Functional evaluation of tryptophanyl residues of bovine and porcine pancreatic deoxyribonucleases

Trp-155 in bovine DNase A (EC 3.1.4.5) appeared to be unessential for the enzymatic activity for the following reasons: (1) A unique peptide which suggests the environmental difference of Trp-155 was obtained from porcine pancreatic DNase A. (2) Inactivation of the porcine DNase A by NBS modification was fairly paralleled with a decrease in the CD signal, which is characteristic of the "buried" tryptophan in the hydrophobic region (trp-191 in bovine DNase) but not of tryptophans in the hydrophilic portion. Binding of DNase to the poly I: poly C double helix confirmed the important role of this tryptophan.

[Futraful and UFT, their metabolic characteristics]

Investigations were made in human on the metabolism of Futraful (FT) and UFT (combination of uracil and FT), both of which are anticancer agents of pyrimidine metabolism antagonist. As a result, it was demonstrated that from the metabolic view point, those drugs essentially have a tumor-selective toxicity. Next, the mechanism of the superior clinical anticancer effect of UFT, compared to FT, was investigated enzymatically, showing the inhibitory effect of uracil on the degradation of 5-fluorouracil generated from FT in the organs and tumor tissues. Discussions were also made for the further development of fluoropyrimidines.

Antiatherogenic action of eicosapentaenoic acid (EPA) in multiple oral doses

The possible antiatherogenic action of eicosapentaenoic acid (EPA) was pharmacologically investigated using purified and ethylesterified fish oil containing 75% EPA (EPA-E) in multiple oral doses in rats and rabbits. EPA-E showed dose-dependent prevention of thrombus formation in a vascular shunt or sudden death caused by arachidonic acid injection in rats. EPA-E in daily doses ranging from 3 to 30 mg/kg slightly altered platelet aggregability and prostacyclin-like activity generated from arterial ring preparations of rats, but these alterations were not statistically significant. Further, EPA-E showed no effect on blood viscosity of rats. In cholesterol-fed rabbits, EPA-E in daily doses of 10 and 30 mg/kg moderately lowered the levels of plasma cholesterol, beta-lipoprotein, triglyceride and phospholipid, but these changes showed neither dose-dependency nor time-dependency. In this experiment, EPA-E moderately altered atherogenic plaque formation and platelet aggregability, but these alterations were not statistically significant. EPA-E showed no effect on prostacyclin-like activity generated from arterial ring preparations and blood viscosity of cholesterol-fed rabbits. It is, therefore, proposed that the antithrombotic action of EPA-E may be partially related to its effects on platelet aggregability and prostacyclin generation, but the major mechanism remains unclear.

[UFT, UFTM, and UFTM-Dpc treatment of gastric cancer]

It became increasingly evident that UFTM chemotherapy, a combination of UFT and mitomycin C is one of the most recommendable therapy for advanced gastric cancer, especially for the treatment of Borrmann type 4 gastric cancer. Objective responses were achieved in 18 out of 26 (69.2%) patients with Borrmann type 4 gastric cancer. Moreover, UFTM-Dpc treatment, a combination therapy of UFTM plus D-penicillamine (suppressor of collagen synthesis), is proposed for the treatment of Borrmann type 4 gastric cancer from the point of view of collagen synthesis inhibition. It is likely that D-penicillamine might inhibit the peritoneal metastatic involvements, which is lethal to the patients finally.

Phase-dependent polymerization and depolymerization of actin in Physarum polycephalum nuclei

G- and F-actin contents in physarum polycephalum nuclei isolated during the progress of cell cycle were estimated and compared both by the inhibiting activity of deoxyribonuclease I (DNase I) and by the fractionation on DEAE-Toyopearl column chromatography. The inhibition of DNase appeared maximal in late S phase or early G2 phase and decreased to a minimal value in late G2 phase or M phase, while total actin content in a nucleus, which was analyzed by SDS-polyacrylamide gel electrophoresis as well as by DNase inhibition assay in the presence of 0.75 M guanidine-HCl, did not show such phase-dependent dynamics through the cell cycle.

Factors affecting the equatorial X-ray diffraction pattern from contracting frog skeletal muscle

Changes in the equatorial X-ray diffraction pattern from tetanized frog sartorius muscles (Rana catesbiana ) were studied by use of time-resolved data collection technique (time resolution, 0.5 sec) to give information about the dynamic properties of the cross-bridges. No significant changes in the intensity ratio of two equatorial reflections (I1,0/I1,1) were observed when isometrically contracting muscles were slowly stretched by 5-6%, in spite of marked force changes. The intensity ratio also showed no significant changes when the load on isometrically contracting muscles was suddenly increased from Po to 1.2-1.5 Po to produce isotonic muscle lengthening. Closer examination of the data indicated that a small decrease in the value of I1,1 was caused by both slow stretch and isotonic lengthening. Because of the scatter of experimental plots in I1,0, the effect of small change in I1,1 on the intensity ratio fell within the range of accuracy of measurement. It is suggested that no marked changes in myosin head orientation or in the number of the cross-bridges in the vicinity of the thin filaments take place in response to slow stretches or isotonic lengthening, and that the decreased regularity of the filament lattice may produce the change in I1,1.

