Chromosome Painting in Gymnotus carapo "Catalão" (Gymnotiformes, Teleostei): Dynamics of Chromosomal Rearrangements in Cryptic Species

The genus Gymnotus is a large monophyletic group of freshwater weakly-electric fishes, with wide distribution in Central and South America. It has 46 valid species divided into six subgenera (Gymnotus, Tijax, Tigre, Lamontianus, Tigrinus and Pantherus) with large chromosome plasticity and diploid numbers (2n) ranging from 34 to 54. Within this rich diversity, there is controversy about whether Gymnotus (Gymnotus) carapo species is a single widespread species or a complex of cryptic species. Cytogenetic studies show different diploid numbers for G. carapo species, ranging from 40 to 54 chromosomes with varied karyotypes found even between populations sharing the same 2n. Whole chromosome painting has been used in studies on fish species and recently has been used for tracking the chromosomal evolution of Gymnotus and assisting in its cytotaxonomy. Comparative genomic mapping using chromosome painting has shown more complex rearrangements in Gymnotus carapo than shown in previous studies by classical cytogenetics. These studies demonstrate that multiple chromosome pairs are involved in its chromosomal reorganization, suggesting the presence of a complex of cryptic species due to a post zygotic barrier. In the present study, metaphase chromosomes of G. carapo occidentalis "catalão" (GCC, 2n = 40, 30m/sm+10st/a) from the Catalão Lake, Amazonas, Brazil, were hybridized with whole chromosome probes derived from the chromosomes of G. carapo (GCA, 2n = 42, 30m/sm+12st/a). The results reveal chromosome rearrangements and a high number of repetitive DNA sites. Of the 12 pairs of G. carapo chromosomes that could be individually identified (GCA 1-3, 6, 7, 9, 14, 16 and 18-21), 8 pairs (GCA 1, 2, 6, 7, 9, 14, 20, 21) had homeology conserved in GCC. Of the GCA pairs that are grouped (GCA [4, 8], [5, 17], [10, 11] and [12, 13, 15]), most kept the number of signals in GCC (GCA [5, 17], [10, 11] and [12, 13, 15]). The remaining chromosomes are rearranged in the GCC karyotype. Analysis of both populations of the G. carapo cytotypes shows extensive karyotype reorganization. Along with previous studies, this suggests that the different cytotypes analyzed here may represent different species and supports the hypothesis that G. carapo is not a single widespread species, but a group of cryptic species.

Silencing of Transposable Elements Mediated by 5-mC and Compensation of the Heterochromatin Content by Presence of B Chromosomes in Astyanax scabripinnis

The way in which transcriptional activity overcomes the physical DNA structure and gene regulation mechanisms involves complex processes that are not yet fully understood. Modifications in the cytosine-guanine sequence of DNA by 5-mC are preferentially located in heterochromatic regions and are related to gene silencing. Herein, we investigate evidence of epigenetic regulation related to the B chromosome model and transposable elements in A. scabripinnis. Indirect immunofluorescence using anti-5-mC to mark methylated regions was employed along with quantitative ELISA to determine the total genomic DNA methylation level. 5-mC signals were dispersed in the chromosomes of both females and males, with preferential accumulation in the B chromosome. In addition to the heterochromatic methylated regions, our results suggest that methylation is associated with transposable elements (LINE and Tc1-Mariner). Heterochromatin content was measured based on the C-band length in relation to the size of chromosome 1. The B chromosome in A. scabripinnis comprises heterochromatin located in the pericentromeric region of both arms of this isochromosome. In this context, individuals with B chromosomes should have an increased heterochromatin content when compared to individuals that do not. Although, both heterochromatin content and genome methylation showed no significant differences between sexes or in relation to the occurrence of B chromosomes. Our evidence suggests that the B chromosome can have a compensation effect on the heterochromatin content and that methylation possibly operates to silence TEs in A. scabripinnis. This represents a sui generis compensation and gene activity buffering mechanism.

A New Variant B Chromosome in Auchenipteridae: The Role of (GATA)n and (TTAGGG)n Sequences in Understanding the Evolution of Supernumeraries in Trachelyopterus

Basic and molecular cytogenetic techniques were carried out in 3 Neotropical region populations of catfishes, two of Trachelyopterus galeatus (one from the marshlands of Paraguay River basin and another from Lago Catalão, Amazon River basin) and one of Trachelyopterus porosus, a sympatric population to T. galeatus from the Amazon River basin. This study aimed to describe and understand the structure and evolution of Trachelyopterus B chromosomes, mainly through physical mapping of repetitive elements. A diploid number of 58 chromosomes was found for all individuals, as well as the presence of B chromosomes. For T. porosus this is the first report of a supernumerary. The sympatric species of T. galeatus and T. porosus from Amazon River had 1-3 B chromosomes and T. galeatus from Paraguay River had 1-2 B chromosomes, all of them showed intra- and interindividual numerical variation. Two females of T. porosus exhibited a new variant B chromosome (B2), previously not seen in Auchenipteridae, which might have originated from B1 chromosomes. All B chromosomes were entirely heterochromatic. In contrast to all complement A and B2 chromosomes, in which the telomeric sequences were found in the telomeric regions, B1 chromosomes of all populations were totally marked by (TTAGGG)n probes. (GATA)n sequence sites were found through all complement A chromosomes, but B1 and B2 chromosomes exhibited only a clustered block in one of the chromosome arms. The most frequent B chromosomes (B1) in all populations/species, including those previously studied in Auchenipteridae catfishes, share the following characteristics: totally heterochromatic, small, metacentric, with accumulation of repetitive (TTAGGG)n sequences, and a low number of (GATA)n copies, which might suggest a common ancient origin in Trachelyopterus species/populations.

