Critical difference in chiral recognition of N-Cbz-D/L-aspartic and -glutamic acids by mono- and bis(trimethylammonio)-beta-cyclodextrins.
Explore the source record for details and available documents.
Journal Article↗
Biomedical subjects
M Kawai
Publications and source records attributed to M Kawai.
Measurement of B(0)(d)-B_(0)(d) mixing rate from the time evolution of dilepton events at the upsilon(4S).
We report a determination of the B(0)(d)-&B_(0)(d) mixing parameter Deltam(d) based on the time evolution of dilepton yields in Upsilon(4S) decays. The measurement is based on a 5.9 fb(-1) data sample collected by the Belle detector at KEKB. The proper-time difference distributions for same-sign and opposite-sign dilepton events are simultaneously fitted to an expression containing Deltam(d) as a free parameter. Using both muons and electrons, we obtain Deltam(d) = 0.463+/-0.008 (stat)+/-0.016 (syst) ps(-1). This is the first determination of Deltam(d) from time evolution measurements at the Upsilon(4S). We also place limits on possible CPT violations.
Journal Article↗
Effect of temperature on elementary steps of the cross-bridge cycle in rabbit soleus slow-twitch muscle fibres.
1. Isometric tension, stiffness and the cross-bridge kinetics in rabbit soleus slow-twitch fibres (STFs) were studied in the temperature range 5-37 degrees C by sinusoidal analysis. 2. The effects of MgATP and phosphate (Pi) on the cross-bridge kinetics were studied, and the temperature dependence of the kinetic constants of elementary steps of the cross-bridge cycle was deduced in the range 20-37 degrees C. 3. The MgATP association constant (K1a) decreased when temperature was increased. The rate constants of the ATP-isomerization step (k1b and k-1b) and the cross-bridge detachment step (k2, and k(-2)) had Q10 values of 3-4, and hence their equilibrium constants (K1b and K2) changed little with temperature. 4. Q10 of the force generation step (k4) was the largest at 6.7; its reversal step (k(-4)) had a Q10 of 2.5, and hence its equilibrium constant (K4) increased significantly with temperature. The Pi association constant (K5) changed little with temperature. 5. The elementary steps of the cross-bridge cycle are more temperature sensitive in soleus STFs than in psoas, which are fast-twitch fibres. This is in accord with a higher temperature sensitivity of the apparent rate constants in STFs.T 6. The temperature dependence of the equilibrium constant of the force generation step (K4) was fitted to the modified Van't Hoff equation to deduce standard enthalpy change (DeltaH degrees; 70 +/- 20 kJ mol(-1)), standard entropy change (DeltaS degrees; 250 +/- 70 J mol(-1) K(-1)), and heat capacity change (DeltaCp; -12 +/- 5 kJ mol(-1) K(-1)). These results indicate that the force generation step is an entropy driven, endothermic reaction that accompanies a burial of large surface area. These observations are consistent with the hypothesis that hydrophobic interaction between residues of actin and myosin and between residues of the myosin head underlies the mechanism of force generation. 7. An increase of isometric tension with temperature is accounted for by the increased number of cross-bridges in tension generating states. Stiffness also increased with temperature, but to a lesser degree.
Adenosine Triphosphate↗
Capillary zone electrophoretic chiral discrimination using a cationic cyclodextrin derivative: determination of velocity and association constants of each enantiomer of the amino acid derivative with 6-trimethylammonio-deoxy-beta-cyclodextrin.
A positively charged beta-cyclodextrin possessing a trimethylammonio group, 6-trimethylammonio-6-deoxy-beta-cyclodextrin chloride 1 was prepared by the reaction of an amino derivative 3 with methyl iodide under very mild conditions. The cyclodextrin derivative discriminated between enantiomers of acetylphenylalanine 2 on capillary zone electrophoresis (CZE) analysis, which was possibly due to an electrostatic interaction between the trimethylammonio group of 1 and the carboxylate group of 2, and also due to the inclusion of 2 in a hydrophobic molecular cavity of 1. Double data normalization based on relative electrophoretic velocity of peaks due to indirect response of 1 and also water in an injected sample may be effective for elimination of variation and fluctuation of physical parameters of medium, such as viscosity and ionic strength, in order to determine intrinsic association constants and velocity of the complexes.
