The synthesis of highly potent, selective, and water-soluble agonists at the human adenosine A3 receptor

Using a combination of parallel and directed synthesis, the discovery of a highly potent and selective series of adenosine A3 agonists was achieved. High aqueous solubility, required for the intended parenteral route of administration, was achieved by the presence of one or two basic amine functional groups.

3'-Aminoadenosine-5'-uronamides: discovery of the first highly selective agonist at the human adenosine A3 receptor

Selective adenosine A(3) agonists have potential utility for the prevention of perioperative myocardial ischemic injury. Herein, we report on the discovery and synthesis of compound 7. This amino nucleoside agonist possesses unprecedented levels of selectivity for the human adenosine A(3) receptor.

The preparation and intra- and intermolecular addition reactions of acyclic N-acylimines: application to the synthesis of (+/-)-sertraline

Intramolecular endo-cyclization reactions of N-acyliminium ions have seen wide application for the synthesis of heterocyclic compounds. The corresponding exocyclic variant, which would provide 1-aminotetralin derivatives, for example, has little precedent. We have discovered that acyclic N-acylcarbamates can be readily reduced to the corresponding N-acylhemiaminal derivatives in high yield using DIBAL as the reducing agent. These intermediates are remarkably stable and, if desired, can be purified and stored. The acyclic N-acylhemiaminals undergo both intra- and intermolecular nucleophilic addition reactions mediated by strong Lewis acids, such as TiCl(4). Diastereoselectivity, induced either by a substituent on the newly formed ring, or by utilizing a chiral ester on the carbamic acid, was disappointingly low. This methodology was successfully applied to the synthesis of the racemic form of the marketed antidepressant sertraline.

Carbohydrate modifications in the spirostane cellobioside cholesterol absorption inhibitor series

Cholesterol absorption inhibition remains an attractive approach for the treatment of hypercholesterolemia. We have continued our SAR development in the spirostanyl cellobioside class of agents seeking a greater understanding of the role carbamoyl substitution has on the potency in this series. In this regard, a series of differentially substituted carbamate analogs were made with and without deoxygenations. From this study, it was determined that the minimal requirements for optimal potency was a lone carbamate at C4" and deoxygenation at the C6" position.

Steroidal glycoside cholesterol absorption inhibitors

We have explored the use of steroidal glycosides as cholesterol absorption inhibitors which act through an unknown mechanism. The lead for this program was tigogenin cellobioside (1, tiqueside) which is a weak inhibitor (ED50 = 60 mg/kg) as measured in an acute hamster cholesterol absorption assay. Modification of the steroid portion of the molecule led to the discovery of 11-ketotigogenin cellobioside (5, pamaqueside) which has an ED50 of 2 mg/kg. Replacement of the cellobiose with other sugars failed to provide more potent analogs. However, large improvements in potency were realized through modification of the hydroxyl groups on the cellobiose. This strategy ultimately led to the 4", 6"-bis[(2-fluorophenyl)carbamoyl]-beta-D-cellobiosyl derivative of 11-ketotigogenin (51) with an ED50 of 0.025 mg/kg in the hamster assay, as well as the corresponding hecogenin analog 64 (ED50 = 0.07 mg/kg).

Phenytoin in the treatment of cocaine abuse: a double-blind study

OBJECTIVES

To evaluate the effectiveness of phenytoin in the treatment of cocaine abuse.

SUBJECTS AND METHODS

A 12-week, double-blind, placebo-controlled outpatient study of phenytoin in the treatment of cocaine abuse was conducted. Sixty cocaine-using subjects were randomly assigned to a daily fixed dose of 300 mg phenytoin or placebo. Forty-four subjects initiated treatment and returned for weekly visits. Primary measures of outcome included weekly quantitative and qualitative cocaine urinalysis, self-reported cocaine use, global functioning and improvement, craving intensity, and subject retention.

RESULTS

Cocaine use, as measured both by weekly urinalysis and self-report, was significantly lower in the phenytoin group. The phenytoin group was also rated as significantly less impaired and more improved than the placebo group. Craving intensity was lower in the phenytoin group, but the difference was not statistically significant. Among phenytoin subjects, serum phenytoin levels above 6.0 micrograms/ml were associated with lower rates of positive cocaine urine specimens and longer cocaine-free periods. No differences were observed between groups in study retention.

CONCLUSIONS

These findings suggest that phenytoin may be useful in the treatment of cocaine abuse. Further studies are needed to replicate these findings.

Interference-contrast and phase-contrast microscopy of sporulation in clostridium thermosaccharolyticum grown under strict anaerobiosis

Cells of Clostridium thermosaccharolyticum grown under strict anaerobiosis (modified Hungate technique) were examined during growth and sporulation by employing Nomarski interference-contrast and Zernike phase-contrast optics to delineate the sequence of morphological changes leading to the formation of free, mature spores. A 0.5% l-arabinose, liquid, complex medium was used to obtain a yield of 30 to 40% free, refractile spores (ca. 10(8)/ml) by 48 hr of incubation. The mean doubling time for the glucose culture (vegetative cells) was found to be 80 min, and that for the l-arabinose culture (sporulating cells), 498 min. By 8 hr of incubation, beginning spore formation became evident in the arabinose culture by the development of a distinct arrowhead-shaped terminal swelling. By 32 hr of incubation or shortly thereafter, Nomarski optics showed the mature spore to be uniformly spherical, whereas the enlarged terminal swelling containing it was not. The use of phase-contrast and interference-contrast optics permitted the characterization of the distinctive morphological changes occurring during sporulation of C. thermosaccharolyticum.

