Design and fabrication of a smart sensor using in silico epitope mapping and electro-responsive imprinted polymer nanoparticles for determination of insulin levels in human plasma.

A robust and highly specific sensor based on electroactive molecularly imprinted polymer nanoparticles (nanoMIP) was developed. The nanoMIP tagged with a redox probe, combines both recognition and reporting capabilities. The developed nanoMIP replaces enzyme-mediator pairs used in traditional biosensors thus, offering enhanced molecular recognition for insulin, improving performance in complex biological samples, and yielding high stability. Also, most of existing sensors show poor performance after storage. To improve costs of the logistics and avoid the need of cold storage in the chain supply, we developed an alternative to biorecognition system that relies on nanoMIP. NanoMIP were computationally designed using "in-silico" insulin epitope mapping and synthesized by solid phase polymerisation. The characterisation of the polymer nanoparticles was performed by transmission electron microscopy (TEM), dynamic light scattering (DLS), Fourier-transform Infrared (FT-IR) and surface plasmon resonance (SPR). The electrochemical sensor was developed by chemical immobilisation of the nanoMIP on screen printed platinum electrodes. The insulin sensor displayed satisfactory performances and reproducible results (RSD = 4.2%; n = 30) using differential pulse voltammetry (DPV) in the clinically relevant concentration range from 50 to 2000 pM. The developed nanoMIP offers the advantage of large number of specific recognition sites with tailored geometry, as the resultant, the sensor showed high sensitivity and selectivity to insulin with a limit of detection (LOD) of 26 and 81 fM in buffer and human plasma, respectively, confirming the practical application for point of care monitoring. Moreover, the nanoMIP showed adequate storage stability of 168 days, demonstrating the robustness of sensor for several rounds of insulin analysis.

Plasma exchange with immunosuppression in pulmonary alveolar haemorrhage due to leptospirosis.

BACKGROUND & OBJECTIVES: Pulmonary involvement due to leptospirosis carries high case fatality rate and is the commonest cause of death due to leptospirosis. Immune mechanisms play a key role in the pathogenesis of leptospiral pulmonary haemorrhage. As other immune pulmonary haemorrhages due to non leptospiral causes are treated with plasma exchange and cyclophosphamide we evaluated their efficacy in patient with leptospiral pulmonary haemorrhage. METHODS: Of the 602 confirmed patients of leptospirosis, 236 (39.2%) had pulmonary haemorrhage. Of these,144 had mild haemorrhage (acute lung injury score < 2.5) and were included in the study. One hundred and fourteen patients were given two cycles of plasma exchange, 24 h apart, 25 ml/kg body weight of plasma was removed in each cycle. Cyclophosphamide (20 mg/kg body weight) was given after the first plasma exchange cycle. The remaining 30 patients were not given this treatment, and used as control. RESULTS: In the control group only 5 (16.6%) patients survived while in the treatment group 70 (61.40%) patients survived. Thrombocytopenia was observed in 111 (77.08%) patients. Renal and hepatic involvement was seen but did not account for mortality. Minor complications were seen in group I patients after plasma exchange and cyclophosphamide treatment, but none were serious. INTERPRETATION & CONCLUSIONS: Our findings showed that plasma exchange with immunosuppression improved survival in patients of pulmonary alveolar haemorrhage due to leptospirosis, suggesting that immune mechanisms play a key role in the pathogenesis of the disease.

Cyclophosphamide in pulmonary alveolar hemorrhage due to leptospirosis.

BACKGROUND AND AIMS: Severe pulmonary involvement in leptospirosis carries high mortality rates. It is the most common cause of death due to leptospirosis in many parts of India and the world. Exacerbated immune response of the host plays an important role in its pathogenesis. Hence, immunosuppressive drugs could be useful in its treatment. Glucocorticosteroids have been found to be useful in several studies. Cyclophosphamide, an immunosuppressive agent, has been found to be useful in a majority of pulmonary alveolar hemorrhages due to non leptospiral causes. This study was carried out to study the effects of cyclophosphamide in patients with leptospiral pulmonary alveolar hemorrhage. METHOD: A total of 65 patients with confirmed leptospirosis with severe pulmonary involvement admitted to a tertiary care center in south Gujarat were included in the study. All of the patients were treated with injection crystalline penicillin, methyl prednisolone pulse therapy, and non invasive mechanical ventilation. A total of 33 patients were given parenteral cyclophosphamide 60 mg/kg body weight stat on diagnosis. Their outcomes were compared with the remaining 32 patients who had not been given this drug. Survival was considered the main outcome indicator. RESULTS: Out of the 33 patients treated with cyclophosphamide, 22 (66.7%) survived, while in the control group out of 32 patients, three (9.4%) survived. On statistical analysis, the odds ratio was 19.33 (4.22-102.13) and the P-value was < 0.001. Leucopenia (78.78%) and alopecia (18.75%) were the main side effects noted. No mortality was noted due to these side effects. CONCLUSION: Cyclophosphamide improves survival in cases of severe pulmonary alveolar hemorrhage due to leptospirosis. Statistically, the improvement is highly significant.