Imaging in gynecological disease (19): clinical and ultrasound features of extragastrointestinal stromal tumors (eGIST).

OBJECTIVE: To describe the clinical and sonographic characteristics of extragastrointestinal stromal tumors (eGISTs). METHODS: This was a retrospective multicenter study. The data of patients with a histological diagnosis of eGIST who had undergone preoperative ultrasound examination were retrieved from the databases of nine large European gynecologic oncology centers. One investigator from each center reviewed stored images and ultrasound reports, and described the lesions using the terminology of the International Ovarian Tumor Analysis and Morphological Uterus Sonographic Assessment groups, following a predefined ultrasound evaluation form. Clinical, surgical and pathological information was also recorded. RESULTS: Thirty-five women with an eGIST were identified; in 17 cases, the findings were incidental, and 18 cases were symptomatic. Median age was 57 years (range, 21-85 years). Tumor marker CA 125 was available in 23 (65.7%) patients, with a median level of 23 U/mL (range, 7-403 U/mL). The vast majority of eGISTs were intraperitoneal lesions (n = 32 (91.4%)); the remaining lesions were retroperitoneal (n = 2 (5.7%)) or preperitoneal (n = 1 (2.9%)). The most common site of the tumor was the abdomen (n = 23 (65.7%)), and less frequently the pelvis (n = 12 (34.3%)). eGISTs were typically large (median largest diameter, 79 mm) solid (n = 31 (88.6%)) tumors, and were less frequently multilocular-solid tumors (n = 4 (11.4%)). The echogenicity of solid tumors was uniform in 8/31 (25.8%) cases, which were all hypoechogenic. Twenty-three solid eGISTs were non-uniform, either with mixed echogenicity (9/23 (39.1%)) or with cystic areas (14/23 (60.9%)). The tumor shape was mainly lobular (n = 19 (54.3%)) or irregular (n = 10 (28.6%)). Tumors were typically richly vascularized (color score of 3 or 4, n = 31 (88.6%)) with no shadowing (n = 31 (88.6%)). Based on pattern recognition, eGISTs were usually correctly classified as a malignant lesion in the ultrasound reports (n = 32 (91.4%)), and the specific diagnosis of eGIST was the most frequent differential diagnosis (n = 16 (45.7%)), followed by primary ovarian cancer (n = 5 (14.3%)), lymphoma (n = 2 (5.7%)) and pedunculated uterine fibroid (n = 2 (5.7%)). CONCLUSIONS: On ultrasound, eGISTs were usually solid, non-uniform pelvic or abdominal lobular tumors of mixed echogenicity, with or without cystic areas, with rich vascularization and no shadowing. The presence of a tumor with these features, without connection to the bowel wall, and not originating from the uterus or adnexa, is highly suspicious for eGIST. Copyright © 2020 ISUOG. Published by John Wiley & Sons Ltd.

Prospective external validation of IOTA three-step strategy for characterizing and classifying adnexal masses and retrospective assessment of alternative two-step strategy using simple-rules risk.

