Vitamin C effects in mice experimentally infected with Trypanosoma cruzi QM2 strain

INTRODUCTION: To evaluate the efficacy of vitamin C in reducing the consequences generated by the production of free radicals in the acute and chronic phases of Chagas disease, two different doses of ascorbic acid were administered orally to 60 mice infected by Trypanosoma cruzi QM2 strain. METHODS: The animals were divided into six groups: G1, G2, and G3 for the acute phase study, and G'1, G'2, and G'3 for the chronic stage. The groups G1 and G'1 received 8.6x10-4mg/g of vitamin C daily, whereas G2 and G'2 received 7.14x10-3mg/g daily. The other groups, G3 and G'3, were considered placebos and received 10µL of mineral water. RESULTS: The study of the acute phase showed statistically significant differences between G1 and the other groups at various count days of the parasitemia evolution. The multiplying parasite was slower in G1 until the 11th day, but on the 22nd day it had greater parasitemia than in G2 and G3, and from the 36th day on, parasitemia stabilized at higher levels. However, when the histopathology of acute and chronic phases is considered, one does not note significant differences. CONCLUSIONS: The administration of two different doses of vitamin C was not able to protect mice and to contain the oxidative stress caused by free radicals formed by the metabolism of oxygen (reactive oxygen species) and nitrogen (reactive nitrogen species).

Changes in the prevalence, incidence and residual risk for HIV and hepatitis C virus in Southern Brazilian blood donors since the implementation of NAT screening

Introduction Previous studies have shown high residual risk of transfusing a blood donation contaminated by human immunodeficiency virus (HIV) or hepatitis C virus (HCV) in Brazil and motivated the development of a Brazilian platform for simultaneous detection of both viruses by nucleic acid amplification test (NAT) denominated HIV/HCV Bio-Manguinhos/Fundação Oswaldo Cruz (FIOCRUZ). The objective of this study was to verify seroprevalence, incidence and residual risk for both viruses before and after the implementation of NAT. Methods Over 700,000 blood samples from all blood banks in the southern Brazilian State of Santa Catarina were analyzed during the period between January 2007 and July 2013. Results Compared with the period preceding the NAT screening, HIV prevalence increased from 1.38 to 1.58 per 1,000 donors, HIV incidence rate increased from 1.22 to 1.35 per 1,000 donor-years, and HIV residual risk dropped almost 2.5 times during the NAT period. For HCV, seroprevalence increased from 1.22 to 1.35 per 1,000 donors, incidence dropped from 0.12 to 0.06 per 1,000 donor-years, and residual risk decreased more than 3 times after the NAT implementation. Conclusions NAT reduced the duration of the immunologic window for HIV and HCV, thus corresponding to approximately 2.5- and 3-fold respective residual risk reductions.

Susceptibility characterization of residual Brazilian populations of Triatoma infestans Klug, 1834 (Hemiptera: Reduviidae) to deltamethrin pyrethroid

INTRODUCTION: Despite years of efforts towards the elimination of Triatoma infestans in Brazil, residual foci still persist in some areas of the States of Bahia and Rio Grande do Sul. The persistence of these T. infestans populations in the country has two different origins of equal concern: operational failures or insecticide resistance. Thus, the objective of this study was to characterize the susceptibility profile of the residual Brazilian populations of T. infestans to deltamethrin. METHODS: The susceptibility reference lineage was derived from Cipein/Argentina. The populations studied were manually collected using a dislodging agent in peridomiciles in the States of Bahia (Novo Horizonte) and of Rio Grande do Sul (Santa Rosa and Doutor Maurício Cardoso). Serial dilutions of deltamethrin were prepared and applied at the dorsal abdomen of first instar nymphs. The control group received only pure acetone. Mortality was evaluated after 72h. Qualitative tests assessed the mortality of a diagnostic dose of 1xLD99 (2.76ng a.i./nymph) determined for the susceptibility reference lineage. RESULTS: The susceptibility profile characterization of the T. infestans populations revealed an RR50 ranging from 1.73 to 3.26. The mortality percentage in response to a diagnostic dose was 100%. The results obtained in the quantitative and qualitative assays corresponded for all populations. CONCLUSIONS: The results of this study indicate that the persistence of residual foci of T. infestans in Bahia and Rio Grande do Sul is not related to insecticide resistance but may be associated with operational failures. In Rio Grande do Sul, we must consider the possibility of continuous reinfestation by Argentinian individuals, which justifies active and efficient epidemiological surveillance.

