardless of lesion characteristics including location, size, histological type, depth of invasion, and Helicobacter pylori status. The detection score improved in 46.4% cases and deteriorated in 4.9% when the modality changed from WLI to LCI. A mixed-effects multivariate logistic regression analysis showed that use of LCI (odds ratio [OR] 2.57), elevated type (OR 1.92), invasion to submucosa (OR 2.18) were significantly associated with improved visibility of EGC.

CONCLUSIONS

Linked color imaging significantly improves visibility of EGC regardless of differences in lesion morphology, histology, location, depth of invasion, and H. pylori status compared to conventional WLI.

P-441 a study in status of use and live birth rates of cryopreserved oocyte for social reasons

Study question

What is status of use and live birth rates of cryopreservation oocyte for social reasons?

Summary answer

11.2% of the cryopreserved oocytes were warmed and transferred, and the oldest of the successful live birth was 39 years old.

What is known already

More people nowadays tend to delay marriage and childbearing due to the social circumstances. It is now gradually known that the pregnancy rate decreases with increasing age, since the donation of gametes from third parties is regulated by the Japanese society, oocyte cryopreservation for social reasons has been becoming common practice. However, not much is known about the subsequent pregnancy and childbirth. Therefore, we conducted a survey on the use and clinical outcomes of cryopreserved oocytes for social reasons in our clinic.

Study design, size, duration

This retrospective single-center study was conducted with a total of 285 women, 424 cycles from March 2014 to December 2019. A total of 2696 oocytes were cryopreserved by vitrification. Written informed consent was obtained from all women who participated in this study.

Participants/materials, setting, methods

Ovarian stimulation was performed mainly with GnRH antagonist protocol. An injection of 5000IU of HCG was administered when the diameter of dominant follicle reached 18mm. All oocytes were denuded enzymatically with 80 IU/ml hyaluronidase, followed by mechanical denudation. The oocytes were then evaluated at metaphase II by confirming the presence of the first polar body. Mature oocytes were cryopreserved by vitrification. The partner's sperm was injected into the vitrified-warmed oocytes.

Main results and the role of chance

The age groups in the first freezing cycle were 30-34 years (7.4%), 35-39 years (49.8%), 40-44 years (37.2%), and 45 years and older (5.6%), respectively. The mean number of OPU cycles was 1.1±0.4, 1.4±1.4, 1.5±1.1, and 1.7±1.7. The average number of retrieved oocytes was 9.5 ± 5.4, 7.3 ± 4.5, 5.6 ± 4.6, and 2.2 ± 2.2. The total number of cryopreserved oocytes was 10.4±5.9, 10.4±7.1, 8.8±6.8, and 3.3±3.4. Sixty-seven women had partners after oocyte cryopreservation, and 33 women (49.3%) had oocytes thawed. The mean age at oocytes freezing was 39.6±2.6 years, and the mean age at thawing was 42.2±2.5 years. The oocytes survival rates, fertilization rates, blastocyst rates and clinical pregnancy rates per embryo transferred of vitrified oocytes were 92.7% (328/354), 69.5% (228/328), 43.9% (87/198) and 31.1% (19/61), respectively. Of these, 15 women (45.5%) became pregnant with vitrified-warmed oocytes, and 10 (30.3%) had livebirth. 18 women did not become pregnant with vitrified-warmed oocytes. Subsequently, 3 of the 18 women then became pregnant in ART (5.6%), by IUI (5.6%), or spontaneously (5.6%), respectively.

Limitations, reasons for caution

Not applicable.

Wider implications of the findings

Of the 33 cases, 10 (30.3%) successfully gave birth, indicating the usefulness of oocyte cryopreservation for social reasons. However, considering that most of our patients were already around 40 years old, awareness of the benefits of oocytes cryopreservation at younger ages and education of reproductive health and rights is essential.

