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Biomedical subjects

T Tokunaga

Publications and source records attributed to T Tokunaga.

At least 19 recordsLinked to original sources
PubMed2006

Influence of tilt and decentration of scleral-sutured intraocular lens on ocular higher-order wavefront aberration.

AIM: To investigate the influence of tilt and decentration of scleral-sutured intraocular lenses (IOLs) on ocular higher-order wavefront aberrations. METHODS: In 45 eyes of 36 patients who had undergone scleral suture fixation of posterior chamber IOL, tilt and decentration of IOLs were determined by Scheimpflug videophotography, and higher-order aberration for a 4-mm pupil was measured using the Hartmann-Shack aberrometer. In another 100 eyes of 100 patients after standard cataract surgery with posterior chamber IOL implantation, ocular higher-order aberration was measured. RESULTS: In eyes with scleral-sutured IOL, the mean (SD) tilt angle and decentration were 4.43 degrees (3.02 degrees ) and 0.279 (0.162) mm, respectively. Ocular coma-like aberration in the sutured IOL group was 0.324 (0.170) microm, which was significantly greater than that of the standard cataract surgery group (0.169 (0.061) microm, p<0.001, Student's t test). No significant difference was found in ocular spherical-like aberration between the sutured IOL group (0.142 (0.065) microm) and standard surgery group (0.126 (0.033) microm; p = 0.254). In the sutured IOL group, IOL tilt significantly correlated with ocular coma-like aberration (Pearson's correlation coefficient r = 0.628, p<0.001), but no significant correlation was found between IOL tilt and ocular spherical-like aberration (r = 0.222, p = 0.175). The IOL tilt did not correlate with corneal coma-like (r = 0.289, p = 0.171) and spherical-like (r = 0.150, p = 0.356) aberrations. The IOL decentration did not correlate with any higher-order aberrations. CONCLUSION: In eyes with scleral-sutured posterior chamber IOL, tilting of the lens induces considerable amount of ocular coma-like aberrations.

Aged↗
PubMed2006

Spread of malignant cells in the surgical margin with stapled excision of lung cancer: comparison of aggressive clump and less traumatic jaw closure type staplers.

BACKGROUND: During stapled excision of lung cancer tissue, malignant cells can spread in the surgical margin. Stapling methods can be classified as aggressive clumping (AC) and less traumatic jaw closing (LTJC) types, thus the ratio of malignant margins may differ between stapler types. METHODS: The malignant status of the stapled margin was retrospectively investigated in 112 cases using a cytology technique. Stapler type, maximum tumor diameter, distance from surgical margin, thoracotomy type, and tumor location were used as variables. In addition, clinical results of excision cases were assessed. RESULTS: The ratio of malignant margins was 22/54 (41 %) in the AC group and 11/58 (19 %) in the LTJC group ( P = 0.01). Multivariate analysis revealed that the stapling method and tumor location were an independently significant factor. Surgical margin recurrence occurred only in 4 (57 %) of 7 cases with malignant margin. CONCLUSIONS: The AC type method showed a greater potential to spread malignant cells, thus there seems to be a higher possibility of regional relapse with that technique.

Aged↗
PubMed2005

Usefulness of peripheral anterior chamber depth assessment in glaucoma screening.

PURPOSE: This study was conducted to determine the usefulness of peripheral anterior chamber depth assessment in angle-closure glaucoma (ACG) screening in Japanese subjects. SUBJECTS AND METHODS: The subjects were 14,779 adults 40 years old or older. Eyes having peripheral anterior chamber depth that is 1/4 the peripheral corneal thickness (van Herick's classification: grade 2) and less than 1/4 the peripheral corneal thickness (van Herick's classification: grade 1) were extracted as narrow angle eyes, and those eyes were further examined. RESULTS: Of 14,779 subjects, 923 eyes of 505 subjects were diagnosed as narrow angle eyes (3.4%). Narrow angle eyes were observed in 4.9% of female subjects and 1.9% of male subjects, indicating a significantly higher frequency in women. The percentage of narrow angle eyes increased with age. Among the narrow angle eyes, 61 eyes of 32 subjects were diagnosed with ACG suspect (6.5%). In contrast to the frequency of ACG suspect in eyes classified as grade 1, according to van Herick's classification, being 17.9%, that in eyes classified as grade 2 was significantly lower at 5.6%. CONCLUSION: Since the incidence of ACG suspect increases as the peripheral anterior chamber depth decreases, caution for the peripheral anterior chamber depth is required for the ACG screening.