Life cycle of Trypanosoma cruzi (y strain) in mice

Since 1958, we have studied experimental Chagas' disease (CD) by subcutaneous inoculation of 1,000 blood forms of Trypanosoma cruzi (Y strain) in Balb/C. mice. Evolution of parasitemia remained constant, beginning on the 5th and 6th day of the disease, increasing progressively, achieving a maximum on about the 30th day. After another month, only a few forms were present, and they disappeared from the circulation after the third month, as determined from direct examination of slides and the use of a Neubauer Counting Chamber. These events coincided with the appearance of amastigote nests in the tissues (especially the cardiac ones), starting the first week, and following the Gauss parasitemia curve, but they were not in parallel until the chronic stage. In 1997, we began to note the following changes: Parasites appeared in the circulation during the first week and disappeared starting on the 7th day, and there was a coincident absence of the amastigote nests in the tissues. A careful study verified that young forms in the evolutionary cycle of T. cruzi (epi + amastigotes) began to appear alongside the trypomastigotes in the circulation on the 5th and 7th post-inoculation day. At the same time, rounded, oval, and spindle shapes were seen circulating through the capillaries and sinusoids of the tissues, principally of the hematopoietic organs. Stasis occurs because the diameter of the circulating parasites is greater than the vessels, and this makes them more visible. Examination of the sternal bone marrow revealed young cells with elongated forms and others truncated in the shape of a "C" occupying the internal surface of the blood cells that had empty central portions (erythrocytes?). We hypothesize that there could be a loss of virulence or mutation of the Y strain of Trypanosoma cruzi.

EFEITO RESIDUAL DE CALAGEM Ε MICRONUTRIENTES EM LATOSSOLO AMARELO SOB ROTAÇÃO DE CULTURAS.

O ensaio de campo foi conduzido por um período de três anos, num Latossolo Amarelo da Amazônia Central cultivado com soja (1985), arroz (1986), caupi (1987) e caupi (1988), em rotação, visando estudar o efeito residual da calagem e interação com micronutrientes. Os tratamentos foram 0,2,3 e 5 t/h de calcário calcítico e 2,3 e 5 t/ha de calcário calcítico + micronutrientes (5 kg/ha Cu; 7,5 kg/ha Mn; 0,5 kg/ha Mo; 4,5 kg/ha Zn; 2,0 kg/ha B). Não houve acréscimo significativo na produção de soja e arroz com doses crescentes de calcário: soja variou de 260 a 732 kg/ha e arroz de 557 a 919 kg/ha. No entanto, com calcário + micronutrientes foram obtidos aumentos significativos de produção com relação aos tratamentos só com calagem e à testemunha: soja variou de 1986 a 2357 kg/ha e arroz de 1471 a 2133 kg/ ha. No terceiro ano (caupi) ainda houve uma pequena resposta à aplicação de micronutrientes, enquanto que no quarto ano de cultivo a produção do caupi foi bem menor que a do ano anterior e não houve r-esposta aos tratamentos estudados. A análise do solo nos dois primeiros anos de cultivo mostrou que a maioria dos micronutrientes analisados encontravam-se acima dos níveis críticos; somente o Cu e o Mn apresentaram baixos teores, principalmente nos tratamentos só com calagem. As produções dos dois primeiros cultivos apresentaram alta correlação positiva com os teores de Cu e Mn no solo. Ε possível que nos dois primeiros cultivos a calagem tenha induzido deficiências de Cu e Mn nos tratamentos sem micronutrientes.

