Synthesis and inhibitory activity of acyl-peptidyl-pyrrolidine derivatives toward post-proline cleaving enzyme; a study of subsite specificity

Several pyrrolidine derivatives have been synthesized and examined for their inhibitory activity on post-proline cleaving enzymes from Flavobacterium meningosepticum and bovine brain. Almost all the compounds tested in this study inhibited the activity of both enzymes at low IC50 values (from nM to microM) but a specificity difference was observed with alkylacyl-peptidyl-pyrrolidine derivatives which strongly inhibited only the bacterial enzyme. The most effective inhibitors have a proline residue on their P2 sites and a substituted or unsubstituted phenoxybutyryl moiety on their P3 sites. Thus phenoxybutyryl-prolyl-pyrrolidine is the most effective partial structure of the inhibitors. The best inhibitors found were: 4-(4-benzylphenoxy)butyryl-prolyl-pyrrolidine for bacterial enzyme (IC50 1.4 nM) and 4-phenylbutyryl-thioprolyl-pyrrolidine for bovine brain enzyme (IC50 67 nM). In the passive avoidance test, using amnesic rats experimentally induced with scopolamine, the pyrrolidine derivatives which had potent inhibitory activity toward post-proline cleaving enzymes also showed strong anti-amnesic activities at doses of 1-5 mg/kg, i.p.

Quantitative analysis of antiatherosclerotic effect of nifedipine in cholesterol-fed rabbits

Reports concerning the effect of slow calcium-channel blockers on experimental atherosclerosis are controversial. We examined the antiatherosclerotic effect of nifedipine (40 mg/day for 16 weeks) on aorta of rabbits on diets containing 0.3%, 0.5%, and 1.0% cholesterol. There were no significant differences in levels of serum lipids with or without nifedipine in the same cholesterol-fed rabbits. The results obtained show that nifedipine suppressed the extent of lipid deposition and surface involvement (S.I.) in aorta in 0.3% cholesterol-fed rabbits, whereas nifedipine only tended to suppress S.I. in 0.5% cholesterol-fed rabbits and had no effect in 1.0% cholesterol-fed rabbits. The log dose-response relationship of S.I. was obtained by plotting the concentration of cholesterol in the feed or the "integrated value" of the total serum cholesterol (TC), i.e., the cumulative sum of the serum TC values obtained at each week. The log dose-response curve was shifted in parallel with the right in nifedipine groups. The Lineweaver-Burk plot constructed from the dose-response curve had the same points crossing the ordinate with or without nifedipine. These results suggested that nifedipine suppressed S.I. in a competitive manner with cholesterol on the specific binding site of lipid deposition. Electron-microscopic findings also demonstrated that fat droplets in smooth muscle cells, extracellular matrix containing collagen, and elastic fibers decreased in nifedipine-treated rabbits.

Synthesis and inhibitory activity of acyl-peptidyl-prolinalderivatives toward post-proline cleaving enzyme as nootropic agents

Several prolinal derivatives were synthesized and examined for their inhibitory activity on post-proline cleaving enzymes from Flavobacterium meningosepticum and bovine brain and their possible properties as nootropic agents. Almost all the compounds tested inhibited the activity of both enzymes at low IC50 values of the order of nM, but a specificity difference was observed with alkylacyl-prolinal derivatives which strongly inhibited only the bacterial enzyme. Prolyl-prolinal derivatives were the most effective inhibitors for both enzymes. In the passive avoidance test using amnesic rats experimentally induced with scopolamine, the prolinal derivatives that have potent inhibitory activity toward post-proline cleaving enzymes showed also strong anti-amnesic activities at dose of 10-1000 micrograms/kg, i.p. Some of the compounds showed a bell-shape dose dependency. These results suggest that the post-proline cleaving enzymes play an important role in the regulation of learning and memory consolidation in the brain and inhibitors of these enzymes are suggested as possible candidates for nootropic agents, particularly for an anti-amnesic drug.