OBJECTIVES: To perform an external validation of the diagnostic performance of the three-step strategy proposed by the International Ovarian Tumor Analysis (IOTA) group for classifying adnexal masses as benign or malignant, when ultrasound is performed by non-expert sonographers in the first two steps. The second objective was to assess the diagnostic performance of an alternative strategy using simple-rules risk (SRR), instead of simple rules (SR), in the second step. METHODS: This was a prospective observational study conducted at two university hospitals, from September 2015 to August 2017, of consecutive patients diagnosed with an adnexal mass. All women were evaluated by ultrasound using the IOTA three-step strategy. Non-expert sonographers performed the first step (use of simple descriptors to classify the masses) and the second step (use of SR if the mass could not be classified in the first step); masses that could not be classified in the first two steps were categorized by an expert sonographer based on their subjective assessment (third step). The reference standard was histological diagnosis in patients who underwent surgery or at least 12 months of follow-up in cases managed expectantly. The sensitivity, specificity, positive (LR+) and negative (LR-) likelihood ratios and overall accuracy of the IOTA three-step strategy were estimated. Furthermore, we evaluated retrospectively an alternative two-step strategy using SRR in the second step to categorize the masses not classifiable with simple descriptors, classifying the lesions as being of low, intermediate or high risk for malignancy. The diagnostic performance of this strategy was estimated by calculating its sensitivity and specificity, assuming surgical intervention for intermediate- or high-risk lesions. RESULTS: The study included 283 patients (median age, 48 (range, 18-90) years), of whom 165 (58.3%) were premenopausal and 118 (41.7%) postmenopausal. Two hundred and sixteen (76.3%) women underwent surgery (154 benign and 62 malignant masses) and 67 (23.7%) were managed expectantly with serial ultrasound follow-up for at least 12 months. All expectantly managed masses were considered benign because no sonographic changes suggestive of malignancy were observed during follow-up. Simple descriptors could be applied in 126 (44.5%) masses. Of the remaining 157 lesions, 112 (39.6%) could be characterized using SR. Therefore, 238 (84.1%) masses could be classified by non-expert sonographers in the first two steps. Of the remaining 45 (15.9%) masses, all could be classified by an expert sonographer. Overall sensitivity, specificity, LR+ and LR- of the IOTA three-step strategy were 95.2%, 97.7%, 42.1 and 0.05, respectively. The diagnostic accuracy was 97.2%. Following the two-step strategy using SRR in the second step, of the 157 lesions not classified with simple descriptors, 42, 38 and 77 presented low, intermediate or high risk for malignancy, respectively. Based on this method, 210 women would have undergone surgical treatment. The sensitivity and specificity of this two-step strategy were 98.4% and 63.8%, respectively. CONCLUSIONS: The IOTA three-step strategy shows high accuracy for discriminating between benign and malignant adnexal lesions when used by non-expert sonographers. An alternative strategy using the SRR calculator in the second step might improve on this diagnostic performance by decreasing the number of surgical interventions and increasing sensitivity. Copyright © 2018 ISUOG. Published by John Wiley & Sons Ltd.

Psychometric validation of the Spanish version of the Dundee Ready Education Environment Measure applied to dental students.

AIM: To carry out a psychometric evaluation of the Spanish-language version of the Dundee Ready Education Environment Measure (DREEM) applied to dental students. METHODS: A total of 1,391 students from nine Spanish public schools of dentistry responded to the DREEM questionnaire. To analyse the reliability of the DREEM questionnaire, the internal consistency was assessed and a 'test-retest' carried out. Validity was evaluated through analysis of item response rate, floor and ceiling effects, corrected item-total and item-subscale correlations and factor structure. A confirmatory factor analysis was performed to analyse the structure of the original DREEM scale. RESULTS: Cronbach's alpha coefficient for the 'Educational Climate' (EC) global scale was 0.92. In the subscales, the 'observed' Cronbach's alpha coefficients ranged between 0.57 and 0.79 and were higher than the 'expected' ones; except for the Social subscale. In the DREEM questionnaire, all of the corrected correlation coefficients between the items and the EC global scale, and the items and their corresponding subscales, were >0.2; except for items 50 and 17. All goodness-of-fit indices of confirmatory factor analysis showed acceptable values (close to one or zero, depending on the case), and there was consistency in the results. CONCLUSIONS: The Spanish-language version of the DREEM questionnaire is a reliable and valid instrument for analysing the EC for dental students and its factor structure is supported by the data. Although our findings indicate that the DREEM may be as culturally independent as was originally stated, more research should be directed at verifying the factor structure in various languages and cultural environments.

Analysis of the 'Educational Climate' in Spanish Public Schools of Dentistry using the Dundee Ready Education Environment Measure: a multicenter study.