Whole-flint corn grain or tropical grass hay free choice in the diet of dairy calves

Tropical grass hay feeding is related to improved ruminal health; however, it may decrease energy intake. On the other hand, whole-flint corn grain may be an alternative fiber source in the diet of dairy calves. Forty-two Holstein calves were used in a randomized block design, considering sex, birth date, and weight at 21 d of age, when the supply of whole-flint corn grain or tropical grass hay started. Three component-fed solid diets were compared: (1) starter concentrate only during the preweaning and starter concentrate with free choice of chopped Tifton-85 hay postweaning (SC), (2) starter concentrate with free choice of chopped Tifton-85 hay pre- and postweaning (SCH), and (3) starter concentrate with free choice of whole-flint corn grain pre- and postweaning (SCW). The animals were evaluated from 21 to 84 d of age. Calves were managed equally during the first 21 d, fed with 6 L/d of whole milk and a commercial starter concentrate (46% nonfiber carbohydrates, small particles, and pelleted) ad libitum. After that, milk feeding was reduced to 4 L/d until gradual weaning at 56 d of age. At 56 d of age, 4 animals per treatment were randomly chosen to be slaughtered for digestive tract weight evaluation and to collect tissue for histological analysis of the ruminal wall, duodenum, and cecum, whereas the other 30 animals were weaned and evaluated for a further 22 d when the SC diet also received hay ad libitum. Feed intake was measured daily. Weight gain and metabolic indicators of intermediate metabolism were evaluated weekly. Ruminal fluid was collected at wk 6, 8, 10, and 12 of age. The SCH diet increased the total and starter dry matter intake, and consequently, the average daily gain and body weight at 56 d of age. The SCW diet promoted an increase in propionate and decreased acetate-to-propionate ratio. Morphometric variables were affected by the SCH diet. The postweaning performance was unaffected by solid diets; however, the SCW diet decreased ruminal and fecal pH. Feeding hay, starting at 21 d of age, can stimulate early solid diet intake, promoting better performance and ruminal and intestinal development, when a highly fermentable and small particle pelleted starter is fed.

Dynamics of Replication and Nuclear Localization of the B Chromosome in Kidney Tissue Cells in Astyanax scabripinnis (Teleostei: Characidae)

B chromosomes are extra genomic compounds found in different taxonomic groups, including plants and animals. Obtaining patterns of resolutive chromosomal bands is necessary to understand the nuclear organization, variability and nature of B chromosome chromatin and possible transcriptional regions. In this study, we analyzed 35 Astyanax scabripinnis specimens sampled from Fazenda Lavrinha, a stream in the Paraíba do Sul river basin, Brazil. Through the incorporation of the thymidine analog 5'-bromo-2'-deoxyuridine (5-BrdU) in vivo, it was possible to recognize the replicating regions of the B chromosome at the beginning of the S phase, differentially characterized in relationship to the regions of late replication. In this perspective, it is possible to suggest that the B chromosome of this species possesses a territory and the chromatin accessible for transcription, especially in the light (i.e., early replicating) bands (p1.1; p1.3; and p2.1 and q1.1, q1.3, q2.1, and q2.2). The late-replicating regions are corresponding to the blocks of constitutive heterochromatin. They show a preferential accumulation of satellite DNA As51. By the use of the fluorochrome chromomycin A3 (CMA3), it was possible to identify GC-rich chromosomal regions, corresponding to late-replicating parts of genome, confirming the revealed data by the replication banding and C-banding. In addition, the analysis by confocal microscopy in kidney cells indicates the location of a peripheral anchorage of this chromosome in the nuclear lamina, reinforcing the idea of downregulation of the associated regions.

Chromosomal analysis of Centromochlus heckelii (Siluriformes: Auchenipteridae), with a contribution to Centromochlus definition

ABSTRACT Historically, there are divergences in the species allocation between Centromochlus and Tatia. This study aimed to generate the first cytogenetic data about Centromochlus and, by analyzing a population of Centromochlus heckelii from the Amazon River basin, to contribute as evidence to a historical taxonomic dilemma. Diploid number of 46 chromosomes and a heteromorphic pair was found in the female karyotypes, thus characterizing a ZZ/ZW sex chromosome system. Pale blocks of heterochromatin were located in centromeric regions of some chromosomes; however, the exclusive female chromosome (W) is almost entirely heterochromatic. AgNORs were detected in terminal position on the short arms of one acrocentric pair in males and two chromosome pairs in females, the acrocentric plus the sex chromosome pair. Notable differences between Centromochlus heckelii and previous data about species of Tatia are: lower diploid number, presence of a sex chromosome system and multiple AgNORs in Centromochlus, while species of Tatia have simple AgNORs and the absence of acrocentric chromosomes. Results in this study show that chromosomal markers could contribute as evidence to taxonomic delimitation studies.

Karyotypic Diversity and Evolutionary Trends in Neotropical Electric Fish of the Genus Gymnotus (Gymnotiformes: Gymnotidae)

Electric fish of the order Gymnotiformes are endemic to the Neotropical region, and their highest diversity is observed in the Amazon region. The family Gymnotidae, which consists of the genera Electrophorus and Gymnotus, is a natural group and is located at the base of the phylogeny of the order. Gymnotus is a widely distributed and specious genus with high karyotypic diversity, especially concerning to the diploid number and the locations of repetitive sequences. Our karyotyping results in five species of the family Gymnotidae (Gymnotus ucamara, Gymnotus cf. stenoleucus, Gymnotus cf. pedanopterus, Gymnotus mamiraua, and Gymnotus carapo "Maranhão") corroborate the proposal of plasticity of the diploid number in this group. Moreover, in this study, we propose that the 5S ribosomal DNA (rDNA) sequences were species-specific markers that act as a potential biogeographical marker for the genus. Besides, the sequence's location, particularly in G. mamiraua from Central Amazon, shows a close relationship with 5S of the Gymnotus species, with 54 chromosomes, from the Paraná-Paraguay basin in the Center-South of Brazil. Considering that the ancestral diploid number for Gymnotidae is 52 chromosomes, we also suggest that the trend in the family is toward a decrease in the chromosome number. However, the carapo clade stands out in this regard, with an increase and a decrease in chromosome number; this pattern may be reinforced with the ecologic behaviors and the geodispersal patterns of this clade.