The residual effect of deltametrine in the control of Malaria as observed on fifferent types Of walls In the Brazilian Amazon 1

The residual power of deltametrine FW (25 mg 1 .a/m2) was evaluated and compared to that of DDT (2 g i.a./m2) by means of biological tests. The different kinds of material used in constructing houses in Amazonia, such as: masonry, wood, and wattle and daub, were used. Data from logistic regression showed that the drop in mortality, the inclination of the curve in relation to time, was similar for the two insecticides in the first samples. The negative coeficient for the variable, months after application, confirmed a reduction in the activity of both insecticides. Wooden and wattle walls showed positive and negative coeficiencies respectively from the beginning. The wooden walls retained a residual effect but the wattle walls were shown to be the least indicated for the application of insecticides The experiments demonstrated a more prolonged residual effect for deltametrine as compared to DDT, and that insecticides work better on brick and cement and wooden walls than they do on wattle and daub constructions. For these reasons, it would be necessary to spray brick and cement walls every 8 months, wooden ones every 9 months and wattle constructions every 7 months to control the vectors of malaria.

Estudo longitudinal dos fatores associados à evolução de sintomas depressivos em idosos institucionalizados

Objetivos : Constatando que a depressão é comum em idosos institucionalizados, associando-se à solidão, à ansiedade e à afetividade, pretendemos descrever a evolução da depressão durante dois anos e verificar que fatores se associam a essa evolução. Métodos : Em um estudo de coorte prospectivo em dois momentos (2011 e 2013), avaliamos 83 idosos institucionalizados, com idade no primeiro momento entre os 60 e os 100 anos, sendo 79,5% mulheres, 86,7% sem companheiro(a), e 72,3% com algum grau de escolaridade. Usamos a Escala Geriátrica da Depressão (GDS), a Escala de Solidão (UCLA-L), o Inventário Geriátrico de Ansiedade (GAI) e a Lista de Afetos Positivos e Negativos (PANAS). Resultados: Verificamos que 59,0% mantiveram a depressão e 10,8% desenvolveram depressão. Os idosos com depressão tiveram significativamente piores resultados na UCLA, GAI e PANAS, e os não depressivos tiveram afetos positivos mais altos. Quanto à evolução da depressão, os idosos que mantiveram depressão tiveram inicialmente pontuações elevadas no GDS, GAI, UCLA e na subescala PANAS negativo e pontuações baixas na subescala PANAS positivo. Esses idosos apresentaram associadamente um agravamento dos sentimentos de solidão, dos sintomas ansiosos e do afeto negativo ao longo dos dois anos. Os que desenvolveram depressão tiveram, no primeiro momento, pontuações elevadas na UCLA. Conclusões: Os sintomas de depressão com ou sem solidão no momento inicial, o agravamento da solidão, a ansiedade, o afeto negativo e o baixo afeto positivo poderão ser fatores de risco para a manutenção da depressão. A solidão poderá ainda ser um fator de risco para o desenvolvimento de depressão.

Efetividade clínica e segurança do tratamento percutâneo da comunicação interatrial tipo ostium secundum, com a prótese Amplatzer®

OBJETIVOS: Analisar a eficácia clínica e segurança da prótese Amplatzer® na oclusão percutânea da comunicação interatrial tipo ostium secundum. MÉTODOS: Foram submetidos ao procedimento orientados pela ecocardiografia transesofágica (ETE) e sob anestesia geral 49 pacientes e acompanhados clinicamente por um período de 12 meses. RESULTADOS: O defeito apresentou-se como orifício único em 91,8% dos casos. As médias dos diâmetros longitudinal e transverso corresponderam a 14,3 ± 5,0 mm e 14,4 ± 4,9 mm. A média dos diâmetros estirados foi de 19,3 ± 5,1 mm e das próteses de 20,3 ± 4,9 mm. Houve sucesso técnico em 97,9% dos casos. Observou-se fluxo residual imediato em 54,1% sendo 45,8% mínimos ou pequenos e 8,3% moderados caindo para 25% após 24h (p = 0,0002). Ao final de 13,1 ± 1,3 meses a incidência do fluxo residual global reduziu-se para 14,6% sendo apenas 4,1% moderados. Houve significante redução do diâmetro diastólico do ventrículo direito nas diversas fases do seguimento clínico (p < 0,001). CONCLUSÃO: O procedimento com a prótese Amplatzer® mostrou-se eficaz e seguro constituindo-se numa opção para o tratamento da comunicação interatrial tipo ostium secundum em casos selecionados.

