Identification of phenotypic markers of B cells from patients with Chagas disease.

Chagas disease was discovered more than a hundred years ago, but its pathogenesis is still not completely understood. Autoimmunity is one of the mechanisms shown to contribute to its pathogenesis, which may indicate an important participation of B lymphocytes. Patients with Chagas disease have shown increased percentage of B cells producing IL-10. However, there are no reports of the phenotypic markers of B cells producing IL-10 in patients with Chagas disease. For the first time in the literature, we evaluated the phenotypic profile of distinct markers of B cells from peripheral blood of noninfected individuals and patients with Chagas disease. Our results showed that patients with Chagas disease had a higher expression of CD21 and CD24 on the surface of CD19+ B cells, while CD43 and CD23 were expressed equally in all groups. Moreover, the expression of MHC-II (HLA-DR), CD80, CD86, caspase-3, granzyme B and intracellular IL-10 and TGF-ß by CD19+ B cells was higher in patients with Chagas disease. The results of IL-10 production within CD19+ CD5+ CD1d+ B cells showed a higher percentage of this cytokine in patients with Chagas disease. Thus, our data bring a new knowledge about distinct markers of B cells in immune responses of Chagas disease.

Characterization of CD4⁺ cytotoxic lymphocytes and apoptosis markers induced by Trypanossoma cruzi infection.

Although the pathophysiology of Chagas disease is not completely understood, it is widely accepted that involvement of the immune response is critical in determining the outcome of the disease. In this context, CD4⁺ T cells may play an important role in generating different mechanisms of protection. In addition to effector and regulatory functions, CD4⁺ T cells may be also involved with lytic activities against the parasite and may have a relevant role on control of the infection. In this study, we have evaluated CD4⁺ T cells expressing cytotoxic and apoptosis markers in response to Trypanossoma cruzi infection in indeterminate (IND) and cardiac (CARD) patients with Chagas disease and non-infected individuals (NI). Our data demonstrated that: (1) CD4⁺ T cells presented higher ex vivo granzyme B expression in patients with Chagas disease compared with healthy individuals and that antigen induced a greater granzyme B expression in IND patients; (2) CD95L expression in CD4⁺ CD95⁺ T cells from IND patients is higher than in CARD and NI; (3) IND and CARD patients had an increased frequency of caspase-3 after in vitro stimulation and also expressed a high frequency of annexinV⁺ 7ADD⁺ within CD4⁺ T cells; (4) Lastly, a positive correlation was seen between cytotoxic molecules and CD45RO memory marker in CD4⁺ T cells and between caspase-3 and CD95L within CD4⁺ CD95⁺ T cells. These results suggest new insights into the functional competence of CD4⁺ T cells among the different clinical forms of Chagas disease, which will lead to a better understanding of their influence during immune responses against T. cruzi.

Mechanism of Trypanosoma cruzi death induced by Cratylia mollis seed lectin.

Incubation of T. cruzi epimastigotes with the lectin Cramoll 1,4 in Ca(2+) containing medium led to agglutination and inhibition of cell proliferation. The lectin (50 microg/ml) induced plasma membrane permeabilization followed by Ca(2+) influx and mitochondrial Ca(2+) accumulation, a result that resembles the classical effect of digitonin. Cramoll 1,4 stimulated (five-fold) mitochondrial reactive oxygen species (ROS) production, significantly decreased the electrical mitochondrial membrane potential (Delta Psi(m)) and impaired ADP phosphorylation. The rate of uncoupled respiration in epimastigotes was not affected by Cramoll 1,4 plus Ca(2+) treatment, but oligomycin-induced resting respiration was 65% higher in treated cells than in controls. Experiments using T. cruzi mitochondrial fractions showed that, in contrast to digitonin, the lectin significantly decreased Delta Psi(m) by a mechanism sensitive to EGTA. In agreement with the results showing plasma membrane permeabilization and impairment of oxidative phosphorylation by the lectin, fluorescence microscopy experiments using propidium iodide revealed that Cramoll 1,4 induced epimastigotes death by necrosis.

