Urany-Less Low Voltage Transmission Electron Microscopy: A Powerful Tool for Ultrastructural Studying of Cyanobacterial Cells

Sample preparation protocols for conventional high voltage transmission electron microscopy (TEM) heavily rely on the usage of staining agents containing various heavy metals, most commonly uranyl acetate and lead citrate. However high toxicity, rising legal regulations, and problematic waste disposal of uranyl acetate have increased calls for the reduction or even complete replacement of this staining agent. One of the strategies for uranyless imaging is the employment of low-voltage transmission electron microscopy. To investigate the influence of different imaging and staining strategies on the final image of cyanobacterial cells, samples stained by uranyl acetate with lead citrate, as well as unstained samples, were observed using TEM and accelerating voltages of 200 kV or 25 kV. Moreover, to examine the possibilities of reducing chromatic aberration, which often causes issues when imaging using electrons of lower energies, samples were also imaged using a scanning transmission electron microscopy at 15 kV accelerating voltages. The results of this study demonstrate that low-voltage electron microscopy offers great potential for uranyless electron microscopy.

Combination of Hypotonic Lysis and Application of Detergent for Isolation of Polyhydroxyalkanoates from Extremophiles

Production of polyhydroxyalkanoates (PHA), microbial biopolyesters, employing extremophilic microorganisms is a very promising concept relying on robustness of such organisms against microbial contamination, which provides numerous economic and technological benefits. In this work, we took advantage of the natural susceptibility of halophilic and thermophilic PHA producers to hypotonic lysis and we developed a simple and robust approach enabling effective isolation of PHA materials from microbial cells. The method is based on the exposition of microbial cells to hypotonic conditions induced by the diluted solution of sodium dodecyl sulfate (SDS) at elevated temperatures. Such conditions lead to disruption of the cells and release of PHA granules. Moreover, SDS, apart from its cell-disruptive function, also solubilizes hydrophobic components, which would otherwise contaminate PHA materials. The purity of obtained materials, as well as the yields of recovery, reach high values (values of purity higher than 99 wt.%, yields close to 1). Furthermore, we also focused on the removal of SDS from wastewater. The simple, inexpensive, and safe technique is based on the precipitation of SDS in the presence of KCl. The precipitate can be simply removed by decantation or centrifugation. Moreover, there is also the possibility to regenerate the SDS, which would substantially improve the economic feasibility of the process.

Combined treatment of primary vitreoretinal lymphomas significantly prolongs the time to first relapse

BACKGROUND

Vitreoretinal lymphomas belong to the family of central nervous system (CNS) lymphomas. The optimal approach for the treatment of isolated primary vitreoretinal lymphoma is unclear because of the lack of large comparative clinical series. Combination of intravitreal and systemic chemotherapy is recommended in many reports. The aim of our retrospective study was to compare the survival rate and prognosis of patients with vitreoretinal lymphoma with and without CNS involvement.

METHODS

Twenty patients with vitreoretinal lymphomas were observed between the years 2004and2016, 10 patients with primary vitreoretinal lymphoma and 10 with primary CNS lymphoma. To compare survival rates, we included 53 patients diagnosed with primary CNS lymphoma without vitreoretinal involvement between the years 2002and2011 from our haemato-oncology department.

RESULTS

The 5-year survival rate was estimated 71% in patients with vitreoretinal lymphoma in our observation. Significantly longer 5-year overall survival (P˂0.01) was observed in patients with vitreoretinal lymphoma compared with patients with primary CNS lymphoma without vitreoretinal involvement. Progression-free survival was almost equal in both groups of patients with primary vitreoretinal lymphoma and primary CNS lymphoma (P=0.363). The relapse of lymphoma was frequent (50%-60%) with the median time to first relapse of 31 months. Combined treatment (local and systemic) in patients without CNS involvement significantly prolonged progression-free survival in our study (P˂0.05).

CONCLUSION

Combined treatment of primary vitreoretinal lymphoma significantly delays the relapse of lymphoma compared with local therapy alone. Intraocular involvement brings significant positive prognostic value when overall survival is compared.

Increased albumin quotient (QAlb) in patients after first clinical event suggestive of multiple sclerosis is associated with development of brain atrophy and greater disability 48 months later

BACKGROUND

The utility of blood-brain barrier (BBB) biomarkers for clinical and magnetic resonance imaging progression in multiple sclerosis (MS) has not been extensively investigated.

OBJECTIVES

To determine whether cerebrospinal fluid (CSF) measures of BBB at clinical onset predict radiological and clinical deterioration over 48 months.

METHODS

This longitudinal study included 182 patients after first clinical event suggestive of MS treated with weekly intramuscular interferon beta-1a. CSF and serum samples were analyzed for leukocytes, total protein, albumin, immunoglobulins, and oligoclonal bands. Optimal thresholds for the albumin quotient (QAlb) were determined. Mixed-effect model analyses, adjusted for age, gender, and treatment escalation, were used to analyze relationship between CSF measures and disease activity outcomes over 48 months of follow-up.

RESULTS

Increased QAlb at clinical onset was associated with enlargement of lateral ventricles (p = .001) and greater whole brain (p = .003), white matter (p < .001), corpus callosum (p < .001), and thalamus (p = .003) volume loss over 48 months. Higher QAlb was associated with higher Expanded Disability Status Scale score over 48 months (p = .002).

CONCLUSIONS

Increased QAlb at clinical onset is associated with increased brain atrophy and greater disability in patients after first clinical event suggestive of MS.