Estudo cardiológico longitudinal em crianças expostas ao vírus da imunodeficiência humana tipo 1 por via perinatal

OBJETIVO: Determinação da freqüência das alterações cardíacas e sua evolução nas crianças expostas ao HIV-1 por via perinatal. MÉTODOS: Realizada avaliação seqüencial clínico-cardiológica, eletrocardiográfica e ecocardiográfica Doppler em 84 crianças expostas ao HIV-1. RESULTADOS: Grupo I (sororreversão) 43 crianças (51,2%). Ausência de alterações clínicas. ECG: distúrbio de condução de ramo direito 5 casos. ECO: CIA (1 caso) e CIV (1 caso). Grupo II 41 infectados (48,8%) com 51,2% de alterações cardiológicas. Crianças assintomáticas ou com sintomas leves, sem imunossupressão: alterações clínico-ecocardiográficas ausentes; ECG: distúrbio de condução de ramo direito (2 casos). Crianças com comprometimento clínico-imunológico moderado e severo: Alterações encontradas: 1) Clínicas (31,7%): taquicardia isolada (1 caso), ICC (12 casos). 2) Eletrocardiográficas (43,9%): taquicardia sinusal associada a outras alterações (10 casos), distúrbio de condução de ramo direito (5 casos), BDAS (1 caso), HBAD (1 caso), alterações da repolarização ventricular (11 casos), SVD (2 casos), SVE (1 caso), desvio do AQRS para direita (1 caso), arritmias (3 casos). 3) Ecocardiográficas (26,8%): miocardiopatia dilatada (5 casos), derrame pericárdico com tamponamento (2 casos), hipertensão pulmonar (2 casos) e prolapso da valva mitral (1 caso). CONCLUSÃO: O envolvimento cardíaco foi uma característica do grupo infectado. Houve maior prevalência de alterações nas crianças pertencentes à categoria clínico-imunológica mais avançada. Os achados clínicos, eletrocardiográficos e ecocardiográficos mais freqüentes foram, respectivamente, ICC, alterações da repolarização ventricular e miocardiopatia dilatada. Esta foi reversível em um caso. As alterações eletrocardiográficas foram significantemente mais freqüentes que as clínicas e ecocardiográficas.

Avaliação da função sistólica longitudinal na insuficiência cardíaca com fração de ejeção normal