Amino Acids↗
A new form of muscular dystrophy with mitochondrial structural abnormalities.
Explore the source record for details and available documents.
Adolescent↗
Occult lymph node metastases detected by cytokeratin immunohistochemistry predict recurrence in node-negative endometrial cancer.
OBJECTIVE: Even after curative resection of early endometrial cancer, some patients die as a result of recurrence. We believe that these patients likely had occult lymph node metastases at the time of diagnosis. In an attempt to identify the responsible occult metastases, the clinicopathological significance of cytokeratin expression in lymph nodes with unconfirmed metastasis was evaluated retrospectively in patients with endometrial carcinoma. METHODS: We examined 304 pelvic lymph nodes and 46 primary tumors excised from 46 patients with endometrial cancer, including 36 with Stage I disease and 10 with Stage IIIc disease. Formalin-fixed paraffin-embedded tissue sections were stained immunohistochemically using antibodies against cytokeratin, CA125, and macrophage-related antigen. Sections were also stained with hematoxylin and eosin. RESULTS: In 10 patients with Stage IIIc disease, cytokeratin expression was detected in cells other than the tumor cells in all 13 lymph nodes with metastasis and also in 20 (30.3%) of 66 lymph nodes without metastasis. Cytokeratin expression was observed in 37 (16.4%) of 225 lymph nodes with unconfirmed metastasis, which were obtained from 14 of 36 patients with Stage I disease. Five of fourteen patients with lymph nodes expressing cytokeratin had recurrent disease in the pelvic cavity, while all 22 patients with unconfirmed cytokeratin expression in their lymph nodes showed no recurrence. Cytokeratin and CA125 were detected simultaneously on macrophages in lymph nodes. Cytokeratin expression in lymph nodes was closely related to lymph-vascular space involvement of the primary tumor, but was not related to either histological grade or depth of myometrial invasion. Multivariate analysis identified cytokeratin expression as an independent risk factor for recurrence in Stage I endometrial cancer. CONCLUSIONS: The immunohistochemical expression of cytokeratin in lymph nodes with undetected metastases predicts occult metastasis to these nodes and is a risk factor for recurrence in early-stage endometrial cancer.
CA-125 Antigen↗
Fission yeast tor1 functions in response to various stresses including nitrogen starvation, high osmolarity, and high temperature.
A target of rapamycin (TOR) protein is a protein kinase that exerts cellular signal transduction to regulate cell growth in response to extracellular nutrient conditions. In the Schizosaccharomyces pombe genome database, there are two genes encoding TOR-related proteins, but their functions have not been analyzed. Here we report that one of the genes, referred to as tor1+, is required for sexual development induced by nitrogen starvation. Ste11 is a key transcription factor for the initiation of sexual development. The expression of ste11+ is normally regulated in tor1- cells; and overexpression of ste11+ hardly rescues the defect in fertility in tor1-. Upon nitrogen starvation, tor1+ cells promote two rounds of the cell cycle to become arrested at the G1 phase before initiation of sexual development. The tor1- cells do not promote such a cell cycle, suggesting that Tor1 is necessary for the response to nitrogen starvation. The tor1- cells show no growth or very slow growth under various stress conditions, including external high pH, high concentrations of salts or sorbitol, and high temperature. These results suggest that Tor1 is necessary for any response to a wide range of stresses. The vegetative growth of tor1- cells is inhibited by rapamycin, although tor1+ cells are resistant to the drug. The tor1- cells are hypersensitive to fluphenazine and cyclosporin A, which specifically inhibit calmodulin and calcineurin, respectively.
Amino Acid Sequence↗
Optimal doses of paclitaxel and carboplatin combination chemotherapy for ovarian cancer: a phase I modified continual reassessment method study.
