Taming hazardous chemistry by continuous flow technology.

Over the last two decades, flow technologies have become increasingly popular in the field of organic chemistry, offering solutions for engineering and/or chemical problems. Flow reactors enhance the mass and heat transfer, resulting in rapid reaction mixing, and enable a precise control over the reaction parameters, increasing the overall process selectivity, efficiency and safety. These features allow chemists to tackle unexploited challenges in their work, with the ultimate objective making chemistry more accessible for laboratory and industrial applications, avoiding the need to store and handle toxic, reactive and explosive reagents. This review covers some of the latest and most relevant developments in the field of continuous flow chemistry with the focus on hazardous reactions.

Evaluation of the transfection efficacies of quaternary ammonium salts prepared from sophorolipids.

Five quaternary ammonium amphiphilic compounds were synthesized from sophorolipid 1. These compounds were formulated in aqueous media and some of them (5 and 6) produced well-defined supramolecular aggregates which were characterized by DLS and zeta measurements. Their capacity to transfect four different eukaryotic cell lines in vitro was assessed. To evaluate the influence of the carbohydrate head group from the sophorolipids on the transfection efficacies, their deglycosylated analogues were also synthesized and tested for gene delivery. For all the compounds, the use of DOPE as a helper lipid in a 1 : 1 molar ratio with the ammonium-based lipids was required to obtain homogeneous formulations. The transfection results indicate that quaternary ammonium-based sophorolipids proved to be more efficient pDNA carriers than their deglycosylated counterparts. Moreover, the presence of the carbohydrate head group clearly contributed to the good biocompatibility of these cationic lipids. These cationic sophorolipid derivatives thus offer good potential for the development of new vectors for gene delivery based on renewable resources.

Beyond the Diketopiperazine Family with Alternatively Bridged Brevianamide F Analogues.

A method for the preparation of 3,5-bridged piperazin-2-ones from a tryptophan-proline-based diketopiperazine is described using diphosgene to induce the ring closure. Density functional theory calculations were conducted to study the mechanism of this C-C bond formation. Several derivatives of the thus obtained α-chloroamine were synthesized by substitution of the chlorine atom using a range of O-, N-, S-, and C-nucleophiles. This novel class of brevianamide F analogues possess interesting breast cancer resistance protein inhibitory activity.

HIV-1 induction-maintenance at the lymph node level: the "Apollo-97" Study.

OBJECTIVE: To assess the effects of five-drug combination therapy on HIV-1 load in lymph nodes and subsequent maintenance with four and three drugs. METHODS: Ten pharmacotherapeutically naive patients received a combination of zidovudine, lamivudine, didanosine, ritonavir, and saquinavir for 24 weeks, then zidovudine, lamivudine, didanosine, and saquinavir for the next 24 weeks, and finally zidovudine, lamivudine, and saquinavir for the last 24 weeks. HIV-1 RNA in lymph nodes was measured using quantitative polymerase chain reaction (PCR) at baseline, after 12, 24, 48, and 78 weeks. Plasma HIV-1 RNA, proviral DNA in peripheral blood mononuclear cells (PBMCs), circulating lymphocyte subsets, and protease inhibitor levels in blood were also regularly measured. Genotypic resistance was assessed in the different compartments in 2 patients who were failed by therapy. RESULTS: HIV-1 RNA decreased in lymph nodes in 9 patients and was stable in 1 despite initial control of plasma replication <20 copies/ml in each patient. Lymph node levels rebounded in 1 patient at week 72 as a result of lack of adherence and remained stable in the 8 others despite maintenance regimens. This represents a mean drop of -3.17 log in lymph nodes for the 8 patients maintaining undetectable viremia at 72 weeks. In the patient with stable lymph node viral RNA, selection of the M184V mutation was demonstrated at this level before detection in plasma and low blood saquinavir levels were found throughout the study. Continuous improvements in immune parameters were observed in all cases, although PBMC proviral DNA levels either showed a continuous decrease or stabilized to a plateau. CONCLUSIONS: More complex regimens do not perform better in lymph nodes than classic triple therapy. The persistence of HIV-1 RNA in lymph nodes could be related with cellular resistance mechanisms rather than an insufficient potency of the regimens.