AIM: To analyse the 'Educational Climate' (EC) of dental students in Spain. METHODS: The study group consisted of 1391 students from nine Spanish Public Schools of Dentistry, who responded to the questionnaire based on 'Dundee Ready Education Environment Measure' (DREEM). This questionnaire has 50 items that are grouped into five domains: Learning, Teachers, Academic, Atmosphere and Social. RESULTS: The global score on the EC was 123.1 (interpretation: 'EC more positive than negative'). The scores obtained in the different domains were: 28.0 in Learning (interpretation: 'a generally positive perception of learning'), 26.8 in Teachers (interpretation: 'teachers are going in the right direction'), 20.8 in Academic (interpretation: 'feeling more on the positive side'), 29.7 in Atmosphere (interpretation: 'a generally positive atmosphere') and 17.7 in Social (interpretation: 'social perception acceptable'). In seven items (14%), an average of <2 was detected, showing that there are some educational problem areas. Regarding the EC in the different Schools of Dentistry, an average of >100 was achieved in all of them, although there were two centres that showed significantly higher values of EC. CONCLUSIONS: Spanish dental students felt that their EC was more positive than negative and considered that the different domains were positive and acceptable. However, they pointed out the existence of several educational problem areas associated with the development of a traditional curriculum. Accordingly, and in parallel with the implementation of an innovative curriculum in all Spanish Dental Schools in the coming years, immediate educational goals must address the problem areas identified, thereby further promoting a more positive perception of EC.

Predictive models of pain following root canal treatment: a prospective clinical study.

AIM: To determine the probability of the incidence, intensity, duration and triggering of post-endodontic pain, considering factors related to the patient (age, gender, medical evaluation) and to the affected tooth (group, location, number of canals, pulp vitality, preoperative pain, periapical radiolucencies, previous emergency access, presence of occlusal contacts with antagonist). METHODOLOGY: A total of 500 one-visit root canal treatments (RCTs) were performed on patients referred to an endodontist. Shaping of root canals was performed manually with Gates-Glidden drills and K-Flexofiles, and apical patency was maintained with a size 10 file. A 5% NaOCl solution was used for irrigation, and canals were filled with lateral compaction and AH-Plus sealer. Independent factors were recorded during the treatment, and characteristics of post-endodontic pain (incidence, intensity, type and duration) were later surveyed through questionnaires. Of the 500 questionnaires, 374 were properly returned and split in two groups for two different statistical purposes: 316 cases were used to adjust the logistic regression models to predict each characteristic of post-endodontic pain using predictive factors, and the remaining 58 cases were used to test the validity of each model. RESULTS: The predictive models showed that the incidence of post-endodontic pain was significantly lower when the treated tooth was not a molar (P = 0.003), demonstrated periapical radiolucencies (P = 0.003), had no history of previous pain (P = 0.006) or emergency endodontic treatment (P = 0.045) and had no occlusal contact (P < 0.0001). The probability of experiencing moderate or severe pain was higher with increasing age (P = 0.09) and in mandibular teeth (P = 0.045). The probability of pain lasting more than 2 days was increased with age (P = 0.1) and decreased in males (P = 0.007) and when a radiolucent lesion was present on radiographs (P = 0.1). CONCLUSIONS: Predictive formulae for the incidence, the intensity and the duration of post-endodontic pain were generated and validated taking account of the interrelation of multiple concomitant clinical factors. A predictive model for triggering post-endodontic pain could not be established.

[Purpura fulminans: functional results in two paediatric patients after suffering multiple amputations]. / Púrpura fulminante: resultado funcional en 2 pacientes pediátricos tras sufrir múltiples amputaciones.

Purpura fulminans (PF) is an unusual haemorrhagic process that is usually associated with meningococcal sepsis and other infectious processes. It usually affects neonates and young children, and starts with a benign infection that progresses to a high fever, purpura ecchymosis, disseminated intravascular coagulopathy, necrosis and gangrene. The treatment of these children usually requires making difficult decisions, since the surgeon and the families must come to terms with the possibility of following an aggressive line of treatment that could lead to multiple mutilating sequelae, or follow palliative treatment. In this study, we review the clinical presentation, treatment and results of two cases of PF treated in our hospital between the years 2002 and 2005. The children presented in this study had a good long-term functional result and an acceptable quality of life, despite being subjected to multiple amputations.

