Catalytic enantioselective Reissert-type reaction: development and application to the synthesis of a potent NMDA receptor antagonist (-)-L-689,560 using a solid-supported catalyst.

Full details of the first catalytic enantioselective Reissert-type reaction are described. Utilizing the Lewis acid-Lewis base bifunctional catalyst 5 or 6 (9 mol %), the Reissert products were obtained in 57 to 99% yield with 54 to 96% ee. Electron-rich quinolines produced better yields and enantioselectivities than electron-deficient substrates. Kinetic studies indicated that the reaction should proceed via the rate-determining acyl quinolinium formation, followed by the attack of a cyanide. The catalyst does not facilitate the first rate-determining step; however, it strongly facilitates the second cyanation step. The reaction was successfully applied to an efficient catalytic asymmetric synthesis of a potent NMDA receptor antagonist (-)-L-689,560. A key step is the one-pot process using the Reissert-type reaction from quinoline 1f, followed by stereoselective reduction of the resulting enamine 2f. This step gave the key intermediate 20 in 91% yield with 93% ee, using 1 mol % of 6. The enantiomerically pure target compound was obtained through 10 operations (including recrystallization) in total yield of 47%. Furthermore, 6 was immobilized to JandaJEL, and the resulting solid-supported catalyst 11 afforded 20 in a comparable yield to the homogeneous 6, but with slightly lower enantioselectivity.

Mineral recovery system for a Closed Ecology Experiment Facility (CEEF).

A unique recovery system, which consists of electrodialysis (ED) and crystallization processes, is proposed for NaCl (salt) from waste water after oxidation of urine. NaCl recovery characteristics from the oxidized urine, which contains KCl and NO3- impurities, were experimentally evaluated. Concentrated NaCl/KCl mixed solution was obtained using the ED process from simulated oxidized urine and sweat. Large amounts of NO3- were contained in the concentrated solution. After the crystallization process, NaCl salt of 90% purity, containing less than 5% NO3-, could be recovered by crystallization from the solution at 90 degrees C because NaNO3 or KNO3 salt has high solubility in water at that temperature. The results show that the proposed mineral recovery system can recover NaCl from waste water in the CEEF.

[Expression of decay-accelerating factor on CD8-positive lymphocytes as an index of aging and of host defense function].

Decay-accelerating factor (DAF) is a membrane glycoprotein that prevents complement activation on blood cells. Among CD8+ T cells, DAF-negative cells can be distinguished from DAF-positive cells. We computed the proportion of DAF-negative CD8+ T cells in the peripheral blood of 59 normal healthy subjects, 27 to 93 years old, and analyzed the differences between subjects of different ages. The proportion of CD8+ T cells that were DAF-negative correlated significantly and positively with age. We also studied these lymphocytes in patients with cerebrovascular dementia, Alzheimer's dementia, cancer, rheumatoid arthritis and systemic lupus erythematosus. The proportion of CD8+ T cells that were DAF-negative did not correlate significantly with age in patients with cerebrovascular dementia, Alzheimer's dementia or cancer, but it correlated significantly and positively with age in patients with rheumatoid arthritis and in those with systemic lupus erythematosus. Therefore, healthy subjects and patients with various diseases can be classified according to age and to the proportion of CD8+ T cells that are DAF-negative. This proportion can then be used as an index of aging and of host defense function.

[Multiple primary malignant neoplasms associated with genitourinary cancer].

Between October 1980 and December 1994, we treated 392 patients with malignant neoplasms associated with genitourinary organs. We made a statistical study on 42 patients (10.6%) with multiple malignant neoplasms. The average age of 42 patients was 72.2 years and 83% of the patients were male. Malignant neoplasms originating from bladder, prostate or kidney were observed in 19 cases (35%), 19 cases (35%) or 10 cases (11%), respectively. The incidence of prostatic cancer was higher than that in other single primary malignant neoplasms associated with genitourinary organs. The other organs having malignant neoplasms accompanying genitourinary organs were the stomach (39%), lungs (12%), esophagus (9%), and pancreas (9%). Only 16 patients (35%) had synchronous multiple malignant neoplasms. However, 35 cases (75%) including these cases had second primary malignant neoplasms within 5 years of the first. In conclusion, the incidence of multiple malignant neoplasms with genitourinary cancer was as high as 10.6% and the prognosis of these patients was poor. These findings suggest the necessity of careful follow-up on patients with genitourinary cancer.