Asymmetrically grooved monolithic crystal monochromators for suppression of harmonics in synchrotron X-radiation: erratum

A typographical error has occurred in Hashizume [J. Appl. Cryst. (1983). 16, 420–427]. The first two complete sentences on page 425 should read: A attains a minimum value of 0.024 at b II = 0.27, where about half of the initial fundamental intensity is preserved. The initial rise of the fundamental intensity, which occurs in the range 1.0 > b II ≥ 0.64, is accounted for by a close examination of the overlap pattern of R (1) HI and, R (1) 0II at the relevant b II values: the shifted and extended peak profile of R (1) 0II admits the high-angle tail of R (1) HI and rejects the low-angle flank of R (1) HI , and the gain due to the former more than compensates for the loss caused by the latter.

Phosphorylation of specific polypeptides in isolated murine splenocyte nuclei which is controlled by cyclic nucleotides

Murine splenocyte nuclei were phosphorylated with a less than 10(-5) M concentration of [gamma-32P]ATP at 0 degrees C and the phosphorylated nuclear proteins were analyzed by SDS-polyacrylamide gel slab electrophoresis and Sephadex gel filtration column chromatography. Two polypeptides of 10K and 11K daltons were predominantly phosphorylated. These polypeptides were likely linked by a disulfide bond to form a nonhistone protein of 21K daltons. Both phosphoserine and phosphothreonine were detected in the hydrolysate of the 10.5K dalton polypeptide, while phosphoserine was predominant in the 10K dalton polypeptide. Maximal activation of phosphorylation by cAMP of both polypeptides was shown at a concentration of 10(-6) M. On the contrary, cGMP activated phosphorylation of the 10K dalton polypeptide at 10(-8) M and at 10(-4) M. The phosphorylation of the 10.5K polypeptide was not activated by 10(-4) M cGMP and suppression of the phosphorylation was seen in both polypeptide chains by cAMP at higher concentrations.

Mitogenic effect of cytoplasmic membranes and a cytoplasmic fraction of Staphylococcus aureus L-forms on human peripheral blood lymphocytes

The cytoplasmic membranes and a cytoplasmic fraction of Staphylococcus aureus L-forms increased the incorporation of [3H]thymidine by human lymphocytes in the presence of fetal bovine serum. Both fractions stimulated cord blood lymphocytes as well as adult peripheral lymphocytes, suggesting the possibility that the observed effect was not due to an antigen-specific reaction, but to an immunologically nonspecific action. The membrane mitogen(s) was resistant to trypsin, although it was partially solubilized by trypsin treatment. The mitogen(s) could not be extracted with a chloroform-methanol mixture (2:1, v/v), although the chloroform-methanol soluble fraction was strongly mitogenic to murine splenocytes. Human serum which was added to the assay system in place of fetal bovine serum definitely suppressed the mitogenic effect of both cytoplasmic membranes and the cytoplasmic fraction, especially the latter.

Three-dimensional architecture and development of lumber intervertebral discs

The three-dimensional architecture of the collagen framework of human lumbar intervertebral discs was studied with scanning electron microscopy and polarized light microscopy concentrating on the fibrillar interconnection between the intervertebral disc and the vertebral bodies. The fibrillar framework of the annulus fibrosus and the cartilage end-plates encircled the nucleus pulposus as a closed-pack system in the adult. This closed-pack system developed in the seventh embryonic month and was completed by the tenth month. In general, fibrils composing the framework in the fetus were thinner than in the adult. There was no fibrillar interconnection between the cartilage end-plate and subchondral bone. In the inner one-third of the annulus, obliquely oriented fibrillar lamellae interconnected with the cartilage end-plate. In the outer two-thirds, the fibrillar bundles of the lamellae were firmly anchored into the vertebral bodies. This fibrillar anchoring system was already present in the full-term fetus although the vertebral rim was not ossified.

Mitogenic activity of cytoplasmic membranes isolated from L-forms of Staphylococcus aureus

Cytoplasmic membranes of L-forms of Staphylococcus aureus exerted a strong mitogenic effect on splenocytes of athymic nude mice as well as normal mice, while a cytoplasmic fraction of the same bacteria did not show definite mitogenicity. The mitogenic principle(s) of the membrane fraction was resistant to treatment with trypsin and was heat stable (at 100 C for 10 min). The active principle(s) in the insoluble residue of the membrane fraction digested with trypsin was not extracted with cold acetone, but could be solubilized by extraction with a cold chloroform-methanol mixture (2:1, v/v). The mitogenic principle(s) in the extract was fractionated by silicic acid column chromatography. Among five fractions separated by chromatography, fractions eluted with chloroform-methanol mixtures (1:1 and 1:20, v/v) were found to be strongly mitogenic. The cytoplasmic membranes of the L-forms also exerted a definite mitogenic effect on guinea pig splenocytes, but not on the thymocytes.