BACKGROUND: A multicenter, phase I study of combination therapy with paclitaxel and carboplatin for epithelial ovarian cancer was conducted to determine the safety and recommended dosages for Japanese women. METHODS: Paclitaxel was administered intravenously over a 3-h period, followed by carboplatin administered intravenously over a 1.5-h period. A modified continual reassessment method (mCRM) was used in two treatment arms to establish the maximum tolerated dose (MTD) and recommended doses of the combination. In group A, the dose of paclitaxel (175 mg/m2) was constant and the dose of carboplatin was increased from 4 to 7 in terms of the target area under the plasma concentration-versus-time curve (AUC). In group B, the dose of carboplatin was constant (AUC 6) and paclitaxel was administered at two dose levels (160 and 175 mg/m2). In both groups, the carboplatin dose was limited to a maximum of 800 mg/body for each administration. RESULTS: Because the calculated probability of toxicity was greatest at a dose of paclitaxel 175 mg/m2 and carboplatin AUC 7, this dose was designated the MTD in group A. Based on this result, treatment in group B was initiated at doses of paclitaxel of 160 mg/m2 and carboplatin AUC 6. While the dose of paclitaxel was escalated to 175 mg/m2, the safety of the combination was confirmed. The most frequent adverse effect was neutropenia, which resolved promptly with the appropriate use of granulocyte-colony stimulating factor (G-CSF). No other severe hematologic or nonhematologic toxicities were observed. CONCLUSIONS: Our study demonstrated that the recommended dose for this combination regimen should be paclitaxel 175 mg/m2 plus carboplatin AUC 6 (maximum dose, 800 mg/body).
Adenocarcinoma, Clear Cell↗
The effect of gravity on surface temperature and net photosynthetic rate of plant leaves.
To clarify the effects of gravity on heat/gas exchange between plant leaves and the ambient air, the leaf temperatures and net photosynthetic rates of plant leaves were evaluated at 0.01, 1.0, 1.5 and 2.0 G of 20 seconds each during a parabolic airplane flight. Thermal images of leaves were captured using infrared thermography at an air temperature of 26 degrees C, a relative humidity of 15% and an irradiance of 260 W m-2. The net photosynthetic rates were determined by using a chamber method with an infrared gas analyzer at an air temperature of 20 degrees C, a relative humidity of 50% and a photosynthetic photon flux of 0.5 mmol m-2 s-1. The mean leaf temperature increased by 1 degree C and the net photosynthetic rate decreased by 13% with decreasing gravity levels from 1.0 to 0.01 G. The leaf temperature decreased by 0.5 degree C and the net photosynthetic rate increased by 7% with increasing gravity levels from 1.0 to 2.0 G. Heat/gas exchanges between leaves and the ambient air were more retarded at lower gravity levels. A restricted free air convection under microgravity conditions in space would limit plant growth by retarding heat and gas exchanges between leaves and the ambient air.
Gravitation↗
FK506 facilitates chemical kindling induced by pentylenetetrazole in rats.
To clarify the possible role played by calcineurin in kindling development, we examined the effects of pretreatment with FK506, a selective calcineurin inhibitor, on pentylenetetrazole (PTZ) kindling in rats. FK506 facilitated the speed of kindling induced by repeated administration of 30-mg/kg PTZ, while FK506 did not ameliorate acute seizure manifestations after a single injection of PTZ. Our results suggested that calcineurin might exert an inhibitory effect on PTZ kindling.
Animals↗
Differences of symptoms and standardized weight index between patients with early-onset and late-onset anorexia nervosa.
OBJECTIVE: There have so far been no studies that directly compared clinical features between patients with early- and late-onset anorexia nervosa (AN). METHOD: We identified 64 patients with DSM-III-R AN. We defined individuals as an early-onset group, who had an age of onset before 14 years (N = 31), and the remaining as a late-onset group (N = 33). The clinical symptoms, body weight and weight index, were compared between the two groups. Subjects were dichotomized into those with extremely low weight and those remaining. We compared the proportion of the patients with extremely low weight between the two groups. RESULTS: The rates of 'self-induced vomiting' and 'purging' were significantly lower in a group of patients with early-onset AN than in those with late-onset AN. There were significantly fewer subjects with extremely low weight in early-onset than in late-onset AN group. CONCLUSION: We found clear differences in clinical features between early- and late-onset AN groups.