Inhibitory effect of di- and tripeptidyl aldehydes on calpains and cathepsins

Eight different di- and tripeptidyl aldehyde derivatives, each having at its C-terminus an aldehyde analog of L-norleucine, L-methionine, or L-phenylalanine with a preceding L-leucine residue, were synthesized and tested for their inhibitory effects on several serine and cysteine endopeptidases. These compounds showed almost no inhibition of trypsin, and only weak inhibition of alpha-chymotrypsin and cathepsin H, while they exhibited marked inhibition of cathepsin B less than calpain II congruent to calpain I less than cathepsin L, being stronger in this order. The mode of inhibition of these cysteine proteinases was competitive for the peptide substrate used and inhibitor constants (Ki) were calculated from the Dixon plot. The best inhibitors found were: 4-phenyl-butyryl-Leu-Met-H for calpain I (Ki, 36 nM) and calpain II (Ki, 50 nM); acetyl-Leu-Leu-nLeu-H for cathepsin L (Ki, 0.5 nM); acetyl-Leu-Leu-Met-H for cathepsin B (Ki, 100 nM).

Response to and control of destructive energy by magnetic resonance

Magnetic resonance imaging techniques can be used to control and monitor the deposition of destructive energy. The authors evaluated the feasibility of phosphorus-31 magnetic resonance spectroscopy for the control, monitoring, and prediction of the three-dimensional extent of tissue destruction during interstitial laser surgery. Characteristic metabolic changes were demonstrated within the lesion and in the adjacent normal tissue during the deposition of thermal energy.

[Clinical analysis of postoperative recurrent nerve palsy in patients undergoing operation of carcinoma of the thoracic esophagus]

From January 1976 to April 1987, 325 cases of carcinoma of the thoracic esophagus were resected in our department. Among these cases, 25 cases were not included because of direct operative deaths or early hospital deaths, and 300 cases were selected for clinical analysis of postoperative recurrent nerve palsy, which occurred in 75 cases (25.0%). The rate of occurrence of this palsy in the last 6-year period was higher than that in the first 6-year period (34.0% and 15.3%, respectively). It was suggested that the extension of surgical procedures to the cervix and upper mediastinum had contributed to this increase in rate. The sides affected by palsy were as follows: left, 56.0%, right 12.0%, bilateral, 24.0%; unknown, 8.0%. The importance of gentle handling of the left recurrent nerve during operation should be emphasized. The rate of occurrence of palsy in the cases of "Iu" was higher than in cases of "Im" and "Ei" (53.3%, 31.6%, 26.8%, respectively). The rate of occurrence of this palsy was significantly higher in the cases in which cervical anastomosis was performed than in cases in which intrathoracic anastomosis was performed (31.9% and 2.8%, respectively; p less than 0.01). Of the cases complicated by this palsy (Group A), tracheostomy was done in 12.0% of the cases and long-term transnasal tracheal tube cannulation or tube reinsertion done in 29.3%. These rates were significantly higher than the rates for cases who did not develop this palsy (Group B). The rates of occurrence of postoperative pulmonary complications within one month after surgery in Group A and Group B were almost same (24.3% and 21.8%, respectively).(ABSTRACT TRUNCATED AT 250 WORDS)

[Effect of androgen on the onset of diabetes in the KK mice treated with monosodium aspartate]

Obese diabetes was induced by monosodium aspartate (MSA) administration in KK male mice and the diabetic KK mice were divided into two groups, younger (12-week-old) and older (35-week-old). The diabetic KK mice were castrated and administered with androgen and effect of androgen on glycosuria appearance was investigated. Androgen dependent tear proteins (Mtp-M) were detected by the method of polyacrylamide gel electrophoresis. Blood androgen level was estimated by observation of change of the pattern of Mtp-M. In the younger mice group, glycosuria disappeared temporarily after castration and then appeared naturally again. The Mtp-M declined with castration, but did not disappear in this experimental period. In the older mice group, glycosuria and Mtp-M disappeared completely and blood glucose level decreased considerably after castration. However, in the castrated older mice, the glycosuria and the Mtp-M appeared again after the administration of dehydroepiandrosterone (DHEA), and the increasing of blood glucose level was observed. These results strongly suggested that androgen had an important role in the onset of diabetes in the KK mice treated with MSA.