Prenatal infection decreases calbindin, decreases Purkinje cell volume and density and produces long-term motor deficits in Sprague-Dawley rats.

The cerebellum is involved in the control of motor functions with Purkinje cells serving as the only output from the cerebellum. Purkinje cells are important targets for toxic substances and are vulnerable to prenatal insults. Intrauterine infection (IUI) has been shown to selectively target the developing cerebral white matter through lesioning, necrosis and inflammatory cytokine activation. Developmental and cognitive delays have been associated with animal models of IUI. The aim of this study was to determine if IUI leads to damage to Purkinje cells in the developing cerebellum and if any damage is associated with decreases in calbindin and motor behaviors in surviving pups. Pregnant rats were injected with Escherichia coli (1 × 105 colony-forming units) or sterile saline at gestational day 17. Beginning at postnatal day (PND) 2, the pups were subjected to a series of developmental tests to examine developmental milestones. At PND 16, some pups were sacrificed and their brains extracted and processed for histology or protein studies. Hematoxylin and eosin (HE) staining was done to examine the general morphology of the Purkinje cells and to examine Purkinje cell density, area and volume. Calbindin expression was examined in the cerebellum via immunohistochemistry and Western blot techniques. The remaining rat pups were used to examine motor coordination and balance on a rotating rotarod at the prepubertal and adult ages. Prenatal E. coli injection did not significantly change birth weight or delivery time, but did delay surface righting and negative geotaxis in pups. Pups in the E. coli group also had a decrease in the number of Purkinje cells, as well as a decrease in Purkinje cell density and volume. HE staining demonstrated a change in Purkinje cell morphology. Calbindin expression was decreased in rats from the E. coli group as well. Locomotor tests indicated that while there were no significant changes in gross motor activity, motor coordination and balance was impaired in both prepubertal and adult rats from the E. coli group. In this model of IUI, we observed changes in Purkinje cell development which were associated with alterations in cerebellum-dependent motor behaviors. The decreases in calbindin and Purkinje cells were associated with developmental delays. These data further support the importance of IUI in brain development.

Gliogenesis and glial pathology in depression.

Recent research has changed the perception of glia from being no more than silent supportive cells of neurons to being dynamic partners participating in brain metabolism and communication between neurons. This discovery of new glial functions coincides with growing evidence of the involvement of glia in the neuropathology of mood disorders. Unanticipated reductions in the density and number of glial cells are reported in fronto-limbic brain regions in major depression and bipolar illness. Moreover, age-dependent decreases in the density of glial fibrillary acidic protein (GFAP) - immunoreactive astrocytes and levels of GFAP protein are observed in the prefrontal cortex of younger depressed subjects. Since astrocytes participate in the uptake, metabolism and recycling of glutamate, we hypothesize that an astrocytic deficit may account for the alterations in glutamate/GABA neurotransmission in depression. Reductions in the density and ultrastructure of oligodendrocytes are also detected in the prefrontal cortex and amygdala in depression. Pathological changes in oligodendrocytes may be relevant to the disruption of white matter tracts in mood disorders reported by diffusion tensor imaging. Factors such as stress, excess of glucocorticoids, altered gene expression of neurotrophic factors and glial transporters, and changes in extracellular levels of neurotransmitters released by neurons may modify glial cell number and affect the neurophysiology of depression. Therefore, we will explore the role of these events in the possible alteration of glial number and activity, and the capacity of glia as a promising new target for therapeutic medications. Finally, we will consider the temporal relationship between glial and neuronal cell pathology in depression.

Neuroprotection by memantine against neurodegeneration induced by beta-amyloid(1-40).