Trial registration number

none

Improved detection of early gastric cancer with linked color imaging using an ultrathin endoscope: a video-based analysis

Background and study aims  Ultrathin endoscopy causes a minimal gag reflex and has minimal effects on cardiopulmonary function. Linked color imaging (LCI) is useful for detection of malignancies in the digestive tract. The aim of this study was to clarify whether LCI with ultrathin endoscopy facilitates detection of early gastric cancer (EGC) despite its lower resolution compared with high-resolution white light imaging (WLI) with standard endoscopy. Patients and methods  This was a retrospective analysis with prospectively collected video, including consecutive 166 cases of EGC or gastric atrophy alone. Ninety seconds of screening video was collected using standard and ultrathin endoscopes with both WLI and LCI for each case. Three expert endoscopists assessed each video and the sensitivity of detecting EGC calculated. Color difference calculations were performed. Results  Sensitivities using ultrathin WLI, ultrathin LCI, standard WLI, and standard LCI for the identification of cancer were 66.0 %, 80.3 %, 69.9 %, and 84.0 %, respectively. The color difference between malignant lesions and surrounding mucosa with ultrathin LCI and standard LCI were significantly higher than using ultrathin WLI or standard WLI, supported subjectively by the visibility score. Ultrathin LCI color difference and visibility score were significantly higher than standard WLI. Conclusions  LCI with a low-resolution ultrathin endoscope is superior to WLI with a high-resolution standard endoscope for gastric cancer screening. This suggests that the high color contrast between EGC and the surrounding mucosa is more important than high-resolution images.

Appropriate Color Enhancement Settings for Blue Laser Imaging Facilitates the Diagnosis of Early Gastric Cancer with High Color Contrast

Purpose

Screening image-enhanced endoscopy for gastrointestinal malignant lesions has progressed. However, the influence of the color enhancement settings for the laser endoscopic system on the visibility of lesions with higher color contrast than their surrounding mucosa has not been established.

Materials and Methods

Forty early gastric cancers were retrospectively evaluated using color enhancement settings C1 and C2 for laser endoscopic systems with blue laser imaging (BLI), BLI-bright, and linked color imaging (LCI). The visibilities of the malignant lesions in the stomach with the C1 and C2 color enhancements were scored by expert and non-expert endoscopists and compared, and the color differences between the malignant lesions and the surrounding mucosa were assessed.

Results

Early gastric cancers mainly appeared orange-red on LCI and brown on BLI-bright or BLI. The surrounding mucosae were purple on LCI regardless of the color enhancement but brown or pale green with C1 enhancement and dark green with C2 enhancement on BLI-bright or BLI. The mean visibility scores for BLI-bright, BLI, and LCI with C2 enhancement were significantly higher than those with C1 enhancement. The superiority of the C2 enhancement was not demonstrated in the assessments by non-experts, but it was significant for experts using all modes. The C2 color enhancement produced a significantly greater color difference between the malignant lesions and the surrounding mucosa, especially with the use of BLI-bright (P=0.033) and BLI (P<0.001). C2 enhancement tended to be superior regardless of the morphological type, Helicobacter pylori status, or the extension of intestinal metaplasia around the cancer.

Conclusions

Appropriate color enhancement settings improve the visibility of malignant lesions in the stomach and color contrast between the malignant lesions and the surrounding mucosa.

New Diagnostic Approach for Esophageal Squamous Cell Neoplasms Using Linked Color Imaging and Blue Laser Imaging Combined with Iodine Staining

A 62-year-old man with a flat early esophageal cancer was referred for endoscopic treatment. White light imaging revealed a pale red lesion, whereas linked color imaging (LCI) and blue laser imaging (BLI) yielded purple and brown images, respectively. Iodine staining demonstrated a large unstained area with a homogenous but very weak pink-color sign. This area appeared more clearly as purple and green on LCI and BLI, respectively; however, a different colored portion was observed at the 4 o’clock position inside the iodineunstained area. Histopathology findings of the resected specimen revealed squamous intraepithelial neoplasia at the 4 o’clock position and an esophageal squamous cell carcinoma in the remaining iodine-unstained area. LCI and BLI combined with iodine staining produce characteristic images that overcomes the pink-color sign, reflecting the histological features of a flat esophageal neoplasm. This new method is useful for detailed evaluation of early flat squamous cell neoplasms.