Adult↗
PubMed2004

Production of L-lactic acid from a mixture of xylose and glucose by co-cultivation of lactic acid bacteria.

The production of optically pure lactic acid in a high yield from xylose or a mixture of xylose and glucose, which is a model hydrolysate of lignocellulose, is described. In a single cultivation, Enterococcus casseliflavus produced 38 g/l of lactic acid with an optical purity of 96% enantiomeric excess (ee) and 6.4 g/l of acetic acid from 50 g/l of xylose when MRS medium was used. When a mixture of 50 g/l of xylose and 100 g/l of glucose was used as the carbon source in a cultivation of E. casseliflavus alone, glucose was converted to lactic acid in the early phase of the cultivation but xylose was hardly consumed. In a co-cultivation where E. casseliflavus and Lactobacillus casei specific for glucose were simultaneously inoculated, little or no lactic acid was produced after the glucose was almost consumed. A co-cultivation with two-stage inoculation (in which E. casseliflavus was added at a cultivation time of 40 h after L. casei cells were inoculated) resulted in complete consumption of 50 g/l of xylose and 100 g/l of glucose. In the co-cultivation, 95 g/l of lactic acid with a high optical purity of 96% ee was obtained at 192 h. Such a co-cultivation using two microorganisms specific for each sugar is considered to be one promising cultivation technique for the efficient production of lactic acid from a sugar mixture derived from lignocellulose.

Coculture Techniques↗
PubMed2004

Comparison of corneal thickness measurements using Orbscan II, non-contact specular microscopy, and ultrasonic pachymetry in eyes after laser in situ keratomileusis.

AIMS: To compare central corneal thickness measurements of three pachymetry devices in eyes after laser in situ keratomileusis (LASIK). METHODS: Central corneal thickness was measured in 203 eyes after myopic LASIK. Orbscan II scanning slit topography (Bausch & Lomb), SP-2000P non-contact specular microscopy (Topcon), and ultrasonic pachymetry (Tomey) were used in this sequence. RESULTS: Three devices gave significantly different corneal thickness readings (p<0.0001, repeated measure analysis of variance). The measurements of Orbscan II (445.6 (SD 60.0) microm) were significantly smaller than those of noncontact specular microscopy (467.9 (SD 40.2) micro m; p<0.0001, Tukey multiple comparison) and ultrasonic pachymetry (478.8 (SD 41.9) microm; p<0.0001). The value obtained with SP-2000P non-contact specular microscopy was significantly smaller than that taken with ultrasonic pachymetry (p<0.001). There were significant linear correlations between scanning slit topography and non-contact specular microscopy (Pearson's correlation coefficient r = 0.912, p<0.0001), non-contact specular microscopy and ultrasonic pachymetry (r = 0.968, p<0.0001), and ultrasonic pachymetry and scanning slit topography (r = 0.933, p<0.0001). CONCLUSION: In post-LASIK eyes, Orbscan II scanning slit topography significantly underestimated corneal thickness. Non-contact specular microscopy gave smaller thickness readings than ultrasonic pachymetry, but these two units showed an excellent linear correlation.

Adult↗
PubMed2004

A prospective, randomised comparison of single and three piece acrylic foldable intraocular lenses.