Progressive neuronal loss and cognitive decline in Alzheimer's disease (AD) might be aggravated by beta-amyloid-enhanced excitotoxicity. Memantine is an uncompetitive NMDA receptor antagonist under clinical development for the treatment of AD. Memantine has neuroprotective actions in several in vitro and in vivo models. In the present study, we determined whether memantine protected against beta-amyloid induced neurotoxicity and learning impairment in rats. Twenty Sprague-Dawley rats received vehicle or vehicle plus memantine (steady-state plasma concentrations of 2.34+/-0.23 microM, n=10) s.c. by osmotic pump for 9 days. After 2 days of treatment, 2 microl of water containing beta-amyloid 1-40 [Abeta(1-40)] were injected into the hippocampal fissure. On the ninth day of treatment, animals were sacrificed, and morphological and immunohistochemical techniques were used to determine the extent of neuronal degeneration and astrocytic and microglial activation in the hippocampus. Psychomotor activity and spatial discrimination were tested on the eighth day of treatment. Abeta(1-40), but not water, injections into hippocampus led to neuronal loss in the CA1 subfield, evidence of widespread apoptosis, and astrocytic and microglial activation and hypertrophy. Memantine treated animals had significant reductions in the amount of neuronal degeneration, pyknotic nuclei, and GFAP immunostaining as compared with vehicle treated animals. These data suggest that memantine, at therapeutically relevant concentrations, can protect against neuronal degeneration induced by beta-amyloid.

Assessment of a preclinical training system with indirect vision for dental education.

The aim of the present study is the evaluation of a pre-clinical training system using indirect vision for dental education purposes. The study population was undergraduate dental students between the ages of 18-20, at the beginning of their first dental course. From a total of 105 students, those presenting some condition that would have had influence on their manual skills and those who for some circumstance left the study after beginning it were excluded, resulting in 69 students (51 female and 18 male) taking part in the study. The study design involved two sessions separated by a 7-day interval in which the students used a reflection box to develop psychomotor skills in mirror use. In every session they performed an initial evaluation test, some training exercises and a final evaluation test. The evaluation tests and the training exercises consisted in following a curved, straight or convoluted shape in the reflection box. Four groups of students were used who trained in different ways using curved or straight lines. Evaluation of the tests was based on the number of errors made and the time to completion. All students showed an improvement in their performance of following curved and straight lines with indirect vision after this form of training. The results after the first training session were statistically significant, while the further improvement was not significant after the 2nd training session. Those students who trained first with curved lines and later with straight lines produced more errors than the other groups. Female students performed better than male students in this assessment.

SB-271046 (SmithKline Beecham).

SmithKline Beecham is developing the 5-HT6 antagonist, SB-271046, as a potential cognition enhancer. By December 1999, phase I trials had commenced [360354]. This drug was originally being developed primarily for the treatment of shizophrenia [284490], however, cognitive disorders, including but not limited to Alzheimer's disease, have been the main target since 1998 [394309]. SB-271046 is a potent, selective 5-HT6 antagonist with a pKi value of 8.9 [333710]. SB-258585, also known as 4-iodo-N-[4-methoxy-3-(4-methylpiperazin-1-yl)phenyl]benzenesulfonamide is an analog of SB-271046 [322488]. Data recently presented at the Society for Neuroscience annual meeting in November 2000 demonstrated that administration of SB-271046 resulted in a signficant increase in glutamate and aspartate levels in the frontal cortex, without affecting noradrenaline, dopamine or 5-HT levels. This was stated to suggest that 5-HT6 antagonists might therefore be useful for treating cognitive dysfunction [390469]. The drug has also been radiolabeled in order to provide an assay for estimating in vivo 5-HT6 receptor occupancy [390470].

Glial fibrillary acidic protein immunoreactivity in the prefrontal cortex distinguishes younger from older adults in major depressive disorder.