Effects of sex and age on serum 1,5-anhydroglucitol in nondiabetic subjects

The aim of this study was to demonstrate the effects of sex and age on serum levels of 1,5-AG in nondiabetic subjects.A total of 1 134 nondiabetic subjects aged 16-96 years with HbA1c less than 6.8% were recruited and divided into 4 HbA1c groups (Q1: HbA1c≤5.3; Q2: 5.4-5.8; Q3: 5.9-6.3; and Q4: 6.4-6.8 [%]). 38 elderly subjects (65 years or older) in the Q3 and Q4 groups (13 men and 25 women) underwent a 75-g oral glucose tolerance test (OGTT).The Q4 group had significantly lower 1,5-AG levels than did the Q1 group among nonelderly males, nonelderly females, and elderly men. In elderly women, 1,5-AG levels did not differ among the 4 HbA1c groups. In both nonelderly and elderly subjects, the 1,5-AG level of the Q1 group was significantly higher in males than in females. Stepwise multivariate regression analysis showed that age was significantly associated with 1,5-AG level in both sexes. HbA1c was significantly associated with the 1,5-AG level in males, while there was no significant association between HbA1c and the 1,5-AG level in females. In the elderly OGTT group, although the glucose levels of both sexes during OGTT were identical, the mean urinary glucose levels and the percentages of subjects with glucosuria were significantly higher in elderly men than in elderly women.Serum 1,5-AG levels were significantly associated with age and sex. The sensitivity of the 1,5-AG level for identifying postprandial hyperglycemia in elderly women with near-normoglycemia is less reliable because they have a higher renal threshold for glucose.

Enhanced inhibitory effects of TBT chloride on the development of F1 rats

Neurotoxicity is one of the major effects of tributyltin (TBT). The effects on the next generation of F(1) rats exposed to TBT via the placenta and their dams' milk may be stronger than those on adults. Pregnant Wister rats were exposed to TBT at 0 and 125 ppm in their food. Half of the female F(1) rats in both groups were exposed to TBT at 125 ppm in their food from 9 to 15 weeks of age. Female F(1) rats were divided into the following groups: the control-control (CC) group, with no exposure; the TBT-control (TC) group, exposed to TBT via the placenta and their dams' milk; the control-TBT (CT) group, exposed to TBT via their food from 9 to 15 weeks of age; and the TBT-TBT (TT) group, exposed to TBT via the placenta, their dams' milk, and their food (n = 10/group). After administration, an open-field test and prepulse inhibition (PPI) test were performed at 15 weeks of age. The mean body weights of the TC and TT groups were significantly lower than that of the CC group from 9 to 15 weeks of age. The mean relative thymus weight of the TC and TT groups was significantly lower than that of the CC group. In the open-field test, a marked decrease in the total locomotion distance was observed in the TT group. The mean values in the TT and TC groups were significantly lower than that in the CC group. For the locomotion distance between 15 and 20 min, the mean values in the CT, TC, and TT groups were significantly lower than that in the CC group. The mean locomotor distance between 25 and 30 min in the TT group was significantly lower than that in the CC and TC groups. The mean values of instances of wall rearing in the TC, CT, and TT groups were significantly lower than that in the CC group. The mean value of face washing or body washing in the TT group was significantly lower than that in the CT group. There were no significant differences in indexes of the PPI test. Exposure to TBT via the placenta and their dams' milk inhibited the development of F(1) rats, which continued after weaning. Inhibition of the rats' activity induced by exposure to TBT via the placenta and their dams' milk and/or via their food was suggested. The effects were most evident in the TT group.

Development of a phantom compatible for MRI and hyperthermia using carrageenan gel—relationship between dielectric properties and NaCl concentration

A phantom has previously been developed containing carrageenan, agarose and gadolinium chloride (called CAG phantom) for MRI with 1.5 T. T(1) and T(2) relaxation times of this phantom are independently changeable by varying concentrations of relaxation-time modifiers to simulate relaxation times of the various types of human tissues. The CAG phantom has a T(1) value of 202-1904 ms and a T(2) value of 38-423 ms, when the GdCl(3) concentration is varied from 0-140 micromol/kg and the agarose concentration is varied from 0-1.6%. A new phantom has now been developed (called CAGN phantom), made by adding an electric conductive agent, NaCl, to the CAG phantom for use in the areas of MRI and hyperthermia research. Dielectric properties of the CAGN phantom were measured and the results of experiments were expressed by the Cole-Cole equation in the frequency range of 5-130 MHz. The relationship between the conductivity of the CAGN phantom and the concentration of NaCl was expressed by a linear function in the frequency range of 1-130 MHz. The linear function involves a parameter of frequency and, when the frequency is 10 MHz, the conductivity of the CAGN phantom can be changed from 0.27-1.26 Sm(-1) by increasing the NaCl concentration from 0-0.7%. The CAGN phantom developed can be employed in basic experiments for non-invasive temperature measurement using MRI and as a loading phantom for MRI with up to 3 T.

