Reversal of crystallization in cryoprotected samples by laser editing.

Advances in cryobiology techniques commonly target either the cooling or the warming cycle, while little thought has been given to ≪repair≫ protocols applicable during cold storage. In particular, crystallization is the dominant threat to cryopreserved samples but proceeds from small nuclei that are innocuous if further growth is forestalled. To this end, we propose a laser editing technique that locally heats individual crystals above their melting point by a focused nanosecond pulse, followed by amorphization during rapid resolidification. As a reference, we first apply the approach to ice crystals in cryoprotected solution and use Raman confocal mapping to study the deactivation of crystalline order. Then, we examine dimethyl sulfoxide trihydrate crystals that can germinate at low temperatures in maximally freeze concentrated regions, as commonly produced by equilibrium cooling protocols. We show how to uniquely identify this phase from Raman spectra and evidence retarded growth of laser-edited crystals during warming.

Robustness of elastic properties in polymer nanocomposite films examined over the full volume fraction range.

Polymers with nanoparticle inclusions are attractive materials because physical properties can be tuned by varying size and volume fraction range. However, elastic behavior can degrade at higher inclusion fractions when particle-particle contacts become important, and sophisticated measurement techniques are required to study this crossover. Here, we report on the mechanical properties of materials with BaTiO3 nanoparticles (diameters < 10 nm) in a polymer (poly(methyl methacrylate)) matrix, deposited as films in different thickness ranges. Two well-known techniques, time and frequency domain Brillouin light scattering, were employed to probe the composition dependence of their elastic modulus. The time domain experiment revealed the biphasic state of the system at the highest particle volume fraction, whereas frequency domain Brillouin scattering provided comprehensive information on ancillary variables such as refractive index and directionality. Both techniques prove complementary, and can in particular be used to probe the susceptibility of elastic properties in polymer nanocomposites to aging.

Serum neuron-specific enolase levels do not increase after electroconvulsive therapy.

BACKGROUND: Cognitive disorders occurring after electroconvulsive therapy (ECT) are regarded as an expression of brain damage, despite computed tomography (CT) and magnetic resonance imaging (MRI) showing no signs of structural brain damage. Serum neuron-specific enolase (NSE) is a sensitive marker of neuronal damage (i.e., after stroke or cardiac arrest). The objective of this study was to investigate whether ECT leads to a rise in the serum NSE level as an expression of neuronal damage. METHODS: We investigated seven patients (four women, three men; mean age 6212 years) with major depressive disorder, who were treated with ECT for the first time. ECT was administered every 2 days, three times a week under standard conditions (anaesthesia: thiopental, succinylcholine, 100% oxygen, unilateral ECT, seizure duration more than 20 s). Blood samples were drawn at the following times. For the first ECT: 15 and 1 min before ECT, and 1, 5, 10, 15, 20, 25, 30, 45, 60, 75, 90, 105, 120 min, and 8, 12, 24 h after ECT. For all subsequent ECT: 1 min before and 4 h after every ECT. Serum NSE was measured by means of enzyme immunoassay (Cobas Core NSE, EIA, Hoffmann-La Roche). RESULTS: On average, each patient underwent ECT 10 times (range 5-20). In the first ECT there was no difference in serum NSE levels before and at all times following ECT. A comparison of serum NSE levels before and after each subsequent bout of ECT revealed no differences. Moreover, comparing the baseline serum NSE levels (before the first ECT) with the values after final ECT showed no differences either. CONCLUSION: ECT did not increase serum NSE values, indicating that electroconvulsive therapy does not cause neuronal damage.

Tubular dimensions and juxtaglomerular granulation index in rat kidneys after unilateral obstruction of the ureter. A study of the morphogenesis of hydronephrosis.

The effect of ligation of a ureter on the tissues in the kidneys in male Wistar rats was studied by morphometry. Dilation of the lumen in the obstructed kidney persisted after ligation only in distal convolutions and collecting ducts. Swelling of epithelial cells in the obstructed kidney was noted only in the distal convolutions and collecting ducts. The Juxtaglomerular Granulation Index (JGI) in the obstructed kidney increased to a maximum 7 days after ligation of the ureter. In the control kidney the lumen of Bowman's space was expanded, epithelial cells in both proximal and distal parts of the nephron were swollen, and the JGI was increased after ligation of the contralateral ureter. The morphological findings support the assumption that reduced cortical blood flow and decreased intratubular flow are the cause of proximal tubular atrophy rather than a persisting increase of proximal intratubular pressure.

Gabexate mesilate in human acute pancreatitis. German Pancreatitis Study Group.

BACKGROUND: A multicenter controlled study was performed to evaluate the effect of high doses of the low molecular weight protease inhibitor gabexate mesilate on mortality and complications associated with moderate and severe acute pancreatitis. METHODS: Two hundred twenty-three patients from 29 hospitals were entered in the randomized, double-blind trial. Admission to the study was based on strict criteria excluding mild acute pancreatitis. The patients received placebo or 4 g gabexate mesilate per day intravenously for 7 days. All patients were followed up for 90 days after randomization. The analysis was based on 14 complications, including death. RESULTS: There was no statistical difference in either mortality or complications associated with acute pancreatitis between the placebo and gabexate mesilate groups. CONCLUSIONS: The results show that gabexate mesilate was not effective in preventing complications and mortality in acute pancreatitis.