Herellea (Acinetobacter) and Pseudomonas ovalis (P. putida) from frozen foods

Seventeen strains of Herellea vaginicola (Acinetobacter antitratus) and 8 of Pseudomonas ovalis (P. putida), isolated from 23 (6.3%) of 364 samples of frozen, foil-pack foods, were identified and characterized morphologically and biochemically. Herellea was isolated from 17 foods (4.7%), P. ovalis from 6 (1.6%). No Mima were found. The food samples included precooked frozen meats, precooked and uncooked frozen vegetables, and uncooked frozen desserts. The bacteria were detected in the food with a procedure used generally for the detection of salmonellae. The pseudomonad simulated the characteristics of Herellea on Sellers differential agar, except for the fact that it fluoresced. From consideration of the habitat and pathogenicity of Herellea and Mima, it is concluded that, although the presence of these bacteria may not be desirable, their significance in food remains unanswered.

Nitrogen-deficient medium in the differential isolation of Klebsiella and Enterobacter from feces

On a nitrogen-deficient agar medium, the tribe Klebsielleae formed large, glistening, mucoid colonies which were easily distinguished from other colony types. Of 113 Klebsielleae isolates from human feces which were characterized, Klebsiella accounted for 88% of the total; 75% were K. pneumoniae; K. ozaenae (13%) was isolated from one individual only. The remaining strains (12%) were identified as Enterobacter cloacae. Counts (for the tribe) ranged from 10(2) to 10(6), with a median of 10(4); 9 of 53 stool specimens were negative. K. pneumoniae was also isolated from 6 of 41 frozen foil-pack foods. Anaerobic studies at room temperature and 37 C revealed no appreciable differences from aerobic plates. The nitrogen-deficient medium appeared better than E M B for isolation of Klebsielleae when they were present in low numbers relative to other coliforms; slime production by Klebsielleae concomitant with minimal growth of other bacteria is involved.

Sporicidal action of auto-oxidized ascorbic acid for Clostridium

Neutralized ascorbic acid (AA), buffered or unbuffered and autoclaved or filter-sterilized, was sporicidal for Clostridium. A 0.2% concentration of AA was generally employed, and spore counts were made in a soft-agar modification of Wynne's medium in Prickett tubes. Spores of Clostridium botulinum 115B were less susceptible than those of C. sporogenes PA 3679, whereas C. bifermentans spores were by far the most sensitive. At 75 C, spores of PA 3679 were killed at a rate of about 9% at 0 min (warm-up) to 99+% at 100 min. The lower the temperature, the longer the time needed for a given lethality. The percentage of killing increased with increasing concentrations of AA, and the rate of killing was lower at a higher concentration of spores. At least two mechanisms were operative: a major mechanism involving a product(s) of AA auto-oxidation, and a minor mechanism involving copper-ascorbate toxicity. AA reduced in natural gas was not sporicidal after 18.5 hr at 25 C, whereas 92% of the spores were killed by oxidized AA. Although H(2)O(2) per se was sporicidal, catalase did not reverse lethality of fresh or oxidized AA. Dehydroascorbate was as sporicidal as any AA preparation. Added copper (0.00001%) increased the rate of lethality of freshly prepared AA from 66 to 83% but was not effective with thoroughly oxidized AA. Ethylenediaminetetraacetic acid, NH(4) (+), and phosphate partially reversed AA toxicity, deionized water had no effect, and complex media, as well as thioglycolate, eliminated AA lethality. Since the percentage of killing was affected by spore concentration, AA did not seem to stimulate "lethal germination."

Agar concentration in counting Clostridium colonies

Decreasing the agar concentration of a counting medium from the usual 1.5% resulted in larger colonies with less interference from gas in Clostridium botulinum 115B and C. sporogenes PA 3679. Optimal agar concentration was 0.65% for C. botulinum with 24-hr incubation and 0.50% for C. sporogenes with 48-hr incubation. Lower concentrations yielded growth too diffuse for counting. Motility was considered the explanation for increased colony size in softer agar. The greater the degree of motility, the greater would be the diffusibility expected, and thus the higher the agar concentration required to insure discrete colonies. For quantitating motility, evaluations were made by use of microscopic examination of liquid cultures and rate of diffusion in a semisolid medium. With both criteria, the degree of motility of C. botulinum 115B clearly exceeded that of C. sporogenes PA 3679. Small-colony variants of C. botulinum in 0.65% agar yielded only small colonies on subculture, with a corresponding decrease in degree of motility of the cells by both criteria. Colony size of the nonmotile C. perfringens ATCC 3624 was unaffected by lowered agar concentrations.

Nitrogen dioxide fixation in bacterial chromatin studies

Eller, Charles (St. John's University, Jamaica, N.Y.), and William H. Beckert. Nitrogen dioxide fixation in bacterial chromatin studies. J. Bacteriol. 90:1710-1712. 1965.-Satisfactory chromatin staining was obtained with two Bacillus species when nitrogen dioxide was used for fixation in conjunction with either the acid Giemsa or Feulgen staining methods. An impression method was employed for the transfer of bacilli to a new environment as well as for smears. Advantages of nitrogen dioxide fixation are discussed.