Pilot study of a combination of highly active antiretroviral therapy and cytokines to induce HIV-1 remission.

A pilot study of a combination of highly active antiretroviral therapy (HAART) and cytokines in early HIV-1 infection has been undertaken to test the hypothesis that HIV-1 remission can be reached with this strategy by flushing latently infected viral reservoirs. Ten previously antiretroviral naive patients have received a combination of zidovudine, lamivudine, didanosine, saquinavir, and ritonavir for 72 weeks. Between weeks 12 and 48, three courses of interleukin (IL)-2 (7.5 millions of international units [MUI] twice a day for 5 consecutive days) and 2 courses of gamma-interferon (IFN) (100 microg every other day during 2 weeks) were administered subcutaneously. All patients reached plasma HIV-1 RNA levels < 20 copies/ml within 12 +/- 4 weeks. Transient increases in plasma levels (< 120 copies/ml) were observed during administration of IL-2, but less frequently during gamma-IFN administration. HIV-1 RNA decreased in lymph node cells by approximately 4 log, then remained stable after week 24. A mean drop of -0.8 log in peripheral blood mononuclear cell (PBMC) proviral DNA was observed during the trial. Isolation of potentially infectious HIV-1 was successful in each case by coculture of CD4+ T cells taken at week 72. The 2 patients who stopped therapy at the end of the trial showed rebounding plasma HIV-1 RNA levels within a few weeks. No additional mutations were selected in comparison with those present at baseline in 8 patients. In addition, 2 patients developed new mutations in the reverse transcriptase or protease gene and in 1 case, resistance selection was found in lymphoid tissue HIV-1 RNA but not in latently infected cells. In all cases, a rapid increase in both naive and memory CD4+ T cells was observed, with a reduction in activation markers and preservation of the CD8+CD28+ subset. Consequently, an aggressive regimen of HAART and cytokines administered in early stage disease is associated with a positive effect in terms of proviral load reduction and immune reconstitution but is unable to induce HIV-1 remission, allowing low levels of viral replication to persist in lymphoid reservoirs.

Correlation between plasma levels of cytokines and HIV-1 RNA copy number in HIV-infected patients.

The plasma levels of HIV-1 RNA, tumor necrosis factor alpha (TNF-alpha), soluble receptors type II of TNF-alpha (sTNF-alpha RII), soluble receptors of interleukin-4 (sR IL-4), interleukin-6 (IL-6), soluble receptors of interleukin-6 (sR IL-6), granulocyte macrophage colony stimulating factor (GM-CSF), soluble receptors of GM-CSF (sR GM-CSF), RANTES, MIP-1 alpha and MIP-1 beta were measured in 80 HIV-infected patients. All patients had not been treated previously with antiretroviral drugs and did not present a recent history of opportunistic infection. A statistically significant correlation was found between HIV-1 RNA and TNF-alpha (p = 0.005) or sTNF-alpha RII levels (p < 0.001). RANTES and MIP-1 alpha levels did not correlate with HIV-1 RNA. MIP-1 beta levels were correlated with plasma RNA titers in patients with CD4+ T cells < 200 x 10(6)/l (p = 0.03). MIP-1 alpha and sR IL-4 levels were significantly different according to the CD4+ T cell range (p = 0.003 and p = 0.0002, respectively). GM-CSF and sR GM-CSF were undetectable in each case. These data confirm that HIV-1 replication in the plasma is correlated with TNF-alpha levels, but do not show a clear correlation with levels of the chemokines studied.

Lymph node expansion of CD4+ lymphocytes during antiretroviral therapy.

