Unidirectional Double- and Triple-Hydrogen Rearrangement Reactions Probed by Infrared Ion Spectroscopy

Unidirectional double-hydrogen (2H) and triple-hydrogen (3H) rearrangement reactions occur upon electron-ionization-induced fragmentation of trans-2-(4-N,N-dimethylaminobenzyl)-1-indanol (1), trans-2-(4-methoxybenzyl)-1-indanol (2), 4-(4-N,N-dimethylaminophenyl)-2-butanol (3), and related compounds, as reported some 35 years ago (Kuck, D.; Filges, U. Org. Mass Spectrom. 1988, 23, 643-653). These unusual intramolecular redox processes were found to dominate the mass spectra of long-lived, metastable ions. The present report provides independent evidence for the structures of the product ions formed by the 2H and 3H rearrangement in an ion trap instrument. The radical cations 1^•+ and 3^•+ as well as ionized 1-(4-N,N-dimethylaminophenyl)-5-(4-methoxyphenyl)-3-pentanol, 5^•+, were generated by electrospray ionization from anhydrous acetonitrile solutions. The 2H and 3H fragment ions were obtained by collision-induced dissociation and characterized by IR ion spectroscopy and density functional theory calculations. Comparison of the experimental and calculated infrared ion spectra enabled the identification of the 2H rearrangement product ion, C₉H₁₄N⁺ (m/z 136), as an N,N-dimethyl-para-toluidinium ion bearing the extra proton ortho to the amino group, a tautomer which was calculated to be 31 kJ/mol less stable than the corresponding N-protonated form. The 3H rearrangement product ion, C₈H₁₃N^•+ (m/z 123), formerly assumed to be a distonic ammonium ion bearing a cyclohexadienyl radical, was now identified as a conventional radical cation, ionized N,N-dimethyl-2,3-dihydro-para-toluidine. Thus, the 3H rearrangement represents an intramolecular transfer hydrogenation between a secondary alcohol and an ionized aromatic ring. Based on these structural assignments, more detailed mechanisms for the unidirectional 2H and 3H rearrangement reactions are proposed.

Treatment with lenalidomide induces immunoactivating and counter-regulatory immunosuppressive changes in myeloma patients

Lenalidomide activates the immune system, but the exact immunomodulatory mechanisms of lenalidomide in vivo are poorly defined. In an observational study we assessed the impact of lenalidomide on different populations of immune cells in multiple myeloma patients. Lenalidomide therapy was associated with increased amounts of a CD8(+) T cell subset, phenotypically staged between classical central memory T cells (TCM) and effector memory T cells (TEM), consequently termed TCM/TEM. The moderate expression of perforin/granzyme and phenotypical profile of these cells identifies them as not yet terminally differentiated, which makes them promising candidates for the anti-tumour response. In addition, lenalidomide-treated patients showed higher abundance of CD14(+) myeloid cells co-expressing CD15. This population was able to inhibit both CD4(+) and CD8(+) T cell proliferation in vitro and could thus be defined as a so far undescribed novel myeloid-derived suppressor cell (MDSC) subtype. We observed a striking correlation between levels of TCM/TEM, mature regulatory T cells (T(regs)) and CD14(+) CD15(+) MDSCs. In summary, lenalidomide induces both activating and inhibitory components of the immune system, indicating the existence of potential counter-regulatory mechanisms. These findings provide new insights into the immunomodulatory action of lenalidomide.

Direct pulp capping with mineral trioxide aggregate in a primary molar: a case report

A case is presented in which pulp capping was performed on a right first mandibular primary molar in a 7-year-old male patient. An alkaline cement powder based on mineral trioxide aggregate (MTA) was used for pulp capping. There were no pathological findings either on a radiograph taken after one year or on clinical examination after 18 months, and the right first mandibular primary molar remained vital after capping with MTA. Further clinical investigation of MTA for direct pulp capping of primary teeth should be performed.

Discontinuation of prophylaxis against Mycobacterium avium complex disease in HIV-infected patients who have a response to antiretroviral therapy. Terry Beirn Community Programs for Clinical Research on AIDS

BACKGROUND

Several agents are effective in preventing Mycobacterium avium complex disease in patients with advanced human immunodeficiency virus (HIV) infection. However, there is uncertainty about whether prophylaxis should be continued in patients whose CD4+ cell counts have increased substantially with antiviral therapy.

METHODS

We conducted a multicenter, double-blind, randomized trial of treatment with azithromycin (1200 mg weekly) as compared with placebo in HIV-infected patients whose CD4+ cell counts had increased from less than 50 to more than 100 per cubic millimeter in response to antiretroviral therapy. The primary end point was M. avium complex disease or bacterial pneumonia.

RESULTS

A total of 520 patients entered the study; the median CD4+ cell count at entry was 230 per cubic millimeter. In 48 percent of the patients, the HIV RNA value was below the level of quantification. The median prior nadir CD4+ cell count was 23 per cubic millimeter, and 65 percent of the patients had had an acquired immunodeficiency syndrome-defining illness. During follow-up over a median period of 12 months, there were no episodes of confirmed M. avium complex disease in either group (95 percent confidence interval for the rate of disease in each group, 0 to 1.5 episodes per 100 person-years). Three patients in the azithromycin group (1.2 percent) and five in the placebo group (1.9 percent) had bacterial pneumonia (relative risk in the azithromycin group, 0.60; 95 percent confidence interval, 0.14 to 2.50; P=0.48). Neither the rate of progression of HIV disease nor the mortality rate differed significantly between the two groups. Adverse effects led to discontinuation of the study drug in 19 patients assigned to receive azithromycin (7.4 percent) and in 3 assigned to receive placebo (1.1 percent; relative risk, 6.6; P=0.002).

CONCLUSIONS

Azithromycin prophylaxis can safely be withheld in HIV-infected patients whose CD4+ cell counts have increased to more than 100 cells per cubic millimeter in response to antiretroviral therapy.

Fire prevention for teenage mothers enrolled in high school

A fire prevention/burn education program has been developed, presented, and evaluated. The program was presented to teenage students in four inner city high schools who were also the parents of infants and toddlers. The program was judged to be effective based on testing results, classroom teacher response, and school administration endorsement.

Diarylamidine derivatives with one or both of the aryl moieties consisting of an indole or indole-like ring. Inhibitors of arginine-specific esteroproteases

A series of 62 diarylamidine derivatives was evaluated for their antiproteolytic activity. In all but two of the compounds one or both of the amidino-substituted aryl moieties was either an indole or an indole-like ring. The latter included indene, benzimidazole, benzofuran, benzol[beta]thiophene, and several other related nitrogen-containing heterocycles. Several of the compounds exhibited considerable inhibitory potency against thrombin, trypsin, and pancreatic kallikrein. An outstanding inhibitor of trypsin was found in bis(5-amidino-2-benzimidazolyl)methane (compound 42) with a Ki value of 1.7 X 10(-8) M(pH. 8.1, 37 degrees C). Another derivative, 1,2-di(4-amidino-2-benzofuranyl)ethane (compound 21), proved to be a highly effective inhibitor of the overall blood clotting process. From a general structure-activity standpoint these compounds demonstrate that minor structural variations of low-molecular-weight inhibitors can result in significant changes in specificity and potency with regard to antiproteolytic activity.