Sclerostin and DKK1 Inhibition Preserves and Augments Alveolar Bone Volume and Architecture in Rats with Alveolar Bone Loss

Alveolar bone is a mechanosensitive tissue that provides structural support for teeth. Alveolar bone loss is common with aging, menopause, tooth loss, and periodontitis and can lead to additional tooth loss, reduced denture fixation, and challenges in placing dental implants. The current studies suggest that sclerostin and DKK1, which are established osteocyte-derived inhibitors of bone formation, contribute to alveolar bone loss associated with estrogen ablation and edentulism in rats. Estrogen-deficient ovariectomized rats showed significant mandibular bone loss that was reversed by systemic administration of sclerostin antibody (SAB) alone and in combination with DKK1 antibody (DAB). Osteocytes in the dentate and edentulous rat maxilla expressed Sost (sclerostin) and Dkk1 (DKK1) mRNA, and molar extraction appeared to acutely increase DKK1 expression. In a chronic rat maxillary molar extraction model, systemic SAB administration augmented the volume and height of atrophic alveolar ridges, effects that were enhanced by coadministering DAB. SAB and SAB+DAB also fully reversed bone loss that developed in the opposing mandible as a result of hypo-occlusion. In both treatment studies, alveolar bone augmentation with SAB or SAB+DAB was accompanied by increased bone mass in the postcranial skeleton. Jaw bone biomechanics showed that intact sclerostin-deficient mice exhibited stronger and denser mandibles as compared with wild-type controls. These studies show that sclerostin inhibition, with and without DKK1 coinhibition, augmented alveolar bone volume and architecture in rats with alveolar bone loss. These noninvasive approaches may have utility for the conservative augmentation of alveolar bone.

Variability and evolutionary implications of repetitive DNA dynamics in genome of Astyanax scabripinnis (Teleostei, Characidae)

DNA sequences of multiple copies help in understanding evolutionary mechanisms, genomic structures and karyotype differentiation. The current study investigates the organization and distribution of different repetitive DNA in the standard complement and B chromosomes in Astyanax scabripinnis (Jenyns, 1842) chromosomes from three allopatric populations in Campos do Jordão region, São Paulo State, Brazil. The location of microsatellite sequences showed different chromosome distribution between Lavrinha Farm Stream (LFS) and Lake of Pedalinho (LP) populations. However, the karyotype of these populations basically followed the pattern of dispersed distribution in the A complement, conspicuous in telomeric/interstitial regions and preferential accumulation in the B chromosome. The B chromosome showed heterogeneous location of microsatellite probes CA, CAC and GA. The H3 and H4 histone genes were isolated from the total genome of the species and then the chromosomal mapping was performed by fluorescence in situ hybridization (FISH). The FISH signals showed high similarity for the probes H3 and H4 mapping in genomes of the populations analyzed. The sequences (GATA) _n revealed a sex-specific trend between the chromosomal location in males and females at (LFS) and (LP) populations. Although species that comprise the Astyanax scabripinnis complex do not have morphologically differentiated sex chromosomes, the preferential GATA location - sex-associated - may represent a sex chromosome in differentiation.

Interrelationship Between Organizational and Relational Aspects and the Return-to-Work Process: A Case Study with Nursing Professionals at a Teaching Hospital in Brazil

Introduction The process of returning to work, especially for individuals with labor restrictions, impacts work teams and interferes with the labor reinsertion process. In this study, we aimed to understand the impact of these situations on a nursing team from both organizational and relational perspectives. Methods We conducted a qualitative research study at a university hospital in the municipality of São Paulo using three strategies: documentary analysis; semi-structured interviews with pairs of workers returning to a labor situation; and a focus group with nursing managers. Results Medical leaves of absence overburden the employees who remain working. Regarding the return to work, the participants reported both positive and negative aspects. One positive aspect reported was that those who return to work contribute to the division of labor, generating solidarity and cooperation. The negative aspects reported were related to the return of workers with labor restrictions who do not fully resume their activities, consequently generating conflicts within the work teams that interfere with the reintegration processes. The supervisors reported difficulties reorganizing work on a broad scale and assessing the workers' diagnoses and symptoms and the workers themselves in terms of the necessity of their leaves and the validity of their labor restrictions. Conclusion The organization of labor and social relationships among peers and supervisors is a significant contributor to the success or failure of the work reintegration process and therefore should be considered. We aimed to address this issue by highlighting the complexity of the return-to-work process among health workers.

