Thermal resilience of ensilicated lysozyme via calorimetric and in vivo analysis

Ensilication is a novel method of protein thermal stabilisation using silica. It uses a modified sol–gel process which tailor fits a protective silica shell around the solvent accessible protein surface. This, electrostatically attached, shell has been found to protect the protein against thermal influences and retains its native structure and function after release. Here, we report the calorimetric analysis of an ensilicated model protein, hen egg-white lysozyme (HEWL) under several ensilication conditions. DSC, TGA-DTA-MS, CD, were used to determine unfolding temperatures of native, released and ensilicated lysozyme to verify the thermal resilience of the ensilicated material. Our findings indicate that ensilication protects against thermal fluctuations even at low concentrations of silica used for ensilication. Secondly, the thermal stabilisation is comparable to lyophilisation, and in some cases is even greater than lyophilisation. Additionally, we performed a mouse in vivo study using lysozyme to demonstrate the antigenic retention over long-term storage. The results suggest that protein is confined within the ensilicated material, and thus is unable to unfold and denature but is still functional after long-term storage.

Ensilication is a novel method of protein thermal stabilisation using silica. It uses a modified sol–gel process which tailor fits a protective silica shell around the protein to enable room temperature storage of biopharmaceuticals.

Correction: Polymers of intrinsic microporosity as high temperature templates for the formation of nanofibrous oxides

Correction for ‘Polymers of intrinsic microporosity as high temperature templates for the formation of nanofibrous oxides’ by H. Al Kutubi et al., RSC Adv., 2015, 5, 73323–73326.

Polymers of intrinsic microporosity as high temperature templates for the formation of nanofibrous oxides

Highly rigid polymers of intrinsic microporosity (PIM) offer novel high temperature template materials for the formation of nano-structured metal oxides, here for nanostructured Pr₆O₁₁.

[Left ventricular function in chronic obstructive lung disease (author's transl)]

Left ventricular function was studied at rest and during post-extrasystolic potentiation in 18 patients with chronic obstructive lung disease. The contractility indices used were obtained from pressures recorded in the isovolumetric period (left ventricular end-diastolic pressure, Vmax., VECmax., dP/dtmax.) and from volume variations during ejection (end-diastolic volume, ejection fraction, VCF). Left ventricular diastolic compliance was also evaluated. All patients were hypoxic (PaO2 = 58 +/- 7 torr); six of them had cor pulmonale (group B); the remaining 12 patients constituted group A. Left ventricular function of groups A and B was similar; we conclude that right cardiac failure, in cor pulmonale, is not secondary to left ventricular failure. However, left ventricular dysfunction exists; the left ventricle is hypertrophied (probably resulting from chronic hypoxia). Pump function is altered (abnormal ventricular function points are found), but left ventricular kinetics is normal or exaggerated (ejection fraction and VCF are increased). Isovolumetric phase contractility indices are diminished; however, they may increase normally during post-extrasystolic potentiation. Left ventricular compliance is abnormal due to left and right ventricular hypertrophy and to paradoxical movement of the interventricular septum which impedes diastolic expansion of the left ventricle. These changes are responsible for decreased left ventricular output. There seems to exist an impairment of left ventricular function related to both intrinsic (secondary to hypoxia, hypercapnia, left ventricular hypertrophy) and extrinsic factors (right ventricula hypertrophy deviating interventricular septum, lowering of left ventricular preload).

[Problems raised by the technique and supervision of home ventilation of chronic respiratory insufficient patients (author's transl)]

The effectiveness of assisted ventilation at home, especially in the case of tracheostomized patients, has been nearly established at the present time. The experience of various centers in France, having or not the support of an independent structured organization, shows that the setting-up and supervision of such therapy can be effectively carried out. Nevertheless, difficult choices remain. Some indications are still questionable, such as the choice of the respirator if the patient has not been tracheostomized. The type of organization is not univocal and could perhaps depend on the number of patients to be cared for. In any case, in the years to come, the experience of the different teams and the technical progress made will lead to a solution to the problems raised: a decrease in the number of hospitalizations and more comfort for the patients can be hoped for.

[Polyradiculoneuritis in a diabetic patient. Ultrastructural study of a biopsy of a peripheral nerve]

We have made a study of a case of polyradiculoneuritis occurring in a diabetic. Clinically, symptoms were very similar to those in classical Guillain-Barré syndrome and respiratory complications necessitated a stay in a Respiratory Resuscitation Centre. Recuperation was slow but practically total. Ultrastructural changes noted in the roots and the peripheral nerves of patients suffering from Guillain-Barré syndrome are similar to those occurring in experimental allergic neuropathies. These changes are specific as the myelin takes on a fishnet appearance and, more important, the myelin is attacked by the projection of a mononucleate cell which has passed through the cytoplasm of the Schwann cells. We did not find this in our case. On the other hand, the lesions we found consisted of a mixture of common segmental demyelinization and axonal lesions, associated with marked Schwann cell hypertrophy coiled around most of the myelinized fibres. Such aspects are very like those found in certain diabetic neuropathies. The existence of significant microangiopathy which was present in this case is also an important, though not a decisive factor. We consider, therefore, that the syndrome of polyradiculoneuritis exhibited by this patient corresponds more closely to diabetic neuropathy than to a classical Guillain-Barré syndrome.

[Postoperative circulatory arrest (apropos of 37 cases)]

Within five years, the authors received 37 patients who had presented a post-operative cardiac arrest. Most of them came from the Bordeaux district (from the hospital as well as the public sector) although they did not represent the totality of such accidents. The study bears first of all upon the data concerning the patients, then upon the surgical intervention, the mode of anaesthesia and ventilation, the posture and finally the treatment. In 10 cases. it was noted, as early as the admission, that the blood volume feel short of the theoretical total blood volume by one liter or more. The authors take into account how traces of previous affections, the localization in O.R.L., and, in ophthalmology, an important number of mistakes in anaesthesia, favour the progress of the genesis of the accident.