FUNDAMENTO: A insuficiência cardíaca com fração de ejeção normal (ICFEN) é hoje o modelo mais prevalente de IC em diferentes estudos epidemiológicos, e anormalidades na função sistólica de grau leve (subclínica) têm sido observadas nesses pacientes quando a contratilidade do ventrículo esquerdo (VE) é avaliada no eixo longitudinal (S') pelo ecocardiograma Doppler tecidual (EDT), mesmo na presença de fração de ejeção do VE normal. OBJETIVO: Avaliar se pacientes com diagnóstico de ICFEN, de acordo com os novos critérios da Sociedade Europeia de Cardiologia, apresentam alterações da função sistólica constatada pela medida de S' quando comparados com os pacientes em que a ICFEN não foi confirmada. MÉTODOS: Cento e dezoito pacientes com sinais ou sintomas de IC foram submetidos a dosagem de BNP e ao EDT com medidas da velocidade do eixo longitudinal na sístole (S') e diástole (E') e medidas do fluxo transmitral durante a diástole (E,A). RESULTADOS: ICFEN foi confirmada em 38 pacientes (32,2%). O pico da velocidade miocárdica durante a sístole (S') e a velocidade miocárdica no inicio da diástole (E') estavam significativamente diminuídas em pacientes com ICFEN em relação aos pacientes em que a ICFEN foi excluída (7,8 ± 2,3 cm/s vs 9,4 ± 2,5 cm/s p=0,002 - 7,7 ± 2,6 cm/s vs 9,4 ± 2,5 cm/s-p=0,001). Valores médios de BNP foram mais elevados em pacientes com ICFEN (140,5 ± 122,4 pg/ml vs 23,1 ± 25,0 pg/ml p< 0,0001). S' se correlacionou de modo significativo com E' (r=0,457 - p< 0,0001) mostrando uma forte ligação entre contração e relaxamento ventricular. CONCLUSÃO: Nossos achados mostram redução da função sistólica, quando avaliada pelo S', na ICFEN, existindo correlação linear entre o grau de disfunção sistólica (S') e diastólica (E/E'e E').

Deformação miocárdica pelo speckle tracking na cardiomiopatia dilatada grave

FUNDAMENTO: A alta e crescente prevalência de Cardiomiopatia Dilatada (CMD) representa sério problema de saúde pública. Novas tecnologias vêm sendo utilizadas objetivando diagnósticos mais sofisticados, que melhorem a abordagem terapêutica. Nesse cenário, o Speckle Tracking (STE) utiliza marcadores miocárdicos naturais para analisar a deformação sistólica do Ventrículo Esquerdo (VE). OBJETIVO: Mensurar o strain transmural longitudinal global (SG) do VE através do STE em pacientes com CMD grave, comparando os resultados com indivíduos normais e com parâmetros ecocardiográficos consagrados para análise da função sistólica do VE, validando o método nessa população. MÉTODOS: Foram estudados 71 pacientes com CMD grave, (53 ± 12a, 72% homens) e 20 controles (30 ± 8a, 45% homens). Foram obtidos os volumes e a FEVE pela ecocardiografia bi e tridimensional, parâmetros do Doppler, Doppler tecidual e o SG pelo STE. RESULTADOS: Comparados ao grupo controle, os volumes do VE foram maiores no grupo CMD; entretanto, a FEVE e velocidade de pico da onda E foram menores neste último. O índice de performance miocárdica foi maior entre os pacientes. As velocidades do miocárdio pelo Doppler tecidual (S', e', a') foram consideravelmente menores e a relação E/e' foi maior no grupo CMD. O SG apresentou-se diminuído no grupo CMD (-5,5% ± 2,3%), em relação aos controles (-14,0% ± 1,8%). CONCLUSÃO: No presente estudo, o SG foi significativamente menor nos pacientes com CMD grave, abrindo novas perspectivas para abordagens terapêuticas nessa população específica.

Estudo da Mecânica Cardíaca pelo Speckle Tracking

Speckles, ou marcadores naturais do miocárdio, originam se da interferência construtiva e destrutiva do feixe de ultrassom que incide sobre os tecidos, podem fornecer um diagnóstico precoce das alterações miocárdicas e atuar na predição de certos eventos cardíacos. Devido à sua relativa estabilidade temporal, os speckles podem ser rastreados durante o ciclo cardíaco por software dedicados, promovendo a análise da função sistólica e diastólica. São identificados tanto pela escala de cinza da ecocardiografia 2D convencional quanto pela ecocardiografia 3D, sendo independentes do ângulo de incidência do ultrassom, permitindo assim a avaliação da mecânica cardíaca nos três planos espaciais: longitudinal, circunferencial e radial. O objetivo do presente artigo é discutir o papel e o significado da deformação cardíaca obtida por meio do speckle tracking durante a avaliação da fisiologia cardíaca, e discutir as aplicações clínicas desta tecnologia ecocardiográfica inovadora.