BACKGROUND: Recent postmortem studies in major depressive disorder (MDD) provide evidence for a reduction in the packing density and number of glial cells in different regions of the prefrontal cortex; however, the specific types of glia involved in those morphologic changes are unknown. METHODS: The territory occupied by the astroglial marker glial fibrillary acidic protein (GFAP) was measured as an areal fraction in cortical layers III, IV, and V in sections from the dorsolateral prefrontal cortex (dlPFC) of MDD and control subjects. In addition, the packing density of GFAP-immunoreactive somata was measured by a direct three-dimensional cell counting method. RESULTS: The mean areal fraction and packing density of GFAP-immunoreactive astrocytes in the dlPFC of MDD subjects were not significantly different from those in control subjects; however, in MDD there was a significant strong positive correlation between age and GFAP immunoreactivity. When the MDD group was divided into younger (30-45 years old) and older (46-86) adults, in the five younger MDD adults, areal fraction and packing density were smaller than the smallest values of the control subjects. In contrast, among older MDD subjects these parameters tended to be greater than in the older control subjects. CONCLUSIONS: The present results suggest that the GFAP-immunoreactive astroglia is differentially involved in the pathology of MDD in younger compared with older adults.

Immunohistochemistry of neural markers for the study of the laminar architecture in celloidin sections from the human cerebral cortex.

Morphometric studies of the cerebral cortex in celloidin sections provide reliable quantitative estimates of cytoarchitectural features in individual brain regions. To increase our knowledge about the morphology and distribution of neuronal and glial cell types using specific cellular markers, we compared two methods of celloidin removal/antigen recovery, and subsequent immunohistochemical staining of free floating sections with specific antibodies. The method based on methanol and NaOH for celloidin removal was the most adequate for optimal recovery of immunoreactivity of the neural markers NF200, MAP2, GFAP, calretinin, parvalbumin, calbindin-D28kD, and synaptophysin. The other method, based on a treatment with ethanol/ether and formic acid, gave good results in the immunostaining of NF200, GFAP and MAP2, but not the other markers named above. The immunostained sections were compared with nearby sections stained with cresyl violet in order to assign the immunoreactive structures to individual layers in the prefrontal cortex. Sections from blocks not embedded in celloidin showed a comparable distribution of all the antigens included in the present study. The present paper provides an antigen recovery technique for celloidin sections that can be applied to optimize studies on the cytoarchitecture and distribution of specific neural elements in the human cerebral cortex.

Histone H1(o) expression in the developing cat retina.

Histone H1(o) is a subtype of the non-core H1 histones located in the linker region of DNA between nucleosome cores and postulated to be involved in the regulation of gene expression. Studies in both the mouse retina and rat brain have correlated the terminal differentiation of cell types in these tissues to the expression of H1(o)a The expression of H1(o) in mouse retina occurs after light exposure suggesting that light may trigger the expression of H1(o). The aims of the present research were to: (1) describe the relationship of the appearance of H1(o) protein immunoreactivity to the formation of cell types and layers in the cat retina; and (2) determine whether H1(o) may be dependent on exposure to light or on other postnatal developmental events. We find the nuclei of ganglion, amacrine, and prospective bipolar cells contain H1(o) immunoreactivity before birth, prior to the terminal differentiation of these cells. In the cat retina, expression of H1(o) occurs prior to light exposure. These results show that the expression of H1 degrees protein is not required for the terminal differentiation of retinal cell types in the cat. Additionally, we find no requirement for light exposure prior to H1(o) expression. These findings are at variance with the findings in the mouse retina and are inconsistent with any cross species requirement for the expression of this histone in the terminal differentiation of cell types in the retina.

Morphometric evidence for neuronal and glial prefrontal cell pathology in major depression.

