Small-molecule proteostasis regulators for protein conformational diseases.

Protein homeostasis (proteostasis) is essential for cellular and organismal health. Stress, aging and the chronic expression of misfolded proteins, however, challenge the proteostasis machinery and the vitality of the cell. Enhanced expression of molecular chaperones, regulated by heat shock transcription factor-1 (HSF-1), has been shown to restore proteostasis in a variety of conformational disease models, suggesting this mechanism as a promising therapeutic approach. We describe the results of a screen comprised of ∼900,000 small molecules that identified new classes of small-molecule proteostasis regulators that induce HSF-1-dependent chaperone expression and restore protein folding in multiple conformational disease models. These beneficial effects to proteome stability are mediated by HSF-1, FOXO, Nrf-2 and the chaperone machinery through mechanisms that are distinct from current known small-molecule activators of the heat shock response. We suggest that modulation of the proteostasis network by proteostasis regulators may be a promising therapeutic approach for the treatment of a variety of protein conformational diseases.

Respiratory vaccination.

Vaccinations are among the most cost-effective preventive health strategies to reduce healthcare costs and prevent morbidities. Every year, many adults and elderly encounter hospitalization because of infectious respiratory diseases. Among these, viral and bacterial pneumonia, tuberculosis, diphtheria and pertussis infections are some of the diseases that can be prevented and managed with fewer complications, with adequate preventive immunization. This review tries to outline the vaccines available for the prevention of these respiratory ailments along with their schedule and dosages.

Antimicrobial prescribing patterns of surgical speciality in a tertiary care hospital in India: Role of persuasive intervention for changing antibiotic prescription behaviour.

BACKGROUND: Inappropriate use of antibiotics globally has been linked to increase in antibiotic resistance. OBJECTIVES: This interventional study assessed the impact of antibiotic prescription feedback and focus group discussions (FGD) on hospital-based prescribers before and after the FGD. STUDY DESIGN: The present study was performed at a tertiary care centre in New Delhi, wherein 45 units from surgical specialities were included for FGD. Thirty-five units were assessed for the antibiotic usage during 12 months pre-intervention and 3 and 6 months post-intervention period. The outcome measured was a change in antibiotic prescription rates reflected as daily defined doses per 100 bed days as defined by the World Health Organisation. RESULTS: Reduction in the level of antibiotic consumption was observed in 15 of 35 units (42.85%) during the 3 months post-intervention period, which was significant (P < 0.05) in 3/35 (8.57%) surgical units. A significant reduction (P < 0.05) was observed for the units of endoscopic gynaecology, super-speciality and transplant surgery units B and C, and orthopaedic unit C during the 6 months period. Decreasing trend (P < 0.05) was observed in 2/35 (5.71%) units during the entire period. Overall reduction of antibiotic consumption (1.88%) was observed, with an increase in the use of low-end antibiotics and a decrease in the use of high-end antibiotics. CONCLUSION: The present study clearly demonstrates a weak impact of FGD in changing antibiotic prescribing behaviour. Further analysis of the sustainability of FGD and its long-term impact on antimicrobial resistance needs to be evaluated. The effect of continuous educational sessions and multifaceted interventions cannot be ignored.

Threshold of galactomannan antigenemia positivity for early diagnosis of invasive aspergillosis in neutropenic children.

PURPOSE: Invasive aspergillosis (IA) is an important cause of morbidity and mortality in immunocompromised patients. Pediatric data on the accuracy and optimal cutoff of galactomannan antigen detection to diagnose IA is sparse and controversial. We evaluated the utility and optimal serum galactomannan assay (GA) cutoff in children. METHODS: Children with febrile neutropenia due to malignancy, hematopoietic stem cell transplant, aplastic anemia, or congenital neutropenia, were prospectively included from 2007 to 2011. All new episodes of febrile neutropenia were recorded. In case of a previous diagnosis of IA, subsequent episodes were excluded. One to four GA were tested by enzyme immunoassay during each episode. Bronchoalveolar lavage and other relevant samples for mycological diagnosis, and computed tomography of chest/sinus were performed wherever appropriate. IA was classified as "proven", "probable", and "possible" as per the 2008 European Organisation for Research and Treatment of Cancer and Mycoses Study Group Guidelines. The optimal cutoff value was determined using receiver operating characteristic curves in episode-wise analysis. RESULTS: There were 145 patients with 211 febrile episodes included: hematopoietic stem cell transplant (n = 15), oncological (n = 113), and hematological disorders (n = 17). Forty-five children (31.0%) developed IA (5 proven, 15 probable, and 25 possible). Cutoff value of single GA ≥ 0.7 for proven/probable/possible IA offered the best combination of sensitivity (82.2%)/specificity (82.5%), and 94.4% negative predictive value. Two consecutive positive GA ≥ 0.7 had a sensitivity/specificity of 75.0%/91.0%. Index GA ≥ 1.9 was associated with significantly higher mortality in children with IA and overall. CONCLUSION: Serum GA is sensitive to diagnose IA in pediatric patients with excellent negative predictive value at an optimal cutoff of ≥0.7. Considering two consecutive values ≥0.7 increases specificity to 91.0%.

