Micellar Brønsted Acid Mediated Synthesis of DNA-Tagged Heterocycles

The translation of well-established molecular biology methods such as genetic coding, selection, and DNA sequencing to combinatorial organic chemistry and compound identification has made extremely large compound collections, termed DNA-encoded libraries, accessible for drug screening. However, the reactivity of the DNA imposes limitations on the choice of chemical methods for encoded library synthesis. For example, strongly acidic reaction conditions must be avoided because they damage the DNA by depurination, i.e. the cleavage of purine bases from the oligomer. Application of micellar catalysis holds much promise for encoded chemistry. Aqueous micellar dispersions enabled compound synthesis under often appealingly mild conditions. Amphiphilic block copolymers covalently functionalized with sulfonic acid moieties in the lipophilic portion assemble in water and locate the Brønsted catalyst in micelles. These acid nanoreactors enabled the reaction of DNA-conjugated aldehydes to diverse substituted tetrahydroquinolines and aminoimidazopyridines by Povarov and Groebke-Blackburn-Bienaymé reactions, respectively, and the cleavage of tBoc protective groups from amines. The polymer micelle design was successfully translated to the Cu/Bipyridine/TEMPO system mediating the oxidation of DNA-coupled alcohols to the corresponding aldehydes. These results suggest a potentially broad applicability of polymer micelles for encoded chemistry.

Regulation of intestinal phosphate cotransporter NaPi IIb by ubiquitin ligase Nedd4-2 and by serum- and glucocorticoid-dependent kinase 1

Serum and glucocorticoid-inducible kinase 1 (SGK1) is highly expressed in enterocytes. The significance of the kinase in regulation of intestinal function has, however, remained elusive. In Xenopus laevis oocytes, SGK1 stimulates the epithelial Na(+) channel by phosphorylating the ubiquitin ligase Nedd4-2, which regulates channels by ubiquitination leading to subsequent degradation of the channel protein. Thus the present study has been performed to explore whether SGK1 regulates transport systems expressed in intestinal epithelial cells, specifically type IIb sodium-phosphate (Na(+)-P(i)) cotransporter (NaPi IIb). Immunohistochemistry in human small intestine revealed SGK1 colocalization with Nedd4-2 in villus enterocytes. For functional analysis cRNA encoding NaPi IIb, the SGK isoforms and/or the Nedd4-2 were injected into X. laevis oocytes, and transport activity was quantified as the substrate-induced current (I(P)). Exposure to 3 mM phosphate induces an I(P) in NaPi IIb-expressing oocytes. Coinjection of Nedd4-2, but not the catalytically inactive mutant (C938S)Nedd4-2, significantly downregulates I(P), whereas the coinjection of (S422D)SGK1 markedly stimulates I(P) and even fully reverses the effect of Nedd4-2 on I(P). The effect of (S422D)SGK1 on NaPi IIb is mimicked by wild-type SGK3 but not by wild-type SGK2, constitutively active (T308D,S473D)PKB, or inactive (K127N)SGK1. Moreover, (S422D)SGK1 and SGK3 phosphorylate Nedd4-2. In conclusion, SGK1 stimulates the NaPi IIb, at least in part, by phosphorylating and thereby inhibiting Nedd4-2 binding to its target. Thus the present study reveals a novel signaling pathway in the regulation of intestinal phosphate transport, which may be important for regulation of phosphate balance.

