Francisca Rius

Stereological Age-Related Changes in Neurons of the Rat Dorsal Lateral Geniculate Nucleus

Quantitative methods were used to compare the changes taking place in the volume of the dorsal lateral geniculate nucleus (dLGN) and corresponding neurons of young, adult and old rats. The study was carried out on male albino rats aged 3, 18, 24 and 28 months. In order to estimate the volume of the dLGN, neuronal volume density, numerical density and total number of neurons, we used serial sections stained according to the Klüver‐Barrera technique and stereological methods. We found that dorsal lateral geniculate nucleus volume increases between 3 and 28 months, with a larger increase between 24 and 28 months. Neuronal volume density and numerical density of neurons are greater at 3 months and undergo a significant decrease between 24 and 28 months. Finally, the total number of neurons is shown to be smaller in adult and old animals than in younger ones, even though no significant variations are found between 18 and 28 months. Furthermore, this study confirms the need to analyze the total number of neurons and not just neuronal density if we want to correctly evaluate some of the microscopic changes occurring during senescence. Anat Rec 255:396–400, 1999.

Impact of Postoperative Unwashed Shed Blood Retrieved after Total Knee Arthroplasty on Endotoxin-stimulated Tumor Necrosis Factor α Release In Vitro

Background:Allogeneic or autologous blood seems to have an immunosuppressive effect that is largely attributable to storage-dependent factors. However, transfusion of postoperative unwashed shed blood (USB) after elective total knee replacement does not undergo storage. Therefore, the authors explored the effects of USB on the mitogen-driven cytokine synthesis by the patient’s peripheral blood mononuclear cells. Methods:Perioperative blood samples were obtained from 12 total knee replacement patients with and 5 without reinfusion of leukoreduced USB, and from USB reinfusion line, before and after leukoreduction. Venous blood obtained at 4–6 postoperative hours was coincubated with USB. Endotoxin-stimulated release of tumor necrosis factor &agr; and interleukin 10 was measured after 24 h of culture by solid-phase enzyme-labeled chemiluminescent immunometric assay. Results:Coincubation of postoperative venous blood with USB, USB cells, or USB plasma resulted in a significant depression of tumor necrosis factor-&agr; synthesis, without significant effects on interleukin-10 synthesis. However, no differences were observed for endotoxin-stimulated cytokine release in perioperative blood samples from patients receiving or not receiving USB. Conclusion:These data suggest that USB seemed to contain an antiinflammatory agent. However, at the actual retransfusion rate, USB does not seem to further enhance the immunosuppression that follows knee replacement surgery.

Quantitative morphological changes in neurons from the dorsal lateral geniculate nucleus of young and old rats

We studied the morphological changes occurring in neurons from the dorsal lateral geniculate nucleus (dLGN) during aging by analysing the size and shape of cell bodies and nuclei.

Female rats show an increased sensibility to the forced swim test depressive-like stimulus in the hippocampus and frontal cortex 5-HT1A receptors

Affective disorders are more common in women. The forced swim test acts like a depressive stimulus. Hippocampus and frontal cortex 5-HT1A receptors of female and male Wistar rats subjected to the forced swim test were compared with a sham group. The forced swim test diminishes (P<0.05) the hippocampus 3H-8OH-DPAT bound in the female rats (184+/-16 fmol/mg protein) with respect to the male rats (309+/-41 fmol/mg protein) and to the female sham rats (255+/-20 fmol/mg protein). The forced swim test increases the frontal cortex 5-HT1A receptors in the female rats with respect to the female sham group (40.4+/-5 versus 24.7+/-4 fmol/mg protein, P<0.05). An increased sensibility of the 5-HT1A receptors to depressive-stimulus may be one mechanism underlying the higher prevalence of depression in female.

Success criteria in pediatric neuroendoscopic procedures. Proposal for classification of results after 67 operations

PurposeControversial issues exist concerning criteria for patient selection and long-term success in pediatric neuroendoscopic procedures. We designed a classification of success grades applicable to high-pressure and chronic hydrocephalus and also to those cases in which different endoscopic maneuvers are performed during the same procedure. We then evaluated the success rate and complications in our series.MethodsA total of 59 patients underwent 67 neuroendoscopic procedures between January 2003 and January 2011. A retrospective study was made of the preoperative history, operative reports, and postoperative imaging findings and medical records. A 5-grade scale was developed to assess the type of success depending on clinical and radiological data. Complications related to the surgical procedure were also recorded.ResultsTwo patients were excluded from the success analysis due to insufficient follow-up time. The final results for the first procedures in 57 patients were complete and permanent success (grade I) in 49.1%, complete but transitory success (grade II) in 10.5%, partial success (grade III) in 12.3%, doubtful success (grade IV) in 5.3%, and failure (grade V) in 22.8%. In eight cases a second procedure followed the failure of the first: grade I success was achieved in seven cases (87.5%) and grade V in one case (12.5%). The highest success rates were achieved in cases of hydrocephalus caused by tumors or arachnoid cysts and the lowest in slit ventricle syndrome.ConclusionsA common classification of degrees of success, such as that proposed here, would aid the development of comparative and cooperative studies.