Evolutionary Dynamics of 5S rDNA and Recurrent Association of Transposable Elements in Electric Fish of the Family Gymnotidae (Gymnotiformes): The Case of Gymnotus mamiraua

Gymnotidae is a family of electric fish endemic to the Neotropics consisting of 2 genera: Electrophorus and Gymnotus. The genus Gymnotus is widely distributed and is found in all of the major Brazilian river systems. Physical and molecular mapping data for the ribosomal DNA (rDNA) in this genus are still scarce, with its chromosomal location known in only 11 species. As other species of Gymnotus with 2n = 54 chromosomes from the Paraná-Paraguay basin, G. mamiraua was found to have a large number of 5S rDNA sites. Isolation and cloning of the 5S rDNA sequences from G. mamiraua identified a fragment of a transposable element similar to the Tc1/mariner transposon associated with a non-transcribed spacer. Double fluorescence in situ hybridization analysis of this element and the 5S rDNA showed that they were colocalized on several chromosomes, in addition to acting as nonsyntenic markers on others. Our data show the association between these sequences and suggest that the Tc1 retrotransposon may be the agent that drives the spread of these 5S rDNA-like sequences in the G. mamiraua genome.

Effects of Swimming on the Inflammatory and Redox Response in a Model of Allergic Asthma

In this study we hypothesized that swimming during sensitization phase could result in a preventive effect in mice with allergic asthma. Swiss mice were divided into 4 groups: Control and Swimming (non-sensitized), OVA and OVA+Swimming (sensitized). The allergic inflammation was induced by 2 intraperitoneal injections and 4 aerosol challenges using ovalbumin. Swimming sessions were performed at high intensity over 3 weeks. 48 h after the last challenge mice were euthanized. Swimming decreased OVA-increased total IgE, IL-1, IL-4, IL-5 and IL-6 levels, as well as the number of total cells, lymphocytes and eosinophils in bronchoalveolar lavage fluid, (p<0.05). Simultaneously, swimming also increased IL-10 and glutathione levels in the Swimming and OVA+Swimming groups (p<0.05). The levels of glutathione peroxidase and catalase were increased only in the Swimming group when compared to all groups (p<0.05). 21 days of swimming resulted in an attenuation of pulmonary allergic inflammation followed by an increase of glutathione levels in the OVA group. Swimming only increased the levels of glutathione peroxidase and catalase in non-sensitized mice (p<0.05). These data suggest that the pulmonary anti-inflammatory effects produced by 3 weeks of high-intensity swimming in this model of OVA-induced asthma may be, at least partly, modulated by reduced oxidative stress and increased IL-10 production.

Communities of Social Bees (Apidae: Meliponini) in Trap-Nests: the Spatial Dynamics of Reproduction in an Area of Atlantic Forest

As most stingless bee species depend on preexisting cavities, principally tree hollows, nesting site availability may represent an important restriction in the structuring of their forest communities. The present study examined the spatial dynamics of stingless bee communities in an area of Atlantic Forest by evaluating their swarming to trap-nests. The field work was performed in the Michelin Ecological Reserve (MER) on the southeastern coast of the state of Bahia, Brazil. Seven hundred and twenty trap-nests were distributed within two forest habitats in advanced and initial stages of regeneration. The trap-nests were monitored between September 2009 and March 2011. Twenty-five trap-nests were occupied by five bee species, resulting in a capture ratio of 0.035 swarms/trap (approximately 0.14 swarms/ha), corresponding to 10 swarms/year (0.056 swarms/ha/year). According to previous study at MER, the most abundant species in natural nests were also the most common in trap-nests in the two forest habitats examined, with the exception of Melipona scutellaris Latreille. Swarms of higher numbers of species were captured in initial regeneration stage forests than in advanced regeneration stage areas, and differences in species compositions were significant between both habitats (p = 0.03); these apparent differences were not consistent, however, when considering richness (p = 0.14) and total abundance (p = 0.08). The present study suggests the existence of a minimum cavity size threshold of approximately 1 L for most local species of stingless bees and sustains the hypothesis of a mass effect of Tetragonisca angustula Latreille populations from surrounding disturbed habitats on the MER forest community in terms of propagule (swarm) pressure. Examining swarm densities with trap-nests can be a promising technique for comparative analyses of the carrying capacities of forest habitats for stingless bee colonies, as long as size thresholds of cavities for nesting are taken into consideration.

Chromosomal polymorphism in two species of Hypancistrus (Siluriformes: Loricariidae): an integrative approach for understanding their biodiversity

Structural chromosome changes are widely described in different vertebrate groups and generate genetic, phenotypic and behavioral diversity. During the evolution of loricariids, several rearrangements (fissions, fusions, inversions) seem to have occurred. Hypancistrus, tribe Ancistrini, are highly demanded for fishkeeping around the world. In this tribe, the diploid chromosome number 2n = 52 is considered a synapomorphy, and paracentric-type inversions appear to be involved in the chromosomal evolution of the tribe. The present study investigated the karyotypes of H. zebra and H. cf. debilittera using cytogenetic, classical and molecular tools, as well as DNA barcoding. Data reveal that, although diploid number in both species corroborates the proposed synapomorphy for the tribe, there is a complex karyotype dynamics, reflected in the intense chromosomal polymorphism, resulting from rearrangements involving ribosomal regions (5S and 18S rDNA), which are suggested to be paracentric inversions. Besides, DNA barcode confirms reciprocal monophyletism between the species, validating the existence of two species, only. This scenario, coupled with genomic instability caused by exogenous sequences such as Rex-3 retrotransposons and the species' sedentary lifestyle, which helps the fast polymorphism fixation, may reflect different phenotypic color patterns in natural populations, as observed in H. cf. debilittera.