Blue liposomes for identification of the sentinel lymph nodes in pigs

Effective preoperative staining of regional lymph nodes improves their intraoperative identification and thus the selectivity of "sentinel node" lymphadenectomy. Unfortunately, aqueous Patent Blue V (PBV) often fails to provide the requisite intensity and duration of contrast (1,2). A comparative study of staining characteristics of PBV in aqueous solution with those of liposomally encapsulated PBV was carried out on 7 female pigs with an average weight of 40 kg. The liposomes, consisting of lecithin and cholesterol in a molar ratio of 3:1, were produced by an extrusion technique using membranes with thicknesses of 5 microm, 1.2 microm, 0.4 microm and 0.2 microm. In each instance, a 0.5-ml depot containing 25 +/- 0.4 mg of PBV/ml was injected into each of the four upper and lower mammary glands in aqueous solution on the left side and in a liposomal preparation on the right side. Stained lymph nodes of the groin, pelvis and neck were identified after 3, 6, 12 or 24 hours, then excised and photographed. Their PBV concentrations were measured by spectrophotometry. In all cases, the liposome preparations provided greater intensity and a longer duration than the aqueous solution. Liposomal PBV compared with aqueous PBV can therefore be recommended for better preoperative lymph node staining and identification of "sentinel" lymph nodes.

Preparing chief information officers for the clinical information systems environment

Over the past decade, the chief information officer (CIO) in the health care enterprise has gained recognition as a member of the senior management team based on an understanding of business processes and business language. The clinical information system (CIS) in the health care environment poses a new frontier for CIOs, who are generally unfamiliar with both clinical languages and clinical processes. The authors discuss the role formal informatics training can have in preparing learners for future careers as CIOs in CIS environments. The health information management (HIM) specialization within the MBA program at the University of Illinois at Chicago is one example of an educational program designed to train future CIOs who can manage the business, technical, and clinical aspects of the health care environment.

[Prognostic value of anterior chamber hemorrhage following glaucoma filtering surgery]

PURPOSE

Evaluation of the prognostic significance of a postoperative anterior chamber hemorrhage (ACH) after glaucoma filtering surgery.

PATIENTS AND METHODS

Records of 332 patients, who had undergone filtering surgery between 1/1993 and 2/1997, were analyzed retrospectively with particular concern on epidemiologic data, pre- and postoperative regulation of intra-ocular pressure (IOP), complications including ACH, postoperative 5-fluouracil (5-FU) therapy and postoperative IOP lowering therapy. Surgical success was defined as (1) IOP reduction below 21 mm Hg, (2) relative IOP reduction at least 20% and (3) no reoperation to control IOP until the first-year examination.

RESULTS

60 out of 332 patients (18.1%) suffered from ACH after glaucoma filtering surgery. 24 patients with ACH were treated with 5-FU, postoperatively. When all patients with ACH were considered in the evaluation, the difference between the success rate of patients with ACH and the success rate of patients without ACH was not statistically significant. In contrast, when ACH was the only complication in patients, who were not treated with 5-FU, the success rate was significantly worse (38%), when compared with the control group (patients, who did not have ACH or who had other complications in addition to ACH) (67%) (p = 0.008). When patients with these criteria received 5-FU postoperatively, the difference between success rates of both groups was not any longer statistically significant (p = 0.99).

DISCUSSION

The postoperative occurrence of anterior chamber hemorrhage is associated with a higher failure rate of filtering surgery. Early administration of 5-FU is recommended in these cases.

Bowel technique in the O.R. Is it really necessary?

Existing inconsistencies in the practice of bowel technique prompted a study to validate this operating room procedure. Minimal reference to intra-operative bowel technique was found in the literature. Needle drivers and tissue forceps utilized to anastomose large bowel were cultured, and the results were analysed. Needle drivers and tissue forceps used to anastomose small bowel were also cultured and used as a control group. Only elective bowel surgery cases were included in the study. The study demonstrated that there was consistent contamination to those instruments used for bowel anastomosis, with significantly greater contamination for large bowel resections. These results indicate that isolating those instruments and equipment which come into direct contact with the bowel lumen is a perioperative practice which will reduce the surgical patient's risk of postoperative wound infection.