Adolescent↗
Degenerative alterations of dermal collagen fiber bundles in photodamaged human skin and UV-irradiated hairless mouse skin: possible effect on decreasing skin mechanical properties and appearance of wrinkles.
Dermal collagen fiber bundles (DCFB) are the major constructional element in the dermis. Although degenerative alterations of DCFB have been reported in chronologically aged skin, changes in photodamaged skin have not been fully investigated. We report ultrastructural alterations of DCFB, and their relation to skin elasticity using photodamaged human skin and UV-irradiated hairless mouse skin. The degree to which DCFB were intact and closely packed was evaluated and scored blindly. Exposed skin (outer forearm) exhibited marked ultrastructural degeneration. In UV-irradiated hairless mouse skin, the intact ultrastructural appearance of DCFB was gradually lost with increasing UV dosage; however, marked alterations in DCFB ultrastructure were absent in either human inner upper arm (unexposed) skin or nonirradiated age-matched control mouse skin. Skin mechanical properties were measured using a Cutometer SEM 474 suction extensometer, recording Ue* immediate deformation, Uv* viscous deformation, Uf* final deformation, and Ur* immediate contraction, all normalized for skin thickness. Uf*, Ue*, Uv*, and Ur/Uf were significantly decreased in exposed compared with unexposed skin. Significant positive correlations between degenerative alterations of DCFB and the decrease in Uf*, Ue*, and Uv* were seen. Changes of "% area of wrinkles" in UV-irradiated mouse skin was significantly correlated with degenerative changes of DCFB. Based on these results, we confirm observations made by others that chronic photodamage may have more severe effects on degeneration of DCFB than that of chronologic aging alone. Furthermore, degeneration of DCFB as detected ultrastructurally may, by its effect on skin elasticity, result in an increase in the appearance of wrinkles.
Adult↗
The effects of dentate granule cell destruction on behavioural activity and Fos protein expression induced by systemic methamphetamine in rats.
1. We destroyed dentate granule cells unilaterally or bilaterally by means of intrahippocampal injection of colchicine in rats. Subsequently, we observed behavioural changes following the intraperitoneal injection of 2 mg kg(-1) methamphetamine or saline, in addition to quantitatively assessing Fos protein expression in several brain regions, including the medial prefrontal cortex, cingulate cortex, piriform cortex, dorsal striatum, and nucleus accumbens. 2. Bilaterally lesioned animals, when administered saline, showed a marked increase in locomotor activity compared with those of non-lesioned animals. With respect to the methamphetamine response, bilateral destruction resulted in a marked enhancement of locomotor activity, while the unilateral destruction led to a marked increase in rotation predominantly contralateral to the lesioned side, with no identifiable change in locomotor activity. 3. Bilaterally lesioned animals, when administered saline and having undergone an immunohistological examination, showed a marked increase in Fos expression in both sides of the nucleus accumbens. Bilaterally lesioned animals administered methamphetamine showed a marked increase in Fos expression in the right and left sides of all regions tested. Unilaterally lesioned animals administered methamphetamine showed a significant and bilateral enhancement in Fos expression in the medial prefrontal and cingulate cortices, and a marked and unilateral (ipsilateral to the lesioned side) enhancement of Fos protein in the piriform cortex, dorsal striatum, and nucleus accumbens. 4. The present findings suggest that dentate granule cells regulate methamphetamine-associated behavioural changes through the function of widespread areas of the brain, mostly the nucleus accumbens.
Animals↗
State-selective optical near-field resonant ionization spectroscopy of atoms near a dielectric surface.
Spin-sensitive optical near-field microscopy and spectroscopy are proposed based on the study on the conserved quantities in optical near-field interactions of atoms with dielectric surfaces. A two-step photoionization spectra of Cs atoms resolving hyperfine structures are demonstrated near a planar dielectric surface by using evanescent waves. These techniques of state/spin-selective excitation and highly sensitive detection, combined with the techniques of optical pumping, will open up possibilities of space- and polarization-sensitive detection of optical near-fields using atomic probes. This novel method provides us with a useful technique for the observation of polarization nature of the optical near-field and controlling the spin states of mesoscopic electronic systems.