Karyotype variability in neotropical catfishes of the family Pimelodidae (Teleostei: Siluriformes)

Karyotypic data are presented for four species of fish belonging to the Pimelodidae family. These species show a conserved diploid number, 2n = 56 chromosomes, with different karyotypic formulae. The analyzed species showed little amount of heterochromatin located preferentially in the centromeric and telomeric regions of some chromosomes. The nucleolus organizer regions activity (Ag-NORs) and the chromosomal location of ribosomal genes by fluorescent in situ hybridization (FISH), with 18S and 5S probes, showing only one chromosome pair marked bearer of ribosomal genes, the only exception was Pimelodus britskii that presented multiple NORs and syntenic location of the 18S and 5S probes. Non-Robertsonian events, as pericentric inversion and NORs duplication are requested to explain the karyotype diversification in Pseudoplatystoma from the rio Paraguay (MS), Pimelodus from the rio Iguaçu (PR), Sorubim from the rio Paraguay (MS) and Steindachneridion from the rio Paraíba do Sul (SP). The obtained data for the karyotype macrostructure of these species corroborates a conserved pattern observed in Pimelodidae. On the other hand, interspecific variations detected by molecular cytogenetics markers made possible cytotaxonomic inferences and differentiation of the species here analyzed.

Optical imaging of Cerenkov light generation from positron-emitting radiotracers

Radiotracers labeled with high-energy positron emitters, such as those commonly used for positron emission tomography studies, emit visible light immediately following decay in a medium. This phenomenon, not previously described for these imaging tracers, is consistent with Cerenkov radiation and has several potential applications, especially for in vivo molecular imaging studies. Herein we detail a new molecular imaging tool, Cerenkov Luminescence Imaging, the experiments conducted that support our interpretation of the source of the signal, and proof-of-concept in vivo studies that set the foundation for future application of this new method.

Multibiomarker assessment of three Brazilian estuaries using oysters as bioindicators

Oysters have been largely employed as bioindicators of environmental quality in biomonitoring studies. Crassostrea rhizophorae was selected to evaluate the health status of three estuarine areas impacted by anthropogenic activities along the Brazilian coast, in three estuarine complexes, ranging in latitude from 7 to 25 degrees S. In each estuary three sites were sampled in Winter and in Summer: a site considered as reference, and two sites next to contamination sources. Condition index was similar at all sites and estuaries, with the highest values found for Itamaracá oysters in Summer. Necrosis, hyperplasia, mucocyte hypertrophy and fusion of ordinary filaments were the main histopathological lesions observed. Muscle cholinesterase activity was overall similar, but with a strong seasonal effect. Inhibition or activation of branchial total ATPase and Na,K-ATPase activities at the contaminated sites was observed. The health status of these estuarine areas is quite similar, and the combined use of biomarkers is recommended.

Apoptosis-regulating proteins and prognosis in diffuse large B cell non-Hodgkin's lymphomas

We evaluated the expression of apoptosis-regulating proteins (p53, Bcl-2, Bax, Bak and Mcl-1) in paraffin-embedded tissues of 33 patients with diffuse large B cell non-Hodgkin's lymphoma, and assessed the relationship of these proteins to clinical outcome and response to chemotherapy. Our results showed that p53 expression was an independent immunohistochemical parameter related to a poor prognosis in these lymphomas. Bcl-2, Bax, Bak and Mcl-1 proteins, though highly expressed in almost all cases were not associated with prognosis or response to treatment.

Apocrine ductal carcinoma in situ of the breast: histologic classification and expression of biologic markers

Apocrine ductal carcinoma in situ (ADCIS) has been called a special type of ductal carcinoma in situ (DCIS) because the histologic grading is considered difficult using the classification schemes that have been proposed for common DCIS. However, ADCIS encompasses a spectrum of lesions with different morphologic aspects ranging from minimally atypical to overtly malignant. To define a classification scheme for ADCIS, 35 cases (22 pure and 13 associated with invasive carcinoma) were selected on the basis of conventional morphology on hematoxylin and eosin (H&E)-stained sections. Each case was assigned to 1 of 3 histologic grades (low, intermediate, and high) based on nuclear morphology and the presence of necrosis. In addition, the expression of hormone receptors p53, bcl-2, c-erbB-2, and Ki-67 was evaluated by immunohistochemistry, and the DNA ploidy was determined by image cytometry. Fifteen cases were classified as high histologic grade, 10 as low histologic grade, and the other 10 as intermediate grade. All but 4 cases, irrespective of grade, had the same hormonal immunophenotype: androgen receptor positivity (97.1%) and estrogen receptor and progesterone receptor negativity (94.3% and 97.1% respectively). Twenty-one cases (61.8%) showed p53 expression, and 47.1% of the cases were positive for c-erbB-2. The median positivity for Ki-67 was 5.2%. ADCIS has a unique morphologic and hormonal profile, distinct from common DCIS, deserving a specific classification. The proposed classification scheme allows for categorization of ADCIS according to the most important morphologic features already seen in common DCIS, ie, nuclear grade and necrosis. The expression of biologic markers other than hormonal receptors and bcl2 in ADCIS seems in general to be similar to that in common DCIS. Ki-67 and c-erbB-2 are expressed more frequently in intermediate and high histologic grade ADCIS.

Inside-out versus standard artery graft to repair a sensory nerve in rats

It is known that a vein graft provides a good microenvironment for axon regeneration in motor peripheral nerves, but the use of artery graft for regeneration of sensory nerves is controversial. We sectioned the saphenous nerve and repaired it by using heterologous inside-out and standard artery graft techniques in rats. After 4, 12, and 20 weeks, the graft and the distal stump were observed under electron microscopy. In each period studied, the pattern, diameters, and thickness of the myelin sheaths of the regenerated axons were measured in the graft and distal stump. There was capillary invasion in both the graft and distal stump, especially in the inside-out artery graft group. Regenerated nerve fibers were prominent in both heterologous artery grafts 4 weeks after the surgical procedures. Conversely, in the distal stump, regenerated nerve fibers were observed only after 12 weeks. In both the inside-out artery graft and standard artery graft, no statistical difference in the diameters and thickness of the myelinated fibers after 20 weeks was observed.