D-Aspartyl residue in a peptide can be liberated and metabolized by pig kidney enzymes.

The presence of an enzyme activity which hydrolyzes glycyl-D-aspartate was found in the homogenates of pig kidney cortex. The activity was inhibited by metal chelating agents and cilastatin, suggesting that the enzyme was a cilastatin-sensitive metallo-peptidase. Of the two hydrolysis products,D-aspartate was found to be less accumulated than glycine. The fate ofD-aspartate was, therefore, examined and the amino acid was found to be converted toL-aspartate,L-alanine and pyruvate, in the presence ofL-glutamate. Experiments with enzyme inhibitors suggested that the conversion involvedD-aspartate oxidase, aspartate aminotransferase and alanine aminotransferase as well as decarboxylation of oxaloacetate produced fromD-aspartate. All the results indicate that the enzymes in the pig kidney can liberate theD-aspartyl residue in the peptide and convert it to the compounds readily utilizable. The finding suggests a probable metabolic pathway of theD-aspartate-containing peptide.

[Usefulness of Dornier MPL9000 lithotriptor with new optional fluoroscopic guiding system (electrode X 155: depth 15.5cm) in treatment of urinary tract stone].

The Dornier MPL9000 lithotriptor was originally equipped with an ultrasound guiding system. Recently an optional fluoroscopic guiding system was developed to overcome the known disadvantages of the ultrasound system and to exploit the merits of both systems by using them in combination. Herein, we examined the effectiveness and safety of this new optional system. From December 1990 to February 1991, we treated 41 patients with upper urinary tract stones with MPL9000 using the optional fluoroscopic system. Treatments were judged as effective if the patients were stone-free or the residual fragments were smaller than 4mm in diameter. The overall effectiveness rates at one month after the treatment were 54.5% for renal stones and 76.9% for ureter stones respectively. At three months after the treatment the effectiveness rate for renal stones was 83.3%, and that for ureter stones 95.5%. The changes in the laboratory data after the treatment were alight and caused no clinical problems. Complications during and after the treatment were also minor and tolerable. MPL9000 was sufficiently effective and safe in the treatment of upper urinary tract stones when it was used the new optional fluoroscopic system instead of the original ultrasonic guiding system.

Tissue distribution of complement regulatory membrane proteins in rats.

Complement regulatory membrane proteins act either on C3/C5 convertase enzymes of the classical and alternative pathways or prevent the formation of membrane attack complexes (MAC). 5I2 is a monoclonal antibody (mAb) directed against a rat erythrocyte membrane inhibitor of the C3 convertase step which seems to be the rat counterpart of mouse Crry/p65. 6D1 is a mAb against rat CD59 which inhibits formation of MAC. Tissue distribution of these membrane inhibitors was visualized by immunohistochemical staining with the appropriate mAb. Rat CD59 (6D1 antigen) and 5I2 antigen were both widely distributed, being predominantly expressed on endothelial cells of the arteries, veins and capillaries as well as on all circulating cells. 6D1 antigen and 5I2 antigen were also detected on immature hepatocytes, systemic endothelial cells, skin fibroblasts, bronchial epithelial cells and bile canaliculi. Both were also expressed in the Schwann sheath of peripheral nerve fibres and ependymal cells. However, glial cells and myelin sheath in the central nervous system were not stained. Anti-CD59 (6D1) staining of epithelial and endothelial cells was observed in the cornea, while 5I2 stained only the epithelial cell layer.