Journal Article↗
Prognostic factors of patients with yolk sac tumors of the ovary.
OBJECTIVE: Our purpose was to evaluate the prognostic factors in yolk sac tumors of the ovary. STUDY DESIGN: We performed a retrospective review of 47 patients with yolk sac tumors of the ovary from 1979 to 1997. RESULTS: Twenty-two patients had pure yolk sac tumors and 25 had germ cell tumors with yolk sac tissue as a component of the disease. The 5-year survival rate in stages I, II, III, and IV was 95%, 75%, 30%, and 25%, respectively. Patients with stage I disease had a more favorable prognosis than those with stage III and IV disease (P <.001). All patients who did not respond to chemotherapy died of this disease within 36 months of the first treatment. Chemotherapy regimens that included cisplatin gave better results than those without cisplatin (P <.05). The difference in prognosis was significant in cases in which the size of residual tumor was <2 cm in diameter (P <.01) and in cases in which ascites was either absent or <100 mL in volume (P <.05). Coexistence of other components of ovarian germ cell tumors in histologic specimens, preoperative serum alpha-fetoprotein level, fertility-sparing surgery, dissection of intrapelvic nodes, and p53 status had no significant correlation with the prognosis in this study. CONCLUSIONS: Staging and tumor-reductive surgery strongly affected the prognosis of this disease. Tumor-reductive surgery is advisable when ascites is minimal. Cisplatin-based chemotherapy after surgery was superior to chemotherapy without cisplatin; however, p53 status seemed to have no impact on chemosensitivity in yolk sac tumors of the ovary.
Antineoplastic Combined Chemotherapy Protocols↗
The structure of physalin T from Physalis alkekengi var. franchetti.
A new steroidal constituent named physalin T (3) was isolated from the aqueous extract of Physalis alkekengi var. francheti. Based on 1H and 13C NMR spectral studies the structure was assigned as 2,3-dihydrophysalin D, i.e., 5alpha,6beta-dihydroxy-2,3,5,6-tetrahydrophysalin B, which is the first example of a natural physalin possessing a saturated ring A moiety. The structure was confirmed by the chemical transformation from the known physalin D (2) to physalin T.
Antineoplastic Agents, Phytogenic↗
Isolation of an intron-containing partial sequence of the gene encoding dermatophyte actin (ACT) and detection of a fragment of the transcript by reverse transcription-nested PCR as a means of assessing the viability of dermatophytes in skin scales.
An internal partial sequence of the gene encoding actin (ACT), 725 to 762 bp in length, was amplified by PCR from the genomic DNA extract of 12 species of dermatophytes and sequenced. An intron that is 56 to 93 bp in length was located along the ACT fragment of all of the dermatophytes at codon position 301 (-3) (a codon number followed by "-3" indicates that the intron directly follows the codon) with reference to the amino acid sequence of human alpha-smooth muscle actin. A primer pair that annealed to exon sequences flanking the ACT-associated intron produced a dermatophyte-specific 171-bp amplicon by reverse transcription-nested PCR (RT-PCR) of dermatophyte ACT mRNA. PCR primer pairs with antisense sequence based on the ACT intron sequence were species specific for dermatophytes, suggesting a potential for use in the identification of dermatophytes. The viability of dermatophytes in skin scales was subsequently assessed by the presence of ACT mRNA in total RNA extracted from a 48-h culture of scale samples in 250 microl of yeast carbon base broth. RT-nested PCR of dermatophyte-infected samples amplified an ACT fragment of the predicted size of 171 bp. The results of viability testing based on ACT mRNA detection by RT-nested PCR correlated with cultural isolation from skin scales. This method is a potential tool for rapidly assessing fungal viability in the therapeutic efficacy testing of antimycotics.
Actins↗
Analysis of the SRY gene in Turner syndrome patients with Y chromosomal material.
Explore the source record for details and available documents.
DNA↗