Development of a phantom compatible for MRI and hyperthermia using carrageenan gel—relationship betweenT1andT2values and NaCl concentration

The authors developed a phantom, designated as the CAGN phantom, compatible for MRI and hyperthermia that is useful in the fundamental studies of non-invasive MR thermometry. The ingredients of this phantom are carrageenan, GdCl3 as a T1 modifier, agarose as a T2 modifier, NaCl as a conductivity modifier, NaN3 as an antiseptic and distilled water. Another phantom that was developed, the CAG phantom, has relaxation times that are adjustable to those of any human tissue. To use this phantom for electromagnetic heating, NaCl was added to change the conductivity of the phantom and clarified the relationship between the conductivity and NaCl concentration. This study examined the relationship between relaxation times and NaCl concentration of the CAGN phantom. The results showed that both T1 and T2 values were affected by NaCl and the experimental results led to the empirical formulae expressing the relationship between the relaxation rates (1/T1, 1/T2) and the concentrations of GdCl3, agarose and NaCl. The appropriate concentrations of T1 and T2 modifiers were calculated from these empirical formulae when making a specified phantom that has the required relaxation times and NaCl concentration.

X-ray analyses of two DNA dodecamers containing N4-methoxy-cytosine paired with adenine or guanine

To investigate mismatch of base-pairings in relation to mutagenesis by oxyamines, crystal structures of two DNA dodecamers with the sequence d(CGCZAA TTmo4CGCG) (Z = A or G), containing N4-methoxy-cytosine (mo4C), have been determined by X-ray analysis. These dodecamers essentially form right-handed B-form duplexes, respectively. In the dodecamer with Z = A, the two mo4C residues are adapted in imino form with the anti methoxyl group to form pairs with A on the opposite strand in a manner of Watson-Crick fashion. While in the dodecamer with Z = G, one mo4C in amino form with the anti methoxyl group forms a normal Watson-Crick pair with G, but the other one in imino form with syn methoxyl conformation wobbles with G. Based on these results, possible mutation mechanism has been proposed.

X-ray analyses of DNA dodecamers containing 2'-deoxy-5-formyluridine

It is known that formylation of thymine base induces purine transition in DNA replication. In order to establish the structural basis for such mutagenesis, crystal structures of two kinds of DNA dodecamers d(CGCGRATf5UCGCG) with f5U = 2'-deoxy-5-formyluridine and R = A or G have been determined. The f5U residues form a Watson-Crick-type pair with A and two types of pairs (wobble and reversed wobble) with G, the latter being the first example. Structural modeling suggests that the DNA polymerase can accept the reversed wobble pair with G, as well as the Watson-Crick pair with A.

Differential expression of VAMP2/synaptobrevin-2 after antidepressant and electroconvulsive treatment in rat frontal cortex

The biological basis for the therapeutic mechanisms of depression is still unknown. We have previously performed expressed-sequence tag (EST) analysis to identify some molecular machinery responsible for antidepressant effect. Then, we developed our original cDNA microarray, on which cDNA fragments identified as antidepressant-related genes/ESTs were spotted. In this study, with this microarray followed by Western blot analysis, we have demonstrated the induction of vesicle-associated membrane protein 2(VAMP2/synaptobrevin-2) in rat frontal cortex not only after chronic antidepressant treatment, but also after repeated electroconvulsive treatment. On the other hand, expression of SNAP-25 and syntaxin-1 was not changed by these treatments. These components make a soluble N-ethylmaleimide-sensitive fusion protein attachment protein receptor complex with VAMP2 and mediate the synaptic vesicle docking/fusion machinery. In conclusion, it is suggested that VAMP2/synaptobrevin-2 plays important roles in the antidepressant effects. Our results may contribute to a novel model for the therapeutic mechanism of depression and new molecular targets for the development of therapeutic agents.

