Synthesis and antidiuretic activities of novel glycoconjugates of arginine-vasopressin

Arginine-vasopressin (AVP) was acylated with various acyl azides (2a-j) in pH 9.1 buffer to give AVP derivatives (11a-j) modified at the tyrosine side chain with a carbohydrate via a spacer arm. Glycoconjugates of AVP modified at the N-terminal amide (12a-e) were also synthesized from AVP and carboxylic acids (3a-e) using dicyclohexylcarbodiimide and 1-hydroxybenzotriazole as coupling agent. Analogues (11a-j) exhibited greater in vivo antidiuretic activity than AVP. AVP and glycoconjugates (12a-e) were stable in rat plasma. On the other hand, glycoconjugates (11a-i) were found to readily convert to AVP according to first order kinetics. Hence, 11a-j are considered to be prodrugs of AVP.     

Evaluation of 9-cis retinoic acid for a new remedy of human retinoblastoma

We investigated the effect of two isomers of retinoic acid (RA), all-trans RA and 9-cis RA, on the proliferation of Y79 human retinoblastoma cells. The two isomers inhibited the cell proliferation in a concentration-dependent manner. The IC50 for this inhibition by all-trans RA and 9-cis RA was 1.50 and 0.15 microM, respectively. The inhibitory effect of 9-cis RA on Y79 cell growth was observed within 24 hr, thereafter the cell number was gradually decreased. In contrast, no inhibition by all-trans RA of Y79 cell growth was observed within 24 hr, thereafter the cell number was slightly increased. In these cases, the cell viability at 4 days after the addition of 9-cis RA and all-trans RA was more than 90% and 95%, respectively. These results indicate that the two RA inhibit the proliferation of Y79 human retinoblastoma cells without inducing the cell death and that the effect of 9-cis RA on the inhibition of Y79 cell growth is much greater than that of all-trans RA.     

Probing the dynamics of nanoparticle growth in a flame using synchrotron radiation

Flame synthesis is one of the most versatile and promising technologies for large-scale production of nanoscale materials. Pyrolysis has recently been shown to be a useful route for the production of single-walled nanotubes, quantum dots and a wide variety of nanostructured ceramic oxides for catalysis and electrochemical applications. An understanding of the mechanisms of nanostructural growth in flames has been hampered by a lack of direct observations of particle growth, owing to high temperatures (2,000 K), rapid kinetics (submillisecond scale), dilute growth conditions (10(-6) volume fraction) and optical emission of synthetic flames. Here we report the first successful in situ study of nanoparticle growth in a flame using synchrotron X-ray scattering. The results indicate that simple growth models, first derived for colloidal synthesis, can be used to facilitate our understanding of flame synthesis. Further, the results indicate the feasibility of studies of nanometre-scale aerosols of toxicological and environmental concern.     

Mutation analysis for prenatal diagnosis of hereditary tyrosinaemia type 1

Presentation of 11 cases of retroperitoneal sarcoma. Mean time from the beginning of symptoms to diagnosis is 6 months. The primary complementary study is CT. Surgery was performed in all cases, using complete resection in 6 cases, and partial resection in 5. Ten patients relapsed. 9 of which were treated with surgical rescue, in one or more occasions; chemotherapy was added in 6 cases and radiotherapy in 7. Survival at five years is 68%, with a mean follow-up of 66 months.