Magnetotactic bacteria at the geomagnetic equator.

Magnetotactic bacteria are present in fresh water and marine sediments of Fortaleza, Brazil, situated close to the geomagnetic equator. Both South-seeking and North-seeking bacteria are present in roughly equal numbers in the same samples. This observation is consistent with the hypothesis that the vertical component of the geomagnetic field selects the predominant polarity type among magnetotactic bacteria in natural environments.

Foxp3+CD25(high) CD4+ regulatory T cells from indeterminate patients with Chagas disease can suppress the effector cells and cytokines and reveal altered correlations with disease severity.

Immunoregulatory mechanisms are important to control the intense immune activity induced in Chagas disease. We evaluated the phenotypic profile and the mechanisms by which Treg cells function in patients with the indeterminate (IND) and cardiac (CARD) clinical forms of Chagas disease. The frequency of Foxp3(+)CD25(high) CD4(+)-T cells is augmented and correlated with the maintenance of a better cardiac function in IND. Treg cells from IND present suppressive activity, although the mechanism is not IL-10 or CTLA-4 dependent and are able to produce augmented levels of IL-17, IL-10 and granzyme B being its frequency correlated with percentage of Annexin V(+) CD4(+)-cells. In contrast, CARD presents higher frequency of IL-6(+), IFN-gamma(+), TNF-alpha(+) and CTLA-4(+) Treg-cells than IND. Thus, our data suggest that Treg cells have an important role in controlling the exacerbated immune response and morbidity in Trypanosoma cruzi infection, probably modulating the cytokine environment and/or killing effector cells.

Histopathological hoof laminar changes in horses with pituitary pars Intermedia adenoma: cases report / Alterações histopatológicas do tecido laminar do casco em cavalos com adenoma da pars intermedia da hipófise: relato de casos

Laminitis in horses is often associated with endocrine disorders, especially the pituitary pars intermedia dysfunction (PPID) in older animals. Morphologic exams of the laminar tissue of the hoof were performed in two horses with suspected PPID, with no clinical signs of laminitis. Changes compatible with laminitis of endocrine origin were observed, such as rounding of the nuclei of the basal cells, thinning and stretching of the secondary epidermal laminae and tissue proliferation. PPID horses with no clinical signs of laminitis may be affected by lesions of the laminar tissue of the hoof that compromise the integrity of the dermal-epidermal junction and may develop clinical symptoms of the disease. It has been suggested that the development stage of endocrine laminitis is longer, but further studies should be conducted to confirm it.

A laminite em cavalos está frequentemente associada a distúrbios endócrinos, como a disfunção da pars intermedia da pituitária (PPID) em animais mais velhos. Exames morfológicos do tecido laminar do casco foram realizados em dois cavalos com suspeita de PPID após o óbito, os quais não apresentaram sinais clínicos de laminite. Alterações compatíveis com a laminite de origem endócrina foram observadas, como arredondamento da núcleo das células basais, alongamento e afilamento das lâminas epidérmicas secundárias e proliferação tecidual. Cavalos com PPID sem sinais clínicos de laminite podem estar acometidos por lesões do tecido laminar do casco que comprometam a integridade das interdigitações dérmico-epidérmicas e podem desenvolver a sintomatologia clínica da doença. Sugere-se que o período de desenvolvimento da laminite endócrina seja mais longo, porém estudos adicionais devem ser realizados para confirmar essa hipótese.

Accurate determination of cast weight for neonates with clubfoot.

The purpose of this study was to determine changes in cast weight during the first 48 hours after application so that the true weight of a neonate can be estimated without the need for removing the cast. Five types of cast materials were compared. Cast weight measurements were obtained before and after application and at intervals during 48 hours. Final cast weight averaged 107.5% of dry weight for plaster and 99% of dry weight for synthetic cast materials. For very low birth weight infants, the difference between the initial wet weight of plaster of Paris and its final dry weight may be significant for calculating drug and fluid dosages. The weight of an infant can now be calculated without the necessity of cast removal.