The evolution of lymphocyte subsets was analyzed in sequential lymph nodes (LN) biopsies and compared with that in the blood of 25 human immunodeficiency virus type 1 (HIV-1)-infected patients receiving highly active antiretroviral therapy. An average of 3 biopsies were obtained from each patient, with a mean follow-up of 5.6 +/- 0.6 months. A correlation was found between the CD4:CD8 ratio in blood and in LN at baseline but not after > or = 2 months of therapy. With therapy, there was a significant increase in CD2+ cells and a much higher CD4+ cell increase and CD8+ cell decrease in LNs compared with levels in blood. A subset of patients had increased expression of Ki-67 and a decreased expression of CD8CD38 or CD3HLA-DR. Expanded CD4+ cells in LNs were mainly CD45RO+, and changes were concomitant with a decrease in LN virus load. These data demonstrate that CD4 cell reconstitution in HIV-1 infection takes place primarily in secondary lymphoid organs and is not related to a simple redistribution of cells.

[Value of anticardiolipin antibody assay in human immunodeficiency virus infection]. / Intérêt du dosage des anticorps anticardiolipine au cours de l'infection par le virus de l'immunodéficience humaine.

Recently published encouraging data concerning the value of anticardiolipin antibody assays in patients with HIV infection, both for prognostic purposes and to diagnose pneumocystosis, have prompted us to evaluate these assays in a series of 116 patients. We were unable to demonstrate any correlation between the levels of these antibodies and the clinical stage of the infection or the presence of thrombocytopenia. Varying levels of anticardiolipin antibodies were found in 29.3 percent of our patients. More frequent positivity and higher levels seemed to be associated only with the development of cerebral toxoplasmosis. The value and the possible physiopathological role of these antibodies in patients with HIV infection should be reconsidered.

[Intestinal spirochetosis in homosexuals infected with HIV. 3 cases]. / Spirochétose intestinale chez les homosexuels infectés par le virus de l'immunodéficience humaine. Trois observations.

We report 3 cases of intestinal spirochetosis in homosexuals infected with the human immunodeficiency virus (2 group III and 1 group IV C1, according to the Centers for Disease Control classification) presenting with moderate, chronic diarrhea. The diagnosis was made based on the histological examination of colorectal biopsies showing a layer of spirochetes carpeting the epithelium. Electron microscopy evaluation and culturing of the microorganism provided information on the bacterium's morphology. Metronidazole effectively treated the diarrhea. Intestinal spirochetes, whose existence has been recognized for more than a century, constitute a heterogeneous group of bacteria whose pathogenic role in man remains controversial. The systemic search for these organisms in a large series of patients would help to situate their place among the various etiologies of infectious diarrhea in immunodepressed subjects.

[Survey of "Neisseria gonorrhoeae" sensitivity to antibiotics by dilution and diffusion methods using a new medium (author's transl)]. / Détermination de la sensibilité de Neisseria gonorrhoeae aux antibiotiques par dilution et diffusion en gélose à l'aide d'un nouveau milieu.

Usual media are not convenient for the determination of minimal inhibitory concentrations (MIC). An agar medium without haemoglobin and seric proteins (ABNG) is proposed. Using the dilution method with less fastidious bacteria, including Neisseria sp., MIC were identical on Mueller-Hinton agar and ABNG. By using diffusion techniques, the correlation was good between MIC and zone diameters; the density of inoculum for gonococci was 2 x 10(6) CFU/ml. Dilution and diffusion techniques were used for penicillin, ampicillin, thiamphenicol, tetracycline and spectinomycin. It appears that the diffusion technique with ABNG medium would simplify the antibiotic sensitivity survey for N. gonorrhoeae, dilution technique remaining the reference method.

[Pulmonary mycobacteriosis due to Mycobacterium chelonei: a report on a new case (authors' transl)]. / Mycobactériose pulmonaire à Mycobactérium chelonei. Une nouvelle observation.

Mycobacterium chelonei is a saprophytic germ usually devoid of pathogenic activity. Over a period of about the last ten years, however, several cases have been reported, including twelve cases of bronchopulmonary affections, in which it has been the infecting organism. The radiographic appearance is in every respect similar to that observed in pulmonary tuberculosis. A positive diagnosis of infection due to this germ can be made by the absence of Kuch's bacillus the lack of therapeutic effect of antituberculous medication, a positive skin reaction to specific antigens, and positive Mycobacterium Chelonei cultures from biopsy specimens. A new case of this infection is reported.