Subclinical Ventricular Dysfunction Detected by Speckle Tracking Two Years after Use of Anthracycline

Background: Heart failure is a severe complication associated with doxorubicin (DOX) use. Strain, assessed by two-dimensional speckle tracking (2D-STE), has been shown to be useful in identifying subclinical ventricular dysfunction. Objectives: a) To investigate the role of strain in the identification of subclinical ventricular dysfunction in patients who used DOX; b) to investigate determinants of strain response in these patients. Methods: Cross-sectional study with 81 participants: 40 patients who used DOX ±2 years before the study and 41 controls. All participants had left ventricular ejection fraction (LVEF) ≥55%. Total dose of DOX was 396mg (242mg/ms2). The systolic function of the LV was evaluated by LVEF (Simpson), as well as by longitudinal (εLL), circumferential (εCC), and radial (εRR) strains. Multivariate linear regression (MLR) analysis was performed using εLL (model 1) and εCC (model 2) as dependent variables. Results: Systolic and diastolic blood pressure values were higher in the control group (p < 0.05). εLL was lower in the DOX group (-12.4 ±2.6%) versus controls (-13.4 ± 1.7%; p = 0.044). The same occurred with εCC: -12.1 ± 2.7% (DOX) versus -16.7 ± 3.6% (controls; p < 0.001). The S’ wave was shorter in the DOX group (p = 0.035). On MLR, DOX was an independent predictor of reduced εCC (B = -4.429, p < 0.001). DOX (B = -1.289, p = 0.012) and age (B = -0.057, p = 0.029) were independent markers of reduced εLL. Conclusion: a) εLL, εCC and the S’ wave are reduced in patients who used DOX ±2 years prior to the study despite normal LVEF, suggesting the presence of subclinical ventricular dysfunction; b) DOX was an independent predictor of reduced εCC; c) prior use of DOX and age were independent markers of reduced εLL.

Comportamento dos cromossômios na meiose de Euryophthalmus rufipennis Laporte (Hemiptera Pyrrhocoridae)