NTP technical report on the toxicity studies of Ethylene Glycol Ethers: 2-Methoxyethanol, 2-Ethoxyethanol, 2-Butoxyethanol (CAS Nos. 109-86-4, 110-80-5, 111-76-2) Administered in Drinking Water to F344/N Rats and B6C3F1 Mice

Glycol alkyl ethers represent a class of high-production-volume chemicals with widespread industrial applications as solvents and chemical intermediates. Comparative toxicity studies with three glycol ethers, 2-methoxyethanol, 2-ethoxyethanol, and 2-butoxyethanol, were conducted in F344/N rats and B6C3F1 mice in both 2-week and 13-week drinking water studies. Toxicologic endpoints evaluated in animals included histopathology, hematology, clinical chemistry, urinalysis, and reproductive system parameters. Genetic toxicity was also evaluated for each glycol ether in several in vitro and in vivo assays. In the 2-week studies, groups of five male and five female rats and mice received 2-methoxyethanol, 2-ethoxyethanol, or 2-butoxyethanol in the drinking water. Estimates of compound consumption based on water consumption by male and female rats ranged from 100 to 400 mg/kg for 2-methoxyethanol, 200 to 1600 mg/kg for 2-ethoxyethanol, and 70 to 300 mg/kg for 2-butoxyethanol. For mice, consumption values ranged from 200 to 1300 mg/kg for 2-methoxyethanol, 400 to 2800 mg/kg for 2-ethoxyethanol, and 90 to 1400 mg/kg for 2-butoxyethanol. There were no chemical-related effects on survival for rats or mice in the 2-week studies. Decreased body weight gains were noted for both male and female rats treated with 2-methoxyethanol or 2-ethoxyethanol for 2 weeks, and there were dose-related decreases in water consumption for rats of each sex treated with the ethylene glycol ethers. Most of the changes in organ weights for rats and mice treated with the glycol ethers were sporadic (mice) or related to low final mean body weights (rats), except for thymic atrophy in male and female rats and testicular atrophy in males of both species receiving 2-methoxyethanol or 2-ethoxyethanol. In the 13-week studies in rats, groups of 10 males and 10 females received 2-methoxyethanol, 2-ethoxyethanol, or 2-butoxyethanol in the drinking water at concentrations ranging from 750 to 6000 ppm, 1250 to 20,000 ppm, or 750 to 6000 ppm, respectively. In the 13-week studies in mice, groups of 10 males and 10 females received 2-methoxyethanol, 2-ethoxyethanol, or 2-butoxyethanol in the drinking water at concentrations ranging from 2000 to 10,000 ppm, 2500 to 40,000 ppm, or 750 to 6000 ppm, respectively. Estimates of compound consumption based on water consumption by male and female rats ranged from 70 to 800 mg/kg for 2-methoxyethanol, 100 to 2200- mg/kg for 2-ethoxyethanol, and 70 to 500 mg/kg for 2-butoxyethanol. For-mice, consumption values ranged from 300 to 1800 mg/kg for 2-methoxyethanol, 600 to 11,000 mg/kg for 2-ethoxyethanol, and 100 to 1300 mg/kg for 2-butoxyethanol. Chemical-related mortality occurred in male and female rats administered 4500 or 6000 ppm 2-methoxyethanol and in male and female rats administered 20,000 ppm 2-ethoxyethanol. No deaths occurred in rats administered 2-butoxyethanol or in mice administered 2-methoxyethanol, 2-ethoxyethanol, or 2-butoxyethanol. Decreased body weight gains occurred in dosed rats and mice in all three studies; the greatest reductions in body weight gain were seen with 2-methoxyethanol. In rats administered 2-methoxyethanol or 2-ethoxyethanol, treatment-related histopathologic changes were observed in the testes, thymus, and hematopoietic tissues (spleen, bone marrow, and liver). A dose-related degeneration of the germinal epithelium in the seminiferous tubules of the testes was more severe in 2-methoxyethanol-treated rats than in rats treated with 2-ethoxyethanol. In special stop-exposure studies in male rats in which administration of the glycol ethers was stopped after 60 days, marked degeneration of the seminiferous tubules was present in rats treated with 3000 ppm 2-methoxyethanol, and mild to moderate degeneration was observed in rats treated with 1500 ppm. Moderate to marked testicular degeneration was present in rats treated with 10,000 or 20,000 ppm 2-ethoxyethanol but not in rats treated with 5000 ppm. After 30 and 56 days of recovery from treatment with these chemicals, only partial recovery from testicular degeneration was observed. There was no testicular degeneration after 60 days of treatment with 1500 to 6000 ppm 2-butoxyethanol. 