AIMS: To compare the postoperative performance of single and three piece acrylic foldable intraocular lenses (IOLs). METHODS: 20 patients underwent bilateral cataract surgery with a single piece SA30AL IOL in one eye and a three piece MA30BA IOL in the other eye. The eyes were randomly assigned to either a single or three piece lens. The amount of IOL decentration and tilt, area of anterior capsule opening, and degree of posterior capsule opacification were measured using the Scheimpflug anterior segment analysis system (Nidek EAS-1000). Visual acuity and contrast sensitivity were examined. Measurements were performed by masked examiners before and 1 day, 1 week, 1, 3, 6, and 18 months after surgery. RESULTS: There were no significant differences between the two groups (p>0.05, paired t test) in the amount of IOL decentration, IOL tilt, area of anterior capsule opening, degree of posterior capsule opacification, best corrected visual acuity, and contrast sensitivity throughout the 18 month follow up period. CONCLUSION: The single and three piece acrylic foldable IOLs are equally stable in the eye after surgery.

Acrylic Resins↗
PubMed2001

Oxindole derivatives as orally active potent growth hormone secretagogues.

A series of substituted oxindole derivatives was synthesized and evaluated for growth hormone (GH) releasing activity using cultured rat pituitary cells. (+)-6-Carbamoyl-3-(2-chlorophenyl)-(2-diethylaminoethyl)-4-trifluoromethyloxindole (SM-130686, 37S) was found to have potent activity (EC(50) = 3.0 nM), while the other enantiomer 37R had reduced activity. The absolute configuration of 37S was confirmed by X-ray crystallographic analysis. Compound 37S showed a good pharmacokinetic profile in rats with 28% oral bioavailability at 10 mg/kg and excellent in vivo activity as evidenced by a significant weight gain after 4 days of oral administration at 10 mg/kg twice a day. Compound 37S displaced the binding of (35)S-MK-677 to human GHS-R with an IC(50) value of 1.2 +/- 0.2 nM.

Administration, Oral↗
PubMed2001

Abnormal uterus with polycysts, accumulation of uterine prostaglandins, and reduced fertility in mice heterozygous for acyl-CoA synthetase 4 deficiency.

Arachidonate released by various stimuli is rapidly reesterified into membrane phospholipids initiated by acyl-CoA synthetase (ACS) and subsequent acyl-transfer reactions. ACS4 is an arachidonate-preferring enzyme abundant in steroidogenic tissues and postulated to modulate eicosanoid production. Female mice heterozygous for ACS4 deficiency become pregnant less frequently and produce small litters with extremely low transmission of the disrupted alleles. Striking morphological changes, including extremely enlarged uteri and lumina filled with numerous proliferative cysts of various sizes, were detected in ACS4+/- females. Furthermore, marked accumulation of prostaglandins was seen in the uterus of the heterozygous females. These results indicate that ACS4 modulates female fertility and uterine prostaglandin production.

6-Ketoprostaglandin F1 alpha↗
PubMed2001

Overproduction of perlecan core protein in cultured cells and transgenic mice.

Heparan sulphate proteoglycan (HSPG) and amyloid P component are the only macromolecules consistently associated with all varieties of amyloid, irrespective of the type of amyloid protein, suggesting that HSPG may play a pathogenetic role in amyloid formation through a common mechanism. In the case of Alzheimer's disease (AD), HSPG, such as perlecan, co-accumulates with amyloid-beta protein (Abeta), a main constituent of amyloid plaques, and paired helical filaments (PHFs). Additionally, in vitro, HSPG accelerates both Abeta fibril and PHF formation and protects Abeta from degradation. Therefore, this study first established lines of P19 mouse embryonic carcinoma cells stably carrying an expression vector encoding the complete perlecan core protein (approximately 400 kD). In the cell lysates, overexpressed perlecan was identified as an approximately 400 kD protein without glycosaminoglycan side-chains, while in the media, secreted perlecan was mostly glycosylated, suggesting that the secretion and glycosylation of perlecan are coupled. Next, transgenic mice were produced using the same expression vector. Marked perlecan overexpression occurred in the cytoplasm of multiple tissues including the brain, heart, kidney, and pancreas, without a discernible increase of perlecan in extracellular matrices. The transgenic mice up to 18 months of age did not develop amyloid or AD-like pathology in the brain or elsewhere, based on histochemical and immunohistochemical analyses. Thus, overproduction of perlecan core protein is insufficient to lead to amyloidosis and AD-like pathology.