BACKGROUND: This report provides histopathological evidence to support prior neuroimaging findings of decreased volume and altered metabolism in the frontal cortex in major depressive disorder. METHODS: Computer-assisted three-dimensional cell counting was used to reveal abnormal cytoarchitecture in left rostral and caudal orbitofrontal and dorsolateral prefrontal cortical regions in subjects with major depression as compared to psychiatrically normal controls. RESULTS: Depressed subjects had decreases in cortical thickness, neuronal sizes, and neuronal and glial densities in the upper (II-IV) cortical layers of the rostral orbitofrontal region. In the caudal orbitofrontal cortex in depressed subjects, there were prominent reductions in glial densities in the lower (V-VI) cortical layers that were accompanied by small but significant decreases in neuronal sizes. In the dorsolateral prefrontal cortex of depressed subjects marked reductions in the density and size of neurons and glial cells were found in both supra- and infragranular layers. CONCLUSIONS: These results reveal that major depression can be distinguished by specific histopathology of both neurons and glial cells in the prefrontal cortex. Our data will contribute to the interpretation of neuroimaging findings and identification of dysfunctional neuronal circuits in major depression.

Neuroprotective role of S12024 against neurodegeneration in the rat dentate gyrus.

We assessed the neuroprotective capabilities of S12024 (R,S 1-methyl 8-(2-morpholinylmethoxy)-1,2,3,4-tetrahydroquinoleine methane sulphonate) in a model of neuronal degeneration in the dentate gyrus of the rat hippocampus. Specific degeneration of a large part of neurons in the lateral blade of the gyrus dentatus occurred after small intrahippocampal injections of water with or without amyloid-beta 1-28 fragment. S12024 reduced the number of animals with neuronal loss in the hippocampus, diminished the extent of the lesion, and reversed deficits of passive avoidance learning acquisition in animals with deposits of amyloid-beta 1-28. These results suggest that S12024 has neuroprotective effects on hippocampal cells and that the neurodegeneration by fluid injection combined with deposit of amyloid-beta 1-28 may be used to assay the neuroprotective activity of pharmacological compounds.

Plasticity of Congo red staining displayed by subpopulations of neurons within the rat central nervous system.

We document the presence of subpopulations of neurons within the rat central nervous system that are labelled with a new Congo red staining technique. These neurons (CR neurons) show shrunken somata, and smaller and darker nuclei than Congo red-negative cells (non-CR cells). With the Bielschowsky and the cresyl violet Nissl staining methods, two comparable subpopulations of cells can be distinguished by the same morphometrical criteria as those used for CR and non-CR cells. CR neurons are located preferentially in some brain regions while in others they are virtually absent. Their distribution and proportion varied greatly from animal to animal and after particular treatments. Injections of water that damaged the hippocampal dentate gyrus, cortical lesions or eye enucleation decreased the number of CR-cells in the CA1 subfield, reflected in a shift from the CR-staining subclass to the non-CR subclass. Treatment with 200 mg/kg of CDP-choline also significantly reduced the number of CR cells observed in CA1. In the red nucleus, CR neurons showed a characteristic distribution of beta-amyloid precursor protein (APP) immunoreactivity. The population of dendrites immunolabelled for microtubule-associated protein 2 was markedly decreased in the areas of the hippocampus with high numbers of CR cells. Therefore, it is proposed that neurons labelled with the present Congo red technique might be in a reversible degenerative state or represent a particular physiological state in some areas of the central nervous system.

Beta-amyloid(1-40)-induced neurodegeneration in the rat hippocampal neurons of the CA1 subfield.

Small volumes of solutions injected into the hippocampus produce dramatic degeneration in dentate gyrus neurons, but not in neurons of the CA1 subfield. The aim of the present study was to ascertain whether solutions with different fragments of the beta-amyloid protein (Abeta) could produce further degeneration in areas beyond the dentate gyrus. It was found that 5 days after injection of an aqueous solution containing the Abeta 1-40 fragment into the hippocampus, long stretches of the CA1 subfield were either deprived of neurons or most of the neurons were degenerating. By contrast, in animals with deposits containing Abeta 1-28, Abeta 1-42 or water, neuronal degeneration or depletion only occurred in a reduced area around the place where the implant needle penetrated the CA1 subfield. In animals injected with Abeta 1-40, many profiles in the CA1 subfield and dentate gyrus were undergoing apoptosis, as seen using preparations processed by routine histology or the TUNEL technique for detection of fragmented DNA. In addition, there was higher infiltration by ED1-positive, activated microglia-macrophagic cells in Abeta 1-42 deposits than in deposits of Abeta 1-40. The present results suggest that the intrahippocampal injection of toxic Abeta fragments produces neuronal degeneration in the rat CA1 subfield when using the appropriate protocol, and, thus, can provide an in vivo model to investigate the neurotoxic effects of Abeta and for the evaluation of drugs with potential anti-neurodegenerative activity.