[Effect of oral contraceptives upon the metabolism of vitamin B6, folic acid, serum iron, glycemia, hemoglobin and hematocrit (author's transl)]. / Efeito das pilulas anticoncepcionais sobre o metabolismo da vitamina B6, acido folico, ferro serico, glicemia, hemoglobina e hematocrito.

PIP: The authors present a review of the medical literature about the effect of oral contraceptives (OCs) on the metabolism of hydrocarbonates, serum iron, vitamins, folic acid, hemoglobin, and hematocrit. This is the 1st Brazilian study clinical about these phenomena. This study examined 21 patients taking OCs for 1 or more years. These female patients followed a regimen of vitamin-mineral supplementation over the course of 2 months when new clinical and laboratory controls were made. Of 21 patients, 18 had adverse symptoms and 3 were asymptomatic. Of the 18 symptomatic, 10 found relief from disturbances. There was also a statistically significant increase in serum folic acid levels. There wre no statistically significant alterations of hematocrit or serum iron in accordance with the literature. (author's)^ieng

Magnetite and magnetotaxis in algae.

Magnetotactic algae of the genus Anisonema (Euglenophyceae) have been isolated from a coastal mangrove swamp in northeastern Brazil. The magnetotactic response is based on a permanent magnetic dipole moment per cell approximately 7 10(-10) emu. Each cell contains many magnetite (Fe(3)O(4)) particles organized in chains.

Birefringence determination of magnetic moments of magnetotactic bacteria.

A birefringence technique is used to determine the average magnetic moments of magnetotactic bacteria in culture. Differences in are noted between live and dead bacteria, as well as between normal density and high density samples of live bacteria.

Magnetic polarity fractions in magnetotactic bacterial populations near the geomagnetic equator.

The relative numbers of North-seeking and South-seeking polarity types in natural populations of magnetotactic bacteria were determined at sites on the coast of Brazil. These sites were South of the geomagnetic equator and had upward geomagnetic inclinations of 1-12 degrees . For upward inclinations >6 degrees , South-seeking cells predominated over North-seeking cells by more than a factor of 10. For upward inclinations <6 degrees , the fraction of North-seeking cells in the population increased with decreasing geomagnetic inclination, approaching 0.5 at the geomagnetic equator. We present a simple statistical model of a stochastic process that qualitatively accounts for the dynamics of the two polarity types in a magnetotactic bacterial population as a function of the geomagnetic field inclination.

[Influence of intergestational interval and parity on infant mortality]. / Influência do intervalo intergestacional e da paridade sobre a mortalidade infantil.

PIP: 526 patients admitted to the Department of Tocogynecology of the Sao Paulo Medical School during 1976-83 comprised of 281 secundiparas, 152 terciparas, and 93 quadriparas with 1390 live births and 864 intergestational intervals, aged no older than 40, took part in the investigation. The short intergestational interval lasted up to 12 months following delivery, and the long interval was 13 months or longer. Infant mortality rate (IMR) was very low among secundiparas (58.7/1000 live births), higher among terciparas (72.4/100 live births), reaching 110.2 among quadriparas with an average of 77.0 for the whole population. The IMR increased to 96.9 among secundiparas when the interval was short (60.1%), and dropped to 38.2 during the long interval (65.1%). Among terciparas the findings were: 116.7 and 57.1 for 2 short and 2 long intervals, respectively, and 51.1 and 98.9 for short-long and long-short combined intervals. The effect of intergestational intervals on IMR was the most pronounced among quadriparas: it soared to 270.80 for only short intervals (25% increase), decreased to 89.3 for only long intervals (18.9% drop), further diminished to 78.9 for 2 long and 1 short intervals, and increased to 94.8 for 2 short and 1 long intervals. These results confirm the benefit of longer intergestational intervals and this knowledge ought to be a vital part of family planning programs.^ieng