Multispectral analysis of the temporal evolution of cerebral ischemia in the rat brain

A major difficulty in staging and predicting ischemic brain injury by magnetic resonance (MR) imaging is the time-varying nature of the MR parameters within the ischemic lesion. A new multispectral (MS) approach is described to characterize cerebral ischemia in a time-independent fashion. MS analysis of five MR parameters (mean diffusivity, diffusion anisotropy, T2, proton density, and perfusion) was employed to characterize the progression of ischemic lesion in the rat brain following 60 minutes of transient focal ischemia. k-Means (KM) and fuzzy c-means (FCM) classification methods were employed to define the acute and subacute ischemic lesion. KM produced an estimate of lesion volume that was highly correlated with postmortem infarct volume, independent of the age of the lesion. Overall classification rates for KM exceeded FCM at acute and subacute time points as follows: KM, 90.5%, 94.4%, and 95. 9%; FCM, 82.4%, 90.6%, and 82.6% (for 45 minutes, 180 minutes, and 24-120 hours post MCAO groups). MS analysis also offers a formal method of combining diffusion and perfusion parameters to provide an estimate of the ischemic penumbra (KM classification rate = 70.3%). J. Magn. Reson. Imaging 2000;12:842-858.

Secondary decline in apparent diffusion coefficient and neurological outcomes after a short period of focal brain ischemia in rats

This study was designed to characterize the initial and secondary changes of the apparent diffusion coefficient (ADC) of water with high temporal resolution measurements of ADC values and to correlate ADC changes with functional outcomes. Fourteen rats underwent 30 minutes of temporary middle cerebral artery occlusion (MCAO). Diffusion-, perfusion-, and T2-weighted imaging was performed during MCAO and every 30 minutes for a total of 12 hours after reperfusion (n = 6). Neurological outcomes were evaluated during MCAO, every 30 minutes for a total of 6 hours and at 24 hours after reperfusion (n = 8). The decreased cerebral blood flow during MCAO returned to normal after reperfusion and remained unchanged thereafter. The decreased ADC values during occlusion completely recovered at 1 hour after reperfusion. The renormalized ADC values started to decrease secondarily at 2.5 hours, accompanied by a delayed increase in T2 values. The ADC-defined secondary lesion grew over time and was 52% of the ADC-defined initial lesion at 12 hours. Histological evaluation demonstrated neuronal damage in the regions of secondary ADC decline. Complete resolution of neurological deficits was seen in 1 rat at 1 hour and in 6 rats between 2.5 and 6 hours after reperfusion; no secondary neurological deficits were observed at 24 hours. These data suggest that (1) a secondary ADC reduction occurs as early as 2.5 hours after reperfusion, evolves in a slow fashion, and is associated with neuronal injury; and (2) renormalization and secondary decline in ADC are not associated with neurological recovery and worsening, respectively.

Multimodal evoked potentials and the ovarian cycle in young ovulating women

There is controversy over how hormonal conditions influence cerebral physiology. We studied pattern-shift visual evoked potentials (PS-VEP), brain stem auditory evoked potentials (BAEP) and short-latency somatosensory evoked potentials (SSEV) in 20 female volunteers at different phases of the menstrual cycle (estrogen phase, ovulatory day and progesterone phase). Statistical analysis showed decreased latencies for P100 (PS-VEP), N19 and P22 (SSEV) waves in the progesterone phase compared with the estrogen phase. There was no significant difference between the estrogen and the ovulation day values. Comparing the three above stages, there were no significant differences in the brainstem auditory evoked potentials. The reduction of the latencies of the potentials generated in multisynaptic circuits provides the first consistent neurophysiological basis for a tentative comprehension of human pre-menstrual syndrome.

Transient and permanent resolution of ischemic lesions on diffusion-weighted imaging after brief periods of focal ischemia in rats : correlation with histopathology

BACKGROUND AND PURPOSE

The early ischemic lesions demonstrated by diffusion-weighted imaging (DWI) are potentially reversible. The purposes of this study were to determine whether resolution of initial DWI lesions is transient or permanent after different brief periods of focal brain ischemia and to evaluate histological outcomes.

METHODS

Sixteen rats were subjected to 10 minutes (n=7) or 30 minutes (n=7) of temporary middle cerebral artery occlusion or sham operation (n=2). DWI, perfusion-weighted imaging (PWI), and T(2)-weighted imaging (T(2)WI) were performed during occlusion; immediately after reperfusion; and at 0.5, 1.0, 1.5, 12, 24, 48, and 72 hours after reperfusion. After the last MRI study, the brains were fixed, sectioned, stained with hematoxylin and eosin, and evaluated for neuronal necrosis.

RESULTS

No MRI or histological abnormalities were observed in the sham-operated rats. In both the 10-minute and 30-minute groups, the perfusion deficits and DWI hyperintensities that occurred during occlusion disappeared shortly after reperfusion. The DWI, PWI, and T(2)WI results remained normal thereafter in the 10-minute group, whereas secondary DWI hyperintensity and T(2)WI abnormalities developed at the 12-hour observation point in the 30-minute group. Histological examinations demonstrated neuronal necrosis in both groups, but the number of necrotic neurons was significantly higher in the 30-minute group (95+/-4%) than in the 10-minute group (17+/-10%, P<0.0001).

CONCLUSIONS

Transient or permanent resolution of initial DWI lesions depends on the duration of ischemia. Transient resolution of DWI lesions is associated with widespread neuronal necrosis; moreover, permanent resolution of DWI lesions does not necessarily indicate complete salvage of brain tissue from ischemic injury.