Intrahippocampal injections of the beta-amyloid 1-28 fragment induces behavioral deficits in rats.

beta-amyloid (beta A) deposition is a key event in the etiopathogenesis of Alzheimer's disease (AD), contributing to neuronal degeneration and cognitive impairment in AD patients. Both neurotrophic and neurotoxic actions of beta A have been demonstrated in experimental conditions. In order to further characterize the effects of brain beta A deposits on behavioral processes, we evaluated psychomotor activity (PMA), psychomotor coordination (PMC) and learning in a passive avoidance task (PAL) in rats with unilateral or bilateral 2 microliters injections of beta-amyloid (1-28) protein (beta A; 1.5 nmol/microliter) or vehicle (water; W) into the hippocampus, 1 and 4 weeks after neurosurgery. The extent of neuronal loss in the lateral blade of the gyrus dentatus (LBGD) and the area percentage occupied by APP immunoreactivity in neurons of the CA3c subfield of the hippocampus were also measured in animals with unilateral beta A implants. PMA levels were similar in water- and beta A-injected animals 1 and 4 weeks after recovery. As compared to water-injected rats, beta A animals showed reduced PMC values 1 week, but not 4 weeks, after injections. beta A also impaired learning acquisition in a passive avoidance task, reducing the number of avoidances and mean latency per trial at both 1 and 4 weeks postsurgery in rats with unilateral or bilateral beta A implants. The extent of neuronal loss in the LBGD) was not different in rats receiving water or beta A injections. Hippocampal APP expression tended to increase in beta A-implanted rats and showed a negative correlation with cognitive performance at the 4-week period. According to these results it seems that beta A implants into the hippocampus reduce psychomotor coordination performance in a transient manner, with no effect on psychomotor activity, and induce durable learning impairment in rats, and that changes in cognitive performance correlate with histochemical parameters such as APP expression. In conclusion, the present results contribute to a better understanding of beta A-induced behavioral alterations and to the identification of potential molecular mechanisms involved in cognitive dysfunctions in this animal model of neurodegeneration.

Effects of anapsos on the activity of the enzyme Cu-Zn-superoxide dismutase in an animal model of neuronal degeneration.

The enzyme Cu-Zn-SOD is a metalloenzyme that catalyzes the dismutation of the superoxide radical into hydrogen peroxide and molecular oxygen, being a defense system against free radical formation. Free radical reactions are implicated in a variety of physiological and pathological processes as aging, apoptosis and neurodegenerative diseases, and abnormalities associated with SOD have been recently documented in several neurodegenerative processes. In this study, we have evaluated the effect of anapsos on Cu-Zn-SOD activity in rats with injections of beta-amyloid protein or water bilaterally into the hippocampus. These injections caused severe cell depletion in the gyrus dentatus. Anapsos is a biological extract obtained from the fern Polypodium leucotomos with immunomodulatory and anti-neoplastic effects tested in animals and humans. Cu-Zn-SOD activity was measured in the hypothalamus, hippocampus, cerebral cortex, liver and spleen of rats treated i.p. with three doses of anapsos for 7 days (4, 20 and 100 mg/kg/day). Control animals were treated with saline solution under the same conditions. Anapsos significantly modified enzyme activity in all the areas tested. Lower doses of anapsos produced decreased SOD activity in the hypothalamus, hippocampus, liver and spleen, while in the cerebral cortex, a significant dose-dependent increase in SOD activity was observed. These results indicate that anapos was able to modify Cu-Zn-SOD activity in this animal model of neuronal degeneration, which may indicate the participation of anapsos in mechanisms of tissue repair after brain damage.