Bile duct stenosis due to portal cavernomas: MR portography and MR cholangiopancreatography demonstration

We report two cases of bile duct stenosis due to portal cavernomas. Smooth stenoses were seen arising from both walls of the common bile duct on magnetic resonance (MR) cholangiopancreatography. On contrast-enhanced MR portography, peribiliary tortuous vessels were evident, indicating portal cavernomas. MR imaging can evaluate the biliary tree and portal systems noninvasively and was useful for evaluating this condition.

Effect of tributyltin on the N-methyl-D-aspartate (NMDA) receptors in the mouse brain

The purpose of this study was to determine the effect of tributyltin chloride (TBTCI) on the NMDA receptor by in vitro and in vivo experiments. In the first in vitro experiment, the binding of [3H]MK-801 and of [3H]-CGP39653 were studied in membrane preparations from the cerebral cortex of intact mice to obtain control values. Saturation experiments for [3H]MK-801 and [3H]CGP39653 revealed single binding sites with Kd values of 10.27 and 37.8 nM, and receptor densities of 1.75 and 2.20 pmol/mg of protein, respectively. In the second in vitro experiment, displacement studies were carried out with TBTCI over a concentration range of 0.1 microM to 2 mM. TBTCI inhibited [3H]MK-801 binding but did not affect [3H]CGP39653 binding. In the in vivo experiments, the mice received 1-125 ppm TBTCI in the diet ad libitum for 30 days. Ligand binding to cortical membrane preparations from each mouse was measured by a one-concentration point (2 nM) binding assay. [3H]MK-801 binding was significantly lowered (P < 0.05) in the 5 and 125 ppm TBTCl-exposed animals compared with the controls. [3H]CGP39653 binding was also significantly lowered (P<0.05) in the 1 and 125 ppm TBTCI-exposed animals compared with the controls. These results suggest that the NMDA receptors in the mouse brain are sensitive to relatively low level exposure to TBTCl.

Crystallographic studies on damaged DNAs IV. N( 4)-methoxycytosine shows a second face for Watson-Crick base-pairing, leading to purine transition mutagenesis

To investigate the mutation mechanism of purine transitions in DNA damaged with methoxyamine, a DNA dodecamer with the sequence d(CGCAAATTmo(4)CGCG), where mo(4)C is 2'-deoxy-N(4)-methoxycytidine, has been synthesized and the crystal structure determined by X-ray analysis. The duplex structure is similar to that of the original undamaged B-form dodecamer, indicating that the methoxylation does not affect the overall DNA conformation. Electron density maps clearly show that the two mo(4)C residues form Watson-Crick-type base pairs with the adenine residues of the opposite strand and that the methoxy groups of mo(4)C adopt the anti conformation to N(3) around the C(4)-N(4) bond. For the pair formation through hydrogen bonds the mo(4)C residues are in the imino tautomeric state. Together with previous work, the present work establishes that the methoxylated cytosine residue can present two alternate faces for Watson-Crick base-pairing, thanks to the amino<-->imino tautomerism allowed by methoxylation. Based on this property, two gene transition routes are proposed.

Histologic analysis of the implanted cartilage in an exact-fit osteochondral transplantation model

PURPOSE

Osteochondral transplantation is one of the useful treatments for articular cartilage defect. However, the histologic change of the implanted cartilage has not been reported in detail. We investigated the histology of exact-fit osteochondral transplants used to repair articular cartilage defects in an animal model.

TYPE OF STUDY

This was a nonrandomized control study using an animal model.

METHODS

Sixteen skeletally mature female Japanese white rabbits were used in the study. The region of the femoral groove was selected as the site for the osteochondral defect. A full-thickness cylindrical defect (7 mm in diameter and 7 mm in depth) through the articular cartilage and into the subchondral bone was made using the Osteochondral Autograft Transfer System (Arthrex, Naples, FL). The entire osteochondral fragment was removed and then returned to its original site in the femoral condyle precisely. Thus, the defect was repaired with an autogenous osteochondral transplantation of exactly the same size and configuration as the defect. Specimens were obtained 2, 4, 12, and 24 weeks postoperatively and were analyzed both macroscopically and histologically.