Temporal evolution of ischemic injury evaluated with diffusion-, perfusion-, and T2-weighted MRI

OBJECTIVE

Ischemic lesions seen on diffusion-weighted imaging (DWI) are reversible if reperfusion is performed within minutes after the onset of ischemia. This study was designed to determine whether acute reversibility of DWI abnormalities is transient following brief temporary focal brain ischemia and to characterize the temporal evolution of in vivo ischemic lesions.

METHODS

Eight rats were subjected to 30 minutes of temporary middle cerebral artery occlusion and underwent diffusion-, perfusion-, and T2-weighted MRI during occlusion; immediately after reperfusion; 30, 60, and 90 minutes after reperfusion; and 12, 24, 48, and 72 hours after reperfusion. Average apparent diffusion coefficient (ADCav) values and the cerebral blood flow index (CBFi) ratio were calculated in both the lateral caudoputamen and overlying cortex at each time point. The size of the in vivo ischemic abnormalities was calculated from the ADCav and the T2 maps. Postmortem triphenyltetrazolium chloride (TTC) staining was used to verify ischemic injury.

RESULTS

Both the CBFi ratio and ADCav values declined significantly in the two regions during occlusion. The CBFi ratio recovered immediately after reperfusion and remained unchanged over 72 hours. However, ADCav values returned to normal at 60 to 90 minutes and secondarily decreased at 12 hours after reperfusion as compared with those in the contralateral hemisphere. The extent of the in vivo ischemic lesions maximized at 48 hours and was highly correlated with TTC-derived lesion size.

CONCLUSIONS

Acute recovery of initial ADCav-defined lesions after reperfusion is transient, and secondary ADCav-defined lesions develop in a slow and delayed fashion.

Neuroprotective effects of a novel broad-spectrum cation channel blocker, LOE 908 MS, on experimental focal ischemia: a multispectral study

Thirty-four rats undergoing 90 minutes of temporary middle cerebral artery occlusion were randomly and blindly assigned to vehicle or (RS)-(3,4-dihydro-6, 7-dimethoxyisoquinoline-1-gamma1)-2-phenyl-N,N-di-2-(2, 3, 4-trimethoxyphenyl)ethyl acetamide (LOE 908 MS; 0.5 mg/kg) i.v. bolus at 30 minutes after arterial occlusion followed by a 5 mg/kg/hr i.v. infusion for 3.8 hours (n =17/group). Perfusion-, diffusion- and T(2)-weighted magnetic resonance imaging was performed before treatment and repeatedly after treatment. Multispectral analysis was used to define ischemic abnormalities. The size of the ischemic abnormalities, including the ischemic core and penumbra, was not different between the two groups before treatment. However, a significant difference in ischemic lesion size was detected beginning 1.5 hours after treatment. The size of the ischemic core was significantly smaller in the treatment group, while the size of the ischemic penumbra was similar in the two groups at 85 minutes after arterial occlusion. Postmortem infarct size at 24 hours was significantly smaller in the drug-treated group than in the placebo group. These results demonstrate that LOE 908 MS can reduce ischemic lesion size, which is probably attributable to inhibition of expansion of the ischemic core. J. Magn. Reson. Imaging 1999;10:138-145.

Lymphoid hyperplasia, CD45RBhigh to CD45RBlow T-cell imbalance, and suppression of Type I diabetes mellitus result from TNF blockade in NOD-->NOD-scid adoptive T cell transfer

Sustained antibody-mediated inhibition of tumor necrosis factor (TNF) activity offers protection against Type I (insulin-dependent) diabetes mellitus in non-obese diabetic (NOD) mice. The mechanism of this effect, however, has remained obscure: TNFalpha might be required for the development of specific immune responses to islet antigens or it could directly participate in destruction of beta cells. In this study, autoimmune destruction of beta cells was initiated in NOD-severe combined immunodeficient (scid) mice by transfer of NOD splenic T-cells to induce diabetes. The blockade of TNFalpha activity was achieved during a narrow window of time after transfer. Transient inhibition of TNFalpha greatly reduced the number of islet lymphocytes and the incidence of diabetes in recipients of prediabetic NOD spleen cells. Protection extended beyond the interval of effective TNF blockade. Furthermore, the protective effect was only observed if cells were obtained from 6-week-old donors. The suppression of autoimmunity was reversible in the context of adoptive transfer as indicated by the transfer of splenocytes from the primary recipient to a second NOD-scid host led to a diabetic outcome. The blockade of TNFalpha was accompanied by a considerable increase in spleen size and doubling of the total splenocyte count, suggesting that TNFalpha might normally eliminate a transplanted T-cell subset within the recipients. Further analysis showed an increase in the absolute count of CD4 + T cells and pronounced distortion of the CD45RBhigh to CD45RBlow ratio, with a relative augmentation in the CD45RBlow count in the spleen. TNFalpha appears to regulate the number and subtype distribution of a transplanted T cell population.

Reconsiderations about the clinical importance of the sympathetic skin response

Over the last few years, neurologists have been showing increasing interest in the study of the sympathetic skin response (SSR). In the present report we describe a simple method that permitted us to determine a wide variation of SSR in response to different stimuli such as respiration, deglutition, blinking, skeletal movements, biting, auditory or light stimuli, vocalization, and sphincter contraction. These results raise doubts about the role of SSR as a complementary diagnostic method.

Compression of the peripheral branches of the sciatic nerve by lipoma

The authors report two female patients with chronic sensitive and motor findings in lower limbs caused by compression of distal branches of sciatic nerve by lipoma. Similar cases were not described on literature. Nerve conduction studies allowed to localize the exact site of compression. At surgery, lipomas compressing the deep peroneal nerve (case 1) and the posterior tibial nerve (case 2) were observed. Histologic studies of tumors confirmed the diagnoses.