Alzheimer Disease↗
PubMed2001

Serum levels of vascular endothelial growth factor and cavity formation in active pulmonary tuberculosis.

BACKGROUND: In active pulmonary tuberculosis, certain cytokines have been postulated to be related to cavity formation, although the detailed mechanism of cavity formation is not yet known. OBJECTIVE: We examined the relationship between cavity formation in pulmonary tuberculosis and vascular endothelial growth factor (VEGF), which functions as an angiogenesis factor. METHODS: Forty-eight patients with active pulmonary tuberculosis were divided into two groups according to cavity formation as evaluated by chest high-resolution computed tomography. We evaluated serum VEGF levels by enzyme immunoassay. RESULTS: Group A (with cavities) was comprised of 22 patients and group B (without cavities) was comprised of 26 patients. The serum levels of VEGF were significantly higher in group B (58.733 +/- 21.612 pg/ml) than those in normal individuals (8.739 +/- 3.656 pg/ml) and in group A (13.053 +/- 8.670 pg/ml) (Mann-Whitney U test, p = 0.0149 and p = 0.0481, respectively). Serum levels of interleukin-8 and tumor necrosis factor-alpha were not significantly different between the two groups. CONCLUSION: These findings suggested that increased serum VEGF levels subdue cavity formation in active pulmonary tuberculosis.

Adolescent↗
PubMed2001

Synthesis and structure-activity relationships in a series of ethenesulfonamide derivatives, a novel class of endothelin receptor antagonists.

In the previous paper, we described a series of the 2-arylethenesulfonamide derivatives, a novel class of ETA-selective endothelin (ET) receptor antagonists, including the compounds 1a, b. Compound 1a showed excellent oral antagonistic activities and pharmacokinetic profiles, and the monopotassium salt of 1 (YM-598 monopotassium) is in clinical trials. In this paper, we wish to report the investigation of the further details of structure-activity relationships (SARs) of the 2-phenylethenesulfonamide region in 1a. It was found that methyl substitutions at the 2-, 4- and 6-positions of the phenyl group in 1a led to the discovery of the ET(A)/ET(B) mixed antagonist (6s) with an IC50 of 2.2 nM for the ET(A) receptor. We also found that introduction of an ethyl group to the 1-position of the ethenyl group in 1a gave the ET(A) selective antagonist (6u) with an oral endothelin antagonistic activity in rats.

Animals↗
PubMed2001

Transient QT interval prolongation with inverted T waves indicates myocardial salvage on dual radionuclide single-photon emission computed tomography in acute anterior myocardial infarction.

In patients with acute myocardial infarction (AMI), transient QT interval prolongation with a prominent negative T wave is frequently observed in cases of early spontaneous reperfusion and often indicates a good prognosis. Additionally, in nuclear cardiac imaging, technetium-99m/thallium-201 overlap on dual single-photon emission computed tomography (dual SPECT) in AMI patients indicates the presence of viable myocardium and early recanalization. To elucidate the clinical significance of this transient QT interval prolongation, 34 patients (64 +/- 8 years) admitted within 24h of the onset of anterior AMI were enrolled and classified into 2 groups according to the presence (group A, n=24) or absence (group B, n=10) of scintigraphic overlap on simultaneous dual SPECT imaging. The maximal QTc interval was 0.59 +/- 0.06 s in group A and 0.52 +/- 0.06 s in group B (p<0.01). The peak creatine kinase was lower in group A (2650 +/- 2160 IU/L) than in group B (3490 +/- 2060 IU/L). The left ventricular ejection fraction (LVEF) at discharge was 62 +/- 11% in group A and 49 +/- 14% in group B (p<0.01). The scintigraphic overlap group had a smaller infarct and better LVEF, which suggests that the QT interval prolongation that appears transiently in the acute phase of AMI indicates scintigraphically the presence of salvaged myocardium.

Aged↗
PubMed2001

Efficient dechlorination of tetrachloroethylene in soil slurry by combined use of an anaerobic Desulfitobacterium sp. strain Y-51 and zero-valent iron.