RESULTS

Macroscopically, there was smooth continuity of the articular surface and the integration of the graft to the normal host cartilage. However, histologic examination showed that the layer of the grafted cartilage was thicker than that of the normal host cartilage and the extracellular matrix of the implanted cartilage exhibited a stronger staining pattern with safranin-O fast green than the normal cartilage. Cell density was higher in the grafted cartilage, particularly in the middle and the deep zones. Round and polygonal hypertrophic clusters of chondrocytes were observed in the middle and deep zones of the grafted cartilage.

CONCLUSIONS

The histologic properties of the exact-fit implanted cartilage were different from that of normal articular cartilage. Further investigation of mechanical and structural properties of grafted cartilage is necessary to verify the long-term effects of osteochondral transplantation.

Kinematic magnetic resonance imaging (MRI) of the normal shoulder: assessment of the shapes and signals of the superior and inferior labra with abductive movement using an open-type imager

A preliminary study was conducted to evaluate the superior and inferior glenoid labra with abductive movement using an open-type MR unit in asymptomatic healthy volunteers. Both fast low angle shot (FLASH) and turbo spin echo (TSE) images were obtained to evaluate the shapes of both the superior and inferior labra, as well as to assess changes in signal at these sites. As the abduction angle was increased, the shape of the superior labrum changed from round or triangular to crescentic and a higher signal was frequently seen. At an abduction angle of 150 degrees, an increase in signal was seen in one-half of the superior labra; this increase was noted more frequently in volunteers over 40 years of age. In some of the superior labra, the increase in signal seen at 150 degrees abduction disappeared on subsequent images obtained at 0 degrees abduction. Hence, the increase in signal was considered to be a reversible change. The shape of the inferior labrum tended to change from crescentic to triangular or round. An increase in signal in the inferior labrum was unrelated to the abduction angle. Abductive kinematic studies using an open-type MR unit provides information about the morphology of the superior and inferior labra, as well as information about signal changes occurring at these sites.

Crystallographic studies on damaged DNAs: III. N(4)-methoxycytosine can form both Watson-Crick type and wobbled base pairs in a B-form duplex

To investigate the mutation mechanism of purine transition in DNA damaged with methoxyamine, a DNA dodecamer with the sequence d(CGCGAATTmo(4)CGCG), where mo(4)C is 2'-deoxy-N(4)-methoxycytidine, has been synthesized and its crystal structure determined. Two dodecamers form a B-form duplex. Electron density maps clearly show that one of the two mo(4)C residues forms a pair with a guanine residue of the opposite strand, the geometry being the canonical Watson-Crick type, and that the other mo(4)C residue forms a wobble pair with the opposite guanine residue. These two pairings are ascribed to the tautomerization of the methoxylated cytosine moieties between the amino and imino forms.

Effects of light and sleep stages on heart rate variability in humans

Effects of light intensity and sleep stages on heart rate variability (HRV) were investigated in young healthy subjects. The low-frequency (LF)/high-frequency (HF) ratio was significantly increased by exposing either to bright lights of 10 000 lx or to extreme darkness (< 0.01 lx), while HF and LF components of HRV were not changed, when compared with those under dim light (100 lx). However, LF was significantly increased at REM sleep, when compared with that at the pre-sleep wake. In contrast, HF was increased at all stages of sleep, and the LF/HF ratio was decreased at slow wave sleep during the baseline night.

A method for the measurement of catechol-O-methyltransferase activity using norepinephrine, an endogenous substrate

We propose a highly sensitive method for the measurement of catechol-O-methyltransferase (COMT) activity with norepinephrine (NE), an endogenous native substrate. The product, normetanephrine, was determined by high-performance liquid chromatography (HPLC)-peroxyoxalate chemiluminescence reaction detection or, if required, less sensitive fluorescence detection. For the measurement of membrane-bound (MB)-COMT activity in the rat erythrocyte, the HPLC-peroxyoxalate chemiluminescence reaction detection was employed. Soluble (S)- and MB-COMT activities in the rat erythrocyte were 22.9 +/- 2.5 and 4.62 +/- 1.23 pmol min-1 (mg protein)-1, respectively (n = 5). The Km values obtained for S- and MB-COMT were 366 +/- 31 mumol l-1 and 12.0 +/- 1.1 mumol l-1, respectively (n = 5), suggesting that the use of NE as a substrate would give more precise information on the role of both isoenzymes. However, with dihydroxybenzoic acid as an artificial substrate, the Km values for S- and MB-COMT were similar, with values of 69.2 +/- 11.4 mumol l-1 and 72.2 +/- 9.2 mumol l-1, respectively. The proposed method is thought to be useful for the measurement of both S-COMT and MB-COMT activities, and would give us critical information on the role of metabolism of catecholamines in rat tissues.

