The surface topography of the choroid plexus. Environmental, low and high vacuum scanning electron microscopy.

Environmental scanning electron microscopy (ESEM) allows the examination of hydrated and dried specimens without a conductive metal coating which could be advantageous in the imaging of biological and medical objects. The aim of this study was to assess the performance and benefits of wet-mode and low vacuum ESEM in comparison to high vacuum scanning electron microscopy (SEM) using the choroid plexus of chicken embryos as a model, an organ of the brain involved in the formation of cerebrospinal fluid in vertebrates. Specimens were fixed with or without heavy metals and examined directly or after critical point drying with or without metal coating. For wet mode ESEM freshly excised specimens without any pre-treatment were also examined. Conventional high vacuum SEM revealed the characteristic morphology of the choroid plexus cells at a high resolution and served as reference. With low vacuum ESEM of dried but uncoated samples the structure appeared well preserved but charging was a problem. It could be reduced by a short beam dwell time and averaging of images or by using the backscattered electron detector instead of the gaseous secondary electron detector. However, resolution was lower than with conventional SEM. Wet mode imaging was only possible with tissue that had been stabilized by fixation. Not all surface details (e.g. microvilli) could be visualized and other structures, like the cilia, were deformed. In summary, ESEM is an additional option for the imaging of bio-medical samples but it is problematic with regard to resolution and sample stability during imaging.

Vitamin E action on oxidative state, endothelial function and morphology in long-term myocardial preservation.

This study assesses the effects of a vitamin E analogue, Trolox, on the oxidative state, endothelial function and morphology in experimental heart transplantation. Heterotopic heart transplantation was carried out in pigs: untreated after 2 and 24 hours of ischemia and treated with Trolox after 24 hours of ischemia. Prolonged preservation of donor hearts was achieved with continuous perfusion and University of Wisconsin solution, in which acid-base balance and enzymes were determined during the procedure. In recipients, hemodynamic and biochemical parameters were determined at baseline and during reperfusion. Trolox diminished the pH of the preservation solution (p<0.01), the left ventricle of the transplanted heart recovered a systolic pressure equaling that of the 2h group and higher than that of the untreated 24h group (p<0.01), the antioxidant levels were not decreased and the glutathione reductase level was maintained throughout the first part of reperfusion. In this group also there was a direct correlation between the concentration of this enzyme and the antioxidant levels (p<0.001). Although the endothelin concentrations increased, the change was less marked in the Trolox group than in the untreated 24h group (p<0.01). Morphologically, mitochondria and myocardial vessels presented a normal structure in the Trolox group, and interstitial edema, inflammatory infiltrate and contraction bands were less prominent than in the untreated group. All these effects indicate that Trolox protected the transplanted heart, at least partially, against ischemia-reperfusion injury.

GFAP and alpha1a-AR staining and nuclear morphometry of oligodendrogliomas by confocal microscopy and image analysis: useful parameters for predicting survival in oligodendrogliomas.

OBJECTIVE: This study attempts to evaluate the GFAP and alpha1a-AR staining and morphometrical nuclear features of oligodendrogliomas and their prognostic implications as compared to present histopathology classification and their survival outcome. STUDY DESIGN: Surgical specimens from 24 patients with oligodendrogliomas during the period 1981-2000 were included. These cases were classified into two groups defined by the grade of the neoplasm: Group I: oligodendrogliomas grade II; Group II: oligodendrogliomas grade III and two groups based on the outcome status: Group of the alive cases and group of the death cases. Death rate for the groups were obtained by patients' charts. Descriptive statistics were used to examine the groups with respect to the morphometrical nuclear variables; area, perimeter, aspect, axes (major and minor), diameters (max, mean and min.), radius (max. and min.) margination, ratio of perimeter-area, roundness and sizes (length and width). In addition, an immunofluorescence method for GFAP and 1a-AR were performed and their area, density and intensity of staining were analyzed. RESULTS: Semiautomated quantitative morphometrical results showed that the variables of nuclear area (GII 48.87 microm2 vs. GIII 43.45 microm2 p-value = 0.02), aspect (GII 1.39 vs. GIII 1.55 p-value = 0.03), axis minor (GII 6.66 microm vs. GIII 6.01 microm p-value = 0.003), diameter minor (GII 5.93 microm vs. GIII 5.27 microm p-value = 0.002), radius minor (GII 2.64 microm vs. GIII 2.25 microm p-value = 0,003), perimeter-area (GII 0.0007 vs. GIII 0.0006 p-value = 0.04), size width (GII 6.60 microm vs. GIII 5.96 microm p-value = 0,003), and density of alpha1a-AR staining (GII 121.38 vs. GIII 146.03 p-value = 0.05) were statistically significant in regard of grade; and that the sum of density of GFAP (p-value = 0.01) and the intensity of alpha1a-AR (p-value = 0.01) were statistically significant in predicting survival. CONCLUSION: These results suggest that some nuclear morphometrical features and the GFAP and alpha1a-AR immunofluorescence staining may be useful parameters for predicting survival in oligodendrogliomas.

Calcium-supplemented University of Wisconsin solution in long-term myocardial preservation.

The purpose of this study was to assess the effects of the addition of calcium to University of Wisconsin solution in long-term myocardial perfusion. In a heterotopic heart transplantation model, performed in pigs, the donor heart was preserved for 24 hours by means of continuous perfusion in this solution, without (24hUW group) or with calcium, 2.4 mmol/L (24hUW+Ca). During this period, the oxygenation and pH of the solution were measured, as were the calcium and lactate concentrations and enzyme release. After two hours of reperfusion, samples were collected from both ventricles for the morphological study. In the control group, there were no signs that reperfusion had triggered the calcium paradox. The addition of this cation to the preservation solution improved the intercellular junction integrity but, at the same time, favored intracellular calcium overload. This is manifested by increased enzyme release during preservation (LDH: 242+/-95 vs 140+/-25; CK: 668+/-371 vs 299+/-83 (U/L). p<0.01 in both cases) and signs of ventricular contracture: hardness and stiffness were significantly more prominent than in the group without calcium supplementation. Moreover, in comparison with the control group, the structural morphology of 24hUW+Ca is characterized by the more prominent and extensive presence of contraction bands and disorganized actin structure. Thus, under the experimental conditions employed in this study, we consider the addition of calcium to Wisconsin solution to be unadvisable.

Proteomic analysis of lung biopsies: Differential protein expression profile between peritumoral and tumoral tissue.

The cellular proteome shows a dynamic profile and is subjected to changes in response to various stimuli and disease progression. Lung cancer remains the leading cause of cancer death in industrialized countries. In an attempt to find new disease markers, patients suffering from lung carcinoma have been selected to achieve differential protein expression patterns between normal and neoplasic tissue. After two-dimensional electrophoresis, the spots of interest were digested and identified by matrix-assisted laser desorption/ionization (MALDI) peptide mass fingerprinting. This information will provide a more comprehensive understanding of the disease progression and might constitute a method to complement histopathological diagnosis.