A laboratory test was conducted to examine the combined effect of bioaugmentation of an anaerobic bacterial Desulfitobacterium sp. strain Y-51 and addition of zero-valent iron (Fe0) on the reductive dechlorination of tetrachloroethylene (PCE) in a non-sterile soil slurry. Introduction of a strain Y-51 culture in soil (3 mg vss (volatile suspended solids)/kg soil) containing PCE (at 60 micromol/kg soil) led to complete conversion of PCE to cis-1,2-dichloroethylene (cis-DCE) within 40 d. Treatments of the same soil slurry with Fe0 (0.1-1.0%) resulted in extended PCE dechlorination to ethylene (ETH) and ethane (ETA). The combined use of a strain Y-51 culture and Fe0 showed effective dechlorination of PCE than did the individual use. The cis-DCE produced from biological PCE dechlorination by strain Y-51 was totally converted to non-chlorinated end products by the following chemical reduction by Fe0. Furthermore, anaerobic corrosion of Fe0 was found to stimulate the biological reductive dechlorination of PCE by keeping proper levels of pH and oxidation-reduction potential (ORP) and by producing cathodic hydrogen, which might be used as an electron donor for respiratory PCE dechlorination. These findings suggest that the combined use of bacterial strain Y-51 and Fe0 is effective for practical treatment of PCE and other chlorinated ethylenes in contaminated sites.

Journal Article↗
PubMed2001

Isolation and characterization of Desulfitobacterium sp. strain Y51 capable of efficient dehalogenation of tetrachloroethene and polychloroethanes.

A strict anaerobic bacterium, strain Y51, was isolated from soil contaminated with tetrachloroethene (PCE). Strain Y51 is capable of very efficiently dehalogenating PCE via trichloroethene (TCE) to cis-1,2-dichloroethene (cis-1,2-DCE) at concentrations as high as 960 microM and as low as 0.6 microM. Strain Y51 was gram-negative, motile with some lateral flagella, and curved rod-shaped. On the basis of the 16S rDNA sequence, the organism was identified to be a species within the genus Desulfitobacterium. Strain Y51 also had dehalogenation activities toward polychloroethanes such as hexa-, penta-, and tetrachloroethanes, from which dichloroethenes were produced as the final products. The cell extracts mediated the dehalogenation of PCE with reduced methyl viologen as an electron carrier at the specific rate of 5.0 nmol min(-1) mg cell protein(-1) (pH 7.2, 37 degrees C). Dehalogenation was highly susceptible to air oxidation, and to potential alternative electron acceptors such as nitrite or sulfite.

Bacillaceae↗
PubMed2001

Effect of dietary short-chain fructooligosaccharides on the cecal microflora in gastrectomized rats.

Total gastric resection is known to lead to changes in the microflora in the whole gastrointestinal tract. Dietary short-chain fructooligosaccharides (Sc-FOS) have been shown to also induce a change in the microflora in the large bowel by promoting an increase in the numbers of Bifidobacterium and Lactobacillus which have beneficial effects on the host. In the present study, 4-week-old male Sprague-Dawley rats received total gastrectomy or laparotomy, and each of these surgically treated groups was randomly divided into two experimental diet groups and given a 7.5% Sc-FOS diet or control diet. Enumeration and identification of the cecal bacteria was performed by using selective and non-selective media. In the gastrectomized rats, the total bacterial count, and the counts of Bacteroidaceae and Enterobacteriaceae were higher than those in the sham-operated rats. Sc-FOS promoted an increase in the numbers of Bifidobacterium and Lactobacillus, In the rats fed on the Sc-FOS diet, the predominant type of bacteria was Lactobacillus and in the rats fed on the control diet, it was Bacteroidaceae irrespective of gastrectomy. We confirmed that both gastrectomy and dietary Sc-FOS changed the composition of cecal microflora in the rats. Dietary Sc-FOS in the gastrectomized rats increased the proportions of Lactobacillus relative to other types of bacteria to levels similar to those seen in healthy normal rats, and decreased the proportion of Bacteroidaceae.

Animals↗