Development and evaluation of a radiological reporting system for use with a personal computer

A computer-assisted radiological reporting system (CRRS) was developed for the efficient management and effective use of a database of radiological information. The system consists of a computer terminal linked to an HIS, a reporting console and a personal computer in the local area network of the radiology department, and a radiography care reader which transfers basic data on the patient from the HIS to the CRRS. The patient's name, hospital ID number, sex and date of birth, the department from which the patient has been referred, in-patient/out-patient status and the procedure needed are recorded on magnetic cards (radiography cards) issued to radiology patients. The system has been successfully used in all diagnostic procedures for 8 months: 16,300 reports have been printed out and stored. The system has made it possible to implement the complete radiological reporting procedure for clinical applications, and the required data can easily be retrieved and used. It has proved to be quite easy to use CRRS to obtain diagnostic histories, and the improved efficiency of the reporting procedure has enabled the cost of a clerk typist to be eliminated.

High-performance affinity chromatography of human serum concanavalin A binding proteins

A high-performance concanavalin A (Con A) affinity column Gelpack GL-L55C (Hitachi Kasei Industries) was successfully used for the fractionation of human serum Con A-binding proteins. Serum proteins that have strong affinity to Con A (ca. 11% of the recovered proteins) could be fractionated within 80 min. By analysing the eluates from the column by micro two-dimensional electrophoresis, followed by blotting and Con A staining, the specificity of the column was effectively visualized. Although the protein-binding capacity of the column gradually decreased during repeated loading of serum or tissue extracts, the specificity of the column to Con A-binding proteins did not change. Serum lipoproteins have been eluted from the column with 6 M urea, suggesting that the capacity decrease is caused by the binding of lipids or lipoproteins to the column.

Synthesis of a new cell penetrating calpain inhibitor (calpeptin)

N-terminal of Leu-norleucinal or Leu-methioninal was modified to obtain a cell penetrative peptide inhibitor against calpain. Benzyloxycarbonyl (Z) derivatives had less active against papain than phenylbutyryl derivatives and leupeptin. Z-Leu-nLeu-H (calpeptin) was more sensitive to calpain I than Z-Leu-Met-H and leupeptin. Calpeptin was most potent among synthesized inhibitors in terms of preventing the Ca2+-ionophore induced degradation of actin binding protein and P235 in intact platelets. After 30 min incubation with intact platelets, calpeptin completely abolished calpain activity in platelets but no effect was observed in case of leupeptin. Calpeptin also inhibited 20K phosphorylation in platelets stimulated by thrombin, ionomycin or collagen. Thus calpeptin was found to be a useful cell-penetrative calpain inhibitor.

Staining of serum concanavalin A-binding proteins after micro two-dimensional electrophoresis and blotting

Human serum proteins separated by micro two-dimensional electrophoresis in the absence of denaturants were electrophoretically transferred to nitrocellulose sheets (blots), and glycoproteins on the blots were stained by sequential incubation with the lectin concanavalin A, the glycoprotein horseradish peroxidase and the substrates of peroxidase diaminobenzidine-hydrogen peroxide. The stained serum concanavalin A-binding glycoproteins were identified by referring to the "identification map" of human plasma proteins, which we have prepared by immunochemical staining of the proteins on the blots. The concanavalin A-peroxidase method applied for the blots after two-dimensional electrophoresis provided information on the location of serum concanavalin A-binding glycoproteins, and showed greater sensitivity than Coomassie Brilliant blue R-250 staining for several serum proteins.

Origin of slow conformer conversion of triostin A and interaction ability with nucleic acid bases

The n.m.r. pattern of triostin A in weakly polar solvents was explained by the presence of two symmetrical conformers. Its S-benzyl derivative still shows the n.m.r. pattern of two conformers, while des-N-tetramethyltriostin A, which lacks the N-methyl groups, gives one conformer. Therefore the slow interconversion of two conformers arises from the cis-trans isomerization of the N-methyl peptide bonds, but not from the reversal of the chirality around the S-S bond. Only one of the two conformers of triostin A interacts with adenosine and guanosine derivatives. Des-N-tetramethyltriostin A can also interact with the purine nucleosides, but more preferentially with the adenosine derivative.