A simple structured mathematical model for biopolymer (PHB) production.

Economic production technology for a biodegradable polymer (poly-beta-hydroxybutyrate, PHB) is urgently required to replace conventional polymers, which have an inherent disadvantage of staying in the environment forever. Various approaches have been applied for improving the productivity and reducing the production cost, which are considered to be the two major problems associated with industrial production of PHB. One of the engineering approaches to improve PHB productivity could be to design and implement model-based fed-batch cultivations to provide desirable nutrient availability. In the present study, growth and intracellular biopolymer storage kinetics of Ralstonia eutropha was studied in a batch cultivation process. It featured 19.7 g/L biomass and 10.89 g/L PHB with a productivity of 0.18 g/L.h. The effect of carbon, nitrogen, and phosphate limitations and inhibitions on growth was studied in detail. A structured model featuring typical growth limitations and/or possible inhibitions was then proposed. The value of the model parameters was found by minimizing the difference between experimental value and model simulation at all data points and for all process variables. The optimal batch model parameter values obtained above were used to solve the differential equations numerically. The simulated data obtained in this way was then compared with the experimental data to establish the validity of the batch model. The proposed model was then compared with literature reported mathematical models to reconfirm its accuracy. Statistical validity of the developed model and historical models to describe the observed experimental kinetics was then investigated to reinforce the accuracy of the developed simple model.

On-line characterization of physiological state in poly(beta-hydroxybutyrate) production by Wautersia eutropha.

Culture fluorescence measurement technique has the potential for on-line characterization of metabolic status of fermentation processes. Many fluorophores present inside the living cells such as NADH + H+, tryptophan, pyridoxine, and riboflavin fluoresce at specific excitation and emission wavelength combinations. Since these key intracellular metabolites are involved in cell growth and metabolism, their concentration change at any time inside the cell could reflect the changes in cell metabolic activity. NADH + H+ spectrofluorometry was used for on-line characterization of physiological state during batch cultivation of poly-beta-hydroxybutyric acid (PHB) production by Wautersia eutropha. The culture fluorescence increased with an increase in the biomass concentration with time. A linear correlation between cell mass concentration and net NADH + H+ fluorescence was established during active growth phase (13 to 38 h) of batch cultivation. The rate of change of culture fluorescence (dF/dt) exhibited a gradual increase during the predominantly growth phase of batch cultivation (till 20 h). Thereafter, a sudden drop in the dF/dt rate and its leveling was recorded indicating major changes in culture metabolism status which synchronized with the start-up of accumulation of PHB. After 48 h, yet another decrease in the rate of change of fluorescence (dF/dt) was observed primarily due to severe substrate limitation in the reactor. On-line NADH + H+ fluorescence signal and its rate (dF/dt) could therefore be used to distinguish the growth, product formation, and nutrient depletion stage (the metabolic state marker) during the batch cultivation of W. eutropha.

Production of poly(3-hydroxybutyric-co-3-hydroxyvaleric acid) having a high hydroxyvalerate content with valeric acid feeding.

The capability of different organic acids to produce a derivative of PHB [poly(3-hydroxybutyric-co-3-hydroxyvaleric acid), P(3HB-co-3HV)] was examined in shake flask cultivations. Propionic and valeric acids demonstrated the potential to produce P(3HB-co-3HV) under nitrogen limiting conditions at 30 degrees C. The addition time and the initial concentration of valeric acid needed for a high cellular HV content were identified by extensive experimentation. Fed-batch cultivation in 7-l bioreactor with valeric acid feeding resulted in the production of PHA containing 54% HV units.

Repeated batch cultivation of Ralstonia eutropha for Poly (beta-hydroxybutyrate) production.

Batch cultivation of Ralstonia eutropha NRRL B14690 attained 21 g biomass l(-1) and 9.4 g poly(beta-hydroxybutyrate) l(-1) (0.45 g PHB g(-1 )dry wt(-1)) in 60 h. Repeated batch operation (empty-and-fill protocol) to remove 20% (v/v) of the culture broth and to supplement an equal volume of fresh media resulted in 49 g biomass l(-1) and 25 g PHB l(-1) (0.51 g PHB g(-1) dry wt(-1)) with an overall productivity of 0.42 g PHB l(-1 )h(-1 )in 67 h. In the two cycles of repeated batch fermentation there was a 3-fold increase in productivity as compared to batch.