Effect of long-term treatment with insulin and/or acarbose on glomerular basement membrane thickening in alloxan-diabetic rats

Acarbose is a competitive inhibitor of the intestinal alpha-glycosidases, that can delay absorption of intestinal carbohydrates causing their malabsorption. In the present paper we studied the effects of insulin, acarbose and their association on glomerular basement membrane thickening in alloxan-diabetic rats. Twenty-five male and female Wistar rats, approximately 3 months old at the beginning of the experiment, were assigned randomly to each of five experimental groups: normal control rats, alloxan-diabetic control rats, alloxan-diabetic rats treated with acarbose, alloxan-diabetic rats treated with insulin, and alloxan-diabetic rats treated with insulin plus acarbose. Alloxan was administered in a single i.v. dose of 442 mg/kg body weight. Insulin was given subcutaneously at doses of 18 to 30 IU/kg corrected daily on the basis of glycosuria and ketonuria. Acarbose was given mixed with rat chow in a dose of 50 mg/100 g chow. Body weight, water and food intake and diuresis, as well as blood and urine glucose were determined after 1, 3, 6, 9, and 12 months of treatment. Glomerular basement membrane (GBM) thickening was determined by electron microscopy at the same times. Clear clinical and laboratory signs of severe diabetes, with blood glucose levels above 200 mg/dl and urine glucose above 3000 mg/dl, were observed in all alloxan-diabetic control rats, in all periods of follow-up, whereas administration of insulin or acarbose reduced the blood glucose levels of treated groups. The most satisfactory control of blood and urine glucose was observed in animals treated with both insulin and acarbose. However, diarrhea was observed in diabetic rats treated with acarbose associated or not with insulin. GBM thickening was correlated with age in all groups. Beginning at six months after diabetes induction, the GBM of untreated diabetic rats was significantly thicker (mean +/- SEM, 4.446 +/- 0.45 mm) than that of normal rats (2.977 +/- 0.63mm). Both insulin and acarbose prevented GBM thickening and their combination induced thickening similar to the age dependent thickening observed for normal rats of the same age. We conclude that acarbose when combined with insulin may be a good option in the control of diabetes and its renal complications.

Chronic motor neuron disease possibly related to intoxication with organochlorine insecticides

We report on two patients with a history of chronic exposure to organochlorine insecticides who developed clinical and electromyographic signs and symptoms of chronic motor neuron disease. Measurements of aldrin, lindane and heptachlor confirmed the intoxication. We emphasize the importance of searching for toxic and environmental factors in cases of motor neuron disease especially in Third World countries, where workers usually wear no adequate protective equipment.

A simple procedure to obtain one-micrometer sections of routinely embedded paraffin material

By freezing blocks of paraffin-embedded tissues to a convenient temperature it is possible to obtain routinely 1 micron sections that can be further processed as normal thicker sections. Normal and disposable steel knives can be used and the staining time should be increased in most procedures. Gradual freezing of blocks to the temperature of dry ice is the simplest and safest way to obtain an adequate temperature. The best results were obtained using as fixative 4% paraformaldehyde in phosphate buffered saline solution.

[Migratory flow of cases of malaria in Cuiabá/MT, 1986]

Foram estudadas 2.406 pessoas que procuraram a SUCAM/Cuiabá para diagnóstico e tratamento da malária. Destes, 1.151 tiveram lâminas positivas através da gota espessa: 720 P. vivax, 421 P. falciparum e 10 forma mista; 1.255 foram negativos à pesquisa de hematozoários. As entrevistas foram realizadas através de questionário padronizado onde procurou-se categorizar as pessoas conforme o sexo, idade, profissão, naturalidade, renda mensal, procedência e destino. Da análise efetuada vimos que os casos de malária originaram-se mais da micro-região Norte-Matogrossense para a Baixada Cuiabana (56,5%), colocando em risco toda a população desta micro-região, que encontra-se com borrificaçâo suspensa (DDT) na maioria das localidades. É também importante o fluxo de casos de malária do Estado de Rondônia (20,6%) e para os Estados da região Sul e Sudeste (4,4%) do país. Concluímos que medidas urgentes devam ser tomadas para a reformulação da campanha de controle da malária, planejando a intervenção nos aspectos sociais, políticos e econômicos.

[Respiratory manifestations in Plasmodium falciparum and vivax malaria]

Foram selecionados 110 pacientes que procuraram a SUCAM/CUIABÁ para diagnóstico e tratamento de malária, com queixa de febre e procedente de área malarígena. Nestes pacientes foram realizados: gota espessa para a pesquisa de Plasmodium; aplicação de questionário padronizado para detectar sintomas respiratórios presentes no momento da entrevista; gasometria arterial e espirometria para avaliar a função pulmonar. Desta amostra, 62 pacientes foram positivos para malária sendo 41 P. vivax, 20 P. falciparum e 01 forma mista (grupo Malárico); 48 mostraram-se negativos à pesquisa de hematozoários através da gota espessa (grupo Não Malárico). As manifestações respiratórias encontradas nesta população quando comparadas os grupos Malárico e Não Malárico, foram respectivamente: 1º) Sintomáticos Respiratórios de 46,8% para 22 9% (p < 0,05); 2°) Alterações Espirométricas de 53,2% para 20,8% (p < 0,05); 3°) Alterações Gasométricas de 62,9% para 25,0% (p < 0,05). Com estes resultados concluímos que há nítida associação entre a Malária produzida pelo P. vivax e P. falciparum e as manifestações respiratórias apresentadas, nesta população de estudo.