2-Methoxyethanol treatment for 13 weeks resulted in a progressive anemia associated with a cellular depletion of bone marrow and fibrosis of the splenic capsule. Anemia was also seen with 2-ethoxyethanol, but evidence of an adaptive response was indicated by increased hematopoiesis in the bone marrow, spleen, and liver. Toxicity with 2-butoxyethanol was limited to the liver and hematopoietic system. Cytoplasmic alteration and a minimal hepatocellular degeneration were present in the liver of male and female rats. A minimal anemia was present, and a hematopoietic response was evident in the bone marrow and spleen. In mice, 2-methoxyethanol and 2-ethoxyethanol had similar effects on the testes, spleen, and adrenal gland (females only). A dose-related degeneration of the germinal epithelium in seminiferous tubules of the testes was more severe with 2-methoxyethanol than with 2-ethoxyethanol. A dose-related increase in splenic hematopoiesis was also more prominent with 2-methoxyethanol. Both 2-methoxyethanol and 2-ethoxyethanol caused a prominent lipid vacuolization of the X-zone of the adrenal gland in female mice. There were no chemical-related lesions attributed to 2-butoxyethanol administration in mice. All three of the glycol ethers were negative in Salmonella typhimurium mutation tests conducted with and without induced hamster and rat liver S9. In the mouse lymphoma L5178Y cell mutation assay, 2-ethoxyethanol was negative without S9 but was weakly positive in the presence of induced rat liver S9; 2-methoxyethanol and 2-butoxyethanol were not tested in this assay. At high concentrations, 2-ethoxyethanol induced sister chromatid exchanges (SCEs) in Chinese hamster ovary cells with and without S9. Chromosomal aberrations (Abs) were also induced by 2-ethoxyethanol, but only in the absence of S9 and without a delay in cell cycle. In contrast, 2-butoxyethanol induced cell cycle delay but did not induce SCEs or Abs with or without S9. 2-Ethoxyethanol was the only glycol ether tested for induction of sex-linked recessive lethal mutations in germ cells of Drosophila melanogaster; both feeding and injection trials were negative. In summary, based on survival, decreased body weight gains, and histopathologic effects, the rank order of toxicity for the three glycol alkyl ethers was 2-methoxyethanol>2-ethoxyethanol>2-butoxyethanol; the toxic effects were more severe in rats than in mice. In the 13-week study of 2-methoxyethanol in rats, a no-observed-adverse-effect level (NOAEL) was not reached, since testicular degeneration in males and decreased thymus weights in males and females occurred at the lowest concentration administered (750 ppm). In the 13-week study of 2-ethoxyethanol in rats, the NOAEL for decreased thymus weights in males was 1250 ppm; for female rats treated with 2-ethoxyethanol for 13 weeks, the NOAEL for all histopathologic and hematologic effects was 5000 ppm. In rats treated with 2-butoxyethanol for 13 weeks, the NOAEL for liver degeneration was 1500 ppm in males and females. For male mice treated with 2-methoxyethanol for 13 weeks, the NOAEL for testicular degeneration and increased hematopoiesis in the spleen was 2000 ppm. A NOAEL was not reached for female mice treated with 2-methoxyethanol, since adrenal gland hypertrophy and increased hematopoiesis in the spleen occurred at the lowest concentration administered (2000 ppm). For male mice treated with 2-ethoxyethanol for 13 weeks, the NOAEL for testicular degeneration and increased hematopoiesis in the spleen was 20,000 ppm. For female mice in the 13-week study of 2-ethoxyethanol, the NOAEL for adrenal gland hypertrophy and increased hematopoiesis in the spleen was 5000 ppm. No clear chemical-related effects were seen in male or female mice administered 2-butoxyethanol for 13 weeks at concentrations as high as 6000 ppm. Synonyms: 2-Methoxyethanol: Ethylene glycol monomethyl ether; methyl cellosolve; 2-Ethoxyethanol: Ethylene glycol monoethyl ether; cellosolve; 2-Butoxyethanol: Ethylene glycol monobutyl ether; butyl cellosolve.