In this paper an account is given of the principal facts observer in the meiosis of Euryophthalmus rufipennis Laporte which afford some evidence in favour of the view held by the present writer in earlier publications regarding the existence of two terminal kinetochores in Hem ip ter an chromosomes as well as the transverse division of the chromosomes. Spermatogonial mitosis - From the beginning of prophase until metaphase nothing worthy of special reference was observed. At anaphase, on the contrary, the behavior of the chromosomes deserves our best attention. Indeed, the chromoso- mes, as soon as they begin to move, they show both ends pronouncedly turned toward the poles to which they are connected by chromosomal fibres. So a premature and remarkable bending of the chromosomes not yet found in any other species of Hemiptera and even of Homoptera points strongly to terminally localized kinetochores. The explanation proposed by HUGHES-SCHRADER and RIS for Nautococcus and by RIS for Tamalia, whose chromosomes first become bent late in anaphase do not apply to chromosomes which initiate anaphase movement already turned toward the corresponding pole. In the other hand, the variety of positions assumed by the anaphase chromosomes of Euryophthalmus with regard to one another speaks conclusively against the idea of diffuse spindle attachments. First meiotic division - Corresponding to the beginning of the story of the primary spermatocytes cells are found with the nucleus entirelly filled with leptonema threads. Nuclei with thin and thick threads have been considered as being in the zygotente phase. At the pachytene stage the bivalents are formed by two parallel strands clearly separated by a narrow space. The preceding phases differ in nothing from the corresponding orthodox ones, pairing being undoubtedly of the parasynaptic type. Formation of tetrads - When the nuclei coming from the diffuse stage can be again understood the chromosomes reappear as thick threads formed by two filaments intimately united except for a short median segment. Becoming progressively shorter and thicker the bivalents sometimes unite their extremities forming ring-shaped figures. Generally, however, this does not happen and the bivalents give origin to more or less condensed characteristic Hemipteran tetrads, bent at the weak median region. The lateral duplicity of the tetrads is evident. At metaphase the tetrads are still bent and are connected with both poles by their ends. The ring-shaped diakinesis tetrads open themselves out before metaphase, showing in this way that were not chiasmata that held their ends together. Anaphase proceeds as expected. If we consider the median region of the tetrads as being terminalized chiasmata, then the chromosomes are provided with a single terminal kinetochore. But this it not the case. A critical analysis of the story of the bivalents before and after the diffuse stage points to the conclusion that they are continuous throughout their whole length. Thence the chromosomes are considered as having a kinetochore at each end. Orientation - There are some evidences that Hemipteran chromosomes are connected by chiasmata. If this is true, the orientation of the tetrads may be understood in the following manner: Chiasmata being hindered to scape by the terminal kinetochores accumulate at the ends of the tetrads, where condensation begins. Repulsion at the centric ends being prevented by chiasmata the tetrads orient themselves as if they were provided with a single kinetochore at each extremity, taking a position parallelly to the spindle axis. Anaphase separation - Anaphase separation is consequently due to a transverse division of the chromosomes. Telophase and secund meiotic division - At telophase the kinetochore repeli one another following the moving apart of the centosomes, the chiasmata slip toward the acentric extremities and the chromosomes rotate in order to arrange themselves parallelly to the axis of the new spindle. Separation is therefore throughout the pairing plane. Origin of the dicentricity of the chromosomes - Dicentricity of the chromosomes is ascribed to the division of the kinetochore of the chromosomes reaching the poles followed by separation and distension of the chromatids which remain fused at the acentric ends giving thus origin to terminally dicentric iso-chromosomes. Thence, the transverse division of the chromosomes, that is, a division through a plane perpendicular to the plane of pairing, actually corresponds to a longitudinal division realized in the preceding generation. Inactive and active kinetochores - Chromosomes carrying inactive kinetochore is not capable of orientation and active anaphasic movements. The heterochromosome of Diactor bilineatus in the division of the secondary spermatocytes is justly in this case, standing without fibrilar connection with the poles anywhere in the cell, while the autosomes are moving regularly. The heterochromosome of Euryophthalmus, on the contrary, having its kinetochores perfectly active ,is correctly oriented in the plane of the equator together with the autosomes and shows terminal chromosomal connection with both poles. Being attracted with equal strength by two opposite poles it cannot decide to the one way or the other remaining motionless in the equator until some secondary causes (as for instances a slight functional difference between the kinetochores) intervene to break the state of equilibrium. When Yiothing interferes to aide the heterochromosome in choosing its way it distends itself between the autosomal plates forming a fusiform bridge which sometimes finishes by being broken. Ordinarily, however, the bulky part of the heterochromosome passes to one pole. Spindle fibers and kinetic activity of chromosomal fragments - The kinetochore is considered as the unique part of the chromosome capable of being influenced by other kinetochore or by the poles. Under such influence the kinetochore would be stimulated or activited and would elaborate a sort of impulse which would run toward the ends. In this respect the chromosome may be compared to a neüròn, the cell being represented by the kinetochore and the axon by the body of the chromosome. Due to the action of the kinetochore the entire chromosome becomes also activated for performing its kinetic function. Nothing is known at present about the nature of this activation. We can however assume that some active chemical substance like those produced by the neuron and transferred to the effector passes from the kinetochore to the body of the chromosome runing down to the ends. And, like an axon which continues to transmit an impulse after the stimulating agent has suspended its action, so may the chromosome show some residual kinetic activity even after having lost its kinetochore. This is another explanation for the kinetic behavior of acentric chromosomal fragmehs. In the orthodox monocentric chromosomes the kinetic activity is greater at the kinetochore, that is, at the place of origin of the active substance than at any other place. In chromosomes provided with a kinetochore at each end the entire body may become active enough to produce chromosomal fibers. This is probably due to a more or less uniform distribution and concentration of the active substance coming simultaneously from both extremities of the chromosome.