Low-intensity pulsed ultrasound initiates bone healing in rat nonunion fracture model

Low-intensity pulsed ultrasound exposure has been shown clinically to shorten the fracture repair process and to induce healing of nonunions in humans, but its mechanism of action remains unclear. In this study we investigated the effect and mechanism of low-intensity pulsed ultrasound on nonunion fracture healing in rat tibias. A consistently reproducible nonunion was produced in rat tibias by muscle interposition without osteotomy. This model was produced by creating a closed tibial fracture with only the distal end of the tibialis anterior muscle interposed into the fracture site. One limb was noninvasively exposed to low-intensity pulsed ultrasound (a 200-millisecond burst of sine waves of 1.5 MHz, repeating at 1.0 kHz) for 20 minutes daily. The incident intensity was approximately 30 mW/cm2. Rats were killed at intervals between 2 and 6 weeks. The events were assessed by radiographs, microfocus X-ray computed tomograms, and histologic examination. After 6 weeks of exposure, 7 of 14 nonunion fractures showed healing on radiologic assessment. The results of three-dimensional microfocus X-ray computed tomographic reconstruction and histologic examination also supported this finding. On the other hand, all control tibias remained in a state of nonunion during the same period. These results indicate that low-intensity pulsed ultrasound promotes healing in the rat nonunion fracture model.

[Grading of light perception and hand movement utilizing a novel device called the low vision evaluator]

PURPOSE

There has been no device for grading very low visual function expressed as light perception or hand movement up to the present. It is necessary to evaluate even slight effects of modern and classical therapies during the follow-up period. The goal of this study was to invent a novel device for grading such low visual function.

METHODS

Sixty-two patients with a visual acuity of counting fingers or worse due to various diseases were examined. The device, which we call the Low Vision Evaluator, has a pair of goggles equipped with two white light-emitting diodes. Nine variations of stimulus for light intensity (1, 10, 100 cd/m2 or 10, 100, 1,000 cd/m2) and duration (0.1, 0.3, 1 second) can be delivered in a random sequence. Patients were asked to push a button whenever they saw a stimulus. Response of patients to the stimuli was recorded.

RESULTS AND CONCLUSIONS

The visual function of light perception and hand movement could be reproducibly assessed by this method. The method represents a valuable new tool for evaluating low visual function.

Sclerosing stromal tumor of the ovary: US, MR, and dynamic MR findings

The US, MR, and dynamic MR findings in four patients with sclerosing stromal tumor of the ovary are reported. US showed a tumor with multilocular cystic components and irregularly thickened septa and tumor walls or a solid tumor including several small cystic components. On T2-weighted MR images, signal intensities of the cystic components were high and those of the solid components were inhomogeneous, ranging from intermediate-high to high. Dynamic MRI demonstrated marked early enhancement of the solid components.

Crystallization and preliminary X-ray analysis of a DNA dodecamer containing 2'-deoxy-5-formyluridine; what is the role of magnesium cation in crystallization of Dickerson-type DNA dodecamers?

To investigate the role of divalent cations in crystal packing, four different crystals of a Dickerson-type dodecamer with the sequence d(CGCGAATXCGCG), containing 2'-deoxy-5-formyluridine at X, were obtained under several conditions with and without divalent cations. The crystal structures are all isomorphous. The octahedrally hydrated magnesium cations found in the major groove cement the two neighbouring duplexes along the b axis. In the Mg(2+)-free crystals, a five-membered ring of water molecules occupies the same position as the magnesium site and connects the two duplexes similarly to the hydrated Mg(2+) ion. It has been concluded that water molecules can take the place of the hydrated magnesium cation in crystallization, but the magnesium cation is more effective and gives X-ray diffraction at slightly higher resolution. In all four crystals, the 5-formyluracil residues form the canonical Watson-Crick pair with adenine residues.