Renin inhibitors. II. Synthesis and structure-activity relationships of N-terminus modified inhibitors containing a homostatine analogue.

The synthesis and structure-activity relationships of N-terminus modified renin inhibitors containing the homostatin analogue, (2RS,4S,5S)-5-amino-2-ethyl-4-hydroxy-7-methyloctanoic acid, are described. The compounds having a 3-alkyl (or aryl)sulfonylpropionyl residue at the N-terminus are found to be potent inhibitors which contain two amino acids. (2RS,4S,5S)-N-Isobutyl-5-[N-[(2S)-3-ethylsulfonyl-2-(1- naphthylmethyl)propionyl]-L-norleucyl]-amino-2-ethyl-4-hydroxy-7- methyloctanamide (20) has an IC50 of 0.5 nM against human plasma renin and the oral bioavailability of 20 is 0.73% in rats. Interaction between renin and the N-terminus of 1 and 20 is discussed in molecular modeling studies.

In vitro biological profile of a highly potent novel endothelin (ET) antagonist BQ-123 selective for the ETA receptor.

The novel endothelin (ET) receptor antagonists BE-18257A and BE-18257B were isolated from the fermentation products of Streptomyces misakiensis. The above-mentioned compounds inhibited [125I]ET-1 binding to ETA receptors (selective for ET-1) on porcine aortic vascular smooth muscle cells (VSMCs) with IC50 values of 1.4 and 0.47 microM, respectively. [125I]ET-1 binding to ETB receptors (nonselective to ET isopeptides) in cerebellar membranes was not inhibited by either of these compounds even at 100 microM. The synthesized analogue BQ-123 induced extremely potent inhibition of [125I]ET-1 binding to ETA receptors (IC50 of 7.3 nM), but it barely inhibited [125I]ET-1 binding to ETB receptors (IC50 of 18 microM) and binding of various other peptides to their receptors. BQ-123 shifted the concentration-response curve for ET-1 toward the right in porcine isolated coronary arteries, indicative of competitive antagonism for the ETA receptor. However, there was a small amount of BQ-123-insensitive vasoconstriction that paralleled the incomplete inhibition of [125I]ET-1 binding in the membrane of the vascular smooth muscle layer. These data suggest that the artery contracts via both ETA and ETB receptors and that BQ-123 selectively inhibits ETA-mediated contraction. Furthermore, BQ-123 revealed large tissue and species differences in the distribution of ETA receptors. Thus, the potent ETA antagonist BQ-123 should be useful in clarifying the (patho)physiological roles of ETA receptors.

Two endothelin receptor subtypes in porcine arteries.

Endothelin-1 (ET-1) and ET-3 caused constrictions of endothelium-denuded porcine coronary artery strips with different concentration-response curves: a typical sigmoidal curve to ET-1 and a two-phase sigmoidal curve to ET-3. Binding assays using a membrane preparation demonstrated different Bmax values for [125I]ET-1 and [125I]ET-3 binding. In addition, [125I]ET-1 binding was inhibited by ET-1 and ET-3 with different potencies (ET-1 greater than ET-3), while [125I]ET-3 binding was inhibited by both ETs equally. From these results, two distinct ET receptor subtypes were proposed in the artery; site 1 (selective to ET-1) and site 2 (equally sensitive to both ETs). However, only site 1 was identified on cultured arterial smooth muscle cells (VSMCs) by the binding assay, and this was confirmed since only ET-1 (not ET-3) caused a significant increase in the intracellular free Ca2+ concentration. Therefore, it seems likely that vasoconstriction is mediated via the binding of ET-1 to site 1 (VSMCs) and site 2 (non-VSMCs), or the binding of ET-3 to site 2 (non-VSMCs). Furthermore, site 2 was predominant in nonvascular tissues such as lung, kidney, and cerebellum, thereby suggesting that site 1 may exist in limited tissues such as VSMCs.