Confocal Backscattering-Based Detection of Leukemic Cells in Flowing Blood Samples

The prognostic value of assessing minimal residual disease (MRD) in leukemia has been established with advancements in flow cytometry and PCR. Nonetheless, these techniques are limited by high equipment costs, complex, and costly cell processing and the need for highly trained personnel. Here, we demonstrate the potential of exploiting differences in the relative intensities of backscattered light at three wavelengths to detect the presence of leukemic cells in samples containing varying mixtures of white blood cells (WBCs) and leukemic cells flowing through microfluidic channels. Using 405, 488, and 633 nm illumination, we identify distinct light scattering intensity distributions for Nalm‐6 leukemic cells, normal mononuclear (PBMC) and polymorphonuclear (PMN) white blood cells and red blood cells. We exploit these differences to develop cell classification algorithms, whose performance is evaluated based on simultaneous acquisition of light scattering and fluorescence flow cytometry data. When this algorithm is used prospectively for the analysis of samples consisting of mixtures of PBMCs and leukemic cells, we achieve an average specificity and sensitivity of leukemic cell detection of 99.6 and 45.2%, respectively. When we consider samples that include leukemic cells along with PMNs and PBMCs, which can be acquired using a simple red blood cell lysis step following venipuncture, the specificity and sensitivity of the approach decreases to 91.6 and 39.5%, respectively. On the basis of the performance of these algorithms, we estimate that 42 or 71 μL of blood would be adequate to confirm the presence of leukemia at an 80% power level in samples containing 0.01% leukemia to either PBMCs or PBMCs and PMNs, respectively. Therefore, light scattering‐based flow cytometry in a microfluidic platform could provide a low cost, highly portable, minimally invasive approach for detection and monitoring of leukemic patients. This could offer significant improvements especially for pediatric patients and for patients in developing countries.

Confocal backscattering spectroscopy for leukemic and normal blood cell discrimination.

Leukemia is the most common pediatric cancer and leading cause of cancer related deaths in children. Improvements in the assessment of leukemic cells have the potential to influence not only the diagnosis of leukemia, but also the risk assessment of patients during the course of the treatment, both of which are important for improving the cure rate for this disease. In this study, we report on the design and performance of a confocal laser based system built to collect backscattered light over a range of 26° at 405, 488, and 633 nm to discriminate leukemic cells from normal red blood cells (RBC) and white blood cells (WBC). The design of the system is based on the spectral differences observed from spectroscopy measurements with a similar system designed with a white light source. Significant differences are observed in the intensity and wavelength dependence of leukemic cells from normal RBC and WBC. Specifically, the distinct light scattering of RBC is due to hemoglobin absorption, allowing for its discrimination from leukemic cells, mononuclear, and polymorphonuclear WBC particularly at certain wavelengths. Meanwhile, the high scattering intensities of polymorphonuclear WBC reflect the intracellular complexity of these cells in comparison to the leukemic or normal lymphocytes. Additionally, the detected light scattering spectra for leukemic cells are consistently steeper in comparison to normal WBC, which we attributed to differences in the fractal organization of intracellular scatterers. Based on our findings, the system has potential applications in the detection and quantification of leukemic cells in blood either in vivo or in vitro, using microfluidic‐based systems, for disease monitoring.

Circadian rhythm in muscarinic receptor subtypes in rat forebrain

The binding of different ligands to muscarinic receptors in the central nervous system is regulated by several factors. Among these are the administration of drugs, disease, ontogeny or aging. Studies carried out in rat brains have demonstrated changes in the density of the muscarinic receptors at different times of the day. These changes might be related to variations in the circadian rhythms. In this work we have studied the binding of the [3H]-N-methyl-escopolamine, the agonist carbachol and the antagonist pirenzepine to muscarinic receptors in rat forebrains at 10.00, 14.00, 18.00, 22.00, 02.00 and 06.00 hr. We have observed changes in the density of muscarinic receptors but not changes in affinity to the radioligand. The Bmax values obtained by saturation studies were maximum at 14.00 hr and minimum at 02.00 hr (P less than 0.05 Mann-Whitneys test). Inhibition studies in the presence of the non-selective agonist carbachol and the selective antagonist pirenzepine, at the same time-points, did not show statistically significant changes in the Bmax values. These data indicate that changes in the Bmax values are only observed in the total population of muscarinic receptors and are not due to modifications in the subtypes of muscarinic receptors nor to the different affinity states of agonist binding.

S-adenosyl-l-methionine prevents 5-HT1A receptors up-regulation induced by acute imipramine in the frontal cortex of the rat

S-adenosyl-L-methionine (SAM) has shown efficacy in speeding the onset of the antidepressant effect of imipramine in depressed patients. This effect may be related to their interactions at the serotonin(1A) (5-HT(1A)) receptors. Acute imipramine up-regulated the frontal cortex 5-HT(1A) receptors (B(max), 51.5 +/- 8.4 fmol/mg protein) vs. saline (B(max), 27.5 +/- 5.9 fmol/mg protein), and did not show antidepressant effect. Acute SAM and imipramine+SAM did not modify frontal cortex 5-HT(1A) receptors, and showed antidepressant effects (decrease of the immobility response of 26%, P<0.01; and 47%, P<0.001) vs. saline. All the chronic treatments showed antidepressant effects and up-regulated the hippocampus 5-HT(1A) receptors. SAM prevents the 5-HT(1A) receptor up-regulation induced by acute imipramine in the frontal cortex. This mechanism may contribute to imipramines antidepressant effect.

The effect of ageing on neurones in the visual sector of the thalamic reticular nucleus

This paper studies the quantitative morphological changes occurring during ageing in neurones of the dorsocaudal or visual sector of the thalamic reticular nucleus. Male Wistar rats aged 3, 6, 18, 24 and 30 months were used in this study which applied morphometric methods. We have observed an increase in the size of neurones from this sector between the 3rd and 24th month and a decrease between the 24th and 30th month. In all the ages studied the majority of neurones are fusiform.