NTP technical report on the toxicity studies of Toxicity Studies of Antimony Potassium Tartrate (CAS No. 28300-74-5) in F344/N Rats And B6C3F1 Mice (Drinking Water and Intraperitoneal Injection Studies)

Antimony potassium tartrate (APT) is a complex salt that until recently was used worldwide as an anti-schistosomal drug. APT was efficacious in humans only if administered intravenously at a near-lethal total dose of 36 mg/kg. Because unconfirmed epidemiologic studies suggested a possible association between APT treatment and bladder cancer, prechronic toxicity studies were initiated with APT to select a route of administration and appropriate doses in the event chronic studies were needed. To determine the most appropriate route for longer-term studies, toxicity and concentrations of tissue antimony were compared in F344/N rats and B6C3F1 mice that were administered APT in drinking water or by i.p. injection for 14 or 16 days. The animals were assigned to dose groups, 5/sex/species. Drinking water doses, estimated by water consumption, were 0, 16, 28, 59, 94, or 168 mg/kg in rats and 0, 59, 98, 174, 273, or 407 mg/kg in mice; i.p. doses were 0, 1.5, 3, 6, 11, or 22 mg/kg in rats and 0, 6, 13, 25, 50, or 100 mg/kg in mice. APT was poorly absorbed and relatively nontoxic when given orally. There was no mortality or histopathological lesions in rats or mice receiving doses of APT as high as 168 or 273 mg/kg, respectively. One mouse in the highest dose group (407 mg/kg) died, and there were treatment-related lesions in the liver and forestomach of most mice in this dose group. In contrast, i.p. administration of the drug was much more toxic, resulting in the deaths of rats administered 22 mg/kg; kidney and liver lesions were found in these rats. In mice, i.p. administration of APT caused deaths and liver lesions at dose levels one-fourth of those that caused similar effects by oral administration. All male and female mice injected with 100 mg/kg APT died; half of the female mice given 50 mg/kg APT died; additional deaths occurred with doses as low as 6 mg/kg. Hepatocellular necrosis and inflammation of the liver capsule were present in both sexes of mice in the 50 mg/kg dose groups. As a result of these findings, an i.p. dose regimen was selected for subsequent studies. Groups of ten male and female F344/N rats and B6C3F1 mice were given 0, 1.5, 3, 6, 12, or 24 mg/kg doses of APT 3 times per week for 13 weeks by i.p. injection. Rats were more sensitive than mice to the toxic effects of APT, exhibiting dose-related mortality and reduction in body weight. Four male rats in the 24 mg/kg dose died; body weights in both sexes of rats from this dose group and in male rats from the 12 mg/kg dose group were 10-20% below controls. No clinical signs of toxicity in the mice, nor gross or microscopic lesions, could be attributed to APT. Increased concentrations of antimony, considered to be dose-related, were detected in the blood, liver, kidney, spleen, and heart of rats, and in the liver and spleen of mice. In rats, hepatocellular degeneration and necrosis were associated with dose-related elevations in activities of the liver-specific serum enzymes, sorbitol dehydrogenase and alanine aminotransferase. By alternating the site of abdominal injection and the days of treatment, mesenteric inflammation at the site of administration was minimized in the rats and mice, indicating that the i.p. route would be suitable for chronic studies. Hepatotoxicity in rats occurred in dose groups where there was little evidence of renal toxicity and no cardiac toxicity; thus, serial measurement of liver-specific serum enzyme activities may be useful to monitor the presence and progression of hepatocellular degeneration in longer-term exposures. Synonyms: APT; Tartar emetic; tartrated antimony; tartarized antimony; potassium antimonyltartrate; Bis [μ-[2,3-dihydroxy- butanedioato(4-)-O1, O2:O3, O4]]-diantimonate dipotassium trihydrate (stereoisomer).