An animal component free medium that promotes the growth of various animal cell lines for the production of viral vaccines

IPT-AFM is a proprietary animal component free medium that was developed for rabies virus (strain LP 2061) production in Vero cells. In the present work, we demonstrated the versatility of this medium and its ability to sustain the growth of other cell lines and different virus strains. Here, three models were presented: Vero cells/rabies virus (strain LP 2061), MRC-5 cells/measles virus (strain AIK-C) and BHK-21 cells/rabies virus (strain PV-BHK21). The cell lines were first adapted to grow in IPT-AFM, by progressive reduction of the amount of serum in the culture medium. After their adaptation, BHK-21 cells grew in suspension by forming clumps, whereas MRC-5 cells remained adherent. Then, kinetics of cell growth were studied in agitated cultures for both cell lines. In addition, kinetics of virus replication were investigated.     

Infection-related ventilator-associated complications in ICU patients colonised with extended-spectrum β-lactamase-producing Enterobacteriaceae

Purpose

To investigate the clinical significance of infection-related ventilator-associated complications (IVAC) and their impact on carbapenem consumption in mechanically ventilated (MV) patients colonised with extended-spectrum β-lactamase-producing Enterobacteriaceae (ESBLE).

Methods

Inception cohort study from the French prospective multicenter OUTCOMEREA database (17 ICUs, 1997–2015) including all ESBLE carriers (systematic rectal swabbing at admission then weekly and/or urinary or superficial surgical site colonisation) with MV duration?>?48 h and?≥?1 episode of IVAC after carriage documentation. All ICU-acquired infections were microbiologically documented.

Results

The 318 enrolled ESBLE carriers (median age 68 years; males 67%; medical admission 68%; imported carriage 53%) experienced a total of 576 IVAC comprising 361 episodes (63%) without documented infection, 124 (21%) related to infections other than ventilator-associated pneumonia (VAP), 73 (13%) related to non-ESBLE VAP and 18 (3%) related to ESBLE VAP. Overall, ESBLE infections accounted for only 43 episodes (7%). Carbapenem exposure within the preceding 3 days was the sole independent predictor of ESBLE infection as the causative event of IVAC, with a protective effect (adjusted odds ratio 0.2, 95% confidence interval 0.05–0.6; P?<?0.01). Carbapenems were initiated in 9% of IVAC without infection, 15% of IVAC related to non-VAP infections, 42% of IVAC related to non-ESBLE VAP, and 56% of IVAC related to ESBLE VAP (ESBLE VAP versus non-ESBLE VAP: P?=?0.43).

Conclusions

IVAC in ESBLE carriers mostly reflect noninfectious events but act as a strong driver of empirical carbapenem consumption. ESBLE infections are scarce yet hard to predict, strengthening the need for novel diagnostic approaches and carbapenem-sparing alternatives.

     

State‐dependent blocking mechanism of Kv1.3 channels by the antimycobacterial drug clofazimine

Background and Purpose

K_v1.3 potassium channels are promising pharmaceutical targets for treating immune diseases as they modulate Ca²⁺ signalling in T cells by regulating the membrane potential and with it the driving force for Ca²⁺ influx. The antimycobacterial drug clofazimine has been demonstrated to attenuate antigen‐induced Ca²⁺ oscillations, suppress cytokine release and prevent skin graft rejection by inhibiting K_v1.3 channels with high potency and selectivity.

Experimental Approach

We used patch‐clamp methodology to investigate clofazimine''s mechanism of action in K_v1.3 channels expressed in HEK293 cells.

Key Results

Clofazimine blocked K_v1.3 channels by involving two discrete mechanisms, both of which contribute to effective suppression of channels: (i) a use‐dependent open‐channel block during long depolarizations, resulting in accelerated K⁺ current inactivation and (ii) a block of closed deactivated channels after channels were opened by brief depolarizations. Both modes of block were use‐dependent and state‐dependent in that they clearly required prior channel opening. The clofazimine‐sensitive closed‐deactivated state of the channel was distinct from the resting closed state because channels at hyperpolarized voltages were not inhibited by clofazimine. Neither were channels in the C‐type inactivated state significantly affected. K_v1.3 channels carrying the H399T mutation and lacking C‐type inactivation were insensitive to clofazimine block of the closed‐deactivated state, but retained their susceptibility to open‐channel block.

Conclusions and Implications

Given the prominent role of K_v1.3 in shaping Ca²⁺ oscillations, the use‐dependent and state‐dependent block of K_v1.3 channels by clofazimine offers therapeutic potential for selective immunosuppression in the context of autoimmune diseases in which K_v1.3‐expressing T cells play a significant role.

Abbreviations

CLF

clofazimine

FDA

Food and Drug Administration

IPI

interpulse intervals

WT

wild type

     

Pneumocystis carinii pneumonia in patients with hematologic malignancies: a descriptive study

Objectives. A retrospective multicentric study was conducted over a five-year period to evaluate the clinical and laboratory characteristics and outcome of patients with proven Pneumocystis carinii pneumonia (PCP) complicating hematologic malignancies.Results. The study included 60 HIV-negative patients with 18 non-Hodgkin's malignant lymphoma (30%), 13 chronic lymphocytic leukaemia (21.7%), 10 acute leukemia (16.6%), 5 multiple myeloma (8.3%), 4 Waldenstr?m's diseases (6.6%), 4 chronic myeloid leukemia (6.6%), 3 myelodysplasia (5%), 2 Hodgkin's diseases (3.3%) and 1 thrombopenia. Bronchoalveolar lavage was diagnostic in all patients. Forty-nine patients received cytotoxic drugs (81.7%), 25 (41.7%) a long-term corticotherapy and 15 (25%) underwent bone marrow transplantation. Twenty-seven patients (45%) required admission in the intensive care unit, 35 (58.3%) received an adjunctive corticotherapy and 18 mechanical ventilation (30%). Twenty patients (33.3%) died of PCP. A previous long-term corticotherapy (p=0.04), high respiratory (p=0.05) and pulse rates (p=0.02), elevated C reactive protein (p=0.01) and mechanical ventilation (OR=13.37; IC: 1.9-50) were associated with a poor prognosis. Adjunctive corticotherapy did not modify the prognosis.Conclusions. These results suggest that PCP can occur during the course of various hematologic malignancies, not only lymphoproliferative disorders. Prognosis remains poor. The diagnosis should be advocated more frequently and earlier to improve the prognosis.